Optimal timing of simethicone administration prior to upper endoscopy: A multicenter, single-blind, randomized controlled trial

Abstract

Background and study aims Simethicone is useful as premedication for upper endoscopy because of its antifoaming effects. We aimed to evaluate the effect of timing of simethicone administration on mucosal visibility. Patients and methods In this multicenter, randomized, endoscopist-blinded study, patients scheduled for upper endoscopy were randomized to receive 40 mg simethicone at the following time points prior to the procedure: 20 to 30 minutes (early group), 0 to 10 minutes (late group) or 20 mg simethicone at both time points (split-dose group). Images were taken from nine predefined locations in the esophagus, stomach, and duodenum before endoscopic flushing. Each image was scored on mucosal visibility by three independent endoscopists on a 4-point scale (lower scores indicating better visibility), with adequate mucosal visibility defined as a score ≤ 2. Primary outcome was the percentage of patients with adequate total mucosal visibility (TMV), reached if all median subscores for each location were ≤ 2. Results A total of 386 patients were included (early group: 132; late group: 128; split-dose group: 126). Percentages of adequate TMV were 55%, 42%, and 61% in the early, late, and split-dose group, respectively ( P < 0.01). Adequate TMV was significantly higher in the split-dose group compared to the late group ( P < 0.01), but not compared to the early group ( P = 0.29). Differences between groups were largest in the stomach, where percentages of adequate mucosal visibility were higher in the early (68% vs 53%, P = 0.03) and split-dose group (69% vs 53%, P = 0.02) compared to the late group. Conclusions Mucosal visibility can be optimized with early simethicone administration, either as a single administration or in a split-dose regimen.

Keywords: Barrett's and adenocarcinoma; Diagnosis and imaging (inc chromoendoscopy, NBI, iSCAN, FICE, CLE); Precancerous conditions & cancerous lesions (displasia and cancer) stomach; Preparation, quality and logistical aspects; Quality management.

Fig. 1

Mucosal visibility score examples for one predefined location (corpus antegrade position). a Score 1: no adherent mucus and clear views. b Score 2: a thin coating of mucus that does not obscure views. c Score 3: mucus/bubbles partially obscuring views. d Score 4: heavy mucus/bubbles obscuring views.

Fig. 2

Patient flow diagram.

Fig. 3

Percentages adequate total mucosal visibility (TMV) and adequate mucosal visibility per organ. Adequate TMV was defined as a score ≤ 2 for all nine of the predefined locations. Adequate mucosal visibility per organ was defined as a score ≤ 2 for each of the respective predefined locations in the esophagus, stomach or duodenum separately. Early group = 40 mg simethicone 20 to 30 minutes prior to gastroscopy. Late group = 40 mg simethicone 0 to 10 minutes prior to gastroscopy. Split-dose group = 20 mg simethicone 20 to 30 minutes, and 20 mg simethicone 0 to 10 minutes prior to gastroscopy. *** denotes statistical significance.

Fig. 4

Adequate mucosal visibility (%) in all patients (n = 260) randomized to either the early group (n = 132) or the late group (n = 128) in relation to the measured time (minutes) of simethicone administration prior to endoscopy. Early group = 40 mg simethicone scheduled at 20 to 30 minutes prior to gastroscopy. Late group = 40 mg simethicone scheduled at 0 to 10 minutes prior to gastroscopy. Of note: patients included in the split-dose group are not represented in this figure. Adequate total mucosal visibility was defined as a score ≤ 2 for all nine of the predefined locations. Adequate mucosal visibility per organ was defined as a score ≤ 2 for each of the respective predefined locations in the esophagus, stomach or duodenum separately.