Monitoring neuromuscular blockade.

Neuromuscular-blocking agents (NMBA) have been used in clinical anesthesia for nearly 60 years. In the perioperative period, a variety of factors can influence a patient’s response to these drugs. To precisely titrate NMBAs to clinical effects in the anesthetized patient, the application of neuromuscular monitoring is essential. The use of a peripheral nerve stimulator allows the clinician to assess the intensity of the neuromuscular block. Profound muscle relaxation (to permit tracheal intubation and ensure immobility), moderate muscle relaxation (to facilitate surgical procedures), and recovery of neuromuscular function can be evaluated by monitoring evoked responses to nerve stimulation. This chapter reviews the physiology of neuromuscular transmission, the fundamental principles of neurostimulation, the patterns of nerve stimulation used in the operating room, and the assessment of evoked responses to peripheral nerve stimulation. In addition, the role of neuromuscular monitoring in detecting, and possibly avoiding, residual paralysis in postoperative patients is examined.