Nondepolarizing neuromuscular blockade does not alter sensory evoked potentials.
OBJECTIVE
The objective of this study was to determine whether changes in nondepolarizing neuromuscular blockade (NMB) alter the latency or amplitude of visual, brain stem auditory, or median nerve somatosensory evoked potentials.


METHODS
Ten adult cynomologous Macaca fascicularis monkeys were studied during continuous ketamine anesthesia infusion. The NMB was incrementally adjusted between no block and complete block using infusions of vecuronium or atracurium. The NMB was measured by observing the mechanical response of the hand muscles to train-of-four stimulation of the median nerve and by quantification of the peak-to-peak electromyographic activity of the thenar muscles to supramaximal median nerve stimulation. The following variables were measured: the latencies of the three major peaks of the brain stem auditory evoked potential, the latency and amplitude of the cortical visual evoked potential, the latency of the spinal cord response, and the latency and amplitude of the cortical median nerve somatosensory evoked response.


RESULTS
No statistically significant changes were observed for any evoked response variable measured at any degree of NMB when compared with values obtained in the unblocked control state.


CONCLUSIONS
The results suggest that fluctuating degrees of NMB may contribute little to changes in these evoked potentials during intraoperative monitoring, given the testing parameters used.
Sloan
T B
TB
Department of Anesthesiology, University of Texas Health Science Center at San Antonio 78284-7838.
D000818:Animals; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects* / Q000502:physiology; D005260:Female; D008252:Macaca fascicularis; D008297:Male; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*
D003473:Neuromuscular Nondepolarizing Agents