Effect of dexmedetomidine-etomidate-fentanyl combined anesthesia on somatosensory- and motor-evoked potentials in patients undergoing spinal surgery

This aim of the present study was to evaluate the effects of dexmedetomidine (DEX) on the intraoperative monitoring of somatosensory-evoked potentials (SEPs) and motor-evoked potentials (MEPs) in patients undergoing spinal surgery. A total of 36 patients who received spinal surgery under general anesthesia were randomly divided into two groups (n=18 per group), group C, the test group and group D, the control group, and these groups were subjected to a matching anesthesia induction. In brief, the anesthesia was administered via injection of etomidate and fentanyl; once the patients were unconscious, a laryngeal mask airway (LMA) was inserted, SEPs and MEPs were monitored and the collected data were considered to be basic data. Cisatracurium was subsequently injected and an endotracheal tube (7#) was inserted to replace the LMA. The following procedures were conducted for anesthesia maintenance: Group C, the anesthesia was maintained via target-controlled infusion of etomidate and intermittent injection of fentanyl; and group D, DEX (0.5 μg/kg) was injected over a duration of 10 min and then pumped at a rate of 0.5 μg/kg/h. In the two groups, all of the other drugs used were the same and a muscle relaxant was not administered. The bispectral index was maintained between 45 and 55 during surgery, and the SEPs and MEPs were monitored continuously until the surgery was completed. No significant difference in duration and amplitude of the SEPs (P15-N20) was identified between group C and D (P>0.05). Furthermore, the MEPs were monitored in the two groups at specific durations and no significant difference was observed between the two groups (P>0.05). The SEPs and MEPs were maintained in the patients who were administered with the DEX-etomidate-fentanyl combined anesthesia during spinal surgery.