A New Tool for the Neurointensive Care Unit: Simultaneous Measurement of Temperature From a Catheter-Tip Pressure Sensor

Traumatic brain injury is a leading cause of death and permanent disability throughout the world. Over the past 15 years, basic science has made important advances in the understanding of this condition. These advances have not, however, translated into treatment of clinically proven benefit. It has been suggested that individualized care for brain injured patients should include improved monitoring of brain function. For clinical gains to be made, clinicians and researchers require appropriate diagnostic and monitoring tools. In this paper, we describe the novel method of acquiring temperature measurement from a pressure sensor. The method allows concurrent measurements of pressure and temperature. The temperature measurement has a sensitivity of 85.08 mV/°C, across the measurement range 20 °C-45 °C. The time constant of the temperature sensor is 610 ± 55 ms. The mean cross-sensitivity of the temperature signal to changes in pressure is 0.74 m°C/mmHg within the typical physiological pressure range (0-160 mmHg). A method to compensate for this pressure-related error is described. We have evaluated the accuracy of the temperature measurement and the long-term stability of 13 sensors over a period of 28 days. The mean difference between temperature measurements made from the sensors and those made from the reference sensor was <;0.2 °C.