Intraoperative use of dexmedetomidine for the prevention of emergence agitation and postoperative delirium in thoracic surgery: a randomized-controlled trial

Purpose: We investigated whether preventive use of dexmedetomidine during surgery was effective for reducing emergence agitation and postoperative delirium. Methods: In this double-blind randomized-controlled trial, 143 patients undergoing thoracoscopic lung resection surgery were randomly assigned to the dexmedetomidine-sevoflurane (DEX-Sevo, n = 73) or sevoflurane (Sevo, n = 70) groups. Dexmedetomidine or saline administration was started after inducing anesthesia and continued until the end of surgery at a fixed dose (0.5 µg·kg ⁻¹ ·hr ⁻¹ ). The primary endpoint was the incidence of delirium up until the end of postoperative day 3. Emergence agitation and postoperative delirium were measured with the Riker sedation agitation scale and the confusion assessment method, respectively. The secondary endpoints were serum cytokine and catecholamine levels. Results: The DEX-Sevo group showed less frequent emergence agitation than the Sevo group (13% vs 35%, respectively; relative risk, 0.38; 95% confidence interval [CI], 0.18 to 0.79; P = 0.011) but the incidence of delirium after discharge from the postanesthesia care unit was not different (25% vs 25%, DEX-Sevo vs Sevo). Both pro- and anti-inflammatory cytokines were lower in the DEX-Sevo group than in the Sevo group. Nevertheless, the interleukin (IL)6/IL10 ratio (median difference, 5.8; 95% CI,1.8 to 10.0; P = 0.012) and IL8/IL10 ratio (median difference, 0.8; 95% CI, 0.2 to 1.3; P = 0.007) were higher in the DEX-Sevo group than in the Sevo group, indicating a pro-inflammatory cytokine balance in the DEX-Sevo group. Norepinephrine and epinephrine levels were lower in the DEX-Sevo group than in the Sevo group (both, P < 0.001). Conclusions: Intraoperative dexmedetomidine reduced emergence agitation but not postoperative delirium in patients undergoing thoracic surgery. Dexmedetomidine seemed to affect emergence agitation through catecholamines, but not through an anti-inflammatory action. Trial registration Clinical Research Information Service (KCT 0001877); registered 7 April, 2016.