Carbon dioxide insufflation for colonoscopy: evaluation of gas volume, abdominal pain, examination time and transcutaneous partial CO₂ pressure

Abstract

Background

Insufflation with carbon dioxide (CO₂) in colonoscopy has not been widely adopted and, consequently, limited data are available on insufflated gas volume and blood pCO₂. The aim of this study was to compare CO₂ and air as an insufflation agent in patients undergoing colonoscopy without sedation in terms of insufflated gas volume, pCO₂, pain and examination time.

Methods

This was a randomized, double-blind, control trial. Consecutive patients presenting for colonoscopy, excluding those with lung or malignant disease, were randomized into two groups: insufflation with air or with CO₂, respectively. Insufflated gas volume, pain, pCO₂ and examination time were assessed.

Results

The study cohort comprised 120 patients (66 randomized to CO₂ group). No significant difference in insufflated gas volumes was found between the CO₂ and air groups. The mean pCO₂ measured before, during (the peak value) and 30 min after colonoscopy were 40, 43 and 40 mmHg, respectively, in both groups. The pain scores in the air group were significantly greater than those in the CO₂ group until 3 h after the examination. There was a significant faster cecal intubation time and a trend toward shorter examination time in the CO₂ group.

Conclusions

The CO₂ gas volume used in our study (14.0 L) was much greater than that reported by others (8.3 L), but the pCO₂ values were still within the normal reference range, indicating the safety of CO₂ insufflation over a greater range of CO₂ gas volume. Among our patients, CO₂ insufflation was associated with relatively less pain and a shorter examination time. Based on our results, we recommend that CO₂ become the standard gas for insufflation in patients undergoing colonoscopy without sedation.