Effect of nasogastric tube size on gastroesophageal reflux and microaspiration in intubated patients

Background: Little evidence exists to support the theory that small-bore nasogastric tubes prevent gastroesophageal reflux and microaspiration in intubated patients. Objective: To determine whether gastroesophageal reflux and microaspiration in intubated patients can be reduced by the use of a small-bore nasogastric tube. Design: Randomized, two-period crossover trial. Setting: Respiratory intensive care unit of a university hospital. Patients: 17 patients intubated for more than 72 hours. Interventions: Radioactive technetium colloid was instilled in each patient's stomach. Patients were studied with two nasogastric tubes (one tube with a 6.0-mm external bore and one tube with a 2.85-mm external bore) in randomized order; measurements of radioactive counts with the alternate size of nasogastric tube were repeated 72 hours after original measurements were taken. Sequential samples of serum, gastric juice, and pharyngeal and tracheal secretions were obtained. Measurements: Comparison of the time course of radioactive counting in all samples (obtained during the use of each nasogastric tube size in each patient). Results: The mean radioactive count of pharyngeal aspirates (P = 0.004) was greater than the baseline count at all time points, as was the cumulative radioactive count of pharyngeal aspirates 17 hours after the first dose of technetium colloid was administered (P = 0.001); however, the count of tracheal aspirates was never greater than the count at baseline. No differences were found between tube types when the time course and cumulative counts of pharyngeal and tracheal samples were compared. Conclusion: Small-bore nasogastric tubes in intubated patients do not reduce gastroesophageal reflux or microaspiration.