Effect of low-concentration sevoflurane with propofol anesthesia on transcranial motor-evoked potential: a crossover interventional trial.

PURPOSE: The aim of this study was to determine the feasibility of intraoperative motor function monitoring using motor-evoked potential (MEP) in combination with low-concentration sevoflurane during propofol anesthesia.

METHODS

This study was a prospective, non-randomized trial that included 38 patients undergoing neurosurgery. MEP were performed under age-adjusted 0, 0.2, and 0.5 minimum alveolar concentrations (MACs) of additional sevoflurane inhalation on propofol anesthesia sequentially. MEP monitoring positive rate, amplitude, latency, and physiological variables were compared between the sections.

RESULTS

The percentages of monitoring positive rate with additional 0.2 and 0.5 MACs of sevoflurane were 86.8% and 36.8%, respectively [p < 0.001, 0.5 MAC; relative risk = 0.424, 95% confidence interval (CI) 0.275-0.655]. The amplitudes and latency were significantly decreased and prolonged with sevoflurane administration and increasing MAC. Areas under the curve for 0.2 and 0.5 MACs of sevoflurane were 0.976 (95% CI 0.923-1.000) and 0.857 (95% CI 0.740-0.974), respectively. The best cutoff values were 462.3 µV and 820.6 µV, respectively.

CONCLUSIONS

Results suggested that combined anesthetic management can be performed if the amplitude is higher than the cutoff values.