Randomized Controlled Trial Comparing Water versus Air Method for Colonoscopy in Female Patients

Abstract

Purpose: In a randomized controlled trial (RCT; NCT01790425), we compared air insufflation vs. water infusion colonoscopy in female non-veteran patients presenting for colonoscopy. Water infusion in lieu of air insufflation for performing colonoscopy has been reported to have beneficial effects when studied in male veteran patients. These include significant reduction in discomfort with higher percentage (98% vs. 76%) of veterans successfully completing scheduled unsedated colonoscopy. The application of water infusion colonoscopy is less well-described in female than in male patients in the United States in a non-veteran setting. Methods: All patients received IV conscious sedation for the colonoscopy. In the conventional air (control) method, air is pumped gently (insufflation) into the colon to open the lumen and aid in colonoscope insertion. In the water (study) method, air button was turned off before scope insertion. Warm (body temperature) water was infused into the colon in place of air to distend the lumen and aid in colonoscope insertion until cecum was reached. Most of the infused water is suctioned during the scope insertion. Pain score was documented by the nurse during scope insertion and on withdrawal. Scope shortening, loop reduction, and suction removal of air or water were done when patient experienced pain/discomfort on scope insertion. For both methods, abdominal compression by the assistant or change in patient's position was performed to facilitate scope advancement in difficult cases. Air was used in both groups on scope withdrawal to facilitate biopsy and removal of lesions. Results: Demographic and baseline variables were comparable between the two groups except for signifi cantly more patients had abdominal surgery (excluding colon resection) in the water (study) group compared with the air (control) group (Table 1). There were no statistically significant differences in cecal intubation time and total procedure time between the two methods. Pain score was significantly higher on insertion with the air method, especially in the proximal colon before reaching the cecum, compared with the water method. There was significantly less need for abdominal compression or position change to facilitate scope insertion with water method. There was also less pain at discharge with a correspondingly better patient experience with the water method (Table 2).Table 1: Demographic and baseline dataTable 2: Primary and secondary outcomesConclusion: Despite having more patients with presumed difficult colonoscopy (prior abdominal surgery), water exchange colonoscopy offered a better patient outcome among non-veteran female patients with less need for abdominal compression for completion, lower pain scores, and better patient experience.