Few studies have evaluated the degree of pain, the amount of retained gas, and the safety of carbon dioxide (CO₂) insufflation in patients undergoing double-balloon enteroscopy (DBE).

To clarify the usefulness and safety of CO₂ insufflation during DBE.

Single-center, prospective, randomized, double-blind, controlled trial.

University hospital.

Forty eligible patients with small-bowel disease for whom DBE was indicated were randomized to a CO₂ insufflation (CO₂) group or an air insufflation (air) group by means of sealed envelopes.

DBE with insufflation of CO₂ or air.

Efficacy evaluation was based on the degree of pain as assessed by use of a visual analog scale (VAS) and the amount of residual gas retention within the small and large bowels on radiography. The safety of CO₂ insufflation was evaluated by arterial blood gas analysis.

Significantly fewer patients in the CO₂ group had severe pain of ≥50 mm on the VAS during DBE than in the air group (P = .02). Significantly less gas was retained in the small bowel just after and at 3 hours after DBE in the CO₂ group than in the air group (P = .003, P = .01, respectively). There was significantly less residual gas retention in the large bowel at 3 hours after DBE in the CO₂ group than in the air group (P = .02). There was no significant difference in pre-DBE and post-DBE partial pressure of oxygen in the blood (PaO₂) and partial pressure of carbon dioxide in the blood (PaCO₂) between groups.

Small sample size.

CO₂ insufflation is a safe and useful procedure when performed during DBE.