Continuous assessment of gastric intramucosal PCO sub 2 and pH in hemorrhagic shock using capnometric recirculating gas tonometry

OBJECTIVESTo test a novel device for continuous monitoring of gut intramucosal PCO2 and pH and to compare its use with conventional intermittent saline balloon-tonometry in a model of hemorrhagic shock. DESIGNA prospective animal study. SETTINGSA university research laboratory. SUBJECTSEight anesthetized, mechanically ventilated mongrel dogs. INTERVENTIONSTwo balloon-tip tonometry catheters, one conventional and one modified for continuous recirculating gas tonometry, were inserted into each animal's stomach by the oral route. Gastric intramucosal PCO2 was recorded continuously by capnometric recirculating gas tonometry throughout the experiment. After a baseline period of 90 mins, vital signs, arterial and mixed venous blood gases, and intramucosal PCO2 values were obtained by recirculating gas tonometry and by the conventional method. Using a modified Wiggers' model, the animals were then subjected to hemorrhage of up to 45 mL/kg, or the volume required to effect a decrease in mean arterial pressure to