Intraoperative tissue oximetry in the human gastrointestinal tract

Tissue oxygen tension was measured using a modified Clark oxygen electrode in the gastrointestinal tract of 33 patients undergoing laparatomy. The electrode, which incorporated a thermistor, had a linear response to oxygen tension (r = 0.995, p less than 0.001). The patients were all maintained on an inspired oxygen concentration of 33 +/- 3% and had a mean arterial oxygen tension (PaO2) of 124.9 +/- 31.9 mm Hg. Tissue oxygen tension measurements (mm Hg, mean +/- SD) were recorded from the serosal surfaces of the stomach (46.3 +/- 15.4), mid-ileum (36 +/- 9.7), terminal ileum (33.5 +/- 11.5), cecum (30.3 +/- 7.4), transverse colon (38.5 +/- 10), descending colon (29.3 +/- 11), and sigmoid colon (39.2 +/- 7.7) and tended to increase with increasing PaO2 (r = 0.70, p less than 0.001). Arterial occlusion resulted in a gradual decrease in tissue oxygen tension. It is concluded that intraoperative tissue oxygen tension measurement is feasible, and that the technique may have clinical applications in the assessment of intestinal viability.