Incidence of gastroesophageal reflux and aspiration in mechanically ventilated patients using small-bore nasogastric tubes

Background. Use of a large-bore nasogastric tube (NGT) and patient position are considered key factors in promoting gastroesophageal reflux (GER) and pulmonary aspiration in critically ill patients. The objective of this study was to determine the incidence of CER and pulmonary aspiration of gastric contents in mechanically ventilated (MV) patients using small-bore NGTs. Methods: We studied 30 patients on mechanical ventilation for acute respiratory failure who tolerated enteral nutrition through a small-bore NGT. Patients were randomly assigned to a group with (n = 16) or without (n = 14) a small-bore NGT and were maintained in a semirecumbent position during the study. GER and aspiration of gastric contents were assessed by a radioisotopic technique. Scans were done 24 hours after technetium-99m administration (n = 30). In 9 patients a dynamic scintigraphy was performed immediately after colloid administration, and samples of blood and tracheal and oropharyngeal secretions were obtained basally, 30 minutes, and 24 hours after technetium administration and analyzed for radioactivity using a gamma counter. Results: Both groups were similar in age, underlying diagnosis, number of days of mechanical ventilation at the day of study, and mortality. There were no GER reaching the oropharynx and aspiration of gastric contents in both groups. Conclusions: GER and aspiration of gastric contents were not detected in MV patients using small-bore NGTs and may be a simple measure to prevent ventilator-associated pneumonia.