A randomized, controlled, double-blind trial of air insufflation versus carbon dioxide insufflation during ERCP

Abstract

Background: Visualization during GI endoscopy requires distention of the bowel lumen. Carbon dioxide (CO(2)) insufflation decreases postprocedure abdominal discomfort and distension after colonoscopy, but there have been few published studies on its use in ERCP.

Objective: To assess the safety and efficacy of CO(2) insufflation during ERCP.

Design: Double-blind, controlled, randomized trial.

Setting: Tertiary-care referral center.

Patients: This study involved consecutive patients referred for ERCP, excluding those with known CO(2) retention or with chronic use of opiate medications.

Intervention: Insufflation of CO(2) versus insufflation of air.

Main outcome measurements: Primary outcomes were abdominal pain assessed on a visual analogue scale and abdominal distension. Secondary outcomes included transcutaneous CO(2) levels (pCO(2)) and procedural complications.

Results: We analyzed 74 patients, 38 in the air group and 36 in the CO(2) group. Pain scores were similar in both groups 1-hour postprocedure (16 vs 11 mm in the CO(2) and air groups, respectively; P = .29) as well as over the subsequent 24 hours. There were also no significant differences between groups in abdominal distension or pCO(2) levels. There were 13 patients with complications in the air group and 5 in the CO(2) group (P = .04; nominal significance removed by Bonferroni correction), although most complications were minor in nature.

Limitations: Single-center study.

Conclusion: The use of CO(2) for insufflation during ERCP was safe in a tertiary-care referral population. However, use of CO(2) during ERCP did not lead to decreased postprocedural pain or less abdominal distension, so its role in this procedure remains in question. NCT00685386.

Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Figures

Figure 1

(A) The Olympus UCR Endoscopic CO2 Regulation Unit (UCR, Olympus Medical, Central Valley, PA. There is a power button (lower left side), a gas supply indicator lamp, a button in the center of the device that starts and stops the flow of CO2, and a gas flow indicator. The back of this unit connects to a CO2 tank, and CO2 is dispensed through the gas outlet on the lower right side of the front of the machine. This, in turn, connects to the lid of a specialized water bottle (B) that also has a standard adaptor which connects the water bottle to the scope.

Figure 1

(A) The Olympus UCR Endoscopic CO2 Regulation Unit (UCR, Olympus Medical, Central Valley, PA. There is a power button (lower left side), a gas supply indicator lamp, a button in the center of the device that starts and stops the flow of CO2, and a gas flow indicator. The back of this unit connects to a CO2 tank, and CO2 is dispensed through the gas outlet on the lower right side of the front of the machine. This, in turn, connects to the lid of a specialized water bottle (B) that also has a standard adaptor which connects the water bottle to the scope.

Figure 2

The study set up. The CO2 insufflator is connected to the CO2 tank as well as to the specialized water bottle lid. For all cases in the study, both the insufflator and the air indicator on the scope processor were completely covered in order to mask treatment assignment.

Figure 3

CONSORT patient flow diagram. Of the patients not meeting inclusion criteria, 2 were known CO2 retainers, 6 were unable to provide consent due to dementia, 9 were medically unstable, 5 required general anesthesia, 9 were on chronic opioids, 4 were non-English speaking, 4 were < 18 years old, 3 had Billroth II post-surgical anatomy precluding use of the duodenoscope, 1 was incarcerated, and 5 were scheduled for other non-ERCP procedures. The 16 cases excluded for other reasons included 5 patients who were screened but did not come for their appointment, and 11 patients who were missed for recruitment. Of the 4 patients who were randomized but not included, 3 were found to be ineligible after randomization (they were undergoing a second endoscopic procedure that day), and technical difficulties precluded patient participation in the other procedure.

Figure 4

Abdominal pain scores as measured on a 100 mm VAS before and 1, 3, 6, and 24-hours post-ERCP. The air insufflation group is in blue and the CO2 group is in green. The arrow points to the primary outcome at 1 hour post-procedure. As measured by GEE, there is no difference between pain scores over the time course of the study.