Peripheral Nerve Stimulator

Peripheral nerve stimulation is an essential intra- and postoperative monitor of neuromuscular function and serves as a guide during critical periods including intubation and recovery from a general anesthetic. This is monitored by evaluating the muscular response to supramaximal electric stimulation of a peripheral motor nerve. Common sites include facial nerve (facial twitch) and ulnar nerve (thumb abduction). There are five patterns of stimulation commonly elicited. These are single-twitch stimulation, train-of-four (TOF) stimulation, double-burst stimulation, tetanic stimulation, and posttetanic count stimulation. There is good emerging evidence that objective monitoring performed perioperatively ensuring a TOF ratio greater than 0.9 will cause a subsequent decrease in the incidence of postoperative residual paralysis.