Dexmedetomidine for prevention of postoperative pulmonary complications in patients after oral and maxillofacial surgery with fibular free flap reconstruction: a prospective, double-blind, randomized, placebo-controlled trial

Background: Postoperative pulmonary complications (PPCs) are common and significant problems for oral and maxillofacial surgery patients. Dexmedetomidine (DEX), an α2-adrenoreceptor agonist, has been proven having lung protection effects. However, since now, there has not been final conclusion about whether DEX can reduce the incidence of PPCs. We hypothesize that, in oral and maxillofacial surgery with fibular free flap reconstruction patients, DEX may decrease the incidence of PPCs.Methods: This was a prospective, double-blind, randomized, placebo-controlled, single-centered trial with two parallel arms. A total of 160 patients at intermediate-to-high risk of PPCs undergoing oral and maxillofacial surgery with fibular free flap reconstruction and tracheotomy were enrolled and randomized to receive continuous infusion of either DEX or placebo (normal saline). 0.4ug/kg dose of DEX was given over 10mins as an initial dose followed by a maintaining dose of 0.4ug/kg/h till the second day morning after surgery. At the same time, the normal saline was administered a similar quantity. The primary outcome was the incidence of PPCs according to Clavien-Dindo score within 7 days after surgery.Results: The two groups had similar characteristics at baseline. 18(22.5%) of 80 patients administered DEX, and 32(40.0%) of 80 patient administered placebo experienced PPCs within the first 7 days after surgery (relative ratio [RR] 0.563,95% confidence interval [CI] 0.346-0.916; P=0.017). In the first 7 days after surgery, the DEX group had a lower incidence of PPCs and a better postoperative survival probability (Log-rank test, P=0.019), and was less prone to occur PPCs (Cox regression, P=0.025, HR=0.516). When the total dose of DEX was more than 328μg, the patients were unlikely to have PPCs (ROC curve, AUC=0.614, P=0.009).Conclusions: Continuous infusion of DEX marks a huge decrease in the appearance of PPCs within the first 7days after surgery, for patients undergoing oral and maxillofacial surgery with fibular free flap reconstruction and tracheotomy.Trial registration: Chinese Clinical Trial Registry, www.chictr.org.cn, number: ChiCTR1800016153; Registered on May 15, 2018.