Efficacy of different dose of dexmedetomidine combined with remifentanil in colonoscopy: a randomized controlled trial

Background: Dexmedetomidine has advantages during colonoscopy as it allows the patient to cooperate during the procedure. Few studies examined the dexmedetomidine-remifentanil combination. This study was to evaluate the effects of different doses of the dexmedetomidine-remifentanil combination in colonoscopy.

Methods: This was a prospective trial carried out at the Fourth Hospital of Hebei Medical University between 02/2018 and 10/2018. The patients were randomized: group I (dexmedetomidine 0.2 μg·kg^{- 1}), group II (dexmedetomidine 0.3 μg·kg^{- 1}), and group III (dexmedetomidine 0.4 μg·kg^{- 1}), all combined with remifentanil. The primary outcomes were the patient's body movements during the procedure and adverse events.

Results: Compared with at admission (T₀), the SBP, HR, and RR at immediately after giving DEX (T₁), at the beginning of the examination (T₂), 5 min after the beginning of the examination (T₃), 10 min after the beginning of the examination (T₄), and at the end of the examination (T₅) in the three groups were all reduced (all P < 0.05), but all were within the clinically normal range. SpO₂ remained > 98% in all patients during the examination. Compared with T₀, the BIS values of the three groups were decreased at T₁ and T₂ (all P < 0.05). There were no significant differences in BIS among the three groups (all P > 0.05). The minimum BIS value in group III was lower than in groups I and II (P < 0.05). The degree of satisfaction with the anesthesia effect was higher in groups II and III that in group I (P < 0.05). No hypotension occurred, seven patients had bradycardia, and four patients had nausea/vomiting.

Conclusions: Dexmedetomidine 0.3 μg·kg^{- 1} combined with remifentanil was effective for colonoscopy and had few adverse reactions. Chinese Clinical Trial Registry: ChiCTR2000029105 , Registered 13 January 2020 - Retrospectively registered.

Keywords: Analgesia; Colonoscopy; Conscious sedation; Dexmedetomidine; Piperidines.