MEASUREMENT OF GASTRIC INTRAMUCOSAL PH DU RING ABDOMINAL SURGICAL-PROCEDURES

Background: Gastric mucosal pH may be a good indicator of splanchnic t issue oxygenation. Aim: To study the effects of abdominal surgical pro cedures on gastric mucosal pH. Patients and methods: Eighteen patients subjected to abdominal surgery were studied. All patients received ge neral anesthesia and hemodynamic parameters were maintained within 20% of basal values. A tonometer was placed in the stomach after inductio n of anesthesia. Arterial blood gases and samples from the tonometer w ere obtained 30 minutes after induction and at 2 hours of surgery. Int ramucosal pH was calculated using Henderson-Haselbach equations. Resul ts: Basal gastric mucosal pH was 7.4 +/- 0.1 and did not change during surgery. Two patients had a pH persistently below 7.35 without hemody namic alterations or systemic acidosis. Conclusions: Gastric mucosal p H is not modified by abdominal surgery and some patients have low valu es despite the absence of hemodynamic derangement.