Effect of Propofol on Acid Reflux Measured with the Bravo pH Monitoring System

Background/Aim. The aim of this study was to determine the effect of propofol on acid reflux as measured with the Bravo pH monitoring system. Methods. 48-hour pH tracings of 88 children were retrospectively evaluated after placement of the Bravo capsule under propofol. Comparisons between day 1 and day 2, as well as 6-hour corresponding segments from day 1 and day 2, were made. Results. The number of reflux episodes was significantly increased during the first six-hour period on day one as compared to day 2 . The fraction of time the pH was <4 was also increased during this period, though it did not reach statistical significance. When comparing full 24-hour periods, there was no difference noted in either the number of reflux episodes or the fraction of time pH < 4 between day one and day two. Conclusion. Our data suggest an increase in gastroesophageal reflux during the postanesthesia period. This could be a direct effect of propofol, or related to other factors. Regardless of the cause, monitoring of pH for the first 6 hours following propofol administration may not be reliable when assessing these patients. Monitoring pH over a prolonged 48-hour time period can overcome this obstacle. 1. Introduction Gastroesophageal reflux is characterized by the retrograde transit of stomach contents, including gastric acid into the esophagus. Clinical symptoms associated with it range from simple heartburn to aspiration pneumonia to ALTES (acute life-threatening events) in infants. The primary method for documenting and characterizing gastroesophageal reflux is a 24–48-hour pH monitor, either wired (simple pH probe) or wireless (Bravo system; Medtronic, Inc., Shoreview, MN, USA). Ambulatory extended esophageal pH monitoring is regarded as the standard test for establishing the presence of abnormal gastroesophageal reflux in children. Standard pH probe monitoring is performed by placing an esophageal catheter through the nose and advancing it to a precalculated distance above the lower esophageal sphincter (LES). Due to the morbidity and intolerability associated with the nasally placed pH catheter, the Bravo pH system has become a more commonly used procedure with comparable results and better tolerance among children. The Bravo pH system consists of a small capsule which contains an antimony pH electrode, a radiotransmitter, and an internal battery. The capsule is attached to the mucosal wall of the distal esophagus and monitors pH, while transmitting data to a pager-sized device that may be easily attached to the patient’s clothes. The disposable capsule