After a successful calibration and insertion on the patient, and approximately 47 hours of use, the trendcare monitor displayed a "verify connection" message and stopped displaying measurements. When the sensor was disconnected from the patient data module, a large amount of blood was found inside the connector. The sensor was returned to diametrics medical limited for investigation.

No fault was found with the device. The investigation revealed that the sensor had most probably been used with the rear clamp sligthly undone, or that there had been a delay in securing the clamp following sensor insertion. Testing confirmed that the passage of fluid along the length of the sensor was only possible when the sensor rear clamp was not fully tightened. Once the rear clamp was tightened securely, no fluid path was present. The paratrend 7f1 instructions for use do indicate that the rear clamp should be loosend half a turn to permit withdrawal of the sensor from the tonometer. However, once the sensor had been attached to the aterial access catheter, the line flushed with heparinised solution and the sensor advanced until it has reached the correct insertion length, it should then be locked in place and the rear clamp tightened securely (see attached extracts from paratrend 7fi instructions for use - page 5 of 5). Once this procedure had been completed and pt monitoring commenced, no leakage of blood through the sensor is possible.