Invasive Pressure Monitoring in Aeromedical Evacuation

The ability to accurately and reliably monitor a critically ill patient's cardiovascular status is essential. The importance of this monitoring becomes even greater during the aeromedical evacuation of a critically ill patient on board a cargo aircraft. There are characteristics of the AE environment that may affect the ability of a pressure monitoring system to faithfully reproduce a pressure waveform; thus increasing the risk of therapeutic mismanagement. No previous research was found, which systematically evaluates factors in the AE environment (specifically altitude and vibration) as they relate to invasive pressure monitoring onboard an aircraft. The following research questions will be addressed: (1) Is there a difference in the measured pressure as indicated by the digital pressure readout during a change in altitude? (2) Does rezeroing the system at a given altitude correct for the change in barometric pressure (ground based pressure = altitude corrected pressure)? (3) Is there a difference in the dynamic response characteristics of a pressure-monitoring system with an increase in altitude? (4) What is the effect of different volumes of air on the dynamic response characteristics at different altitudes? (5) What is the effect of vibration (c/w the different aircraft) on the dynamic response characteristics of a pressure-monitoring system? (6) What is the effect of different volumes of air on the dynamic response characteristics of a pressure-monitoring system at different vibration frequencies? (7) In a field study, what is the effect of the aeromedical evacuation environment in opportune AE aircraft (C-130, C-141, C-17) on the dynamic response characteristics with and without volumes of air in the system? These research questions will be answered using a repeated measures design, in a controlled environment (altitude chamber and vibration table) and in a field test onboard aircraft commonly used for AE transport. The results of this study are of particular importance to the military AE and military nurses given the extremely challenging military AE environment. In the AE environment the nurse plays the central role in preparing and using the pressure measurements to assess and treat the critically ill patients. The results of this study have the potential to directly inform the practice of invasive pressure monitoring in the military AE environment.