[Comparison of the effects of continuous infusion of two doses of mivacurium in laryngeal microsurgery].

Objective: To compare the neuromuscular blocking effects and postoperative recovery profiles of continuous infusion of two doses of mivacurium during laryngeal microsurgery. Methods: From October to December 2022, 62 patients scheduled for elective laryngeal microsurgery under general anesthesia with endotracheal intubation were enrolled prospectively at Beijing Tongren Hospital, Capital Medical University. Patients were randomly assigned using a random number table to the low-dose mivacurium group (Group L,mivacurium 0.3 mg·kg-1·h-1) or the high-dose mivacurium group (Group H,mivacurium 0.5 mg·kg-1·h-1) based on different infusion doses of mivacurum. The following parameters were compared between the two groups: extubation time, surgical condition rating, recovery index, Cooper's intubation score, Cormack-Lehane (C-L) laryngoscopy grade, incidence of postoperative residual neuromuscular blockade, and incidence of allergy-related adverse events. Results: There were 17 males and 14 females in Group L, with a mean age of (48.0±13.7) years. Group H included 19 males and 12 females, aged (47.7±9.8) years. No significant differences in age or gender were observed between the two groups (all P>0.05). The extubation time in Group L was significantly shorter than that in Group H [(15.2±4.8) min vs (18.5±6.8) min, P<0.05]. The surgical condition grade (excellent/good) in group L and group H were 28/3 and 29/2, with no significant difference (P>0.05). No statistically significant differences were observed in recovery index, Cooper's intubation score, Cormack-Lehane laryngoscopy grade, incidence of postoperative residual neuromuscular blockade, or adverse events between Group L and Group H (all P>0.05). Conclusion: In laryngeal microsurgery, compared with continuous infusion of mivacurium at 0.5 mg·kg⁻¹·h⁻¹, a continuous infusion of 0.3 mg·kg⁻¹·h⁻¹ resulted in a shorter extubation time, maintained deep intraoperative neuromuscular blockade, provided satisfactory surgical conditions, and improved postoperative recovery.