Aspiration of oropharyngeal and gastric contents during surgery, although infrequent, is a recognized complication of general anesthesia that carries significant risk for serious complications. Complications of aspiration have been reported to cause 10% to 30% of anesthesia-related deaths. Unconsciousness interferes with multiple biologic mechanisms that guard the airway against aspiration, and this is compounded in surgery by anesthesia-induced neurologic impairment and the risks related to placement of nasogastric and endotracheal tubes. Consequences of anesthesia-related aspiration include aspiration pneumonia, acute respiratory distress syndrome, pulmonary edema, and long-term complications such as laryngotracheal damage and decreased lung compliance. Therefore, averting aspiration, particularly in the elderly and other high-risk patients, should be part of the perioperative plan. Although antacids and histamine 2-receptor antagonists have been used perioperatively with some success, they are limited by short duration of action and systemic side effects, among other factors. Proton pump inhibitors are currently being investigated in surgical patients at risk for aspiration or stress ulcers and seem to be potent, extremely effective, and well tolerated. This article reviews the risks for, and potential outcomes of, anesthesia-related aspiration, identifies high-risk populations, and outlines the experience to date with available preventive treatments.

Aspiration of gastric contents is a relatively common cause of acute and chronic pulmonary disease. However, a reliable method of diagnosing recurrent aspiration is currently lacking. The aim of this study was to determine whether the presence of gastric pepsin in tracheal aspirates of infants and children might be used as a reliable marker of the microaspiration of refluxed gastric contents.Ninety-eight children undergoing general anesthesia and tracheal intubation participated in the study. Sixty-four of 98 children underwent endoscopy for clinically significant gastroesophageal reflux. Thirty-four children from routine operative lists were nonreflux controls. These two groups were further subdivided based on the presence or absence of associated respiratory symptoms. After endotracheal intubation, tracheal aspirates were obtained and subsequently assayed for gastric pepsin using a fluoroscein isothiocyanate casein.Pepsin was detected in 7 of 27 children with reflux symptoms alone and in 7 of 8 of those with chronic respiratory symptoms. In addition, pepsin was present in 31 of 37 children with a history of both reflux and chronic respiratory symptoms. Tracheal pepsin was not detected in any of the 26 children without gastroesophageal reflux or respiratory symptoms. Tracheal pepsin was found significantly more frequently in children with reflux symptoms than in those without, particularly in children with both reflux and respiratory problems.Tracheal pepsin assay as a reliable marker of gastroesophageal reflux aspiration.

The acute effects of continuous intragastric administration of 1500 ml (4200 kJ/liter) of a polymeric and of a nonpolymeric formula on gastric function were studied in 15 healthy subjects. During 450 min 1500 ml, containing 6300 kJ (1500 kcal), was given through a nasogastric tube. At regular intervals the volume, the pH, the titratable acidity, and the pepsin activity of the gastric contents and the plasma gastrin concentration were determined. Maximal observed intragastric volumes occurred after 120 min (118 +/- 16 ml during polymeric formula, 212 +/- 37 ml during nonpolymeric one) and volumes subsequently halved (at 450 min 68 +/- 13 and 104 +/- 16 ml, respectively). During the administration of both polymeric and the nonpolymeric formula intragastric pH fell progressively to 3.15 and 2.67, respectively, at 450 min. Incremental plasma gastrin values increased between 120 and 450 min from 7 to 12 ng/liter during the polymeric formula. During the nonpolymeric one it stabilized after 120 min at 12 ng/liter. When the whole test periods were considered integrated, mean intragastric volumes tended to be larger during the nonpolymeric formula (153 +/- 23 ml) than during the polymeric formula (107 +/- 12 ml), but this difference was not statistically significant. Median integrated mean pH was lower during the nonpolymeric formula (2.89) compared with the polymeric one (3.26). Despite the limitation that the investigations were performed in healthy subjects only, it is concluded from this study that the risk of aspiration during continuous nasogastric tube feeding is probably greatest during the first few hours of administration because of the larger intragastric volumes.(

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A 54-year-old man who died from acute upper gastrointestinal blood loss was found on postmortem examination to have a large amount of blood in the intestinal lumen from perforation of a gastric ulcer into the inferior vena cava. Gastric contents had also embolized into the pulmonary circulation. Most of the stomach was located posteriorly in the right thoracic cavity because of prior esophageal surgery, which had brought the posterior wall of the stomach in apposition to the anterior wall of the inferior vena cava. This is thought to be the first report of a gastric ulcer forming a fistula into the inferior vena cava, with food embolization to the lung.