Impact of dexmedetomidine supplemented analgesia on delirium in patients recovering from orthopedic surgery: A randomized controlled trial

BACKGROUND: Dexmedetomidine promotes normal sleep architecture; the drug also improves analgesia. We therefore tested the hypothesis that supplementing intravenous analgesia with dexmedetomidine reduces delirium in older patients recovering from orthopedic surgery. METHODS: In this double-blinded randomized controlled trial, we enrolled 712 older (aged 65–90 years) patients scheduled for major orthopedic surgery. Postoperative analgesia was provided by patient-controlled intravenous sufentanil, supplemented by randomly assigned dexmedetomidine (1.25 μg/mL) or placebo, for up to three days. The primary outcome was the incidence of delirium assessed twice daily with the Confusion Assessment Method. Among secondary outcomes, pain severity was assessed twice daily and sleep quality once daily, each with an 11-point scale where 0 = no pain/the best possible sleep and 10 = the worst pain/the worst possible sleep. RESULTS: The incidence of postoperative delirium was 7.3% (26 of 354) with placebo and 4.8% (17 of 356) with dexmedetomidine; relative risk 0.65, 95% CI 0.36 to 1.18; P = 0.151. Dexmedetomidine reduced pain both at rest (median difference -1 to 0 points, P ≤ 0.001) and with movement (-1 points, P < 0.001) throughout the first 5 postoperative days; it also improved subjective sleep quality during the first 3 postoperative days: day one median difference -1 point (95% CI -1 to 0), P = 0.007; day two 0 point (-1 to 0), P = 0.010; and day three 0 point (-1 to 0), P = 0.003. The incidence of adverse events was similar in each group. CONCLUSIONS: Supplementing sufentanil intravenous analgesia with low-dose dexmedetomidine did not significantly reduce delirium, but improved analgesia and sleep quality without provoking adverse events. TRIAL REGISTRATION: www.chictr.org.cn: ChiCTR1800017182 (Date of registration: July 17, 2018); ClinicalTrials.gov:NCT03629262 (Date of registration: August 14, 2018). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12871-021-01441-3.