鼻中隔矯正術を受ける成人患者における覚醒時せん妄予防のための先行的静脈内マイクロドースデクスメデトミジン

Emergence agitation (EA) is characterised by confusion, restlessness or aggressive behaviour during recovery from general anaesthesia. EA is more common following ear, nose, & throat (ENT) surgery. The exact cause and pathophysiology of EA are unknown, although risk factors include preschool age, preoperative anxiety, postoperative pain, nausea, vomiting, otolaryngology operations, and the use of inhalational anesthetics particularly sevoflurane. EA might cause injury, accidental removal of intravenous cannulation, self-extubation, post-operative wound bleeding and increase the nursing requirements in the post-anesthesia care unit (PACU). There are limited studies concerning adult EA, and although its prevalence is less than child EA, it carries more risk of injury due to serious uncontrolled behaviors. Intravenous (IV) anesthetics, sedatives and opioids are the most frequently utilized medications to manage EA, with variable success rates and significant potential to delay recovery and cause undesirable side-effects. Dexmedetomidine is a highly selective α2 agonist which produces sedation and anxiolysis through reduction in sympathetic central nervous system activity. It has a major advantage over other sedatives; it is associated with minimal respiratory depression. According to a recent meta-analysis, intraoperative administration of dexmedetomidine decreases postoperative pain and the incidence of EA in adults. Considering the short length of corrective nasal reduction surgery (CR), an intraoperative infusion of dexmedetomidine as an anesthetic adjuvant may prolong the anesthesia and recovery time. Low dose infusion of dexmedetomidine (0.2 µg /kg/h) has been reported to reduce incidence of EA and opioid consumption effectively in elderly patients undergoing cancer surgeries under GA. Previous studies have shown that a single dose of dexmedetomidine, not as a premedication, is also effective in reducing EA and facilitating smooth extubation after pediatric adenotonsillectomy. Also recent study reported the efficacy of pre-operative dexmedetomidine administration (1 μg/kg) in preventing EA in adults undergoing CR of a nasal bone fracture. Up till now no clinical studies investigated the efficacy of single pre-operative micro dose of dexmedetomidine in prevention of EA, so in this clinical study we hypothesize that preoperative micro dose of dexmedetomidine may be beneficial in mitigation of EA in short timed Septoplasty surgeries safely and without prolongation of recovery time.