P01 - Does the use of dexmedetomidine upon emergence from anesthesia reduce bleeding complications following free flap reconstruction of the head and neck? – A retrospective study

Abstract: Purpose
The use of dexmedetomidine has been shown to be associated with decreased delirium, pulmonary complications, and cough reflex from emergence from anesthesia following free flap reconstructive surgery of the head and neck (1-3). However, its potential association with hemodynamics and surgical site bleeding in the early postoperative period ( < 24 hours) following major head and neck surgery has not been well studied. The purpose of this study is to compare postoperative bleeding complications at the recipient site following microvascular free flap reconstruction of the head and neck in patients who receive dexmedetomidine upon emergence from anesthesia. The specific aims of the study were to 1) compare the postoperative complications between treatment groups, 2) identify predictors for complications, and 3) compare the length of hospitalization between treatment groups. The authors hypothesize that patients who receive dexmedetomidine upon emergence from anesthesia will have lower incidence of bleeding-related postoperative complication at the recipient site and an associated shortened length of hospitalization as well.

Methods
Retrospective analysis of patients who underwent microvascular head and neck reconstruction from 2014–2021. The predictor variable was the use of dexmedetomidine upon emergence from anesthesia. The primary and secondary outcomes were POC within one day, and length of hospitalization (LOS), respectively. Covariates included age, sex, tobacco and alcohol history, hypertension, pathology, location, flap used, tracheostomy, and neck dissection. Perioperative mean systolic and diastolic blood pressure (SBP/DBP) readings were also recorded for analysis. For all statistical tests, P values of < 0.05 were regarded as statistically significant.

Results
A total of 602 patients were included for analysis (298, DEX and 304, control). The mean age was 59 years (range, 14-94), 61% were male, and 73% had malignant disease. Absence of alcohol use (RR=0.809, 95%CI=0.686-0.954, P=0.011), tracheotomy (RR=1.435, 95%CI=1.226-1.679, P< 0.001), and increased preoperative SBP/DBP (P < 0.01) were associated with DEX. Overall incidence of POC was 5% and lower in the DEX group (RR=0.947, 95%CI=0.912-0.982, P=0.004). Advanced age had 0.976-odds for POC (95%CI=0.953-0.999, P=0.044). LOS was shorter in the DEX group compared to the control (7.75 vs. 9.43 days, P=0.001). Tobacco use and neck dissection were independent predictors for LOS.

Conclusions
The use of dexmedetomidine in the early preoperative period is associated with decreased postoperative complications and length of hospitalization following microvascular head and neck reconstruction without major changes in hemodynamic changes.

References
1. Yang X, Li Z, Gao C, Liu R. Effect of dexmedetomidine on preventing agitation and delirium after microvascular free flap surgery: a randomized, double-blind, control study. Journal of Oral and Maxillofacial Surgery. 2015 Jun 1;73(6):1065-72.
2. Liu Y, Zhu X, Zhou D, Han F, Yang X. 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. BMC anesthesiology. 2020 Dec;20(1):1-4.
3. Kim SH, Kim YS, Kim S, Jung KT. Dexmedetomidine decreased the post‐thyroidectomy bleeding by reducing cough and emergence agitation–a randomized, double‐blind, controlled study. BMC anesthesiology. 2021 Dec;21(1):1-0.