Effect of dexmedetomidine on Sensory Evoked Potential monitoring during cervical spine surgery with total intravenous anesthesia : a randomized controlled trial

Abstract

Background :The effect of α2 adrenergic receptor agonist-dexmedetomidine on evoked potentials in cervical spinal cord remains unclear at the current stage. Therefore,this research investigates the effect of dexmedetomidine on sensory evoked potential during cervical spine surgery under total intravenous anesthesia, so as to provide reference for clinical practice. Methods:A total of 45 patients undergoing cervical spine surgery at the teaching hospital were randomly divided into group D (Dexmedetomidine group,n=23) and group C (Control group,n=22). Both groups were anesthetized with propofol and remifentanil. Group D was infused with dexmedetomidine starting at 1ug/kg for 10 minutes before induction, and then maintained at 0.4ug/kg/h during the operation. Group C was injected with the same dose of saline. Evoked responses were evaluated under seven conditions: awaking (T0), at the end of the loading dose infusion(T1), after induction of anesthesia (T2), after intubation (T3), positioning (T4), spinal canal decompression (T5), and interbody fusion cage insertion (T6).The amplitude (N13-P15, N45-P37) and latency (N13, P15, N45, P37) of SEP, heart rate (HR), mean arterial pressure (MAP), body temperature (T), and bispectral index (BIS) were recorded at these seven time points. The pre-and post-operative red blood cell specific volume (HCT) counts, as well as the intraoperative dosage of propofol and remifentanil were recorded in both groups. Results:A total of 40 patients completed the study. 1. Compared with T0, the N13-P15 amplitude decreased at T1 and T6 in group D （P＜0.05）, and significantly decreased at T6 in group C（P＜0.01）; The amplitude of N45-P37 decreased at T1, T5, and T6 in group D(P＜0.05) , and significantly decreased at T5 and T6 in group C（P＜0.01）.Compared with group D, the N45-P37 amplitude significantly decreased at T4 in group C （P＜0.05）.2. Compared with T0, the N13, P15, N45, and P37 latency were not statistically significant in both groups (P>0.05). 3. There was no statistical difference in MAP, HR, T, and BIS between the two groups (P>0.05) . Conclusion:Dexmedetomidine has no effect on the amplitude and latency of SEP in patients undergoing cervical spine surgery. More importantly, dexmedetomidine may have a protective effect on nerves during the positioning process. Trial registration:The study registered on the Chinese Clinical Trial Registry (www.chictr.org.cn), Clinical Trials identifier ChiCTR2300072621(19/06/2023).