Questions under study: Surgery of abdominal aortic aneurysms involves a high risk of postoperative complications. It has been suggested that the incidence of postoperative complications is related to the development of gastrointestinal acidotic episodes of the mucosa. The goal of this study was, therefore, to determine the incidence of gastrointestinal acidotic episodes during repair of abdominal aortic aneurysms, and to test the hypothesis that these episodes predict an adverse postoperative course.
Methods: In 49 consecutive patients undergoing elective surgery for repair of an abdominal aneurysm, intramucosal gastric pH (pHi) was measured perioperatively. The length of the surgical procedure, perioperative intravenous fluid intake, use of vasoactive drugs, APACHE-II scores, days with an endotracheal tube in place, days of intensive care and major postoperative complications were prospectively assessed. The patients were assigned to either a group with a pHi > or = 7.35 or a group with pHi < 7.35 measured towards the end of the surgical procedure, and then compared.
Results: The pHi decreased from 7.42 +/- 0.09 after induction of anesthesia to 7.37 +/- 0.07 (p < 0.05) during clamping of the aorta, and continued to decrease to 7.34 +/- 0.08 (p < 0.001) towards the end of surgery and on admission to the surgical intensive care unit (mean +/- standard deviation). The percentage of patients with pHi < 7.35 increased from 10% at the beginning of the operation to 55% on admission to the intensive care unit (p < 0.0001). There was no difference in the postoperative course between patients with pHi > or = 7.35 and those with pHi < 7.35 measured after declamping of the aorta. Patients who had a major complication during their stay in the intensive care unit had lower perioperative pHi values than patients without complications (p < 0.001).
Conclusions: Perioperative gastrointestinal acidotic episodes of the mucosa are common during repair of abdominal aortic aneurysms. The perioperative course, however, is not influenced by these acidotic episodes, despite the fact that patients with complications during their stay in the intensive care unit had lower perioperative pHi values. The routine use of pHi measurements during elective surgery of abdominal aortic aneurysms, therefore, is not justified.