A simple method for frequent monitoring of gastric carbon dioxide.

Intragastric PCO2 has been recognized to rise in states of gastric hypoperfusion. A device including a gas-permeable balloon on a conventional sump nasogastric tube (TRIP catheter, Tonometrics) has permitted simple measurement of the intragastric PCO2 following equilibration of intragastric PCO2 with saline in the balloon. This method is slow to equilibrate and time-consuming. We describe an automated method using air instead of saline in the balloon with measurement using capnography. Equilibration is much faster using air and the automated system permits measurements to be taken at regular intervals (10 minutes) without additional workload.