Prophylactic administration of diphenhydramine/paracetamol reduced emergence agitation and postoperative pain following maxillofacial surgeries: a randomized controlled trial.

Background: Emergence agitation after maxillofacial surgeries is an anxious and problematic complication for the surgeon and anesthesiologist that may lead to self-extubation, haemorrhage, and surgical destruction. In this study, we investigated the effects of preemptive administration of diphenhydramine on emergence agitation and quality of recovery after maxillofacial surgery in adult patients.

Methods: Eighty-five patients undergoing maxillofacial surgery were randomized into two groups. The diphenhydramine group (Group D, n = 40) received diphenhydramine premedication 0.5 mg/kg before anesthesia induction, while the control group (Group C, n = 40) received volume-matched normal saline as a placebo. Before incision, all patients receive 0.1 mg/kg morphine sulfate slowly intravenously within 5 min. Continuous infusion of remifentanil 0.2 μg/kg/h and inhalation of isoflurane was maintained during the anesthesia period. Paracetamol 1 g was infused 15 min before extubation. We evaluated the incidence of agitation during the extubation period after general anesthesia, hemodynamic parameters, and recovery characteristics during the postoperative period.

Results: During extubation time, the incidence of emergence agitation was lower in Group D than in Group C (16% vs. 49%, P = 0.041). The time from isoflurane discontinuation to extubation (7.7 min in Group D vs. 6.8 min in Group C, P = 0.082) was not different. Grade of cough during emergence, the severity of pain, analgesic requirements, and hemodynamic changes were lower in group D compared with Group C.

Conclusions: Preemptive administration of diphenhydramine provided smooth emergence from anesthesia. It also improved the quality of recovery after maxillofacial surgery.

Trial Registration Number: This study was registered at http://irct.ir (registration number IRCT20130304012695N3).