Intraoperative changes of mucosal pCO2 during gastric tube formation

The formation of a gastric tube after esophagectomy with ligation of the left gastric artery and resection of the lesser curvature is associated with microcirculatory changes, especially in the anastomotic region of the fundus. This influences the healing of the esophagogastrostomy. The presented prospective protocol was designed to assess continuous tonometry as a tool to demonstrate microcirculatory changes during gastric tube formation. In 15 patients with esophageal carcinoma, pCO2 of the gastric mucosa (pCO2i) was measured intraoperatively during formation of a gastric tube. This was done by a nasogastric tube with a silicon balloon connected to a Tonocap recirculating gas analyser. pCO2i measurements were compared for a period of 90 min before and after ligation of the left gastric artery and correlated to the corresponding end expiratory pCO2 (pCO2e). In 14 of 15 patients examined (93.3%), an increase of pCO2i after ligation of the left gastric artery was demonstrated. pCO2i (mean+/-SD) before ligation of the left gastric artery (87 measurements: 40.6+/-7.5 mmHg; range, 29-67 mmHg) was significantly lower (P<0.001) compared to the mean pCO2i after ligation of the left gastric artery (88 measurements: 49.1+/-10.2 mmHg; range, 31-79 mmHg). Continuous tonometry is a valid method to detect changes in mucosal pCO2 during gastric tube formation and should be assessed to monitor the gastric interposition graft during the postoperative course.