Background: Carbon dioxide (CO2) insufflation has been shown to reduce the procedure-related pain and discomfort during colonoscopy. However, the effects of CO2 insufflation on the improvement of participant's stress had not been objectively analyzed.
Methods: Using a randomized, double-blinded design, 100 consecutive patients undergoing colonoscopy were assigned to have their examination performed with either CO2 or air insufflation. Patients completed a questionnaire to grade their discomfort using a visual analogue scale (VAS). The salivary alpha-amylase (SAA) level was also measured at these times as a marker of stress.
Results: The total VAS score did not show any statistically significant differences between the CO2 and air insufflation groups. However, the VAS score for abdominal fullness significantly decreased in the CO2 insufflation group in comparison to the air insufflation group in the patients who had a longer examination. The titer of the maximum SAA was significantly increased by colonoscopy (P <0.01). CO2 insufflation significantly reduced the total SAA after the colonoscopy in comparison with air insufflation (P < 0.05). The examination time and SAA tended to have a positive relationship in the air insuflation group. However, no such relationship was observed in the CO2 insufflation group.
Conclusions: CO2 insufflation significantly reduced the post-examination discomfort, as indicated by a salivary stress marker. The use of CO, rather than air insufflation reduced the patients' stress and may contribute to better acceptance of colonoscopy. The usefulness of CO2 insufflation was more prominent when a longer examination was necessary.