Abstract:Abstract: Objective?To compare the VAS score, abdominal distension and satisfaction of carbon dioxide insufflation on the patients underwent painless colonoscopy.?Methods?We divided 200 patients who underwent painless colonoscopy into two groups randomly (air insufflation group and carbon dioxide insufflation group), record and compared the maximal VAS score, the time of abdominal distension and satisfaction. All the data was analyzed by SPSS16.0.?Results?The maximal VAS score was (1.42 ± 0.55) score in the air insufflation group whereas (0.52 ± 0.16) score in the carbon dioxide insufflation group (t = 10.78, P < 0.01), the time of distension after painless colonoscopy was (45.60 ± 16.78) min in the air insufflation group whereas (21.31 ± 19.67) min in the carbon dioxide insufflation group (t = 10.13, P < 0.01), the patients’ satisfaction in the air insufflation group was (92.46 ± 1.93) score, the carbon dioxide insufflation group was (99.95 ± 0.36) score, (t = -37.95, P < 0.01), the time of painless colonoscopy was (10.55 ± 5.33) min in the air insufflation group whereas (10.96 ± 5.23) min in the carbon dioxide insufflation group, (t = -0.54, P > 0.05).?Conclusion?Carbon dioxide insufflation during painless colonoscopy can decrease the patients’ pain, shorten the time of abdominal distension and increase the patients’ satisfaction after painless colonoscopy.