Assessment of Facial Nerve Stimulation Methods to Determine the Optimal Time for Tracheal Intubation after Vecuronium Injection

Kim, Kyo Sang; Han, Jeong Uk; Jun, Jong Hun; Shim, Jae Chul; Kim, Kyoung Hun; Lee, Dong Ho; Suh, Jung Kook; Yoo, Hee Koo; Seung, Ik Sang; Chon, Se Ung

Abstract

Absence of response to train of four(TOF) and single twitch stimulation at ulnar nerve did not guarantee ided intubation conditions after vecuronium. The double burst stimulation (DBS) introduced by Viby-Mogensen, made it easier to evaluate postoperative residual neuromuscular blockade manually than did the use of the TOF method. The purpose of this study was to examine which will be the best stimulus among DBS, TOF and single twitch stimulation(STS) for an indicator of the optimal time for tracheal intubation. One hundred and nine healthy patients were randomly allocated to three groups in which DBS(n=34), TOF(n=38) and STS(n=37) group. Anesthesia was induced with thiopental sodium 3-5 mg/kg and maintained 1% enflurane until intubation. Neuromuscular block was induced by intravenous vecuronium0.1 mg/kg, and applied facial nerve stimuli immediately by DBS, TOF and STS using INNERVATOR(Fisher and Paykel Co.) continuously. The complete relaxation time of orbicularis oculi muscle was closely observed with authors naked eyes. Tracheal intubation was performed immediately by the author after disappearance of the response to stimuli. The intubation time from intravenous injection of vecuronium was recorded, and the intubating conditions were evaluated by vocal cords opening, coughing reflex and response to laryngoscopy attempts. The intubation time was 195.9+/-74.7(90-390) seconds in DBS group, 180.9+/-49.8(100-290) seconds in TOF group and 167.7+/-37.9(90-270) seconds in STS group and there were no statistically significant difference. There were also no significance on vocal cords opening and response to laryngoscopy attempts in three groups but DBS group was statistically less cough reflex than TOF group and STS group(p<0.05). With the above results the authors concluded that DBS on the facial nerve with the orbicularis oculi muscle was most reliable index to determine the optimal time for tracheal intubation and the time was about l96 seconds after vecuronium.