[Influence of non-depolarizing relaxant on facial nerve monitoring during total intravenous anesthesia].

Objective: To study the feasibility of using non-depolarizing relaxant in intraoperative facial nerve monitoring (IFNM) during total intravenous anesthesia (TIVA).

Methods: Thirty adult patients, aged 37 (20-50), with ASA class I or II, without disorder of facial nerve, underwent IFNM during TIVA, using fentanyl, midazolam, and propofol, to record the compound muscle action potentials (CMAPs) of the facial nerve. Train of four (TOF) pattern was used to evaluate the degree of peripheral neuromuscular blockade. The relationship between the TOF value and CMAP was studied.

Results: When the TOP value was 1 the wave amplitude of the CMAP of facial nerve was 0.19 +/- 0.08 mv, significantly lower than that when no muscle relaxant was used (2.72 +/- 0.34 mv, P < 0.01), however, when the TOF values were > or = 2 there were no statistically significant differences in the amplitude of the CMAP of facial nerve. In addition, clear graph of CMAP could be obtained when the TOF values were > or = 2.

Conclusion: IFNM can be safely and efficaciously performed when neuromuscular blockade is monitored carefully during TIVA.