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| Tex Heart Inst J. 2008; 35(3): 273–278. | PMCID: PMC2565551 |
Copyright © 2008 by the Texas Heart Institute, Houston Hurricane Katrina Impact on Cardiac Surgery Case Volume and Outcomes Faisal G. Bakaeen, MD, Joseph Huh, MD, Danny Chu, MD, Joseph S. Coselli, MD, Scott A. LeMaire, MD, Kenneth L. Mattox, MD, Matthew J. Wall, Jr., MD, Xing Li Wang, MD, PhD, Salwa A. Shenaq, MD, Prasad V. Atluri, MD, Samir S. Awad, MD, and David H. Berger, MD Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery (Drs. Bakaeen, Chu, Coselli, Huh, LeMaire, Mattox, Wall, and Wang), Baylor College of Medicine; Michael E. DeBakey Veterans Affairs Medical Center (Drs. Atluri, Awad, Bakaeen, Berger, Chu, Huh, and Shenaq); Texas Heart Institute at St. Luke's Episcopal Hospital (Drs. Coselli, LeMaire, and Wang); and Ben Taub General Hospital (Drs. Mattox and Wall); Houston, Texas 77030
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Abstract Hurricane Katrina produced a surge of patient referrals to our facility for cardiac surgery. We sought to determine the impact of this abrupt volume change on operative outcomes. Using our cardiac surgery database, which is part of the Department of Veterans Affairs' Continuous Improvement in Cardiac Surgery Program, we compared procedural outcomes for all cardiac operations that were performed in the year before the hurricane (Year A, 29 August 2004–28 August 2005) and the year after (Year B, 30 August 2005–29 August 2006). Mortality was examined as unadjusted rates and as risk-adjusted observed-to-expected ratios. We identified 433 cardiac surgery cases: 143 (33%) from Year A and 290 (67%) from Year B. The operative mortality rate was 2.8% during Year A (observed-to-expected ratio, 0.4) and 2.8% during Year B (observed-to-expected ratio, 0.6) (P = 0.9). We identified several factors that enabled our institution to accommodate the increase in surgical volume during the study period. We conclude that, although Hurricane Katrina caused a sudden, dramatic increase in the number of cardiac operations that were performed at our facility, good surgical outcomes were maintained. Key words: Cardiac surgical procedures/standards/statistics & numerical data, data collection, delivery of health care/organization & administration, emergency medical services/organization & administration, health services research, hospitals, veterans/standards, natural disasters, quality assurance, health care, surgery department, hospital/standards, Texas, United States Department of Veterans Affairs |
Hurricane Katrina, which struck the U.S. Gulf Coast on 29 August 2005, was the most destructive and costly natural disaster in U.S. history. 1 In the aftermath of the storm, hundreds of thousands of affected residents were displaced. Houston, the nearest large city to the stricken areas, was a logical destination for many hurricane victims. The leaders of Houston, backed by strong public support, participated in the relief effort. The effects of the hurricane were far-reaching, affecting all aspects of life and interrupting public services, including health care. The Houston medical community, led by Baylor College of Medicine, the Harris County Hospital District, and the Michael E. DeBakey Veterans Affairs Medical Center (MEDVAMC), organized a rapid and effective medical relief effort. 2 This was necessary, because it was ordered that the New Orleans Veterans Affairs Medical Center (NOVAMC) be closed shortly after the hurricane because of flooding, water damage, and power outages. Among other specialized services at that facility, the cardiothoracic surgery service was disrupted. Veterans in need of open-heart surgery who would normally have been treated at the NOVAMC were thereafter cared for at the MEDVAMC. The MEDVAMC—the primary healthcare provider for more than 137,000 veterans in southeastern Texas—is part of Veterans Integrated Service Network 16, which encompasses a geographic area from Houston to Pensacola in the south and from Little Rock to Oklahoma City in the north. The surge in cardiac surgery referrals to the MEDVAMC was therefore precipitated by geographic and administrative factors. Necessary measures for absorbing the abrupt and sustained increase in cardiac-surgery volume were put into place. From the beginning, the emphasis was on maintaining the delivery of the highest quality of care to our veterans. In this study, the aim was to evaluate and compare cardiac surgery outcomes in the periods before and after Hurricane Katrina and to examine the effectiveness of various approaches that had been adopted to meet this challenge. |
Patients and Methods Study Population The Veterans Affairs (VA) Continuous Improvement in Cardiac Surgery Program (CICSP) prospectively collects risk and outcome data on all patients who undergo cardiac surgery at 44 VA cardiac surgery centers. 3-6 After obtaining institutional review board approval, we used the Houston component of the CICSP to locate and review the records of all open cardiac surgical procedures that were performed on veterans at the MEDVAMC during the year before Hurricane Katrina (Year A, 29 August 2004–28 August 2005) and the year after (Year B, 30 August 2005–29 August 2006). Outcome Variables Two outcome variables were evaluated separately in this study: 30-day operative death, and perioperative morbidity. In CICSP, 30-day operative death is defined as the number of deaths that occur during the index hospitalization or within 30 days after surgery, plus any deaths that occur more than 30 days after surgery as a direct result of a perioperative surgical complication. Perioperative morbidity is defined as the presence of any of the following major sequelae, alone or in combination: endocarditis, renal failure necessitating dialysis, mediastinitis, reoperation for bleeding, mechanical ventilation for longer than 48 hours, repeat cardiopulmonary bypass to treat a sequela, stroke, coma for longer than 24 hours, and cardiac arrest that necessitates cardiopulmonary resuscitation during the inpatient perioperative period or within 30 days after surgery. This evaluation of the sequelae uses standard definitions and criteria that have been adopted by the VA Cardiac Surgery Consultants Board. Patient-specific risk factors for death and morbidity are summarized in Table I, and surgical variables are summarized in Table II.  | Table I. Patient Characteristics and Risk Factors for Death and Morbidity |
| Table II. Type and Extent of Surgery |
Statistical Analyses The mean ± SD was computed for continuous variables. After we examined the parametric distributions, we used independent Student t tests to compare the differences in the parametric data that were collected before and after Hurricane Katrina. We used χ 2 analyses to test for differences in categorical data. The ratios of observed-to-expected (O/E) 30-day deaths and 30-day morbidities were calculated separately by use of the CICSP risk model. 3 This model involves stepwise logistic regression analysis in which postoperative morbidity and death are treated as dependent variables, and patients' preoperative factors (including those listed in Table I) are entered as independent variables. Only those factors that remain significant at P < 0.05 are retained and are incorporated into the risk calculation model. In the coronary artery bypass surgery 30-day-death risk model, the retained predictors were patient age, serum creatinine level, use of a preoperative intra-aortic balloon pump, prior myocardial infarction, peripheral vascular disease, cerebral vascular disease, chronic obstructive pulmonary disease, functional status, sex, and pulmonary rales. The predicted probability of death and morbidity was calculated for each patient. The total expected morbidity and death for the year before and the year after the hurricane was then calculated. The derived O/E ratios for morbidity and death for the 2 periods were compared by use of independent Student t tests. A 2-tailed P value < 0.05 was considered statistically significant. All statistical analyses were conducted by use of SPSS v. 14.0 software (SPSS Inc.; Chicago, Ill). Administrative and Organizational Approaches We tracked the steps that were taken at various levels in our institution after Hurricane Katrina that helped accommodate the increase in patient referrals with maintenance of high-quality care. The postal (ZIP) codes of the patients who were included in the study were used to determine the geographic origin of each referral, as is shown in Figure 1 and detailed in Table III. Key administrators and managerial staff were interviewed and relevant records were reviewed in order to document the changes that were made in the approaches to patient transfer, admissions, operating room (OR) scheduling, bed allocation, staffing, and educational endeavors.  | Fig. 1 The locations from which individual patients were referred to our institution are depicted as black dots and are mapped according to their postal (ZIP) codes. A) The number and geographic distribution of referrals in the year before Hurricane Katrina (more ...) |
| Table III. Distances Traveled by Patients |
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Results A total of 433 cardiac operations were performed during the study period. The number of such procedures that were performed in the year after Hurricane Katrina (Year B, n=290) was more than double the number performed in the year before Hurricane Katrina (Year A, n=143). The patient risk profiles were similar in the 2 periods ( Table I) except for the prevalence of hypertension and prior myocardial infarction. With regard to operative procedures and surgical details ( Table II), the type and extent of the procedures that were performed before and after the hurricane were similar. Approximately 75% of the procedures were isolated coronary artery bypass grafting (CABG) operations. There was, however, a statistically significant reduction in cardiopulmonary bypass times in Year B (145 ± 61 min in Year A vs 128 ± 61 min in Year B; P = 0.01). Also, the percentage of emergent cases increased from 2% in Year A to 11% in Year B ( P = 0.005). There were very few differences in morbidity and death ( Table IV) between Year A and Year B. For the entire study, the 30-day operative mortality rate was 2.8%. Overall, the perioperative morbidity rate for the 9 chief sequelae was 16.6%. In the subset of patients who underwent isolated coronary artery bypass surgery (CABG only), the operative morbidity (11.5% in Year A vs 14.4% in Year B) and death (1.9% in Year A vs 2.3% in Year B) were also similar between years. The O/E ratios for operative morbidity and death during the 2 time periods were not statistically significant, which indicated no demonstrable relationship between the time period evaluated and the risk-adjusted outcomes. | TABLE IV. Surgical Outcomes |
We identified several factors that enabled surgical volume to increase during the study period without an adverse effect on operative outcomes: - A dedicated transfer center was created to facilitate patient referrals and transfers, which ensured a smooth flow of patients into and out of our facility.
- Greater flexibility in OR scheduling was granted. The cardiothoracic surgery service was allowed toschedule cases on short notice and with later cut-off times, and OR staff members were concomitantly willing to work longer hours. (Additional ORs could not be routinely allocated to the cardiothoracic service because of the increase in the workloads of other surgical departments.)
- The status of 2 cardiac OR nurses was changed from part-time to full-time, which raised the total number of dedicated cardiac surgery nurses to 5. The addition of 4 new beds expanded the capacity of the surgical intensive care unit (SICU) by 25%. Two full-time SICU nurses were recruited (which increased the SICU nursing staff by 7%), and more nurses worked overtime in order to maintain the SICU's average nurse-to-patient ratio of 1:2. Intensive in-service seminars and training ensured that the nursing staff was capable of handling the additional volume and acuity associated with the treatment of more postoperative cardiac surgery patients. A new surgical step-down (telemetry) unit effectively doubled the capacity of the original 6-bed dedicated cardiothoracic unit and enabled timely transfers of patients from the SICU. The existing step-down nursing-staff-to-patient ratio (1:3) was maintained by doubling staff numbers through new recruitment efforts.
- Baylor College of Medicine's cardiothoracic surgery program maintained the educational and academic milieu for our trainees, who took up part of the extra caseload within the constraints of an 80-hour workweek.
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Discussion Hurricane Katrina, a large-scale natural disaster, disrupted parts of our health network and created an unprecedented scenario in which, overnight, the MEDVAMC assumed the care of most of the veterans in the stricken areas. At the MEDVAMC, the goal was to provide the veterans with high-quality care that was consistent with the mission statement of the Veterans Health Administration. 7This study focused on the response and performance of the cardiac surgery service at the MEDVAMC. The pivotal question was how a sudden increase in cardiac surgery caseload that was not previously planned for would affect the quality of outcomes. We found that the MEDVAMC was able to handle such an increase without any decrement in outcomes. The 1st large, multi-institutional effort to monitor cardiac surgery quality began with the VA in 1971. Starting with unadjusted operative death and volume as its main quality indicators for 44 VA cardiac surgery programs, the Cardiac Surgery Advisory Group, now called the VA Cardiac Surgery Consultants Board, moved in 1987 to logistic regression methods to develop risk models for various open-heart procedures. 3 The quality assurance program adopted by the Board, CICSP, incorporates the cardiac surgery data from all VA heart surgery centers and publishes semiannual risk-adjusted outcome reports. 5-7Our results show that our cardiac surgery case volume more than doubled in the year after Hurricane Katrina. This can be explained by the geographic proximity of Houston to the disaster zone and by the administrative factors that facilitated the shifting of patient care to the MEDVAMC. This is an example of a crisis-management situation in which specialized healthcare delivery was sustained by a system that was able to institute a contingency plan immediately. The MEDVAMC cardiac surgery service increased its productivity in order to offset the hurricane-related disruption of service at other VA facilities without compromising quality of care. For both Year A and Year B, the O/E mortality ratios were better than expected. Operative morbidity was similar in the 2 years. Respiratory sequelae occurred in more than 10% of the patients in each year. More than 30% of the patients had a documented history of chronic obstructive pulmonary disease, and a great many were active smokers until the time of surgery; both factors are associated with adverse postoperative respiratory outcomes. Approximately half of the patients in both years experienced significant heart failure and had New York Heart Association functional class III or IV symptoms. A quarter of the patients presented with documented evidence of cerebrovascular disease, and many patients had peripheral vascular disease or diabetes mellitus. The prevalence and severity of comorbidities in the patient population in both years constituted significant risk factors, which underscores the value of our use of risk-adjusted models to evaluate outcomes in this study. There were more emergent cases in Year B, which reflects a higher index of acuity during that period. It is interesting that, although the proportion of different types of procedures was similar between the 2 years, cardiopulmonary bypass times decreased in Year B, which may reflect a sense of urgency that arose from the increase in surgical caseload and activity. However, this decrease did not translate into a significant decrease in total operative time. The MEDVAMC cardiothoracic surgery service adopted an open-door policy toward all veterans who were referred as patients from the disaster-stricken areas. This included direct admission to the cardiothoracic service for patients who required or potentially required cardiothoracic surgery. Our approach was to verify the diagnosis, complete the preoperative evaluation, and proceed with surgery. Our service took charge of caring for the patients, instead of assuming only a consulting role. This approach produced a dedicated and efficient system that was able to keep up with the surge of cardiac surgery referrals. Busier schedules in Year B did not compromise cardiac surgery protocols that the MEDVAMC already followed. Operating-room efficiency and scheduling were key elements in accommodating the increased caseload. The usual OR allocation schedule was cleared on the night before surgery, which is a process that is known to enable greater flexibility in scheduling and in maximizing the use of OR time. 8 The capacities of the SICU and surgical step-down unit were increased, additional nurses were recruited, and overtime shifts were added to maintain an appropriate nurse-to-patient ratio. Our social workers played an instrumental role in planning discharges from the hospital, which enabled us to accommodate the increased patient volume and to ensure continued bed availability. The social workers arranged efficient transportation and travel for out-of-town patients. This is reflected in the similar mean postoperative lengths of hospital stay in the years before and after the hurricane ( Table IV). The MEDVAMC's leadership took all necessary administrative steps to facilitate the movement of patients into and out of our institution through a dedicated transfer center. Bureaucratic hurdles were bypassed, and the cardiothoracic service was given the support necessary to boost and maintain its clinical productivity. Additional staff recruitment and equipment needs were fulfilled without delay. Baylor College of Medicine contributed from the beginning by providing the academic framework and flexibility to achieve the established goals. 2 The cardiothoracic residents were crucial to the cardiothoracic team's efforts. They worked harder within their permitted hours and helped deliver high-quality perioperative care to the veterans. The cardiothoracic surgery staff at the MEDVAMC closely monitored patient care via resident supervision and a direct, hands-on approach. In conclusion, Hurricane Katrina resulted in a sudden and unexpected increase in the number of cardiac procedures that were performed at our facility. The quality of surgical outcomes was maintained by an effective response at various stages of care delivery. |
Acknowledgments Stephen N. Palmer, PhD, ELS, contributed to the editing of this manuscript. Clara Kistner, RN, provided administrative assistance. The regional maps were obtained from the Continuous Improvement in Cardiac Surgery Program Expansion (CICSP-X) study. The CICSP-X study was initially funded by VA Health Services Research and Development Grant #IHY 99214–1 (Dr. Shroyer, principal investigator), with ongoing support from the Office of Patient Care Services, VA Central Office, Washington, DC. Special acknowledgment is accorded Randy Johnson, Lisa Schade, and Missy Bell as the team members who were responsible for the CICSP-X access-to-care report sections that worked under the leadership of Dr. Gerald McDonald (VA Central Office). |
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