In this randomized, controlled trial of adult patients undergoing CR of a nasal bone fracture, pre-operative administration of intravenous dexmedetomidine demonstrated several benefits such as a lower incidence of EA, reduced agitation severity, and a shorter duration of agitation. In addition to these beneficial effects on EA, we observed more stable maintenance of intraoperative anesthesia with less movement during surgery in patients who were premedicated with dexmedetomidine. Furthermore, there was no statistical difference between the groups in terms of the incidence of complications, such as pre-operative sedation and hypo- or hypertension; however, the PACU stay duration was longer in the dexmedetomidine group.
EA after anesthesia is common during the immediate postoperative period; however, its etiology in adults is unclear, and serious sequelae of EA have rarely been studied in adult patients.[14, 15] Many factors predispose a patient to EA, which is frequently initiated by uncomfortable stimuli. Nasal surgery is known to be associated with a relatively high incidence of EA.[6, 13] After a CR of a nasal fracture, external splints and nasal packing are commonly used to stabilize and protect the reduction in lieu of screw insertion or fixation. The presence of external splints and nasal packing can be uncomfortable and make it difficult for patients to breathe, possibly contributing to the development of EA. Severe EA can result in nasal bleeding, re-dislocation of the reduced fracture, and even the need for reoperation. Additionally, in patients who develop respiratory depression after anesthesia, respiratory support with a face mask or airway can be difficult.
Dexmedetomidine induces sedation and analgesia without respiratory depression. Several studies have advocated the beneficial effects of intraoperative administration of dexmedetomidine for reducing the incidence of perioperative morbidities after nasal surgery, such as intraoperative bleeding, postoperative pain, and EA.[13, 18, 19] Considering the short length of CR surgery, an intraoperative infusion of dexmedetomidine as an anesthetic adjuvant may prolong the anesthesia and recovery time. 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. However, there were no reports about single-dose premedication of dexmedetomidine in adult patients. Thus, we aimed to evaluate the efficacy of pre-operative dexmedetomidine administration in preventing or reducing the severity of EA in adults undergoing CR of a nasal bone fracture.
In our study, fewer patients developed EA, and the severity of agitation was also significantly lower in the dexmedetomidine group as compared to previous studies. Two patients in the dexmedetomidine group developed pre-operative sedation (RASS score ≤ -3, no verbal response); however, no patients showed desaturation (SpO2 <95%), and the incidence of sedation was not statistically different between the two groups (P = 0.49). Even though the duration of the PACU stay was significantly longer in the dexmedetomidine group than in the control group, the anesthesia time was significantly shorter in the dexmedetomidine group. This may be due to a higher incidence of agitation in the control group. Transport to the PACU after extubation is sometimes delayed in patients who experience EA because of patient safety concerns. In this study, the time from the end of surgery to extubation was not significantly different between the two groups, and the duration of the PACU stay was clinically acceptable in both groups (32 min vs. 41 min).
Dexmedetomidine can cause hemodynamic changes including hypotension, hypertension, and bradycardia. We analyzed the patients’ mean arterial pressure at three-time points (baseline, pre-operative, and postoperative in the PACU) and there were no significant differences between the groups (P = 0.75). Furthermore, there was no patient who showed hypotension that required ephedrine in both groups. One patient developed bradycardia (heart rate <45 beats per minute) and was treated with ephedrine; however, the incidence of bradycardia was not statistically different between the groups (P = 0.93). The use of pre-operative dexmedetomidine showed no analgesic advantage as the NRS pain scores in the PACU were not different between the two groups. Even though a standardized anesthetic technique and administration of a muscle relaxant was used in both groups, significantly fewer patients in the dexmedetomidine group showed movement during the operation; therefore, pre-operative dexmedetomidine may be useful as an adjuvant anesthetic to help maintain stable intra-operative anesthesia.
First, we did not assess the effect of different doses of dexmedetomidine. According to the results of a previous study, a single dose of dexmedetomidine (0.5 μg•kg-1) was effective in reducing EA in children. In this study, we used a larger dose of 1 μg•kg-1, and there was no significant difference in the incidence of hypo- or hypertension, bradycardia, or other side effects related to dexmedetomidine between the two groups. Second, we did not evaluate the effect of dexmedetomidine on the inhalational anesthetic dose. The dose of sevoflurane was titrated to maintain a specific BIS range, but we did not compare the inhalational anesthetic consumption and we could not directly assess the anesthetic-sparing-effect of the premedicated dexmedetomidine. It would be worthwhile to perform a future study using a different dose of dexmedetomidine and controlled inhalational anesthetic drug.