Inferior Mesenteric Venous Sampling, Pulse Oximetry, and Assessment of Colonic Perfusion During Aortic Aneurysm Surgery.

Ischemic colitis is a serious complication ofaortic surgery. The condition continues to be difficultto diagnose at an early stage. This study monitors thebiochemical changes in systemic and selective inferior mesenteric vein (IMV) blood samplingduring aortic surgery and compares the reproducibilityof this method to intraoperative colonic pulse oximetryin a series of 18 patients undergoing infrarenal aortic aneurysm repair. Base excess, pH,pCO₂, and lactate were altered by aorticcross-clamping but returned to normal within 48 hr. IMVinorganic phosphate levels were higher than systemic values, suggesting improved sensitivity withselective sampling. BB isoenzymes of creatine kinaseremained normal in all patients. Pulse oximetry signalswere inconsistently obtained from the colon. This study establishes the physiological changes inIMV biochemistry during aortic surgery. Unlikeintraoperative pulse oximetry, selective IMV samplingprovides reproducible measurements of colonic perfusion. This simple and safe technique warrants furtherassessment of its accuracy at diagnosing ischemiccolitis. [ABSTRACT FROM AUTHOR]