Effect of nasal continuous positive airway pressure on esophageal function

Abstract

Objective: The purpose of this study was to conduct a prospective investigation of the mechanism(s) of nasal continuous positive airway pressure (CPAP) upon the reduction of recumbent gastroesophageal reflux.

Design: Prospective assessment.

Setting: Health Sciences Center and St. Boniface General Hospital, Winnipeg, Manitoba.

Methods: An esophageal motility examination was conducted on 16 patients during the application of nasal CPAP set at 0 cm, 4 cm, and 8 cm water pressure. Esophageal parameters studied were wave amplitude and velocity, midesophageal resting pressure, and upper and lower esophageal sphincter resting pressure.

Results: The midesophageal resting pressure increased significantly from a baseline of -3.5 +/- 1.4 mm Hg to -1.6 +/- 1.8 mm Hg at 4 cm CPAP (p < .01) and -0.9 +/- 1.2 mm Hg at 8 cm CPAP (p < .01).

Conclusions: The known reduction of nocturnal reflux that occurs when patients use an application of nasal CPAP appears to be related to direct mechanical compression of the esophagus. Results of an earlier report suggesting a reflex response by the lower sphincter were not reproduced.