Endoscopic tonometric assessment of intestinal perfusion in a canine model.

In an anesthetized canine model tonometric balloons were colonoscopically placed into the right colon, left colon, and rectum. A femoral arterial line was established for the measurement of blood pressure and arterial bicarbonate. Laparotomy was performed and additional balloons were placed, via enterotomies, into the duodenum, jejunum, and ileum. Baseline measurements of intramural pH were obtained, and then the origin of the superior mesenteric artery was occluded. Additional measurements in all areas were made for two 1-hour intervals. Results showed rapid and marked acidosis as demonstrated by significant (p less than 0.001) pH changes in the jejunum, ileum, and right colon. There were no significant changes in the pH in the duodenum, left colon, or rectum. Systemic arterial pH remained normal. These data demonstrate that tonometric balloons endoscopically placed into the right colon will reflect superior mesenteric artery occlusion at an early stage, and that similar information is likely to be gained by endoscopic placement of these balloons into the jejunum.