What anesthetic restrictions are there for TcMEP monitoring?
TcMEPs recorded from muscle are significantly affected by the use of halogenated agents and nitrous oxide as well as the level of neuromuscular blockade. At a minimum alveolar concentration (MAC) of 1.0 or higher of the gases, TcMEPs are often unobtainable. We recommend low levels of gas (0.5 MAC of Halogenated Agent or 50 percent Nitrous oxide) supplemented with intravenous narcotics and propofol infusion. A neuromuscular blockade of at least 2/4 twitches is also minimally necessary. The ideal anesthetic would involve a total intravenous technique of narcotics, propofol, and benzodiazepine with no neuromuscular blockade.
