A defoaming agent should be used with pronase premedication to improve visibility in upper gastrointestinal endoscopy

Background and Study Aims: The study tested whether pronase can improve endoscopic visibility and alter the accuracy of the CLO test for H. pylori detection. Patients and Methods: A total of 160 patients were randomly assigned to receive one of five premedications for endoscopy: group A: dimethylpolysiloxane (DMPS) alone; group B: DMPS plus water (up to 100 ml); group C: pronase only, with 100 ml water; group D: pronase and sodium bicarbonate plus water up to 100 ml; group E: pronase, sodium bicarbonate, and DMPS, plus water up to 100 ml. Endoscopists, who were unaware of the premedication method administered, assessed visibility scores (range 1-4) for the antrum, lower gastric body, upper gastric body, and fundus. The higher the score, the less clear the visibility. The sum of scores from the four locations was defined as the total visibility score. A CLO test was also done during the endoscopy. One week after their endoscopy, patients in groups C, D, and E were scheduled for a C-13-urea breath test (UBT). Results: Group E patients had a significantly lower total visibility score than those in the other four groups (P < 0.05). Groups C and D had higher total visibility scores than the other three groups (P < 0.05). The scores did not significantly differ between groups A and B. Based on the UBT results, the sensitivity and specificity of the CLO test were 92.6% and 96.2%, respectively. Conclusions: Premedication as in group E provided the clearest endoscopic visibility. Without the application of DMPS, pronase alone cannot improve endoscopic visibility. Pronase does not influence H. pylori identification using the CLO test.