Continuous electromyography for monitoring depth of anesthesia

Utilizing a randomized, controlled study design, the clinical utility of monitoring spontaneous electromyography during methohexital anesthesia was evaluated for short outpatient gynecologic procedures. In the experimental group (n = 20), the anesthesiologist used conventional monitors as well as the Datex ABM device for determining the maintenance anesthetic requirement. The control group (n = 20) was monitored in an identical fashion, but the video monitor screen was turned off during the operation. The methohexital maintenance requirement was nonsignificantly decreased (5.0 +/- 1.2 vs 5.6 +/- 1.8 mg/min) in the experimental group. Adequacy of anesthesia (as determined by cardiorespiratory stability and the absence of purposeful movement during the maintenance period) did not differ between the two study groups. Although the awakening time for the experimental group (2.9 +/- 1.9 minutes) was decreased to a statistically significant degree compared to the control group (4.5 +/- 3.0 minutes), the difference was of no clinical significance. Thus, continuous electromyographic and EEG monitoring with the Datex ABM device did not significantly improve administration of methohexital during brief outpatient procedures.