Am. J. Respir. Crit. Care Med., Vol 149, No. 6, Jun 1994, 1659-1662.
Gastroesophageal reflux with nasogastric tubes. Effect of nasogastric tube size
RG Dotson, RG Robinson and SK Pingleton
Department of Medicine, University of Kansas Medical Center, Kansas City 66160.
Pulmonary aspiration of gastric contents results initially from reflux of
stomach contents into the esophagus. Small-bore enteral feeding tubes are
thought to result in less pulmonary aspiration and less reflux. We
prospectively investigated the effect of nasogastric tube size upon
gastroesophageal (GE) reflux in normal volunteers in a randomized crossover
trial. Reflux was assessed by gastroesophageal scintiscanning, a
radioisotopic technique that detects and quantitates GE reflux. A total of
11 subjects were studied three times: control, no nasogastric tube,
small-bore (8F) nasogastric tube, and large-bore (14F) nasogastric tube.
Reflux was assessed in each subject under each experimental condition by
provocative testing in which abdominal pressure was increased from 0 to 100
mm Hg by 20-mm Hg increments with an abdominal pressure device. GE reflux
indices were calculated for each measurement and the groups compared. A
positive indicator of reflux was defined as a > or = 4% reflux index.
Gastroesophageal reflux was not detected at any level of abdominal pressure
regardless of the presence or size of a nasogastric tube. With maximum 100
mm Hg abdominal pressure, the reflux index was control, 1.75 +/- 0.45%;
small- bore tube, 1.67 +/- 0.28%; and large-bore tube, 1.88 +/- 0.35% (NS).
The reflux index was not different between small-bore and large-bore
nasogastric tubes. Our data suggest the size of a nasogastric tube is not
an important determinant of GE reflux in normal subjects during short-term
intubation. Large-bore tubes did not cause more reflux than small-bore
tubes. The presence of a nasogastric tube did not cause reflux in normal
subjects. These data suggest that factors other than the size of
nasogastric tube are more important in GE reflux in normal subjects.
