RESUMO
BACKGROUND: Dexmedetomidine (DEX) has sedative, sympatholytic and analgesic effects and might be beneficial if used as an adjuvant to: improve analgesia; modulate haemodynamic responses to intubation and pneumoperitoneum and; reduce the number of opioid-associated adverse events. The aim of this study was to evaluate the efficacy and safety of DEX infusion during elective laparoscopic cholecystectomy (LC). METHODS: A randomized, single-centre, parallel-group, placebo-controlled study was carried out between May 2016 and June 2017. Adult patients (18-79 years) with American Society of Anesthesiology (ASA) physical status I-II were randomly assigned to 0.5 µg/kg/h DEX infusion from induction of anaesthesia to extubation (Group D; n = 30) or normal saline infusion (Group C; n = 30). The primary efficacy outcomes were postoperative morphine consumption. Secondary efficacy outcomes included: time to first use of rescue analgesia; postoperative morphine consumption; intraoperative fentanyl consumption; time from end of surgery to extubation; lengths of intensive care unit (ICU) and general ward stay; degree of postoperative pain 3, 6, 12 and 24 h after surgery; incidence of persistent post-surgical pain. RESULTS: DEX infusion was associated with a decrease in postoperative morphine consumption (p = 0.001), lower incidence of severe postoperative pain (odds ratio [OR] 9, 95% confidence interval [CI] 1.1-77, p = 0.04) and significantly longer time to first use of rescue analgesia (p = 0.001). Group D also had significantly lower fentanyl consumption both intraoperatively (p = 0.001) and in the time from end of surgery to extubation (p = 0.001) plus decreased incidence of persistent post-surgical pain (OR 14.5, 95% CI 1.7-122, p = 0.005). The incidence of postoperative nausea and vomiting was lower in Group D than Group C (OR 5, 95% CI 1.1-26, p = 0.005). Median pain intensity did not differ between the groups 3, 6, 12 or 24 h after surgery and there were no inter-group differences in the lengths of ICU stay or overall hospital stay between groups. The incidence of hypertension was significantly higher in Group C (OR 13.8, 95% CI 4-48, p < 0.0001); there were no inter-group differences in incidences of hypotension and bradycardia. CONCLUSIONS: Intraoperative DEX infusion is safe and effective for improving analgesia during and after elective LC. DEX appears to significantly reduce the number of patients with severe postoperative pain, postoperative morphine consumption and prolong time to first use of rescue analgesia. TRIAL REGISTRATION: ClinicalTrials.gov: Retrospectively registered on July 7, 2017, NCT03211871 .
