Carbon Dioxide Insufflation for Potentially Difficult Colonoscopies Performed Without Sedation: Valuable Training for Inexperienced Colonoscopists

Abstract

Background and Aims: Colonoscopy is a preferred method for screening, diagnosing and treating colorectal cancer, but prolonged cecal intubation can cause increased patient abdominal pain and discomfort especially in difficult cases. A prospective randomized controlled study was conducted to clarify effectiveness of carbon dioxide (CO2) insufflation in potentially difficult cases particularly in relation to the experience levels of participating colonoscopists. Methods: A total of 120 potentially difficult cases involved female patients with a low body mass index and patients with earlier abdominal and/or pelvic open surgery or previously diagnosed left-side colon diverticulosis. Exclusion criteria were severe heart or lung disease, a prior colorectal resection, inflammatory bowel disease, therapeutic procedures as well as incomplete colonoscopies. All examinations were performed without sedation using a pediatric variable-stiffness colonoscope with patients divided into CO2 and standard air insufflation groups. Midazolam (2-3mg/iv) was administered based on an individual colonoscopist's judgment or a patient's request after complaining of abdominal pain or distension. Insufflation procedures were also evaluated based on the background of colonoscopists who were divided into experienced colonoscopist (EC) and less experienced colonoscopist (LEC) groups. Study measurements included a visual analogue scale (VAS) to assess patient pain during and after colonoscopy examinations in addition to cecal intubation and withdrawal times. Results: There were no significant differences in baseline patient characteristics including eligibility criteria for potentially difficult cases between the two groups. Neither were there any procedure-related complications in either group. Midazolam was administered to two patients (4%) in each group. Examination times did not differ, but VAS scores were significantly better in the CO2 group than in the air group (p<0.001; two-way ANOVA) from immediately following the procedures until two hours afterwards. There were no significant differences between either insufflation method in the EC group (p=0.29), but VAS scores for CO2 were significantly better than those for air in the LEC group (p=0.023) from right after the procedures until four hours later. Conclusions: The clinical effectiveness of CO2 insufflation was clearly demonstrated in potentially difficult colonoscopy examination cases performed without sedation. In particular, this procedure's rapid CO2 absorption and improved efficacy reduced patient pain after colonoscopies performed by LECs so we recommend incorporating its use in colonoscopy training programs.