Factors influencing intraoperative gastric regurgitation: a prospective random study of nasogastric tube drainage.

A prospective study was conducted to determine the incidence of "silent" gastric regurgitation and aspiration during general anesthesia in 146 patients randomized with respect to presence of a nasogastric tube. A bland dye was instilled in the stomach to serve as the determinant marker. The overall incidence of regugitation was 8.9% and of aspiration, 2.1% in spite of the uniform use of an endotracheal tube. The incidence of regurgitation was twice as high when anesthesia was given by an inexperienced anesthetist (11% vs 5.6%) and in patients without nasogastric tubes (12% vs 6%), although such differences were not statistically significant. The primary agent used, difficulty of endotracheal intubation, location of surgical incision, and duration of anesthesia did not alter the incidence of regurgitation or aspiration. No correlation was found between the detection of subclinical aspiration and the development of postoperative pulmonary complications.