Interventions to prevent hypothermia at birth in preterm and/or low birthweight infants

McCall EM, Alderdice FA, Halliday HL, Jenkins JG, Vohra S

Background - Methods - Results - Characteristics of Included Studies - References - Data Tables and Graphs

Dates

Date edited: 14/11/2007
Date of last substantive update: 13/09/2007
Date of last minor update: / /
Date next stage expected 13/11/2009
Protocol first published: Issue 2, 2003
Review first published: Issue 1, 2005

Contact reviewer

Ms Emma M McCall
Research Fellow
Division of Maternal & Child Health
Queen's University Belfast
Institute of Clinical Sciences
Grosvenor Road
Belfast
Northern Ireland UK
BT12 6BJ
Telephone 1: +44 02890 635056
Telephone 2: +44 02890 632652
Facsimile: + 44 02890 236455
E-mail: e.mccall@qub.ac.uk

Contribution of reviewers

The review was conceived by the Northern Ireland Neonatal Intensive Care Outcomes Research and Evaluation Group (NICORE).

The review was co-ordinated and the manuscript prepared in RevMan version 4.2.5 by the contact reviewer (EC). The search strategy was designed by EC and the QUB Medical Faculty Librarian. The data extraction proforma was drafted by EC and edited by FA, HH, JJ and SV.

FA, HH, JJ, SV and EC screened abstracts and papers against the inclusion criteria, appraised the quality and extracted the data. Entry onto RevMan was carried out by EC.

HH, JJ and SV provided clinical input at all stages of the review process. FA and HH also provided methodological input.

All reviewers were involved equally in the development of the content of the final manuscript.

Internal sources of support

Northern Ireland Neonatal Outcomes Research and Evaluation Group (NICORE), UK

External sources of support

Research & Development Office - Northern Ireland, UK

What's new

This review updates the existing review of "Interventions to prevent hypothermia at birth in preterm and/or low birthweight babies", published in The Cochrane Library, Issue 1, 2005 (McCall 2005).

Literature searches were updated to July week 4, 2007. No additional studies fulfilled the criteria for inclusion in this review. Secondary outcome measures for Vohra 2004a were updated as a result of publication of the full manuscript.

There were no changes to the reviewer's conclusions nor to implications for practice or research.

Dates

Date review re-formatted: / /
Date new studies sought but none found: / /
Date new studies found but not yet included/excluded: / /
Date new studies found and included/excluded: 31/07/2007
Date reviewers' conclusions section amended: / /
Date comment/criticism added: / /
Date response to comment/criticisms added: / /

Text of review

Synopsis


Preventing low body temperature at birth in premature and low birth weight infants may be important to survival and long-term outcome.

Babies rely on external help to maintain body and skin temperature particularly in the first 12 hours of life. For vulnerable infants born prematurely or that are very small, abnormally low body temperature (hypothermia) is a world-wide issue across all climates and can lead to a variety of diseases and even death. Preventative action is taken by reducing heat loss and/or providing warmth using external heat sources. Precautionary steps routinely include a warm delivery room; drying the newborn immediately, especially the head; wrapping in pre-warmed dry blankets that cover the head; pre-warming surfaces and eliminating drafts. A review of six studies involving 295 infants used additional preventative actions in the first 10 minutes of life to prevent problems with hypothermia. Results showed that the use of special plastic wraps, heated mattresses and skin-to-skin contact kept the infants warmer than routine preventative action. Limitations included the small numbers of infants and studies included; variations in the methods and definitions of normal body temperature, routine care; and the use of different materials. Although this review confirmed that some of these measures are effective in preventing hypothermia, we do not yet know the long-term consequences of these interventions therefore the authors recommend that further research is carried out.

Abstract



Background


Hypothermia incurred during routine postnatal resuscitation is a world-wide issue (across all climates), associated with morbidity and mortality. Keeping vulnerable preterm infants warm is problematic even when recommended routine thermal care guidelines are followed in the delivery suite.

Objectives


To assess efficacy and safety of interventions designed for prevention of hypothermia in preterm and/or low birthweight infants applied within ten minutes after birth in the delivery suite compared with routine thermal care.

Search strategy


The standard search strategy of The Cochrane Collaboration was followed. Electronic databases were searched: MEDLINE (1966 to July Week 4 2007 ), CINAHL (1982 to July Week 4 2007), EMBASE (1974 to 01/08/2007), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2007), Database of Abstracts of Reviews of Effects (DARE 1994 to July 2007), conference/symposia proceedings using ZETOC (1993 to 17/08/2007), ISI proceedings (1990 to 17/08/2007) and OCLC WorldCat (July 2007). Identified articles were cross-referenced. No language restrictions were imposed.

Selection criteria


All trials using randomised or quasi-randomised allocations to test a specific intervention designed to prevent hypothermia, (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery suite to infants of < 37 weeks' gestational age or birthweight ≤ 2500 g.

Data collection & analysis


Methodological quality was assessed and data were extracted for important clinical outcomes including adverse effects of the intervention by at least three independent review authors. Authors were contacted for missing data. Data were analysed using RevMan 4.2.5. Relative risk (RR), risk difference (RD) and number needed to treat (NNT) with 95% confidence limits were calculated for each dichotomous outcome and mean differences (MD) with 95% confidence limits for continuous outcomes.

Main results


Six studies giving a total of 304 infants randomised and 295 completing the studies were included. Four comparisons to 'routine care' were undertaken within two categories:
1) barriers to heat loss (four studies): plastic wrap or bag (three), stockinet caps (one) and
2) external heat sources (two studies): skin-to-skin (one), transwarmer mattress (one).

Plastic barriers were effective in reducing heat losses in infants < 28 weeks' gestation (three studies, n = 159; WMD 0.76 °C; 95% CI 0.49, 1.03), but not in infants between 28 to 31 week's gestation. There was insufficient evidence to suggest that plastic wrap reduces the risk of death within hospital stay (three studies, n = 161; typical RR 0.63; 95% CI 0.32, 1.22; typical RD -0.09; 95% CI -0.20, 0.03). There was no evidence of a significant difference in major brain injury, mean duration of oxygen therapy or hospitalisation for infants < 29 weeks' gestation. Stockinet caps were not effective (borderline significant for infants < 2000 g birthweight) in reducing heat losses.

Skin-to-skin care was shown to be effective in reducing the risk of hypothermia when compared to conventional incubator care for infants 1200 to 2199 g birthweight (one study, n = 31; RR 0.09; 95% CI 0.01, 0.64; NNT 2; 2 to 4). The transwarmer mattress kept infants ≤ 1500 g significantly warmer and reduced the incidence of hypothermia on admission to NICU
(one study, n = 24; RR 0.30; 95% CI 0.11, 0.83; NNT 2 range 2 to 4).

Reviewers' conclusions


Plastic wraps or bags, skin-to-skin care and transwarmer mattresses all keep preterm infants warmer, leading to higher temperatures on admission to neonatal units and less hypothermia. Given the low NNT, consideration should be given to using these interventions in the delivery suite. However, the small numbers of infants and studies and the absence of long-term follow-up mean that firm recommendations for clinical practice cannot be given. There is a need to conduct large, high quality randomised controlled trials looking at long-term outcomes.

Background


Neonatal hypothermia after birth is a world-wide issue (Costeloe 2000) across all climates (Christensson 1988; Johanson 1992; Tafari 1973; Laptook 2007) and, if prolonged, can lead to harm and in severe cases death. Keeping preterm infants sufficiently warm immediately after birth, especially during resuscitation, is problematic even when routine thermal care guidelines are followed. The newborn cannot shiver (Scopes 1963), and relies on interventions to protect it against exposure to cold. The ability to maintain an equilibrium between heat loss and heat gain (Bickmann 1992) despite variation in environmental temperatures is restricted during the first 12 hours of life (Smales 1978). After birth, deep body and skin temperature of the term newborn can drop at a rate of approximately 0.1 °C and 0.3 °C per minute respectively unless immediate action is taken (Adamsons 1965a). Silverman 1958 and Day 1964 showed that reducing heat losses in preterm infants in the first few days after birth increased survival rates. Early intervention in the delivery suite is therefore of high priority if hypothermia is to be prevented.

What are the clinical implications of cold stress?

Although cold stress may be important for initiating breathing (Harned 1970) and induced cooling may help protect the brain of asphyxiated term newborns, prolonged exposure to cold should be avoided. Extended periods of cold stress can lead to harmful side effects, which include hypoglycaemia (Elliott 1957), respiratory distress (Pomerance 1974), hypoxia, metabolic acidosis (Gandy 1964), coagulation defects (Chadd 1972), delayed readjustment from fetal to newborn circulation (Stephenson 1970), acute renal failure, necrotizing enterocolitis, failure to increase weight or weight loss (Glass 1968) and in extreme cases death (Elliott 1957). Nayeri 2006 concluded that hypothermia at birth is one of the most significant risk factors causing death in newborn infants of all birthweights and gestational ages. Factors that increase the risk of hypothermia include prematurity, intrauterine growth retardation (Borse 1997; Hey 1975), asphyxia, certain congenital anomalies such as gastroschisis and damage to the central nervous system (Bickmann 1992).

What causes hypothermia immediately at birth?

Rapid postnatal fall in body temperature is attributable to a combination of the physical characteristics of the infant (e.g. large surface area in relation to body weight and a thin layer of insulating fat) and environmental factors in the delivery suite. Extent of total heat loss and the four modes of heat exchange (conduction, convection, radiation and evaporation) are influenced by the ambient air temperature, pressure and relative humidity, and temperature of surrounding surfaces (Capobianco 1980; Thomas 1994). Increased rate of heat loss is mainly caused by evaporation of amniotic fluid from the skin surface (Hammarlund 1980) when the wet newborn moves from the warm environment of the uterus (Adamsons 1965a) into a cool, dry delivery suite.

In an attempt to maintain core body temperature within the normal range of 36.5 to 37.5 °C (skin temperature of 0.5 to 1.0 °C lower) (Hey 1970 ; Oliver 1965), the term infant responds mainly by production of heat from the breakdown of brown fat (non-shivering thermogenesis) (Stern 1970) and peripheral vasoconstriction. When skin temperature falls to 35 to 36 °C, non-shivering thermogenesis is initiated (Bruck 1961). The World Health Organisation classifies a core body temperature for newborns of 36 to 36.4 °C as mild hypothermia, 32 to 35.9 °C as moderate and < 32 °C as severe (WHO 1997). The preterm infant has the combined disadvantages of decreased fat for heat production and insulation, decreased glycogen stores, immature skin which increases water loss and poor vascular control. They experience even higher evaporative heat losses than term infants in the first day, especially at low ambient relative humidities (Hammarlund 1979). Five hundred and sixty calories of heat are lost for each millilitre of water which evaporates from the skin (Rutter 2000). Currently, there is no accepted formal definition of 'normal' temperatures for preterm infants and methods and accuracy of temperature measurement continue to be debated (Bailey 2000; Smith 2004).

The external (skin-environment) temperature gradient is pivotal in influencing the infant's response to cold (Adamsons 1965) and it is here that health professionals can intervene in the delivery suite to minimise the risk of hypothermia.

What preventative action can be taken?

Standard care includes providing a warm delivery room at a minimum of 25 °C (although rarely achieved in practice) (WHO 1997), drying the infant thoroughly, immediately after birth (especially the head) (Bloom 1994), removing any wet blankets, wrapping in a prewarmed blanket, prewarming any contact surfaces, eliminating drafts and close proximity to outside walls (Capobianco 1980). If available, radiant warmers for resuscitation and stabilization allow easy access and are effective in preventing heat losses, provided that the infant is immediately dried and placed under the prewarmed heater (Du 1969; Dahm 1972). Although the infant gains heat by radiation, there are increased potential losses through convection and evaporation and these losses are exacerbated if the infant is inadequately dried. Servocontrol is advantageous for the avoidance of overheating or underheating if absorption of heat is being obstructed by coverings. Watkinson 2006 suggested two reasons why conventional thermal care has failed to prevent hypothermia at birth: 1) current recommended techniques are inadequate and 2) thermal management awareness needs to be increased among personnel carrying out the resuscitation of newborns. The latter has also been highlighted in reviews of practice for care of very immature infants during resuscitation and transfer (Lyon 2006).

Studies to investigate the effectiveness of additional measures to reduce heat loss in the immediate postnatal period fall into two groups:
(1) barriers to heat loss and
(2) external heat sources
Interventions in the first group focus mainly on reducing evaporative heat losses (LeBlanc 1991) and have included wraps and/or headcoverings made from a variety of materials (Chaput 1979; Coles 1979; Holzman 1985 ; Lang 2004). Baum 1968 tested a polyester suit lined with aluminum, known as the 'silver swaddler', designed to prevent hypothermia by reducing all modes of heat transfer to the environment. This was effective for infants with birthweights > 3000 g but, since the material is opaque, it is not practical during resuscitation. Transparent plastic coverings such as bubble wrap (Besch 1971) and single layer gowns (Hobbs 1975) are effective in the delivery suite for full-term healthy newborn infants and those with birthweights > 2000 g respectively and where the intervention was polyethylene wrap for infants of < 33 weeks' gestation (Lenclen 2002). Hoods or heat shields that are not in contact with the infant's body have also been used in conjunction with a radiant warmer or incubator (Baumgart 1981; Bell 1980). Barrier creams, waxes or protective films such as Aquaphor ® (Nopper 1996) have also been utilised to reduce heat losses in immature infants but are not normally applied within 10 minutes of birth.

Interventions in the second group have included heated mattresses (Almeida 2000) and as an alternative to radiant warmers, for a healthy term newborn skin-to-skin contact, (where the infant is thoroughly dried and placed on the mother's chest and abdomen with a light blanket around them), can reduce radiant and conductive heat loss and promote temperature stabilization (Britton 1980; Christensson 1992).

All of these interventions have potential disadvantages; for example, Newton 2003 reported that significantly more infants (with gestational ages < 30 completed weeks) wrapped in polythene bags were hyperthermic ( > 37 °C) when compared to unwrapped historical controls. Brun 1997 noted that a chemical hot pack during resuscitation of a newborn infant resulted in third degree burns and recommended that these should not be used unless the peak temperature of the pack is < 44 °C.


Review focus

Interventions should either decrease total heat losses or provide external heat without compromising accessibility during resuscitation and should have minimal side effects (such as hyperthermia, burns, maceration, or infection). This review focuses on individual interventions applied within 10 minutes after birth in the delivery suite and is limited to preterm and/or low birthweight infants since these are most susceptible to the adverse effects of hypothermia. Longer term thermal management and spatial or environmental strategies for increasing warming are beyond the scope of this review.

Objectives


PRIMARY OBJECTIVE

To assess the efficacy and safety of interventions, designed for the prevention of hypothermia in preterm and/or low birthweight infants, and applied within 10 minutes after birth in the delivery suite, compared with routine thermal care.

Subgroup analyses to be carried out by intervention, by birthweight/gestational age and by developmental status of the country of study, to determine whether effectiveness varies according to:

birthweight (< 1500 g), (1500 g to 2500 g)
gestational age (< 28 wk), (28 to 32 wk) and (33 to 37 wk)

However, the subgroups reported in the included studies were not compatible with those pre-specified. Therefore, post facto subgroup analyses based on reported gestational age and birthweight subcategories were carried out where appropriate within each comparison group.

SECONDARY OBJECTIVES

To assess effects on complications associated with preterm birth, hypothermia, and adverse outcomes.

Criteria for considering studies for this review



Types of studies


All trials using randomised or quasi-randomised allocation to test a specific intervention designed to prevent hypothermia immediately after birth.

Types of participants


Preterm infants of less than 37 weeks' gestational age (according to best obstetric estimate at time of delivery) or low birth weight infants of ≤ 2500 g, where the intervention to prevent hypothermia is applied within 10 minutes after birth in the delivery suite. Both appropriate and small-for-gestational age infants were eligible.

Exclusions
Infants with major congenital malformations, especially abdominal wall defects.

Types of interventions


Any intervention applied within 10 minutes after birth in the delivery suite apart from ROUTINE THERMAL CARE, which was defined as any of the following routine practices: providing a warm delivery suite at a minimum of 25 °C (rarely achieved in practice), drying the infant immediately after birth, removing any wet blankets and wrapping in a pre-warmed blanket, pre-warming any contact surfaces, avoiding draughts and, in developed countries, the use of radiant warmers or incubators. The control intervention comprised any elements of routine thermal care.

The interventions studied were to include:

(1) Barriers to heat loss applied to any part of the body of the preterm and/or low birthweight infant within 10 minutes after birth in the delivery suite


(2) External heat sources (non-routine) initiated within 10 minutes after birth in the delivery suite



Types of outcome measures


PRIMARY OUTCOMES

The temperature of the infant taken on admission to the Neonatal Intensive Care Unit (NICU) or up to two hours after birth. Temperature was assessed as both continuous and dichotomous variables.

Rectal, axillary, oral or tympanic temperature measurements were accepted as equivalent core body temperature and abdominal skin temperature was accepted for skin temperature. Where both core temperature and skin temperature were recorded core temperature took priority. Where multiple temperatures were recorded (i.e. within different time frames up to two hours after birth) the lowest temperature recorded took priority.

A core body temperature of < 36.5 °C or a skin temperature of < 36 °C indicated the presence of hypothermia within the control and intervention groups.

For hypothermia, core body temperature and skin temperature subgroupings as defined by WHO 1997 were used to determine three levels of severity


SECONDARY OUTCOMES

These were categorised as (1) morbidity and (2) adverse outcomes due to the intervention.

(1) Morbidity


(2) Adverse outcomes due to the intervention



Search strategy for identification of studies


The standard search strategy of the Cochrane Collaboration was used (Clarke 2002). This included searches of electronic databases: MEDLINE (1966 to July Week 4 2007 ), CINAHL (1982 to July Week 4 2007), EMBASE (1974 to 01/08/2007), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2007) and the Database of Abstracts of Reviews of Effects (DARE 1994 to July 2007), conference/symposia proceedings using ZETOC (1993 to 17/08/2007) and ISI proceedings (1990 to 17/08/2007). In addition, OCLC WorldCat (July 2007) was searched and identified articles were cross referenced. No language restrictions were imposed. The MEDLINE search strategy is detailed below and similar search strategies were devised using appropriate terminology for each electronic database.

1. plastic barrier*.ab,ti.
2. polyethylene*.ab,ti.
3. (bubble wrap* or bubble-wrap* or bubblewrap*).ab,ti.
4. (clingfilm* or cling film* or cling-film*).ab,ti.
5. (plasticwrap* or plastic-wrap* or plastic wrap*).ab,ti.
6. exp Polyethylenes/
7. exp Polyvinyls/
8. (polyvinyl* or poly-vinyl*).ab,ti.
9. (low density polyethylene* or low-density polyethylene*).ab,ti.
10. (gladwrap* or glad wrap* or glad-wrap*).ab,ti.
11. (polybag* or poly bag* or poly-bag*).ab,ti.
12. (saranwrap* or saran-wrap* or saran wrap*).ab,ti.
13. transparent baby bag*.ab,ti.
14. baby bag*.ab,ti.
15. (headwrap* or polyester headwrap*).ti,ab.
16. silver swaddling*.ti,ab.
17. (silver and swaddling*).ti,ab.
18. swaddling*.ti,ab.
19. exp Incubators, Infant/
20. radiant warmer*.ti,ab.
21. exp Membranes, Artificial/
22. (semi-permeable membrane* or semipermeable membrane*).ti,ab.
23. exp POLYURETHANES/
24. polyurethane*.ti,ab.
25. kangaroo care*.ti,ab.
26. skin to skin contact*.ti,ab.
27. heat* mattress*.ti,ab.
28. chemical gel mattress*.ti,ab.
29. gel mattress*.ti,ab.
30. chemical mattress*.ti,ab.
31. head hood*.ti,ab.
32. head insulation*.ti,ab.
33. swaddl*.ti,ab.
34. plastic bag*.ti,ab.
35. early suck*.ti,ab.
36. Breast Feeding/
37. (breast feed* or breastfeed*).ti,ab.
38. skin-to-skin.ti,ab.
39. suckl*.ti,ab.
40. bath*.ti,ab.
41. radiant heater*.ti,ab.
42. radiant heat lamp*.ti,ab.
43. (mother* adj5 (bab* or infant*) adj5 (contact* or hold*)).ti,ab.
44. heated bed*.ti,ab.
45. resuscitat*.ti,ab.
46. exp RESUSCITATION/
47. (intervention* or procedure* or method*).ti,ab.
48. exp Infant, Low Birth Weight/
49. ((birth* or bab* or infant) and (premature or pre-mature or preterm or pre-term or low weight or low birth weight or very low birth weight or VLBW or LBW)).ab,ti.
50. Infant, Newborn/
51. Body Temperature Regulation/ or Body Temperature/
52. HYPOTHERMIA/
53. (hypothermia or cold stress or heat loss or temperature regulation or body temperature).ab,ti.
54. temperature drop*.ti,ab.
55. heat loss.ti,ab.
56. or/1-47
57. or/48-50
58. or/51-55
59. 56 and 57 and 58

Methods of the review


The standard method of The Cochrane Collaboration for conducting a systematic review as described in The Cochrane Reviewers' Handbook (Clarke 2002) was followed.

SELECTION AND QUALITY ASSESSMENT

The search strategy was designed and electronic databases searched in association with the Medical Faculty Librarian, Queen's University Belfast. At least three review authors independently assessed the full list of titles and abstracts for eligibility and the full texts of those considered to be relevant were retrieved. Reasons for exclusion of studies were clearly stated by each review author. Formal translation of studies was not required.

At least three independent review authors assessed those studies which fulfilled the criteria for inclusion for quality and extracted data using prepared proformas. Methodological quality was judged according to: (1) blinding of randomisation, (2) blinding of intervention, (3) completeness of follow-up and (4) blinding of outcome measurement. There was complete agreement among team members. Additional information was sought from investigators for three included trials (Vohra 2004a; Vohra 1999; Knobel 2005). The information retrieved is detailed in the Table of "Characteristics of included studies".

Review authors were not blinded to authors or to institution. In two papers, a team member was also an author of a selected trial so that team member was excluded from the study appraisal process.

ANALYSIS

Meta-analysis was carried out using the fixed effect model. Relative risk (RR) and 95% confidence limits were calculated for dichotomous outcomes. From the risk difference (RD), the number needed to treat (NNT) or the number needed to harm (NNH) and 95% confidence limits for each homogenous subgroup were calculated. Mean differences (MD) and 95% confidence limits were calculated for continuous outcomes.

Had there been more studies, the influence of the trial quality on the findings of the review would have been explored by conducting a sensitivity analysis of adequate versus unclear versus inadequate allocation concealment as outlined in The Cochrane Reviewers' Handbook (Clarke 2002).

Where heterogeneity was identified, subgroup analyses were carried out for gestational age and birthweight. Had there been sufficient studies, sensitivity analyses would have provided valuable information on the role of variations in methodological quality, definitions of hypothermia, type of patient group and intervention.

Description of studies


One hundred and thirty-two studies potentially eligible for inclusion in our review were identified. Of these, eighty-four were randomised or quasi-randomised controlled studies and forty-eight were non-randomised studies. On assessment, six studies were identified as fulfilling all of our criteria for inclusion. Seventy-eight randomised or quasi randomised studies did not fulfill our criteria for inclusion and are detailed in the Table of "Characteristics of excluded studies". We decided not to include in the Table of "Characteristics of excluded studies" non-randomised studies. Further details of these non-randomised trials can be obtained from the authors on request. In all, six studies involving 304 randomised infants were included in this review: two theses (Brennan 1996; Roberts 1981), four published papers (Bergman 2004; Vohra 1999; Vohra 2004a; Knobel 2005 ).

Four studies compared barriers to heat loss to no barriers (Roberts 1981; Vohra 1999; Vohra 2004a; Knobel 2005) and two studies compared external heat sources (non-routine) to no external heat sources (Bergman 2004; Brennan 1996). There were two comparison groups within the barriers to heat loss category : plastic wrap or bag versus routine care (Vohra 1999; Vohra 2004a; Knobel 2005) and stockinet cap versus routine care (Roberts 1981). There were also two comparison groups within the external heat source category: skin-to-skin care versus routine care (Bergman 2004) and transwarmer mattress versus routine care (Brennan 1996).

All interventions were applied immediately after birth in the delivery suite. Participants were categorised by gestational age (all preterm) in four studies and by birthweight (all low birthweight) in two studies. One study was conducted in a developing country, (South Africa) (Bergman 2004), and all other studies took place in developed countries (USA: Brennan 1996; Roberts 1981; Knobel 2005 and Canada: Vohra 1999; Vohra 2004a). Routine external heat sources were utilised as part of care (control group and/or intervention group) in all studies : servo controlled incubator (Bergman 2004), radiant warmer (Brennan 1996; Vohra 1999; Vohra 2004a ), warmer table (Knobel 2005) and radiant warmer ± transport incubator (Roberts 1981). The main outcome measure (temperature of the infant on admission to NICU or up to 2 hours after birth) was reported as a continuous variable in five studies and as a dichotomous variable only in one study (Bergman 2004). Five studies reported core body temperature (rectal:3, axillary:2) and in one study skin temperature was reported. In addition, three studies also provided dichotomous data pertaining to incidence of hypothermia in the intervention and control groups. Definitions of hypothermia were not consistent across studies. There was limited reporting of pre-specified secondary outcomes.

SUMMARY DESCRIPTIONS OF INDIVIDUAL STUDIES

Further details for each study are given in the Table of "Characteristics of included studies."


BARRIERS TO HEAT LOSS

ROBERTS 1981

Participants
Forty inborn infants of 32 to 36 completed weeks' gestation born between 7 am to 5 pm on weekdays were included in this single centre study conducted at Parkland Memorial Hospital in Dallas, Texas, USA. Infants were excluded from the study if they were not appropriate for gestational age, had an Apgar score < 7 at 5 minutes, signs of central nervous system defect, developed sepsis or where the maternal temperature > 37.8 °C during labour.

Intervention Stockinet cap (CAP) - sterile headpiece made of stockinet that covers the forehead, the ears, underneath the occipital bone and all the area above this plane.
CAP group (n = 17): infants received a stockinet cap after delivery as soon as possible after being dried under a radiant warmer.
Control group (n = 23): infants received the same treatment as the intervention group but did not receive a stockinet cap.
All infants weighing < 2500 g were transported to the nursery in a transport incubator.

Outcomes
Core body temperature (axillary °C) was measured within 10 minutes of admission to the neonatal unit. The amount of heat lost from the time the axillary temperature was taken in the delivery room until the temperature was taken in the neonatal unit was also reported.

VOHRA 1999

Participants
Sixty-two inborn infants of < 32 completed weeks' gestation, where the neonatal resuscitation team were present, were included in this single centre study conducted at the Grace Hospital (later the IWK Grace Health Centre) in Halifax, Nova Scotia, Canada. Infants were excluded from the study if they had major congenital anomalies with open lesions and where the infant was considered "previable" by the attending Obstetrician.

Intervention Polyethylene bag (WRAP) - 20cm x 50cm manufactured by Eastern Paper, a Division of EPC Industries.
WRAP group (n = 27): a transparent polyethylene bag was opened at resuscitation under a radiant warmer and the infant was placed on it from the shoulders down. Only the head of the infant was dried; the body was wrapped without drying.
Control group (n = 32): infants were managed with the protocol described by the Neonatal Resuscitation Program. Infants were routinely dried under the radiant warmer.
All infants were transferred to NICU in incubators.

Outcomes
Core body temperature (rectal °C) was measured on removal of the bag/wrap on admission to the neonatal unit. Incidence of mortality, hyperthermia, infection, skin maceration and interference with resuscitation were also reported.

VOHRA 2004a

Participants
Fifty-five inborn infants of < 28 completed weeks' gestation, where the neonatal resuscitation team were present, were included in this single centre study conducted at McMaster University Medical Center in Hamilton, Ontario, Canada. Infants were excluded from the study if they had major congenital anomalies that were not covered by the skin and blistering skin conditions.

Intervention Polyethylene wrap (WRAP) - 20cm X 50cm manufactured by Eastern Paper, a Division of EPC Industries.
WRAP group (n = 26): infants were placed on polyethylene, wrapped from the neck down, only the head was dried and stabilised under a radiant warmer.
Control group (n = 27): infants were dried completely according to the International Guidelines for Neonatal Resuscitation and stabilised under a radiant warmer.
All infants were carried by one member of the neonatal team from the delivery room to the neonatal unit and placed in a single walled incubator with 60 percent humidity.

Outcomes
Core body temperature (rectal °C) on removal of the bag/wrap on admission to the neonatal unit, core body temperature (rectal °C) 1 hour later and incidence of mortality from all causes were reported. Secondary outcome measures have been updated as reported in the publication of the full manuscript (Vohra 2004a): Apgar score at 1 minute, Apgar score at 5 minutes, blood gas pH, Bicarbonate (mmol/L), Glucose mmol/L, hyperthermia (rectal °C > 37.5) and interference with resuscitation.

KNOBEL 2005

Participants
Eighty-eight infants of < 29 completed weeks' gestation were included in this single centre study conducted at Pitt County Memorial Hospital, Greenville, NC, USA. Infants were excluded from the study if they had congenital anomalies with open lesions, meconium staining of the amniotic fluid or if they were considered previable or subsequent assessment indicated that the infant was ≥ 29 completed weeks' gestation.

Intervention Polyurethane bag (WRAP) - 19" X 18" sterile isolation transport bag DeRoyal REF30-5510.
WRAP group (n = 41): infants were placed immediately into a polyurethane bag, on a radiant warmer bed, while still wet, up to their necks. The head and face were dried and infants were resuscitated according to the guidelines for Neonatal Resuscitation.
Control group (n = 47): infants were resuscitated according to these guidelines without the bags.
All infants were taken to the neonatal unit on a warmer table, (with the heat off) with warm blankets on top of the infant.

Outcomes
Core body temperature (rectal°C) and incidence of hypothermia (rectal °C < 36.4) on admission to the neonatal unit, incidence of mortality, major brain injury, duration of oxygen therapy and hospitalisation, incidence of hyperthermia and interference with assessment or resuscitative interventions.

EXTERNAL HEAT SOURCES (NON-ROUTINE)

BERGMAN 2004

Participants
Thirty-five inborn infants delivered, (excluding caesarean sections), having a birthweight between 1200 and 2199 g were included in this study conducted at two secondary level referral hospitals (Mowbray Maternity Hospital and Karl Brenar Hospital) in Cape Town, South Africa. Infants were excluded from the study if they had a birthweight below 1200 g or above 2199 g, an Apgar score below six at five minutes, congenital malformations detected at birth or where the mother was too severely ill to be able to look after herself or the infant, was known to have a positive HIV status or had given up the infant for adoption.

Intervention: Skin-to-skin care (SSC)
All infants were delivered onto a theatre cloth on the mother's abdomen/chest, dried, assessed, then placed on the mother's naked chest and covered with double layered cotton cloth. The bed was then placed in the semi-Fowlers position.
SSC group (n = 18): the infant remained in skin-to-skin contact, was secured to the mother's chest, hips and arms were flexed and placed in a 'frog' position.
Control group (n = 13): the infant was immediately transferred to a pre-warmed servo-controlled closed incubator which remained with the mother in the delivery ward for the first hour. A cap, booties and heat shield were applied if the infant skin temperature fell below 36 °C.

Outcomes
Infant stability was measured in terms of a set of pre-defined physiological parameters. Observations for heart rate, oxygen saturation and body temperature (skin °C) were recorded at five minute intervals in the first half hour, then 15 minute intervals. Continuous observations for apnoea and signs of respiratory distress, and blood sugar were measured at one, three and six hours.

BRENNAN 1996

Participants
Twenty-four inborn infants having a birthweight ≤ 1500 g were included in this single centre study conducted at Shands Hospital located in north-central Florida, USA. Infants were excluded from the study where the maternal temperature at delivery was > 38.0 °C, the infant had an obvious neural tube defect, an omphalocele, gastroschisis, extrophy of the bladder, cloacal exstrophy, any other open lesion that would cause greater than normal heat loss at delivery, sacral teratoma, or any other lesion that would prevent the infant from being positioned and evaluated in the normal manner.

Intervention: Transwarmer Infant Transport Mattress (TM) manufactured by Prism Technologies, San Antonio, Texas. These are filled with a gel of sodium acetate, water and thickeners. Once activated they heat to approximately 40 °C for two hours.

TM group (n = 12): the mattress was activated and placed on the radiant warmer surface with blankets on top of it when delivery was imminent. The newborn infant was immediately placed on the blankets and dried. Blankets were removed and the infant was then placed directly onto the warming mattress.
Control group (n = 12): infants received the same care as the intervention group but without the warming mattress.

Both groups were evaluated and resuscitated according to the Neonatal Resuscitation Program and transported to the neonatal unit on the radiant warmer surface. The infants in the intervention group remained on the mattress until the admission temperatures were taken.

Outcomes
Core body temperature (axillary °C) was measured as soon as possible after arrival at the neonatal unit. Incidence of interference with resuscitation was also monitored. Individual patient data was reported in this study.

Methodological quality of included studies



BARRIERS TO HEAT LOSS

The generation of allocation sequence was adequate (computer randomisation or lot drawing) in three studies and unclear in one. Allocation concealment was adequate in three studies using varying degrees of sealed/opaque/double enclosed envelopes and in one study the method was unclear. No attempt was reported in any of the studies to blind participants or care providers to the intervention. Follow-up was complete in two studies. In the remaining two studies Vohra 1999 (3 of 62 or 5%) and Vohra 2004a (2 of 55 or 4%) of infants randomised were lost to follow-up. Reasons for loss to follow-up were reported adequately in each study. No studies reported any attempt to blind the outcome assessors to the intervention.

EXTERNAL HEAT SOURCES (NON-ROUTINE)

The generation of allocation sequence was adequate (computer randomisation or lot drawing) in both studies, however, the method of allocation concealment for each study was unclear. No attempt was reported in any of the studies to blind participants or care providers to the intervention. Follow-up was complete in one study. In the remaining study Bergman 2004 (4 of 35 or 11%) of infants randomised were lost to follow-up. Reasons for loss to follow-up were adequately reported. Only one study Bergman 2004 reported any attempt to blind the outcome assessors to the intervention where the principal investigator and data analysis team were blinded.

In all, no studies in either category fulfilled all the methodological quality criteria. Further details for each study are given in the Table of "Characteristics of included studies."

Results



RESULTS OF META-ANALYSES

Six studies were identified which fulfilled our criteria for inclusion giving a total of 304 infants randomised and 295 infants completing the studies. Four studies compared barriers to heat loss to no barriers giving a total of 245 infants randomised and 240 infants completing the studies (Roberts 1981; Vohra 1999; Vohra 2004a; Knobel 2005). Two studies compared external heat sources (non-routine) to no external heat sources giving a total of 59 infants randomised and 55 infants completing the studies (Brennan 1996; Bergman 2004). There were two comparisons within the barriers to heat loss category: plastic wrap versus routine care (Vohra 1999; Knobel 2005; Vohra 2004a) and stockinet cap versus routine care (Roberts 1981). There were also two comparisons group within the external heat source category: skin-to-skin care versus routine care (Bergman 2004) and transwarmer mattress versus routine care (Brennan 1996). There were insufficient studies to carry out subgroup analysis according to developmental status of the country.

BARRIERS TO HEAT LOSS

PLASTIC WRAP VERSUS ROUTINE CARE (COMPARISON 01):

Primary outcomes

Core body temperature (°C) of the infant taken on admission to NICU or up to 2 hours after birth (Outcome 01.01):

Three studies comprising 200 infants (Vohra 1999; Vohra 2004a; Knobel 2005) reported core body temperature (rectal °C) on admission to NICU. Each individual study showed a significant effect in favour of the intervention (plastic wrap) group for infants with a gestational age < 28 completed weeks. Although the infants in the Knobel 2005 study had a gestational age < 29 completed weeks, these infants were included in the < 28 completed week subgroup for meta-analysis.

Overall

For infants with a gestational age < 32 completed weeks, a statistically significant difference was shown in core body temperature on admission to NICU favouring the intervention (plastic wrap) group when compared to those who received routine care immediately after birth in the delivery suite (three studies, n = 200; WMD 0.60°C 95% CI 0.37, 0.83).

However, the overall test for homogeneity and for the subgroup of infants with a gestational age < 32 completed weeks fails with I2 values > 75%. We note the most likely reason for this failure is the contribution of the small Vohra 1999 study for the subgroup of infants < 28 completed weeks which gives rise to a 95% CI range somewhat outside the range suggested by the other studies. Rather than excluding this study purely on statistical grounds the possible reasons for this heterogeneity are explored in the discussion section of this review.


Outcome 01.01.01: For infants with a gestational age < 28 completed weeks a statistically significant difference was shown in core body temperature on admission to NICU favouring the intervention (plastic wrap) group when compared to those who received routine care immediately after birth in the delivery suite (three studies, n = 159; WMD 0.76 °C; 95% CI 0.49, 1.03).

Outcome 01.01.02: For infants with a gestational age of 28 to 31 completed weeks no statistically significant difference in the effects of the two interventions (plastic wrap and routine care) for core body temperature on admission to NICU was shown (one study, n = 41; MD 0.17 °C; 95% CI -0.27, 0.61).

Core body temperature taken 1 hour after initial admission temperature to the NICU was taken (Outcome 01.02):

This outcome was reported in one small study (Vohra 2004a) in terms of core body temperature (rectal °C) one hour after the initial admission temperature was taken. This was not pre-defined at review protocol stage. The reason stated for collection of this outcome measure was to ascertain whether the intervention (plastic wrap) prevented rather than delayed the postnatal fall in body temperature immediately after birth.

Outcome 01.02.01 For infants with a gestational age < 28 completed weeks no statistically significant difference in the effect of the two interventions (plastic wrap and routine care) was shown for core body temperature one hour after the initial admission temperature to NICU was taken, although the direction was in favour of the intervention (one study, n = 53; MD 0.20 °C; 95% CI -0.24, 0.64).

Hypothermia on admission to NICU (core body temperature < 36.5 °C or skin temperature < 36 °C) (Outcome 01.03):

Outcome 01.03.01 Knobel 2005, in addition to reporting core body temperature on admission to NICU as a continuous variable, also provided data in a dichotomous format in terms of incidence of hypothermia in intervention and control groups (plastic wrap and routine care). Hypothermia was defined in this study as a core body temperature (rectal) < 36.4 °C on admission to NICU. For infants of gestational age < 29 completed weeks, (classed as < 28 wk for previous subgroup analysis for 01.01.01), plastic wrap significantly reduces the risk of hypothermia on admission to NICU (one study, n = 88; RR 0.63, 95% CI 0.42, 0.93; RD -0.26; 95% CI -0.46, -0.06).

This finding is consistent with those for the outcome measure 01.01.01. Four infants would need to be wrapped in plastic in order to prevent one infant from becoming hypothermic (NNT 4, 95% CI 3 to 17).


Secondary outcomes

Mortality (death prior to hospital discharge) (Outcome 01.04):

Three studies which included 112 infants (Vohra 1999; Vohra 2004a; Knobel 2005) reported this outcome in terms of death within hospital stay. Mortality figures for the Vohra 2004a study included two infants who died in the delivery room. The test for homogeneity passed with an I2 value of 3.6%.

Outcome 01.04.01: For infants with a gestational age < 28 completed weeks the results of the meta-analysis are in the direction in favour of the intervention group (plastic wrap). However, this is being pulled by the (Vohra 1999) study with five events in the control group and showing borderline significance. Overall there is insufficient evidence to suggest that plastic wrap reduces the risk of death within hospital stay for this group of infants (three studies, n = 161; typical RR 0.63; 95% CI 0.32, 1.22; typical RD -0.09; 95% CI -0.20, 0.03).

Outcome 01.04.02: For infants with a gestational age of 28 to 31 completed weeks there were no deaths within hospital stay in either group. Data were provided from one study Vohra 1999 (41 infants).


Major brain injury (defined as sonographic evidence of intraventricular haemorrhage with ventricular dilation, parenchymal haemorrhagic infarction or periventricular leukomalacia) (Outcome 01.05):

This outcome was reported in one study (Knobel 2005) but it was not pre-defined at review protocol stage.

Outcome 01.05.01: For infants of gestational age < 29 completed weeks there was no evidence of a difference in risk of major brain injury (one study, n = 88; RR 1.15; 95% CI 0.36, 3.68; RD 0.02; 95% CI -0.12, 0.15).

Duration of oxygen therapy (days) (Outcome 01.06):

This outcome was reported in one study (Knobel 2005) but it was not pre-defined at review protocol stage.

Outcome 01.06.01: For infants of gestational age < 29 completed weeks, there was no significant difference in duration of oxygen therapy (one study, n = 88; MD -6.51 days; 95% CI -23.30, 10.28).

Duration of hospitalisation (days) (Outcome 01.07):

This outcome was reported in one study (Knobel 2005).

Outcome 01.07.01: For infants of gestational age < 29 completed weeks, there was no significant difference in duration of hospitalisation (one study, n = 88; MD -5.49 days; 95% CI -19.93, 8.95).

Apgar score at one minute (Outcome 01.08):

This outcome was reported in one study (Vohra 2004a) but it was not pre-defined at review protocol stage.

Outcome 01.08.01: For infants of gestational age < 28 completed weeks, median Apgar scores were comparable in the intervention and control group (one study, n=53; P = 0.6).

Apgar score at five minutes (Outcome 01.09):

This outcome was reported in one study (Vohra 2004a) but it was not pre-defined at review protocol stage.

Outcome 01.09.01: For infants of gestational age < 28 completed weeks, median Apgar scores were comparable in the intervention and control group (one study, n=53; P = 0.9).

First blood gas pH (Outcome 01.10):

This outcome was reported in one study (Vohra 2004a). This was not pre-specified at review protocol stage.

Outcome 01.10.01: For infants of gestational age < 28 completed weeks, there was no significant difference in first blood gas pH (one study, n = 53; MD -0.04 ; 95% CI -0.10, 0.02).

Bicarbonate (mmol/L) (Outcome 01.11):

This outcome was reported in one study (Vohra 2004a).

Outcome 01.11.01: For infants of gestational age < 28 completed weeks, there was no significant difference in bicarbonate (one study, n = 53; MD 1.00 mmol/L; 95% CI -0.85, 2.85).

First serum glucose concentration (mmol/L) (Outcome 01.12):

This outcome was reported in one study (Vohra 2004a). This was not our pre-specified definition of hypoglycaemia at review protocol stage.

Outcome 01.12.01: For infants of gestational age < 28 completed weeks, there was no significant difference in first serum glucose concentration (one study, n = 53; MD -0.30 mmol/L; 95% CI , -1.11, 0.51).

Other secondary outcomes

The following secondary outcome measures were not available for any of the included studies for this comparison: hypoglycaemia, respiratory distress syndrome, surfactant given at any time, intubation in the delivery room, requirement for ventilation, duration of ventilation, severe metabolic acidosis, intraventricular haemorrhage, patent ductus arteriosus, chronic lung disease, necrotizing enterocolitis, acute renal failure, burns, antibiotics or negative psychological outcomes.

Adverse occurrences

There were no occurrences of adverse events attributable to the intervention (i.e. hyperthermia, infection, skin maceration or interference with resuscitation) for infants in the intervention and control groups in the Vohra 1999 study. Knobel 2005 reported that one participant in the intervention group was hyperthermic with a rectal admission temperature of 38.3°C; the delivery room environmental temperature was 26.7 °C. Knobel 2005 also reported that the clear, pliable polyurethane bag did not interfere with either assessment (visualization, auscultation, palpation) or resuscitative interventions. Vohra 2004a reported that the wrap procedure was accepted by the neonatal staff and did not interfere with resuscitation in the delivery room. Two infants in the intervention group (Vohra 2004a) were reported to have a rectal temperature on admission above 37.5 °C.

Hyperthermia on admission to NICU: core body temperature > 37.5°C (Outcome 01.13):

A clear definition of hypothermia was reported in only one study (Vohra 2004a). This was not our pre-specified definition of hyperthermia at review protocol stage.

Outcome 01.13.01: For infants of gestational age < 28 completed weeks, there was no significant difference in risk of hyperthermia between those infants who received plastic wrap and those who received routine care (one study, n=53; RR 4.82, 95% CI 0.24, 95.88; RD 0.07; 95% CI -0.04, 0.19).

STOCKINET CAP VERSUS ROUTINE CARE (COMPARISON 02):

Primary outcomes

Core body temperature (°C) on admission to NICU or up to 2 hours after birth (Outcome 02.01):

Roberts 1981 reported core body temperature (axillary °C) on admission to NICU in a study of 40 infants. This study reported figures for all infants with a gestational age 32 to 36 completed weeks, and also for the subgroup of infants < 2000 g birthweight. We have tried to disaggregate the data using the information available, in order to obtain data for the subgroup of infants weighing 2000 g or more at birth. These subgroup analyses by birthweight class were not pre-specified in the protocol for this review.

Overall:

The I2 value of 65.8% indicates that there is a moderate degree of heterogeneity of effect across these two birthweight subgroups. Overall, the results show no statistically significant difference in the effects of the two interventions (stockinet cap versus routine care) on core body temperature on admission to NICU (one study, n = 40; MD 0.15 °C; 95% CI -0.18, 0.48).

Outcome 02.01.01: For infants with a birthweight < 2000 g a borderline statistically significant difference was shown in core body temperature on admission to NICU favouring the intervention (stockinet cap) group when compared to those who received routine care (one study, n = 10; MD 0.70 °C; 95% CI -0.01, 1.41).

Outcome 02.01.02: For infants with a birthweight ≥ 2000 g no statistically significant difference in the effects of the two interventions (stockinet cap versus routine care) for core body temperature on admission to NICU was shown (one study, n = 30; MD 0.00 °C; 95% CI -0.37, 0.37).

Hypothermia on admission to NICU (core body temperature < 36.5 °C or a skin temperature < 36 °C) (Outcome 02.02):

Outcome 02.02.01: Roberts 1981, in addition to reporting core body temperature on admission to NICU as a continuous variable, also provided data in a dichotomous format in terms of incidence of hypothermia in both groups (stockinet cap and routine care). Hypothermia was defined in this study as a core body temperature (axillary ) < 36 °C on admission to the NICU. For infants with a gestational age 32 to 36 completed weeks (birthweight range 1360 to 2965 g), there was no significant difference in risk of hypothermia (as defined by the study) between those infants who received stockinet cap and those who received routine care (one study, n = 40; RR 0.90; 95% CI 0.48, 1.71; RD -0.05; 95% CI -0.36, 0.26).

Secondary outcomes

The following secondary outcome measures were not reported for this comparison: hypoglycaemia, respiratory distress syndrome, surfactant given at any time, intubation in delivery room, requirement for ventilation, duration of ventilation, length of stay, mortality, severe metabolic acidosis, intraventricular haemorrhage, patent ductus arteriosus, chronic lung disease, necrotizing enterocolitis, acute renal failure and adverse events due to the intervention (hyperthermia, burns, maceration, skin or systemic infection, antibiotics, interference with resuscitation and other practices, fluid problems, negative psychological outcomes).


EXTERNAL HEAT SOURCES (NON-ROUTINE)

SKIN-TO-SKIN CARE VERSUS ROUTINE CARE (COMPARISON 03):

Primary outcomes

Hypothermia (skin temperature < 35.5 °C for two consecutive recordings) (Outcome 03.01):

Bergman 2004 reported this outcome in terms of skin temperature remaining below 35.5 °C for two consecutive readings (five minute intervals for the first hour, thereafter 15 minute intervals during the six hour observation period). This outcome was not pre-specified at review protocol stage.

Outcome 03.01.01: For infants with a birthweight between 1200 and 2199 g evidence suggests that skin-to-skin contact significantly reduces the risk of hypothermia (as defined by the study) within 6 hours of birth when compared to conventional incubator care (one study, n = 31; RR 0.09; 95% CI 0.01, 0.64; RD -0.56; 95% CI -0.84, -0.27). Two infants would need to receive skin-to-skin contact in order to prevent one infant from becoming hypothermic (NNT 2, 95% CI 1 to 4).

Secondary outcomes

Hypoglycaemia (blood glucose < 2.6 mmol/L) (Outcome 03.02):

Bergman 2004 reported this outcome which was confirmed by laboratory estimation within the 6 hour observation period where blood glucose was measured by heel prick at one, three and six hours. This was not our pre-specified definition of hypoglycaemia at review protocol stage.

Outcome 03.02.01: For infants with a birthweight between 1200 and 2199 g there is no significant difference in risk of hypoglycaemia (as defined by the study) between those infants who received skin-to-skin contact and those who received conventional incubator care (one study, n = 31; RR 0.24; 95% CI 0.03, 2.06; RD -0.18; 95% CI -0.43, 0.08).

Other secondary outcomes

This study reported the following additional outcome measures: heart rate below 100, or above 180 beats per minute for two consecutive recordings, apnoea longer than 20 s, oxygen saturation below 87% for two consecutive recordings despite supplementation with nasal prong oxygen, FiO2 up to 0.60 and CPAP up to 5 cm water, and overall data (transfers to NICU, exceeded parameters, mean SCRIP score within first 6 hours and number of perfect scores, mean SCRIP score in the sixth hour and number of perfect scores).

The following secondary outcome measures were not reported for this comparison group: respiratory distress syndrome, surfactant given at any time, intubation in delivery room, requirement for ventilation, duration of ventilation, length of stay, mortality, severe metabolic acidosis, intraventricular haemorrhage, patent ductus arteriosus, chronic lung disease, necrotizing enterocolitis or acute renal failure.

Adverse occurrences
Bergman 2004 reported that "there were no adverse events related to the intervention".

TRANSWARMER (SODIUM ACETATE) MATTRESS VERSUS ROUTINE CARE (COMPARISON 04):

Primary outcomes

Core body temperature (°C) on admission to NICU or up to two hours after birth (Outcome 04.01):

Brennan 1996 reported core body temperature (axillary °C) on admission to NICU in a study of 24 infants.

Outcome 04.01.01: For infants with a birthweight ≤ 1500 g a statistically significant difference was shown in mean c favouring the intervention (transwarmer mattress) group when compared to those who received routine care (one study, n = 24; MD 1.60 °C; 95% CI 0.83, 2.37).


Hypothermia on admission to NICU (core body temperature < 36.5°C or skin temperature < 36°C) (Outcome 04.02):
Brennan 1996 in addition to reporting core body temperature on admission to NICU as a continuous variable, also provided data in a dichotomous format in terms of incidence of hypothermia in the intervention and control groups (transwarmer mattress and routine care). Hypothermia was defined in this study as a core body temperature (axillary °C) < 36.5 on admission to NICU.

Outcome 04.02.01: For infants with a birthweight ≤ 1500 g evidence suggests that the transwarmer mattress significantly reduces the risk of hypothermia on admission to NICU (one study, n = 24; RR 0.30 95% CI 0.11, 0.83; RD -0.58; 95% CI -0.91, -0.26). Two infants would need to receive a sodium acetate mattress in order to prevent one infant from becoming hypothermic (NNT 2, 95% CI 1 to 4 ).

Secondary outcomes

The following secondary outcome measures were not reported for this comparison group: hypoglycaemia, respiratory distress syndrome, surfactant given at any time, intubation in delivery room, requirement for ventilation, duration of ventilation, length of stay, mortality, severe metabolic acidosis, intraventricular haemorrhage, patent ductus arteriosus, chronic lung disease, necrotizing enterocolitis, acute renal failure and adverse events due to the intervention (hyperthermia, burns, maceration, skin or systemic infection, antibiotics, fluid problems, negative psychological outcomes).

Adverse occurrences

Brennan 1996 reported that the intervention did not at any time interfere with the care of the infants.


Discussion


Hypothermia (body temperature below normal) on admission to neonatal units is a problem world-wide across all climates, particularly for small infants and those born too early. Early intervention in the delivery room is vital. This review focused on individual interventions to prevent hypothermia applied immediately at birth apart from 'routine' care in comparison to 'routine care' only. The studies fell into two major groups: barriers to prevent heat losses and additional external heat sources. The strengths of the review lie in the fact that a comprehensive literature search was undertaken encompassing both published and unpublished studies. In addition, strict inclusion criteria were adhered to ensuring that the review was focused on interventions that were applied within the first 10 minutes after birth for preterm and/or low birthweight infants as opposed to bigger infants or long-term thermal management. Limitations of the review were dictated by the number and size of the relevant studies and by the lack of reported data for the pre-specified secondary outcomes.

Six studies were identified which fulfilled our criteria for inclusion giving a total of 304 infants randomised and 295 infants completing the studies. Four studies compared barriers to heat loss to no barriers (Roberts 1981; Vohra 1999; Vohra 2004a; Knobel 2005) and two studies compared external heat sources (non-routine) to no external heat sources (Brennan 1996; Bergman 2004). There were two comparisons within the barriers to heat loss category: plastic wrap versus routine care (Vohra 1999; Vohra 2004a; Knobel 2005) and stockinet cap versus routine care (Roberts 1981). There were also two comparisons within the external heat source category: skin-to-skin care versus routine care (Bergman 2004) and transwarmer (sodium acetate) mattress versus routine care (Brennan 1996). Each technique was successful to a greater or lesser degree in increasing temperature on admission to NICU.

Barriers to heat loss

Plastic barriers were effective in reducing heat losses for the younger group of infants with gestational ages of < 28 completed weeks. The results showed that there was a high level of heterogeneity within this subgroup of infants. Possible causes may lie within the variations in methods used in the three studies (Vohra 1999; Vohra 2004a; Knobel 2005). The authors of these studies were contacted and potential differences were explored. In both the Vohra 1999 and Vohra 2004a studies the study sample represented all preterm infants within the eligible gestational age range born at the institution. The intervention consisted of a polyethylene bag which was cut into a wrap, only the head of the infant was dried, the body was wrapped from the neck down, a radiant warmer was used, and no parental consent was sought although institutional consent was given. No attempt was made to change standard delivery room temperatures during the studies. Infants were transferred to the NICU in incubators in the first study (Vohra 1999) and in the arms of one of the neonatal team in the second (Vohra 2004a). In contrast, in Knobel 2005, the study sample excluded infants for whom no consent was given (and who might have been smaller or more ill and thus more prone to heat loss); and the intervention consisted of polyurethane bag with a drawstring, and the body was wrapped from the neck down while still wet. Attempts to control delivery room temperatures (Knobel 2005), as recommended by the World Health Organisation, failed and resulted in a wide spread of delivery room temperatures during the study period. Infants were transferred to the NICU down a very long, drafty hallway on an open warmer with its heat off with warm blankets over the infants. All three studies followed the NRP protocol and exclusion criteria were similar. An additional point of interest was the reported imbalance of birthweight between study groups in the Vohra 1999 study. The birthweight-adjusted difference in rectal temperatures for infants with a gestational age of < 28 completed weeks remained significant but decreased from 1.90 °C, SD(0.43 °C) to 1.54 °C, SD(0.42 °C).

There was limited reporting of pre-specified secondary outcomes for this group of studies. There was insufficient evidence to suggest that plastic barriers reduce the risk of death within hospital stay for the younger infants and no deaths were reported for the older group of infants. Similarly, there was no evidence of a significant difference in major brain injury, mean duration of oxygen therapy or hospitalisation, for infants with a gestational age < 29 completed weeks ( Knobel 2005) nor median Apgar score at one and five minutes, first serum glucose concentrations, first blood pH for infants < 28 completed weeks gestational age (Vohra 2004a).

Where the barrier to heat loss was stockinet caps, a borderline statistically significant difference in temperature on admission to NICU in favour of the intervention group was shown for those infants with a birthweight < 2000 g but no difference for those infants ≥ 2000 g. This finding is consistent with those reported by Greer 1988 in which various head coverings were compared under radiant warmers for infants > 2500 g. Where head coverings were applied within one minute of birth, results showed that infants wearing 'stockinettes' had lower mean core body temperatures at 5, 15 and 30 minutes after delivery than either the hatless group or the group wearing an insulated fabric bonnet. As a result, 'stockinettes' were not recommended for use in conjunction with a radiant warmer.

External heat sources (non-routine)

Skin-to-skin care was shown to be effective in reducing the risk of hypothermia when compared to conventional incubator care for infants with a birthweight between 1200 and 2199 g and the transwarmer mattress significantly kept infants ≤ 1500 g warmer and reduced the incidence of hypothermia on admission to NICU. There was no evidence that skin-to-skin care reduced the risk of hypoglycaemia. There was limited reporting of secondary outcomes.

Overall

Despite the variations in interventions applied, definitions of 'routine care', definitions of hypothermia and groups of infants included, across all studies there is a similar pattern emerging showing that infants in the intervention group are significantly warmer (or show a non-significant trend in that direction) when compared to infants receiving 'routine care'. There is also an indication from these studies that the effect is greater in the lightest and most immature infants. Babies of < 28 weeks or those weighing ≤ 1500 g appeared to derive most benefit from interventions in the delivery suite to prevent hypothermia. These are also the infants most likely to suffer from the adverse effects of hypothermia and in whom further studies should be undertaken.

There was limited reporting of pre-specified secondary outcomes across all studies. There were no occurrences of adverse events attributable to the intervention (i.e. hyperthermia infection, skin maceration or interference with resuscitation) for infants in the intervention and control groups in the Vohra 1999 study. Knobel 2005 reported that one participant in the intervention group was hyperthermic with a rectal admission temperature of 38.3°C; the delivery room environmental temperature was 26.7 °C. Knobel 2005 also reported that the clear, pliable polyurethane bag did not interfere with either assessment (visualization, auscultation, palpation) or resuscitative interventions. Vohra 2004a reported that the wrap procedure was accepted by the neonatal staff and did not interfere with resuscitation in the delivery room. Two infants in the intervention group (Vohra 2004a) were reported to have a rectal temperature on admission above 37.5 °C. Bergman 2004 reported that "there were no adverse events related to the intervention" and Brennan 1996 stated that the intervention did not at any time interfere with the care of the infants.

There is a need for the measurement of hyperthermia and other potential adverse events in neonatal units where such interventions are adopted as routine practice. For example, Knobel 2005a reported that twenty percent of responding level three neonatal intensive care units used occlusive material instead of drying preterm infants in the delivery room. They also found that only one of the one-hundred and twenty-five responding neonatal intensive care units reported any adverse effects from using wrap or bags in the delivery room. This unit reported that a single infant was hyperthermic on admission to the neonatal intensive care unit but did not report the actual infant temperature.

More recently, the International Liaison Committee on Resuscitation (ILCOR) consensus statement recommends that plastic bags or plastic wrapping under radiant heat be considered as standard techniques to maintain temperature ( ILCOR 2006). As its recommended use expands there will now be an opportunity to document the safety of this practice and in particular the occurrence of any serious adverse events. Clarification on 'normal' temperatures for these populations of infants is also essential as is better data correlating axillary versus rectal versus other temperatures.

Paradoxically hypothermia is more of a problem in the developing world where climates are generally warmer. Only one of the included studies was conducted in a developing country, South Africa (Bergman 2004). Although South Africa is classified as developing, the units participating in this study carried out in Cape Town provided secondary level care for inborn babies and is therefore not truly representative of the developing world.

Further studies are needed of interventions such as plastic bag wrapping for infants under 30 weeks' gestation with adequate sample size to assess both short-term and long-term neurodevelopmental outcomes. Such a multicentre study (HeLP) is currently underway in partnership with the Vermont Oxford Network (n=1600). The primary study outcome is all cause mortality while secondary outcomes include neurodevelopmental status at 18 months corrected age and safety data. This study will yield important prospective data on "normal" temperatures in this population, including correlating axillary and rectal temperature. The plastic wraps utilised in this study cost approximately 157 Canadian Dollars for 5000 wraps which when calculated per infant is approximately three cents.

Reviewers' conclusions



Implications for practice


Health professionals strive to minimise risk of cold stress for newborn infants immediately after birth by adhering to good practice guidelines such as: providing a warm delivery room at a minimum of 25 °C (although this is difficult to achieve in practice), drying the infant, removing any wet blankets and wrapping in a prewarmed blanket, prewarming any contact surfaces, avoiding draughts and in developed countries, using radiant warmers or incubators. Despite this hypothermia remains a world-wide problem, especially for small infants and those born too early (Costeloe 2000). Any additional intervention designed for prevention of hypothermia in very preterm and/or low birthweight infants, and applied within 10 minutes after birth in the delivery suite, compared with routine thermal care may be beneficial in practice. The interventions in this review (plastic wraps and bags, skin-to-skin contact, and transwarmer mattresses) keep infants warmer and lead to higher temperatures on admission to the NICU and to decreased incidence of hypothermia. As hypothermia increases the risk of morbidity and mortality in preterm infants, consideration should be given to using these interventions in the delivery suite. However, given the small numbers of infants and the small numbers of studies in this review and the fact that no long-term data on follow-up are available, firm recommendations for clinical practice cannot be given at this time.


Implications for research


Due to the small numbers and size of trials in this review there is a need conduct high quality randomised controlled trials where the specifically designed intervention to prevent hypothermia is applied within the first few minutes after birth in the delivery suite. These studies should be large enough to look at long-term neurodevelopmental outcomes and could also include economic evaluations to assess feasibility for use in poorer countries where cost is a fundamental concern. We report in the Table of "Characteristics of ongoing studies" that a large multicentre randomised controlled trial of heat loss prevention (HeLP) in the delivery room commenced in September 2004 (Vohra 2004a). This trial will include infants < 28 weeks' gestational age, the intervention will be polyethylene skin wrap and the study will look at mortality as its primary outcome. Eighteen-month neurodevelopmental follow-up is also planned.

Acknowledgements


Mr Diarmuid Kennedy, Ms Angela Thompson and Ms Alex McIlroy, Faculty Librarians - Medicine and Health Sciences, Queen's University Medical Library, Mulhouse Building, Belfast, BT12 6DP.
Mr Mike Stevenson, Senior Lecturer in Medical Statistics - Epidemiology & Public Health, Queen's University Belfast, Mulhouse Building, Grosvenor Road, Belfast BT12 6BJ.
Ms Suzanne Sweeney, Texas Woman's University Library, Texas Woman's University, Box 23717, TWU Station, Denton, Texas 76204.

Potential conflict of interest


SV is principal investigator on two studies that met the review eligibility criteria. This team member was excluded from the study appraisal process for these studies.
SV is also co-leading the current multicentre HeLP study.

Characteristics of included studies

StudyMethodsParticipantsInterventionsOutcomesNotesAllocation concealment
Bergman 2004Randomised.
Multicentre (2).
Blinding of randomisation: unclear.
Generation of allocation sequence: adequate, (computer minimisation method).
Allocation concealment: unclear, ("... a computer minimisation method determined allocation in a concealed manner" , ".. second hospital... minimisation factors and subsequent allocation by the computer were exchanged by mobile telephone, with no delays").
Blinding of intervention: participants - no/unfeasible, care providers - no/unfeasible.
Blinding of outcome measurement: yes, after the pilot phase, the principal investigator and data analyses team were blinded. A statistician, blinded to the allocation, performed the statistical analyses.
Complete follow-up: no, (31 of 35 infants randomised completed the study, 1 infant was excluded after 2 hours when the mother required a caesarean section for a second twin, 3 further infants 'bailed out' within the first 3 hr requiring additional respiratory support and moved to neonatal intensive care).

Room temperature, maternal temperature and incubator temperature were recorded.
Ethical approval was obtained.
Informed consent.

Infants delivered with a birthweight 1200 to 2199 g.
35 infants randomised: intervention group (n = 21), control group (n =14), 31 completed study: intervention group (n = 18), control group (n =13).
Setting: South Africa.

Exclusion criteria:
Mother: 1) delivered outside the unit, 2) had a caesarean section, 3) too severely ill to be able to look after themselves or their infants, 4) known to have positive HIV status, 5) giving their babies up for adoption.
Infant: 1) birthweight below 1200 g or above 2199 g, 2) Apgar score below 6 at 5 min, 3) congenital malformations detected at birth.

Intervention group (skin-to-skin care) characteristics:

Mothers: gravidity mean (1.9), parity mean (1.8), race African (8), race Coloured (12), smoking in pregnancy (7), alcohol use( 6), opiate in labour (9), Oxytocin in labour (3), hypertension (3), antepartum steroids (5).
Infants: male (12), resuscitation (4), birthweight (g) mean (1813) SD(260), gestational age (wks) mean (34.2) SD(1.9), appropriate for GA (13), small for GA (7).

Control group (conventional care) characteristics:

Mothers: gravidity mean (1.9), parity mean (1.6), race African (4), race Coloured (10), smoking in pregnancy (4), alcohol use (2), opiate in labour (6), Oxytocin in labour (1), hypertension (1), antepartum steroids (3).
Infants: male: (7), resuscitation baby (1), birthweight (g) mean (1866) SD(258), gestational age (wks) mean (35.3) SD(1.9), appropriate for GA (10), small for GA (5).

INTERVENTION: SKIN-TO-SKIN CARE

All infants were delivered onto a theatre cloth on the mother's abdomen/chest , dried gently and assessed. They were then placed naked on the mother's naked chest and covered with double layered cotton cloth. The bed was placed in semi-Flowers position.

Intervention group:
The infant remained in skin-to-skin contact, was secured to the mother's chest, the hips were flexed and placed in a 'frog position', arms also flexed.

Control group:
The infant was immediately transferred to a prewarmed servocontrolled closed incubator which remained with the mother in delivery ward for the first hour. If the infant temperature was below 36 degrees centigrade, a cap and booties were applied along with a heat shield placed over the infant. If this was insufficient a sheet of plastic was framed over the foot end of the heat shield and the outlet of the warm air funnelled over the infant.

Infant stability in terms of a set of predetermined physiological parameters. Observations for heart rate, respiratory rate, oxygen saturation and temperature were recorded at 5 minute intervals in the first hour, then 15 minute intervals. Continuous observations for apnoea and signs of respiratory distress, blood sugar measured at 1, 3 and 6hr.

Primary Outcomes:
1) neonatal intensive care admissions
2) number of exceeded parameters
3) composite stabilization score (SCRIP) (1-6h)
4) composite stabilization score (SCRIP) (6th h)

Secondary outcomes:
1) skin temperature degrees centigrade remaining below 35.5 C for 2 consecutive readings
2) heart rate below 100 or above 180 beats per minutes for 2 consecutive readings
3) apnoea longer than 20 seconds
4) oxygen saturation below 87% for 2 consecutive recordings, despite supplementation with nasal prong oxygen, FiO2 up to 0.6 and CPAP up to 5cm water
5) blood glucose below 2.6 mmol/L reading confirmed by laboratory.


B
Brennan 1996Randomised.
Single centre.
Blinding of randomisation: unclear.
Generation of allocation sequence: adequate, (lot drawing - pulling cards from an envelope in which 24 cards had been placed. Equal numbers of cards had either 'mattress' or 'no mattress' written on them).
Allocation concealment: unclear.
Blinding of intervention: participants: no/unfeasible, care providers: no/unfeasible.
Blinding of outcome measurement: no.
Complete follow-up: yes, all 24 infants randomised completed the study.

Gestational age, birthweight, and the time temperature taken after birth were recorded.
The proposal for the study underwent a full review by the Institutional Review Board of the University of Florida, Health Science Centre.
Informed consent.

Infants delivered with a birthweight less than or equal to 1500 g.
24 infants randomised: intervention group (n = 12), control group (n = 12).
Setting: USA.

Exclusion criteria:
1) the maternal temperature at delivery was greater than 38.0 degrees Centigrade, 2) the infant had an obvious neural tube defect,
3) the infant had an omphalocele, gastroschisis, exstrophy of the bladder, cloacal exstrophy, or any other open lesion than would cause greater than normal heat loss at delivery, 4) the infant had a sacral teratoma, or any other lesion that would prevent the infant from being positioned and evaluated in the normal manner.

All infants characteristics: gestational age range (wks) 24 to 32, birthweight range (g) 531 to 1498.
Intervention group (transwarmer mattress) characteristics: gestational age (wks) mean (27.8), birthweight (g) mean (1033).
Control group characteristics: gestational age (wks) mean (27.3), birthweight (g) mean (1027).


INTERVENTION: TRANSWARMER INFANT TRANSPORT MATTRESS (Prism Technologies, San Antonio, Texas). These mattresses are filled with a gel of sodium acetate, water and thickeners. Once activated they heat to approximately 40 degrees centigrade for 2 hours.

Intervention group:
The NICU nurse activated the mattress when delivery was imminent and placed it on the radiant warmer surface with blankets on top of it and the newborn infant was immediately placed on the blankets, dried and the blankets removed, then placed directly onto the warming mattress.

Control group:
Infants received the same care as the intervention group but without the warming mattress.

Both groups were evaluated and resuscitated according to the Neonatal Resuscitation Program and transported to NICU on the radiant warmer surface. The infants in the intervention group remained on the mattress until the admission temperatures were taken in the NICU.


Primary outcomes:
1) core body temperature degrees centigrade (axillary) was measured using the IVAC 2080A Temp Plus 11 (IVAC, San Diego, California) as soon as possible after arrival at NICU.

Secondary outcomes:
1) interference to resuscitation.

Individual patient data was reported in this study therefore dichotomous data for hypothermia on admission to NICU for the control and intervention group was calculated.B
Knobel 2005Randomised.
Single centre.
Blinding of randomisation: yes.
Generation of allocation sequence: unclear.
Allocation concealment : adequate, (opaque envelopes).
Blinding of intervention: participants - no/unfeasible, care provider - no/unfeasible.
Blinding of outcome measurement: no.
Complete follow-up: yes, all 88 infants randomised completed the study.

Delivery to admission time was also recorded.

Parental consent was sought if the mother was expected to deliver before completing 29 weeks gestation.

Infants delivered with a gestational age less than 29 completed weeks.
88 infants randomised: intervention group (n = 41), control group (n = 47).
Setting: USA.

Exclusion criteria:
1)congenital anomalies with open lesions (e.g. gastroschisis, meningomyelocele), 2) resuscitation not undertaken because of previability, 3) meconium staining of amniotic fluid, 4) subsequent assessment indicated that infant had a gestational age greater than or equal to 29 completed weeks.

Intervention group (Polyurethane bag) characteristics: birthweight (g) mean (918) SD (259), gestational age (wks) mean (26.5), SD (1.4).

Control group (conventional care) characteristics: birthweight (g) mean (850) SD (253), gestational age (wks) mean (26.1) SD (1.4).

INTERVENTION: POLYURETHANE BAG -
measured 19" x 18" DeRoyal REF30-5510

Intervention group:
Infants were placed immediately into a polyurethane bag, while still wet, up to their necks and resuscitated according to the guidelines for Neonatal Resuscitation.

Control group:
Controls were resuscitated according to these guidelines without bags.

Both groups were taken to the neonatal intensive care unit on a warmer table, (with the heat off) with warm blankets on top of the infant.

Primary outcome:
1) core body temperature degrees centigrade (rectal) on admission to the NICU.

2) hypothermia on admission to the NICU defined by a core body temperature (rectal) < 36.4 degrees centigrade.

Secondary outcomes:
1) mortality.
2) major brain injury.
3) duration of oxygen therapy.
4) duration of hospitalisation.
5) hyperthermia
6) interference with assessment and resuscitation

A
Roberts 1981Randomised.
Single centre.
Stratified randomisation by gestational age 32 to 34 and 35 to 36 completed weeks' gestation.
Blinding of randomisation: unclear.
Generation of allocation sequence: adequate, (lot drawing - index cards were utilised to pre-arranged randomisation - random number tables).
Allocation concealment: unclear.
Blinding of intervention: participants - no/unfeasible, care providers- no/unfeasible.
Blinding of outcome measurement: no
Complete follow-up: yes, all 40 infants randomised completed the study.

Delivery room, transport incubator, highest maternal temperatures, birthweight, gestational age, method of delivery, time elapsed from birth to onset of drying and time elapsed from birth to arrival in nursery were recorded.
Informed consent.

Infants delivered from 7am until 5 pm Monday through Friday with a gestational age of 32 to 36 completed weeks.
40 infants randomised: intervention group (n = 17), control group (n = 23).
Setting: USA.

Criteria for exclusion:
1) infant not appropriate birthweight for gestational age, 2) Apgar score @ 5 min less than 7, 3) signs of central nervous system defect, 4) infant dropped from study on development of sepsis, 5) maternal temperature greater than or equal to 37.8 degrees centigrade, 5) delivered outside of delivery room.

Intervention group (stockinet cap) characteristics: male (4), female (13), white (6), black (5), Mexican - American (6), vaginal delivery (15), caesarean section (2), gestational age (wks) (32 to 34 (5), 35 to 36 (12)), gestational age (wks) mean (34.9 ), birthweight (g) range (1420 to 2890), birthweight (g) mean (2253.4), Apgar score @ 5 min equal to 9 (16), infants transported in incubator (7), highest maternal temperature (degrees centigrade) range (36.6 to 37.7) mean (37.1).


Control group (conventional care) characteristics: male (12), female (11), white (8), black (13), Mexican - American (2), vaginal delivery (18), caesarean section (5), gestational age (wks) ( 32 to 34 (4), 35 to 36 (19)), gestational age (wks) mean (35.2), birthweight (g) range (1360 to 2965), birthweight (g) mean (2276.8), Apgar score @ 5 min equal to 9 (22), infants transported in incubator (12), temperature (degrees centigrade) transport incubator range ( 33 to 37) mean (35.2), highest maternal temperature (degrees centigrade) range (36.2 to 37.8) mean (37.2).

INTERVENTION: STOCKINET CAP - a sterile headpiece made of stockinet (a material used to protect skin under orthopedic casts) which covers the forehead, the ears, underneath the occipital bone, and all the area above this plane.

Intervention group:
Infants received a stockinet cap after delivery as soon as possible after being dried under a radiant warmer.

Control group:
Infants received the same treatment as the intervention group but did not receive a stockinet cap.

All infants weighing less than 2500 g were transported to the nursery in a transport incubator.

Primary outcomes:
1) core body temperature degrees centigrade (axillary) within 10 minutes of admission to NICU (IVAC electric thermometer Model 821)

Core body temperatures degrees centigrade (axillary) in the delivery room were also recorded to enable calculation of the "amount of heat lost from the time the axillary temperature was taken in the delivery room until the axillary temperature was taken in the nursery".

Secondary outcomes:
None reported.

B
Vohra 1999Randomised.
Single centre.
Prognostic stratification was by gestational age 23 to 27 and 28 to 31 completed weeks' gestation.
Blinding of randomisation: yes.
Generation of allocation sequence: adequate, (computer generated random sequence).
Allocation concealment: adequate, (double-enclosed, opaque, sealed, and sequentially numbered envelopes).
Blinding of intervention: participants - no/unfeasible, care providers - no/unfeasible.
Blinding of outcome measurement: no.
Complete follow-up: no, (59 of 62 infants randomised completed the study, 1 infant was excluded as no rectal temperature was recorded, two infants were excluded due to an imperforate anus).

Delivery room, nursery temperatures and other potential confounding variables, (birthweight, maternal temperature, illnesses, medications, length of second stage of labour, length of time to arrival at nursery) were recorded.
Ethics approval was obtained.
No informed consent.

Institutional consent was given.

Infants delivered with a gestational age of less than 32 completed weeks.
62 infants randomised: 59 completed study, intervention group (n = 27), control group (n = 32).
Setting: Canada.

Exclusion criteria:
1) major congenital anomalies with open lesions, 2) infants whom the attending obstetrician considered "previable".

Intervention group (polyethylene wrap) characteristics < 28 wks: birthweight (g) mean (914) SD (163), gestational age (wk) mean (26.1) SD (1.4) Apgar score @ 1min mean (5.0) SD (3.0), Apgar score @ 5 min mean (6.7) SD (1.7), ruptured membranes (min) mean (186) SD (471), length 2nd stage (min) mean (26) SD (55).

Control group (conventional care) characteristics < 28 wks: birthweight (g) mean (742) SD (206), gestational age (wks) mean (25.7) SD (1.5), Apgar score @ 1 min mean (4.3) SD (2.1), Apgar score @ 5 min mean (7.1) SD (1.4), ruptured membranes (min) mean (10) SD (21), length 2nd stage (min) (18) SD (24).

Intervention group (polyethylene wrap) characteristics >= 28 wks: birthweight (g) mean (1251) SD (282), gestational age (wk) mean (29.6) SD (1.1) Apgar score @ 1min mean (6.5) SD (1.8), Apgar score @ 5 min mean (8.5) SD (1.1), ruptured membranes (min) mean (105) SD (310), length 2nd stage (min) mean (15) SD (25).

Control group (conventional care) characteristics >= 28 wks: birthweight (g) mean (1265) SD (206), gestational age (wks) mean (29.4) SD (1.5), Apgar score @ 1 min mean (6.0) SD (2.1), Apgar score @ 5 min mean (8.0) SD (1.4), ruptured membranes (min) mean (108) SD (21), length 2nd stage (min) (13) SD (24).

INTERVENTION: POLYETHYLENE BAG - measured 20 cm x 50 cm and was manufactured by Eastern Paper, a Division of EPC Industries.

Intervention group:
A transparent polyethylene bag was opened at resuscitation under a radiant warmer and the infant was placed on it from the shoulders down. Only the head of the infant was dried; the body was wrapped without drying.

Control group:
Controls were managed with the protocol described by the Neonatal Resuscitation Program. Infants were routinely dried under the radiant warmer.

Infants were transferred to the neonatal unit in an incubator.

Primary outcome:
1) core body temperature degrees centigrade (rectal) was measured with a digital rectal thermometer on removal of the bag/wrap on admission to NICU.

Secondary outcomes:
1) mortality
2) hyperthermia
3) infection
4) skin maceration
5) interference with resuscitation.

42 infants who met the inclusion criteria were not enrolled in the study reasons were as follows: still birth (1), 34wks gestational age (2), failure to reach delivery in time (8), failure of staff to pick up envelope on the way to the delivery room (31). The non-enrolled infants did not differ significantly from those in the study population.A
Vohra 2004aRandomised.
Single centre.
Blinding of randomisation: yes.
Generation of allocation sequence: adequate, (computer generated random sequence balanced in blocks of 4 subjects). Concealment of allocation: adequate, (double enclosed, opaque, sealed and sequentially numbered envelopes).
Blinding of intervention: participants - no/ unfeasible, care provider - no/unfeasible.
Blinding of outcome measurement: no.
Complete follow-up: no, (53 of 55 infants randomised completed the study, 2 infants died in the delivery room).

Multiple eligible births were separately randomised.

Institutional consent was given.

Infants delivered with a gestational age less than 28 completed weeks where the birth was attended by the neonatal team.
55 infants randomised: intervention group (n = 28), control group (n = 27), 53 completed study: intervention group (n = 26), control group (n = 27).
Setting: Canada.

Exclusion criteria:
1) neonatal team did not attend the delivery, 2) major congenital anomalies that were not covered by skin e.g. gastroschisis, meningomyelocele, 3) blistering skin conditions.

Intervention group (polyethylene wrap) characteristics: female (14), birthweight (g) mean (858) SD (199), gestational age (wks) mean (26) SD (1.5).
Control group (conventional care) characteristics: female (13), birthweight (g) mean (825) SD (270), gestational age (wks) mean (26) SD (1.4).

INTERVENTION: POLYETHYLENE WRAP - measured 20 cm x 50 cm and was manufactured by Eastern Paper, a Division of EPC Industries LTD.

Intervention group:
Infant placed on polyethylene, wrapped from the neck down, only the head was dried, stabilised under radiant warmer.

Control group:
Control infants were dried completely according to the International Guidelines for Neonatal Resuscitation and stabilised under a radiant warmer.

All infants were carried by one member of the neonatal team from the delivery suite to the neonatal unit and placed in a single walled incubator with 60 percent humidity.

Primary outcomes:
1) core body temperature degrees centigrade (rectal) on admission to NICU following removal of wrap.

Secondary outcomes:
1) core body temperature degrees centigrade (rectal) taken one hour later.
2) mortality - death before discharge.

Further secondary outcomes are reported for Apgar scores, blood gas pH, Bicarbonate (mmol/L), Glucose (mmol/L), hyperthermia and interference with resuscitation.

A

Characteristics of excluded studies

StudyReason for exclusion
Almeida 2000Query over randomisation, (40 participants in the intervention group and 75 participants in the control group) unable to contact authors for clarification.
Anderson 2003No thermal outcome measures were reported.
Andrade 2005No thermal outcome measures were reported. Query re: randomisation.
Baum 1968Participants had a birthweight greater than or equal to 6 lb.
Bergstrom 2005Participants were normal infants, mean gestational age at delivery : 38 wks (Intervention group), 38.4 wks control group. Intervention not strictly for the prevention of hypothermia immediately at birth.
Besch 1971Participants had a birthweight greater than 2000 g.
Bier 1996Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Boo 2007Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants were normal term infants undergoing phototherapy.
Brice 1981Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Bystrova 2003Participants had a birthweight greater than 2500 g.
Carfoot 2005Participants were term.
Cattaneo 1998Intervention was not applied immediately at birth (within 10 mins) in the delivery suite.
Chaput 1979Participants had a birthweight greater than 2000 g.
Charpak 1997Intervention was not applied immediately at birth (within 10 mins) in the delivery suite. No thermal outcome measures were reported.
Cheah 2000Participants were term.
Christensson 1992Participants were term.
Christensson 1996Participants were term delivered by caesarean section.
Christensson 1998Intervention was not applied immediately at birth (within 10 mins) in the delivery suite.
Chwo 1999Intervention was not applied immediately at birth (within 10 mins) in the delivery suite but on the day following birth.
Chwo 2002Intervention was not applied immediately at birth (within 10 mins) in the delivery suite but on the day following birth.
Coles 1979Participants were term.
Dahm 1972Participants were term.
Daniel 2004Unable to obtain a copy of the abstract.
Darmstadt 2007Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Day 1964Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Dodd 2003No thermal outcome measures were reported.
Erlandsson 2007Participants were term delivered by caesarean. No thermal outcome measures were reported.
Fallis 2006Participants were term. Intervention was maternal warming during caesarean section.
Fardig 1980Participants were term.
Ferber 2004Participants were term. Intervention was not applied immediately at birth (within 10 mins) in the delivery suite. No thermal outcome measures were reported.
Gray 2004Intervention was not applied immediately at birth (within 10 mins) in the delivery suite. Participants were at least three days old.
Green-Abate 1994Intervention was not applied immediately at birth (within 10 mins) in delivery suite. Participants were less than 1 week old.
Greer 1988Participants were term and had a birthweight greater than 2500 g.
Grover 1994Participants were term and the intervention was not applied immediately at birth (within 10 mins) in the delivery suite. Participants were aged 11 to 95 days.
Gulezian 1980Insufficient information - unable to obtain abstract.
Harrison 2004Insufficient information - unable to obtain a copy of the abstract.
Hellin Martinez 2000Participants were term.
Hobbs 1975Participants were term.
Holzman 1985Participants were term.
Horn 2002Query if participants were term as infants were delivered by elective caesarean section. The author was contacted for verification. Intervention was active warming during caesarean section.
Huang 2002Participants had a birthweight greater than or equal to 2500 g.

Huang 2006Participants were term. Intervention was not applied immediately at birth (within 10 mins) in the delivery suite.
Johanson 1992Participants were term with a mean gestational age 39.1 weeks. Randomised controlled intervention study compared to a prospective observational study.
Kadam 2005Intervention was not applied immediately at birth (within 10 mins) in the delivery suite. (Verified by author).
Kaushal 2005Intervention was not applied immediately at birth (within 10 mins) in the delivery suite.
Legault 1993Intervention was not applied immediately at birth (within 10 mins) in the delivery suite. Participants were aged one week or more.
Ludington-Hoe 1994Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants in intervention group averaged 18 days old and control participants averaged 13 days old.
Ludington-Hoe 2000Participants had a postnatal age of 6 to 53 days on enrollment to the study.

Ludington-Hoe 2004Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Marks 1985Participants had a gestational age of 36 plus or minus one week. Intervention was not applied immediately at birth (within 10 mins) in the delivery suite. Participants were aged 14 to 68 days.
Mazurek 1999Participants were term.
Medves 2004Participants were term.
Meyer 2001Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Intervention applied on arrival at NICU.
Meyer 2006This study compared plastic wrap plus radiant warmer to plastic wrap plus incubator for transport to NICU. All infants were wrapped under a radiant warmer at birth but it is unlikely that assignment to incubator or radiant warmer took place
within 10 minutes of birth for all infants. This comparison is not within the scope of this review.
Miles 2006Intervention not applied immediately at birth (within 10 mins) in the delivery suite. No thermal outcome measures were reported.
Monterosso 1999Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants were at least one week of age at time of study.
Moore 2007Participants were term. No thermal outcome measures were reported.
Nopper 1996Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants enrolled within the first 96 hours after birth.
Nuntnarumit 2004This study compared plastic wrap and plastic bag to plastic wrap only. Plastic wrap only was not considered to be 'routine care' as pre-specified in the review inclusion criteria.
Omene 1978Participants were term.
Pattinson 2005Intervention was an educational package (with/without facilitation visits) on the implementation of kangaroo mother care.
Punthmatharith 2001No thermal outcomes were measured.
Raman 1992Participants were term.
Ramanathan 2001Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Thermal outcome measures were not reported.
Roberts 2000Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants were born at 30 or more weeks' gestation or corrected age.
Rojas 2001Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Thermal outcome measures were not reported.
Ruiz 1998Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Temperature was not an outcome measure.
Sankaranarayanan2005Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Thermal outcome measures were not reported.
Sarman 1989Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Sarman 1992Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants were 3 to 32 days of age during the study.
Short 1998Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Participants day of life 32.9 plus or minus 15.9 days.
Sloan 1994Intervention not applied immediately at birth (within 10 mins) in the delivery suite. No thermal outcome measures were reported.
Syfrett 1993Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Tsogt 2005Participants were term. Intervention not applied immediately at birth (within 10 mins) in the delivery suite.
Vaidya 2005Participants were term. Intervention not applied immediately at birth (within 10 mins) in the delivery suite. No thermal outcomes were measured.
van den Bosch 1990Participants were term.
van den Bosch 1996Intervention not applied immediately at birth (within 10 mins) in the delivery suite. Intervention applied after 48 hours in the NICU.
Worku 2005Intervention not applied immediately at birth (within 10 mins) in the delivery suite.

Characteristics of ongoing studies

StudyTrial name or titleParticipantsInterventionsOutcomesStarting dateContact informationNotes
Vohra 2004Multicentred randomised controlled trial of heat loss prevention (HeLP) in the delivery room.Infants less than 28 weeks gestation.Polyethylene occlusive skin wrap applied immediately following birth in the delivery suite.Mortality, axillary temperature, rectal temperature (in some) and clinically important variables including: APGAR scores, incidence of acidosis, hypotension, hypoglycaemia, seizures, patent ductus arterious, respiratory distress syndrome/chronic lung disease, necrotizing enterocolitis, intraventricular haemorrhage. Also length of stay and cause of death.September 2004Dr Sunita Vohra
Director CARE (Complementary and Alternative Research and Education) Program
Stollery Children's Hospital
Associate Professor of Pediatrics
University of Alberta

Email:
svohra@cha.ab.ca

This multicentre trial will involve 40 centres, Canada, US and UK, all part of the Vermont-Oxford Network.

References to studies

References to included studies

Bergman 2004 {published data only}

Bergman NJ, Linley LL, Fawcus SR. Randomized controlled trial of skin-to-skin contact from birth versus conventional incubator for physiological stabilization in 1200- to 2199- gram newborns. Acta Paediatrica 2004;93:779-85.

Brennan 1996 {published data only}

Brennan AB. Effect of sodium acetate transport mattresses on admission temperatures of infants <= 1500 grams [dissertation]. Gainesville (FL): University of Florida, 1996.

Knobel 2005 {published data only}

Knobel RB, Wimmer JE, Holbert D. Heat loss prevention for preterm infants in the delivery room. Journal of Perinatology 2005;25:304-8.

Roberts 1981 {published data only}

Roberts JR. Use of a stockinet cap on premature infants after delivery [dissertation]. Denton (TX): Texas Woman's University, 1981.

Vohra 1999 {published data only}

Vohra S, Frent G, Campbell V, Abbott M, Whyte R. Effect of polyethylene occlusive skin wrapping on heat loss in very low birth weight infants at delivery: a randomized trial. Journal of Pediatrics 1999;134:547-51.

Vohra 2004a {published data only}

Vohra S, Roberts R, Zhang B, Janes M, Schmidt B. Heat loss prevention (HELP) in the delivery room: a randomized controlled trial of polyethylene occlusive skin wrapping in very preterm infants. The Journal of Pediatrics 2004;145:750-3.

References to excluded studies

Almeida 2000 {published data only}

Almeida PG, Chandley JM, Rubin LP. Improving admission temperature of very low birth weight (VLBW) newborns: an interventional trial. Pediatric Research 2000;47:282A [Abstract 1661].

Anderson 2003 {published data only}

Anderson GC, Chiu S H, Dombrowski M A, Swinth J Y, Albert J M, Wada N. Mother-newborn contact in a randomised trial of kangaroo (skin-to- skin) care. Journal of Obstetric,Gynecologic, & Neonatal Nursing 2003;32:604-11.

Andrade 2005 {published data only}

Andrade I. Succao do recem-nascido prematuro: comparacao do metodo mae-canguro com os cuidados tradicionais [Suckling of the premature newborn child: comparison between the kangaroo with traditional care]. Revista Brasileria de Saude Materno Infantil 2005;5:61-9.

Baum 1968 {published data only}

Baum JD, Scopes JW. The silver swaddler. Device for preventing hypothermia in the newborn. Lancet 1968;1:672-3.

Bergstrom 2005 {published data only}

Bergstrom A, Byaruhanga R, Okong P. The impact of newborn bathing on the prevalence of neonatal hypothermia in Uganda: a randomized, controlled trial. Acta Paediatrica 2005;94:1462-7.

Besch 1971 {published data only}

Besch NJ, Perlstein PH, Edwards NK, Keenan WJ, Sutherland JM. The transparent baby bag. A shield against heat loss. New England Journal of Medicine 1971;284:121-4.

Bier 1996 {published data only}

Bier JA, Ferguson AE, Morales Y, Liebling JA, Archer D, Oh W, Vohr BR. Comparison of skin-to-skin contact with standard contact in low-birth-weight infants who are breast-fed. Archives of Pediatrics & Adolescent Medicine 1996;150:1265-9.

Boo 2007 {published data only}

Boo N Y, Chew E L. A randomised control trial of clingfilm for prevention of hypothermia in term infants during phototherapy. Singapore Medical Journal 2007;47:757-62.

Brice 1981 {published data only}

Brice JEH, Rutter N, Hull D. Reduction of skin water loss in the newborn II. Clinical trial of two methods in very low birthweight babies. Archives of Disease in Childhood 1981;56:673-5.

Bystrova 2003 {published data only}

Bystrova K, Widstrom AM, Matthiesen AS, Ransjo-Arvidson, Wells-Nystrom B, Wassberg C et al. Skin-to-skin contact may reduce negative consequences of "the stress of being born": a study on temperature in newborn infants, subjected to different ward routines in St. Petersburg. Acta Paediatrica 2003;92:320-6.

Carfoot 2005 {published data only}

Carfoot S, Williamson P, Dickson R. A randomised controlled trial in the North of England examining the effects of skin-to-skin care on breast feeding. Midwifery 2005;21:71-9.

Cattaneo 1998 {published data only}

Cattaneo A, Davanzo R, Worku B, Surjono A, Escheverria M, Bedri A et al. Kangaroo mother care for low birthweight infants: a randomized controlled trial in different settings. Acta Paediatrica 1998;87:976-85.

Chaput 1979 {published data only}

Chaput de Saintonge DM, Cross KW, Hathorn MK, Lewis SR, Stothers JK. Hats for the newborn infant. British Medical Journal 1979;2:570-1.

Charpak 1997 {published data only}

Charpak N, Ruiz-Pelaez JG, Figueroa de CZ, Charpak Y. Kangaroo mother versus traditional care for newborn infants <= 2000 grams: a randomized, controlled trial. Pediatrics 1997;100:682-8.

Cheah 2000 {published data only}

Cheah FC, Boo NY. Risk factors associated with neonatal hypothermia during cleaning of newborn infants in labour rooms. Journal of Tropical Pediatrics 2000;46:46-50.

Christensson 1992 {published data only}

Christensson K, Siles C, Moreno L, Belaustequi A, De La Fuente P, Lagercrantz H et al. Temperature, metabolic adaptation and crying in healthy full-term newborns cared for skin-to-skin or in a cot. Acta Paediatrica 1992;81:488-93.

Christensson 1996 {published data only}

Christensson K. Fathers can effectively achieve heat conservation in healthy newborn infants. Acta Paediatrica 1996;85:1354-60.

Christensson 1998 {published data only}

Christensson K, Bhat GJ, Amadi BC, Eriksson B, Hojer B. Randomised study of skin-to-skin versus incubator care for rewarming low-risk hypothermic neonates. Lancet 1998;352:1115.

Chwo 1999 {published data only}

Chwo MJ. Early kangaroo care for 34-36 week preterm infants: effects on temperature, weight, behavior, and acuity [dissertation]. Clevland(OH): Case Western Reserve University, 1999.

Chwo 2002 {published data only}

Chwo MJ, Anderson GC, Good M, Dowling DA, Siau SH, Cho DM. A randomized controlled trial of early kangaroo care for preterm infants: effects on temperature, weight, behaviour and acuity. Journal of Nursing Research 2002;10:129-42.

Coles 1979 {published data only}

Coles EC, Valman HB. Hats for the newborn infant. British Medical Journal 1979;2:734-5.

Dahm 1972 {published data only}

Dahm LS, James LS. Newborn temperature and calculated heat loss in the delivery room. Pediatrics 1972;49:504-13.

Daniel 2004 {published data only}

Daniel LM. Prevention of neonatal hypothermia. In: Proceedings of the 13th congress of the Federation-of-Asia-and-Oceania-Perinatal-Societies (FAOPS 2004) APR 14-18, 2004 (Kuala Lumpur, Malaysia). 2004.

Darmstadt 2007 {published data only}

Dramstadt GL, Kumar V, Yadav R, Singh V, Singh P, Mohanty S, et al. Introduction of community-based skin-to-skin care in rural Uttar Pradesh, India. Journal of Perinatology 2006;26:597-604.

Day 1964 {published data only}

Day LD, Caliguiri L, Kamenski C, Ehrlich F. Body temperature and survival of premature infants. Pediatrics 1964;34:171-81.

Dodd 2003 {published data only}

Dodd VL. Effect of kangaroo care in preterm infants [dissertation]. Storrs (CT): The University of Connecticut, 2003.

Erlandsson 2007 {published data only}

Erlandsson K, Dsilna A, Fagerberg I, Christensson K. Skin-to-skin care with the father after cesarean birth and its effect on newborn crying and prefeeding behavior. Birth 2007;34:105-14.

Fallis 2006 {published data only}

Fallis WM, Hamelin K, Symonds J, Wang X. Maternal and newborn outcomes related to maternal warming during cesarean delivery. Journal of Obstetric, Gynecologic and Neonatal Nursing 2006;35:324-31.

Fardig 1980 {published data only}

Fardig JA. A comparison of skin-to-skin contact and radiant heaters in promoting neonatal thermoregulation. Journal of Nurse-Midwifery 1980;25:19-28.

Ferber 2004 {published data only}

Ferber SG, Makhoul IR. The effect of skin-to-skin contact (kangaroo care) shortly after birth on the neurobehavioral responses of the term newborn: a randomized, controlled trial. Pediatrics 2004;113:858-65.

Gray 2004 {published data only}

Gray PH, Paterson S, Finch G, Hayes M. Cot-nursing using a heated, water-filled mattress and incubator care: a randomized clinical trial. Acta Paediatrica 2004;93:350-5.

Green-Abate 1994 {published data only}

Green-Abate C, Tafari N, Rao MR, Yu K, Clemens JD. Comparison of heated water-filled mattress and space-heated room with infant incubator in providing warmth to low birthweight newborns. International Journal of Epidemiology 1994;23:1226-33.

Greer 1988 {published data only}

Greer PS. Head coverings for newborns under radiant warmers. Journal of Obstetric, Gynecological and Neonatal Nursing 1988;17:265-71.

Grover 1994 {published data only}

Grover G, Berkowitz CD, Lewis RJ, Thompson M, Berry L, Seidel J. The effects of bundling on infant temperature. Pediatrics 1994;94:669-73.

Gulezian 1980 {published data only}

Gulezian GZ. Effect of skin-to-skin contact on transitional newborns infants' temperature [dissertation]. Chicago (IL): University of Illinois at the Medical Center, 1980.

Harrison 2004 {published data only}

Harrison M. Kangaroo mother care:an innovative way of care for infants [dissertation]. Hattiesburg (MS): University of Southern Mississippi, 2004.

Hellin Martinez 2000 {published data only}

Heillin Martinez MJ, Lopez Terol E, Perez Lopez M, Vidagany Escrig I. Maintain the temperature of a healthy newborn infant. Revista Rol de Enfermeria 2000;23:63-5.

Hobbs 1975 {published data only}

Hobbs JF, MacKuanying N, Eidelman I, Schneider KM. A new transparent insulating infant gown to maintain thermal stability. Pediatric Research 1975;9:366 [Abstract 658].

Holzman 1985 {published data only}

Holzman IR. A method to maintain infant temperature. American Journal of Diseases of Children 1985;139:390-2.

Horn 2002 {published data only}

Horn EP, Schroeder F, Gottschalk A, Sessler DI, Hiltmeyer N, Standl T, et al. Active warming during cesarean delivery. Anesthesia and Analgesia 2002;94:409-14.

Huang 2002 {published data only}

Haung L, Chwo M, Chu D, Chang Y. Effects of very early kangaroo care on infants' extrauterine adaptation. Journal of Nursing (China) 2002;49:37-51.

Huang 2006 {published data only}

Huang YY, Huang CY, Lin SM, Wu SC. Effect of very early kangaroo care on extrauterine temperature adaptation in newborn infants with hypothermia problems. Hu Li Tsa Chih - Journal of Nursing 2006;53:41-8.

Johanson 1992 {published data only}

Johanson RB, Spencer SA, Rolfe P, Jones P, Malla DS. Effect of post-delivery care on neonatal body temperature. Acta Paediatrica 1992;81:859-63.

Kadam 2005 {published data only}

Kadam S, Binoy S, Kanbur W, Mondkar JA, Fernandez A. Feasibility of kangaroo mother care in Mumbai. The Indian Journal of Pediatrics 2005;72:35-8.

Kaushal 2005 {published data only}

Kaushal M, Agarwal R, Aggarwal R, Singal A, Upadhyay M, Sirnivas V, at al. Cling wrap, an innovative intervention for temperature maintenance and reduction of insensible water loss in very low-birthweight babies nursed under radiant warmers: a randomized, controlled trial. Annals of Tropical Paediatrics 2005;25:111-8.

Legault 1993 {published data only}

Legault M, Goulet C. Etude comparative de deux methodes de sortie du premature: methode kangourou versus methode traditionnelle [Comparative study of two methods of holding premature infants: the kangaroo method versus traditional method]. Canadian Journal of Nursing Research 1993;25:67-80.

Ludington-Hoe 1994 {published data only}

Ludington-Hoe S, Thompson C, Swinth J, Hadeed AJ, Anderson GC. Kangaroo care: research results and practice implications and guidelines. Neonatal Network 1994;13:19-27.

Ludington-Hoe 2000 {published data only}

Ludington-Hoe SM, Nguyen N, Swinth JY, Satyshur RD. Kangaroo care compared to incubators in maintaining body warmth in preterm infants. Biological Research for Nursing 2000;2:60-73.

Ludington-Hoe 2004 {published data only}

Ludington-Hoe SM, Anderson GC, Swinth JY, Thompson C, Hadeed AJ. Randomized controlled trial of kangaroo care: cardiorespiratory and thermal effects on healthy preterm infants. Neonatal Network 2004;23:39-48.

Marks 1985 {published data only}

Marks KH, Devenyi AG, Bello ME, Nardis EE, Seaton JF, Ultman JS. Thermal head wrap for infants. Journal of Pediatrics 1985;107:956-9.

Mazurek 1999 {published data only}

Mazurek T, Mikiel-Kostyra K, Mazur J, Wieczorek P, Radwanska B, Pachuta-Weigier L. Wplyw postepowania z noworodkiem bezpoSrednio po porodzie na cechy jego adaptacji do Srodowiska [Influence of immediate newborn care on infant adaptation to the environment]. Medycyna Wieku Rozwojowego 1999;3:215-24.

Medves 2004 {published data only}

Medves JM, O'Brien B. Effect of bather and location of first bath on maintaining thermal stability in newborns. Journal of Obstetric, Gynecologic and Neonatal Nursing 2004;33:175-82.

Meyer 2001 {published data only}

Meyer MP, Payton MJ, Salmon A, Hutchinson C, de Klerk A. A clinical comparison of radiant warmer and incubator care for preterm infants from birth to 1800 grams. Pediatrics 2001;108:395-401.

Meyer 2006 {published data only}

Meyer MP, Bold GT. Admission temperatures following radiant warmer or incubator transport for preterm infants < 28 weeks: a randomised study. Archives of Disease in Childhood Fetal and Neonatal Edition 2006;92:F295-7.

Miles 2006 {published data only}

Miles R, Cowan F, Glover V, Stevenson J, Modi N. A controlled trial of skin-to-skin contact in extremely preterm infants. Early Human Development 2006;82:447-55.

Monterosso 1999 {published data only}

Monterosso L, Percival P, Cole J, Evans SF. Effect of nappy liners on temperature stability in very preterm infants. Journal of Paediatrics and Child Health 1999;35:363-6.

Moore 2007 {published data only}

Moore ER, Anderson GC. Randomized controlled trial of very early mother-infant skin-to-skin contact and breastfeeding status. Journal of Midwifery & Women's Health 2007;52:116-25.

Nopper 1996 {published data only}

Nopper AJ, Horri KA, Sookdeo-Drost S, Wang TH, Mancini AJ, Lane AT. Topical ointment therapy benefits premature infants. Journal of Pediatrics 1996;128:660-9.

Nuntnarumit 2004 {published data only}

Nuntnarumit P, Deesomchok A. Efficacy of polyethylene occlusive skin wrapping with plastic bag in preventing hypothermia in infants less than 32 weeks' gestational age at delivery. In: Marathon Multimedia LLC [www.pas.meeting.org/], editor(s). 2004 Pediatric Academic Societies' Annual Meeting. May 1-4, 2004, San Francisco, (CA). Pediatric Academic Societies, 2004.

Omene 1978 {published data only}

Omene JA, Diejomaoh FM, Faal M, Diakparomre MA, Obiaya M. Heat loss in Nigerian newborn infants in the delivery room. International Journal of Gynaecology and Obstetrics 1978-79;16:300-2.

Pattinson 2005 {published data only}

Pattinson RC, Arsalo I, Bergh AM, Malan AF, Patrick M, Phillips N. Implementation of kangaroo mother care: a randomized trial of two outreach strategies. Acta Paediatrica 2005;94:924-7.

Punthmatharith 2001 {published data only}

Punthmatharith B. Randomized controlled trial of early kangaroo (skin-to-skin) care: effects on maternal feelings, maternal-infant interaction and breastfeeding success in Thailand [dissertation]. Clevland (OH): Case Western Reserve University, 2001.

Raman 1992 {published data only}

Raman S, Shahla A. Temperature drop in normal term newborn infants born at the University Hospital, Kuala Lumpar. Australian and New Zealand Journal of Obstetrics and Gynaecology 1992;32:117-9.

Ramanathan 2001 {published data only}

Ramanathan K. Kangaroo mother care in very low birth weight infants. Indian Journal of Pediatrics 2001;68:1019-23.

Roberts 2000 {published data only}

Roberts KL, Paynter C, McEwan B. A comparison of kangaroo mother care and conventional cuddling care. Neonatal Network 2000;19:31-5.

Rojas 2001 {published data only}

Rojas MA, Kaplan M, Mayes L, Quevedo ME, Foster LB, Sherwonit E, et al. Traditional holding (TH) and skin-to-skin care (SSC) for newborn infants <= 1500 grams. A randomized controlled trial. Pediatric Research 2001;49:360A.

Ruiz 1998 {published data only}

Ruiz JG. Kangaroo mother versus 'traditional' care for newborn infants <= 2000 grams: a randomised control trial. Journal of Clinical Epidemiology 1998;51 Suppl:125.

Sankaranarayanan2005 {published data only}

Sankaranarayanan K, Mondkar JA, Chauhan MM, Mascarenhas BM, Mainkar AR, Salvi RY. Oil massage in neonates: an open randomized controlled study of coconut versus mineral oil. Indian Pediatrics 2005;42:877-84.

Sarman 1989 {published data only}

Sarman I, Tunell R. Providing warmth for preterm babies by a heated, water filled mattress. Archives of Disease in Childhood Fetal and Neonatal Edition 1989;64:29-33.

Sarman 1992 {published data only}

Sarman I. Thermal responses and heart rates of low-birth-weight premature babies during daily care on a heated, water-filled mattress. Acta Paediatrica 1992;81:15-20.

Short 1998 {published data only}

Short MA. A comparison of temperature in VLBW infants swaddled versus unswaddled in a double- walled incubator in skin control mode. Neonatal Network 1998;17:25-31.

Sloan 1994 {published data only}

Sloan NL, Camacho WL, Rojas EP, Stern C, and Maternidad Isidro Ayora Study Team. Kangaroo mother method: randomised controlled trial of an alternative method of care for stabilised low-birthweight infants. The Lancet 1994;344:782-5.

Syfrett 1993 {published data only}

Syfrett BE. Very early and virtually continuous kangaroo care for 34 to 36 week gestation preterm infants [dissertation]. Tallahassee (FL): University of Florida, 1993.

Tsogt 2005 {published data only}

Tsogt B, Maniseki-Holland S, Pollock J, Blair P, Fleming P. The development of thermoregulation in a harsh environment: a prospective controlled study of the effects of swaddling on infants' thermal balance in a Mongolian winter. In: 2005 The Neonatal Societies Meeting Bristol, 30th June - 1st July 2005. 2005.

Vaidya 2005 {published data only}

Vaidya K, Sharma A, Dhungel S. Effect of early mother-baby close contact over the duration of exclusive breastfeeding. Nepal Medical College Journal 2005;7:138-40.

van den Bosch 1990 {published data only}

van den Bosch CA, Bullough CH. Effect of early suckling on term neonates' core body temperature. Annals of Tropical Paediatrics 1990;10:347-53.

van den Bosch 1996 {published data only}

van den Bosch CA, Nhlane C, Kazembe P. Trial of polythene tobacco-wrap in prevention of hypothermia in neonates less than 1500 grams. Tropical Doctor 1996;26:26-8.

Worku 2005 {published data only}

Worku B, Kassie A. Kangaroo mother care: a randomized controlled trial on effectiveness of early kangaroo mother care for the low birthweight infants in Addis Ababa, Ethiopia. Journal of Tropical Pediatrics 2005;51:93-7.

References to ongoing studies

Vohra 2004 {unpublished data only}

Vohra S. Multi centered randomised controlled trial of heat loss prevention (HeLP) in delivery room. Personal communication 08 July 2004 and September 2007.

* indicates the primary reference for the study

Other references

Additional references

Adamsons 1965

Adamsons K, Gandy GM, James LS. The influence of thermal factors upon oxygen consumption of the newborn human infant. Journal of Pediatrics 1965;66:495-508.

Adamsons 1965a

Adamsons K, Towell M E. Thermal homeostasis in the fetus and newborn. Anesthesiology 1965;26:531-48.

Bailey 2000

Bailey J, Rose P. Temperature measurement in the preterm infant: A literature review. Journal of Neonatal Nursing 2000;6:28-32.

Baumgart 1981

Baumgart S, Engle WD, Fox WW, Polin RA. Effect of heat shielding on convective and evaporative heat losses and on radiant heat transfer in the premature infant. Journal of Pediatrics 1981;99:948-56.

Bell 1978

Bell MJ, Ternberg JL, Feigin RD, Keating JP, Marshall R, Barton L et al. Neonatal necrotizing enterocolitis. Therapeutic decisions based on clinical staging. Annals of Surgery 1978;187:1-7.

Bell 1980

Bell EF, Weinstein MR, Oh W. Heat balance in premature infants: comparative effects of convectively heated incubator and radiant warmer, with and without plastic heat shield. Journal of Pediatrics 1980;96:460-5.

Bickmann 1992

Buczkowski-Bickmann MK. Thermoregulation in the neonate and the consequences of hypothermia. CRNA: The Clinical Forum for Nurse Anesthetists 1992;3:77-82.

Bloom 1994

Bloom RS, Cropley C, the AHA/AAP Neonatal Resuscitation Steering Committee, editors. In: Textbook of neonatal resuscitation. 3rd edition. Dallas (TX): American Heart Association, 1994:2-9.

Borse 1997

Borse N, Deodhar J, Pandit AN. Effects of thermal environment on neonatal thermoregulation. Indian Pediatrics 1997;34:718-20.

Britton 1980

Britton GR. Early mother-infant contact and infant temperature stabilization. JOGN Nursing 1980;9:84-6.

Bruck 1961

Bruck K. Temperature regulation in the newborn infant. Biology of the Neonate 1961;3:65-119.

Brun 1997

Brun C, Stokvad P, Alsbjorn BF. Brandsar efter genoplivning af en nyfodt pige [Burn wounds after resuscitation of a newborn girl]. Ugestrift for Laeger 1997;159:6531-2.

Capobianco 1980

Capobianco JA. Keeping the newborn warm: how to safeguard the infant against life-threatening heat loss. Nursing 1980;10:64-7.

Chadd 1972

Chadd MA, Gray OP. Hypothermia and coagulation defects in the newborn. Archives of Disease in Childhood 1972;47:819-21.

Christensson 1988

Christensson K, Ransjo-Arvidson AB, Kakoma C, Lungu F, Darkwah G, Chikamata D et al. Midwifery care routines and prevention of heat loss in the newborn: a study in Zambia. Journal of Tropical Pediatrics 1988;34:208-12.

Clarke 2002

Clarke M, Oxman AD, editors. Cochrane Reviewers' Handbook 4.1.5 [updated April 2002]. In: Cochrane Database of Systematic Reviews, Issue 2002, 2. Oxford: Update Software.

Costeloe 2000

Costeloe K, Hennessy E, Gibson AT, Marlow N, Wilkinson AR. The EPICure study: outcomes to discharge from hospital for infants born at the threshold of viability. Pediatrics 2000;106:659-71.

Davis 1980

Davis V. The structure and function of brown adipose tissue in the neonate. JOGN Nursing 1980;9:368-72.

Du 1969

Du JN, Oliver TK Jr. The baby in the delivery room. A suitable microenvironment. Journal of the American Medical Association 1969;207:1502-4.

Elliott 1957

Elliott RI, Mann TP. Neonatal cold injury due to accidental exposure to cold. Lancet 1957;272:229-34.

Gandy 1964

Gandy GM, Adamsons K, Cunningham N, Silverman WA, James LS. Thermal environment and acid-base homeostasis in human infants during the first few hours of life. Journal of Clinical Investigation 1964;43:751-8.

Glass 1968

Glass L, Silverman WA, Sinclair JC. Effects of the thermal environment on cold resistance and growth of small infants after the first week of life. Pediatrics 1968;41:1033-46.

Hammarlund 1979

Hammarlund K, Sedin G. Transepidermal water loss in newborn infants. III. Relation to gestational age. Acta Paediatrica Scandinavica 1979;68:795-801.

Hammarlund 1980

Hammarlund K, Nilsson GE, Oberg PA, Sedin G. Transepidermal water loss in newborn infants. V. Evaporation from the skin and heat exchange during the first hours of life. Acta Paediatrica Scandinavica 1980;69:385-92.

Harned 1970

Harned HS Jr, Herrington RT, Ferreiro JI. The effects of immersion and temperature on respiration in newborn lambs. Pediatrics 1970;45:598-605.

Hey 1970

Hey EN, Katz G. The optimal thermal environment for naked babies. Archives of Disease in Childhood 1970;45:328-34.

Hey 1975

Hey E. Thermal neutrality. British Medical Bulletin 1975;31:69-74.

ILCOR 2006

The International Liaison Committee on Resuscitation. The International Liaison Committee on Resuscitation (ILCOR) consensus on science with treatment recommendations for pediatric and neonatal patients: neonatal resuscitation. Pediatrics 2006;117:e978-88.

Knobel 2005a

Knobel RB, Vohra S, Lehmann CU. Heat loss prevention in the delivery room for preterm infants: a national survey of newborn intensive care units. Journal of Perinatology 2005;25:514-8.

Lang 2004

Lang N, Bromiker R, Arad I. The effect of wool versus cotton head covering and length of stay with mother following delivery on infant temperature. International Journal of Nursing Studies 2004;41:843-6.

Laptook 2007

Laptook A, Salhab W, Bhaskar B and the Neonatal Research Nerwork. Admission temperature of low birth weight infants: predictors and associated morbidities. Pediatrics 2007;119:643-9.

LeBlanc 1991

LeBlanc MH. Thermoregulation: incubators, radiant warmers, artificial skins and body hoods. Clinics in Perinatology 1991;18:403-22.

Lee 2000

Lee SK, McMillan DD, Ohlsson A, Pendray M, Synnes A, Whyte R et al and the Canadian NICU Network. Variations in practice and outcomes in the Canadian NICU Network 1996-1997. Pediatrics 2000;106:1070-9.

Lenclen 2002

Lenclen R, Mazraani M, Jugie M, Couderc S, Hoenn C, Carbajal R et al. Utilisation d'un sac en polyethylene: un moyen d'ameliorer l'environnement thermique du premature en salle de naissance [Use of a polyethylene bag: a way to improve the thermal environment of the premature newborn at the delivery room]. Archives de Pediatrie 2002;9:238-44.

Lyon 2006

Lyon A. Applied physiology: temperature control in the newborn infant. Current Paediatrics 2006;16:386-92.

Nayeri 2006

Nayeri F, Nili F. Hypothermia at birth and its associated complications in newborns: a follow up study. Iranian Journal of Public Health 2006;35:48-52.

Newton 2003

Newton T, Watkinson M. Preventing hypothermia at birth in preterm babies: at a cost of overheating some? Archives of Disease in Childhood Fetal and Neonatal Edition 2003;88:F256.

Niermeyer 2000

Niermeyer S, Kattwinkel J, Van Reempts P, Nadkarni V, Phillips B, Zideman D et al. International Guidelines for Neonatal Resuscitation: an excerpt from the Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: International Consensus on Science. Contributors and Reviewers for the Neonatal Resuscitation Guidelines. Pediatrics 2000;106:E29.

Oliver 1965

Oliver TK Jr. Temperature regulation and heat production in the newborn. Pediatric Clinics of North America 1965;12:765-79.

Papile 1978

Papile LA, Burstein J, Burstein R, Koffler H. Incidence and evolution of subependymal and intraventricular hemorrhage: a study of infants with birth weights less than 1500 gm. Journal of Pediatrics 1978;92:529-34.

Pomerance 1974

Pomerance JJ, Madore C. Effect of temperature on survival of infants with RDS. Pediatric Research 1974;8:449 [Abstract].

Rutter 2000

Rutter N. Clinical consequences of an immature barrier. Seminars in Neonatology 2000;5:281-7.

Scopes 1963

Scopes JW, Tizard JP. The effect of intravenous noradrenaline on the oxygen consumption of new-born mammals. Journal of Physiology 1963;165:305-26.

Shennan 1988

Shennan AT, Dunn MS, Ohlsson A, Lennox K, Hoskins EM. Abnormal pulmonary outcomes in preterm infants: prediction from oxygen requirement in the neonatal period. Pediatrics 1988;82:527-32.

Silverman 1958

Silverman WA, Fertig JW, Berger AP. The influence of the thermal environment upon the survival of newly born premature infants. Pediatrics 1958;22:876-86.

Smales 1978

Smales ORC, Kime R. Thermoregulation in babies immediately after birth. Archives of Disease in Childhood 1978;53:58-61.

Smith 2004

Smith LS. Temperature monitoring in newborns: A comparison of thermometry and measurement sites. Journal of Neonatal Nursing 2004;10:157-65.

Stapleton 1987

Stapleton FB, Jones DP, Green RS. Acute renal failure in neonates: incidence, etiology and outcome. Pediatric Nephrology 1987;1:314-20.

Stephenson 1970

Stephenson JM, Du JN, Oliver TK Jr. The effect of cooling on blood gas tensions in newborn infants. Journal of Pediatrics 1970;76:848-52.

Stern 1970

Stern L. The newborn infant and his thermal environment. Current Problems in Pediatrics 1970;1:1-29.

Tafari 1973

Tafari N, Olsson E. Neonatal cold injury in the tropics. Ethiopian Medical Journal 1973;11:57-65.

Thomas 1994

Thomas K. Thermoregulation in neonates. Neonatal Network 1994;13:15-25.

UNICEF 2002

The United Nations Children's Fund (UNICEF). The State of the World's Children Report 2003 - Child Participation. New York: UNICEF, 2002.

Watkinson 2006

Watkinson M. Temperature control of premature infants in the delivery room. Clinics in Perinatology 2006;33:43-53.

WHO 1997

Department of Reproductive Health and Research (RHR), World Health Organisation. Thermal protection of the newborn: a practical guide (WHO/RHT/MSM/97.2). Geneva: World Health Organisation, 1997.

Other published versions of this review

McCall 2005

McCall EM, Alderdice FA, Halliday HL, Jenkins JG, Vohra S. Interventions to prevent hypothermia at birth in preterm and/or low birthweight babies. In: Cochrane Database of Systematic Reviews, Issue 1, 2005.

Comparisons and data

Comparison or outcome Studies Participants Statistical method Effect size
01 Plastic wrap versus routine care
01 Core body temperature (degrees C) on admission to NICU or up to 2 hours after birth 4 200 WMD (fixed), 95% CI 0.60 [0.37, 0.83]
02 Core body temperature (degrees C) 1 hour after the initial admission temperature to the NICU was taken 1 53 WMD (fixed), 95% CI 0.20 [-0.24, 0.64]
03 Hypothermia on admission to NICU: core body temperature < 36.5 C or skin temperature < 36 C 1 88 RR (fixed), 95% CI 0.63 [0.42, 0.93]
04 Death within hospital stay 4 202 RR (fixed), 95% CI 0.63 [0.32, 1.22]
05 Major brain injury 1 88 RR (fixed), 95% CI 1.15 [0.36, 3.68]
06 Duration of oxygen therapy (days) 1 88 WMD (fixed), 95% CI -6.51 [-23.30, 10.28]
07 Duration of hospitalisation (days) 1 88 WMD (fixed), 95% CI -5.49 [-19.93, 8.95]
08 Apgar at 1 minute     Other data No numeric data
09 Apgar at 5 minutes     Other data No numeric data
10 First blood gas pH 1 53 WMD (fixed), 95% CI -0.04 [-0.10, 0.02]
11 Bicarbonate (mmol/L) 1 53 WMD (fixed), 95% CI 1.00 [-0.85, 2.85]
12 First serum glucose concentration (mmol/L) 1 53 WMD (fixed), 95% CI -0.30 [-1.11, 0.51]
13 Hyperthermia on admission to NICU: core body temperature > 37.5 C 1 53 RR (fixed), 95% CI 4.82 [0.24, 95.88]
02 Stockinet cap versus routine care
01 Core body temperature (degrees C) on admission to NICU or up to 2 hours after birth 2 40 WMD (fixed), 95% CI 0.15 [-0.18, 0.48]
02 Hypothermia on admission to NICU: core body temperature < 36.5 C or skin temperature < 36 C 1 40 RR (fixed), 95% CI 0.90 [0.48, 1.71]
03 Skin-to-skin care versus routine care
01 Hypothermia: skin temperature < 35.5 C for 2 consecutive recordings 1 31 RR (fixed), 95% CI 0.09 [0.01, 0.64]
02 Hypoglycaemia: blood glucose level < 2.6 mmol/L 1 31 RR (fixed), 95% CI 0.24 [0.03, 2.06]
04 Transwarmer mattress versus routine care
01 Core body temperature (degrees C) on admission to NICU or up to 2 hours after birth 1 24 WMD (fixed), 95% CI 1.60 [0.83, 2.37]
02 Hypothermia on admission to NICU: core body temperature < 36.5 C or skin temperature < 36 C 1 24 RR (fixed), 95% CI 0.30 [0.11, 0.83]

 

01 Plastic wrap versus routine care

01.01 Core body temperature (degrees C) on admission to NICU or up to 2 hours after birth

01.01.01 < 28 completed weeks' gestational age

01.01.02 28 to 31 completed weeks' gestational age

01.02 Core body temperature (degrees C) 1 hour after the initial admission temperature to the NICU was taken

01.02.01 < 28 completed weeks' gestational age

01.03 Hypothermia on admission to NICU: core body temperature < 36.5 C or skin temperature < 36 C

01.03.01 < 28 completed weeks' gestational age

01.04 Death within hospital stay

01.04.01 < 28 completed weeks' gestational age

01.04.02 28 to 31 completed weeks' gestational age

01.05 Major brain injury

01.05.01 < 28 completed weeks' gestational age

01.06 Duration of oxygen therapy (days)

01.06.01 < 28 completed weeks' gestational age

01.07 Duration of hospitalisation (days)

01.07.01 < 28 completed weeks' gestational age

01.08 Apgar at 1 minute

01.08.01 < 28 weeks' gestational age

01.09 Apgar at 5 minutes

01.09.01 < 28 weeks' gestational age

01.10 First blood gas pH

01.10.01 < 28 weeks' gestational age

01.11 Bicarbonate (mmol/L)

01.11.01 < 28 completed weeks' gestational age

01.12 First serum glucose concentration (mmol/L)

01.12.01 < 28 completed weeks' gestational age

01.13 Hyperthermia on admission to NICU: core body temperature > 37.5 C

01.13.01 < 28 completed weeks' gestational age

02 Stockinet cap versus routine care

02.01 Core body temperature (degrees C) on admission to NICU or up to 2 hours after birth

02.01.01 < 2000 g birthweight

02.01.02 > or = 2000 g birthweight

02.02 Hypothermia on admission to NICU: core body temperature < 36.5 C or skin temperature < 36 C

02.02.01 32 to 36 completed weeks' gestational age

03 Skin-to-skin care versus routine care

03.01 Hypothermia: skin temperature < 35.5 C for 2 consecutive recordings

03.01.01 1200 g to 2199 g birthweight

03.02 Hypoglycaemia: blood glucose level < 2.6 mmol/L

03.02.01 1200 g to 2199 g birthweight

04 Transwarmer mattress versus routine care

04.01 Core body temperature (degrees C) on admission to NICU or up to 2 hours after birth

04.01.01 < or = 1500 g birthweight

04.02 Hypothermia on admission to NICU: core body temperature < 36.5 C or skin temperature < 36 C

04.02.01 < or = 1500 g birthweight

Contact details for co-reviewers

Dr Fiona Alderdice
Director
Nursing and Midwifery Research Unit
Queen's University Belfast
School of Nursing and Midwifery
10 Malone Road
Belfast
Northern Ireland IRELAND
BT9 5BN
Telephone 1: +44 28 90976566
E-mail: f.a.alderdice@qub.ac.uk

Prof Henry L Halliday
Perinatal Room
Royal-Jubilee Maternity Service
Royal Maternity Hospital
Grosvenor Road
Belfast
Northern Ireland UK
BT12 6BA
Telephone 1: + 44 02890 894687
Facsimile: 02890 236203
E-mail: h.halliday@qub.ac.uk

Dr John G Jenkins
Consultant Paediatrician
Antrim Area Hospital
45 Bush Road
Antrim
Northern Ireland UK
BT41 2RL
Telephone 1: + 44 02894 424163
Telephone 2: + 44 02894 24156
Facsimile: +44 02890 236455
E-mail: j.jenkins@qub.ac.uk

Dr Sunita Vohra, MD, FRCPC, MSc
Associate Professor
Department of Pediatrics
University of Alberta
Aberhart Centre One, Room 8213
11402 University Avenue NW
Edmonton
Alberta CANADA
T6G 2J3
Telephone 1: 780 407 2106
Facsimile: 780 407 7136
E-mail: svohra@ualberta.ca
This review is published as a Cochrane review in The Cochrane Library, Issue 1, 2008 (see http://www.thecochranelibrary.com for information). Cochrane reviews are regularly updated as new evidence emerges and in response to feedback. The Cochrane Library should be consulted for the most recent version of the review.