Purpose: The recently introduced Bravo (wireless) ambulatory esophageal pH system offers a mechanism of monitoring gastroesophageal (GE) reflux episodes over a 48-hour period and establishing a correlation between symptoms and acid reflux. Prior studies with the Bravo system have generally analyzed GE reflux over the entire 48-hour period. Minimal data is available comparing day 1 with day 2 results. However, since patients are usually sedated to clip the esophageal pH electrode to the esophagus, this sedation may potentially affect the day 1 results, possibly increasing GE reflux on day 1. This study compared day 1 with day 2 results.
Methods: A retrospective study of 26 consecutive adult patients at our institution who underwent Bravo (wireless) ambulatory esophageal pH monitoring. All patients underwent EGD under IV conscious sedation just prior to clipping the pH electrode to the esophagus. Acid reflux analysis for day 1 was compared to day 2, including total time of pH < 4, upright and supine position reflux, number of reflux episodes, number of long refluxes, and duration of longest reflux episodes. A symptom score was calculated by dividing episodes of heartburn correlating with pH < 4 by total number of heartburn episodes, and compared between day 1 and day 2. The study was statistically analyzed by Wilcoxon signed rank test with significance indicated by p-value < 0.01.
Results: The mean doses of fentanyl and midazolam were 86 mcg and 7.0 mg, respectively. Day 1 results were significantly more elevated than day 2 in respect to total time of pH < 4 (p= 0.0049), upright position reflux (p= 0.0051), and mean number of long refluxes (p= 0.0077). No statistical difference was noted between the two days for supine position reflux, number of refluxes, duration of longest reflux, episodes of heartburn, and symptoms score.
Conclusions: Patients undergoing Bravo (wireless) ambulatory esophageal pH monitoring in association with conscious sedation experience significantly more acid reflux (pH < 4) on day 1 compared to day 2. The IV sedation may be responsible for the increased reflux on day 1. Performed this way, 48-hour Bravo results may not be entirely representative of the true patient GE reflux profile. Placing the pH electrode without sedation may eliminate the problem, but may not be acceptable to patients. Performing 72-hour studies with elimination of day 1 data may circumvent the problem.