During unsedated colonoscopy, fewer patients receiving water infusion for cecal intubation requested pain medication, compared with patients receiving air insufflation, reported Dr. Jürgen Pohl and colleagues in the December issue of Clinical Gastroenterology and Hepatology.
Dr. Pohl of the University of Mainz (Germany) and colleagues studied 116 consecutive outpatients presenting for screening, surveillance, or diagnostic colonoscopy who elected not to receive preprocedure sedation.
Patients were subsequently randomized to receive either standard air insufflation of the colon when needed, or water infusion, whereby warm water (37° C) was used exclusively to distend the colon and the air supply was turned off until the cecum was reached.
"If sufficient visualization of colonic lumen could not be achieved with water infusion within 5 minutes, and the endoscopist judged it risky to advance the colonoscope further, the water pump was switched off and the procedure was completed with air," wrote the authors (Clin. Gastroenterol. Hepatol. 2011 July 11 [doi:10.1016/j.cgh.2011.06.031]). These cases were recorded as failures.
Throughout the procedure, patient discomfort and desire for sedation and/or analgesia were assessed in both groups at intervals of 2-3 minutes on a scale of 0-10, with higher numbers signifying worse pain.
Overall, 104 of 116 colonoscopies (89.7%) were completed to the cecum. "During colonoscope insertion in the water group, significantly fewer patients requested sedation (8.6% vs. 34.5% in the air group; P = .003)," they wrote.
The water group’s average maximum pain scores were lower, too (2.8 vs. 4.2 in the air group; P = .02), and less sedation and/or analgesia was administered to the water cohort (P = .02).
However, the authors also pointed out that the rate of complete cecal intubation was significantly lower among water-infusion patients, compared with the air group (82.8% vs. 96.5%, respectively; P = .03), with 10 procedures considered failures in the water group.
These 10 failures, explained Dr. Pohl, occurred when "residual stool [that was] mixed with infused water impaired visibility to an extent that made safe advancement impossible in difficult segments." The procedures were subsequently completed after suction and air insufflation, he added.
There were no significant differences with regard to the proportion of patients requiring abdominal compression or a position change during insertion of the endoscope. "Nor were any significant differences observed between the two groups with regard to recovery times," added Dr. Pohl and colleagues.
The researchers postulated that the success rate of water infusion "might be improved if moderate insufflation of air were to be applied as needed to enhance visualization in case of difficult areas and/or impaired viewing due to suspended residual fecal matter."
They added, "However, longer procedure times with water infusion colonoscopy remain a major problem, given the absolute necessity of time efficiency in a demanding reimbursement environment."
The authors disclosed that this study was supported by Fujinon Inc., maker of colonoscopes and other devices. They declared no individual conflicts.