Choice of injection time of conscious sedation and its impact on pain control in colonoscopy

PurposeThe aim of this study was to identify the effect of different injection times on pain during colonoscopy procedure. MethodsIn this retrospective study, the data of patients who underwent colonoscopy from June 2020 to September 2020 were assessed to investigate the effect of different injection time of sedative drugs (midazolam and dezocine). The primary endpoint was evaluating the pain intensity of the patients using visual analogue scale (VAS) immediately after colonoscopy . ResultsA total of 152 patients were eligible for this study. Of them, 76 received midazolam and dezocine injection 1 min prior to the colonoscopy procedure (the 1 Min group) and the other 76 patients received the injection 3 min prior to the procedure (the 3 Min group). The vital signs of all patients were stable except for one patient who was diagnosed with inflammatory bowel disease in the 3 Min group. A transient drop in blood pressure for this patient was observed during colonoscopy but returned to normal after general treatment. The two groups had similar rates of cecal intubation (84.21% vs. 90.97%, P = 0.22), addition of sedative drugs during procedure (2.63% vs. 5.26%, P = 0.68), and adequate bowel preparation (Boston Bowel Preparation Scale >= 6, 61.84% vs. 61.84%, P = 1.0). However, patients in the 3 Min group had significantly lower VAS than those in the 1 Min group [0 (0, 1) vs. 1 (0, 2), P = 0.041]. ConclusionThe timing of drug injection during conscious sedation may affect pain control during colonoscopy, with 3 min prior to the procedure showing lower VAS.