Sedation-Free Colonoscopy Using an Upper Endoscope Is Tolerable and Effective in Patients with Low Body Mass Index: A Prospective Randomized Study

OBJECTIVE Small-caliber upper endoscopes can be used safely and effectively for sedation-free colonoscopy. The objective of the study is to assess the efficacy of a small-caliber upper endoscope (9.2 mm) comparing with a standard colonoscope (12.2 mm). METHODS In a prospective trial, patients undergoing sedation-free colonoscopy were randomly assigned to the upper endoscope (E) or the standard colonoscope (C). Outcome measures included patient self-assessed pain score (4-point scale), endoscopist-assessed pain score (4-point scale), cecal intubation rate, difficult cecal intubation rate (>900 s), number of polyps detected, and complication rates. RESULTS A total of 244 patients were entered. Clinical characteristics were not different between the two groups. Cecal intubation was achieved in 91.0% of the patients in each group. The mean patient self-assessed pain score (SD) was significantly lower in the E group compared with the C group: 1.44 (0.81) versus 2.08 (1.10), p < 0.001. The mean endoscopist assessment of patient pain score (SD) was significantly lower in the E group compared with the C group as well: 1.27 (0.67) versus 1.58 (0.90), p = 0.003. In patients with low body mass index (BMI < 22 kg/m2), the cecal intubation rate was significantly higher in the E group (97.7% vs 79.4%, p = 0.026) and the difficult cecal intubation rate was significantly lower in the E group (9.3% vs 32.4%, p = 0.011). There were no significant differences in the number of polyps detected and complication rates between the two groups. CONCLUSION A small-caliber upper endoscope is tolerable and effective for sedation-free colonoscopy, especially in patients with low BMI.