[Gastrointestinal ischemia in patients undergoing coronary artery bypass surgery--comparison of two methods for gastric intramucosal PCO2 monitoring].

To assess the adequacy of gastrointestinal mucosal perfusion perioperatively, the gastric intramucosal PCO2 (PiCO2) was monitored in ten patients undergoing elective coronary artery bypass grafting operation. Extracorporeal circulation was performed with mild hypothermia (temperature between 30 degrees C and 32 degrees C) and nonpulsatile flow. Plasma levels of interleukin-6 and endothelin-1 remained elevated up to twelve hours after surgery. The PiCO2 using the ion-sensitive field effect transistor (ISFET) sensor, attached to the tip of a nasogastric tube, increased significantly to 64 +/- 9 mmHg (mean +/- SD) at 6th postoperative hour from a baseline value of 48 +/- 7 mmHg. A similar trend was observed in PiCO2 as measured by capnographic gas tonometry. Although there was a close correlation between these two techniques (r2 = 0.4923), values with ISFET sensor were significantly higher (11-16 mmHg) than those by capnographic gas tonometry. Gastrointestinal mucosal ischemia, probably related to systemic inflammatory response, was observed during the immediate postoperative period. The PiCO2, measured directly and continuously with ISFET sensor, may be a more sensitive indicator compared with capnographic gas tonometry in evaluating the development of gastrointestinal mucosal injury.