Objective

This study aimed to evaluate differences in transcranial electrical motor evoked potential (tcMEP) amplitudes between desflurane/remifentanil and propofol/remifentanil anesthesia treatment plans in patients without preexisting motor deficits (PMDs) undergoing carotid endarterectomy (CEA).

Methods

This prospective trial included 21 patients who were randomly assigned to an effect group (Group^DESFLURANE; n = 14) or a control group (Group^{STANDARD-PROPOFOL}; n = 7). tcMEP amplitudes were measured 35 min post-induction (T1) either with desflurane or propofol. Treatment was then changed to propofol in Group^DESFLURANE. After an additional 35 min, the tcMEP amplitudes were reevaluated (T2). Differences in amplitudes (DW) between T1 and T2 were calculated for each patient, and the means of these differences were compared between groups.

Results

tcMEPs were recorded in all 21 patients. At T1, the mean amplitude was 840.1 (SD 50.3) μV and 358.9 (SD 74) μV for Group^{STANDARD-PROPOFOL} and Group^DESFLURANE, respectively. The absolute mean difference (T1−T2) between groups was −496.75 μV (p = 0.0006).

Conclusion

Desflurane reduces the tcMEP amplitude significantly more than propofol in patients without PMDs undergoing CEA.

Significance

TcMEPs were recorded in all patients regardless of the anesthesia regimen. In patients with initially small amplitudes, desflurane may limit tcMEP recording because it produces a remarkable amplitude reduction, even in patients without PMDs.