[Testing of neuromuscular function during anaesthesia (author's transl)]

Traditionally clinical signs are used to evaluate neuromuscular blockade during anaesthesia. Recent research has shown that patients managed by clinical signs alone will often demonstrate postoperative residual curarization. The systematic use of nerve stimulator during and after anaesthesia can facilitate accurate evaluation and management of neuromuscular blockade. Unlike single twitch stimulation, train-of-four (TOF) stimulation can be used without preoperative control values. TOF stimulation is less painful than tetanic stimulation, does not influence the neuromuscular block itself and does not require a special recording apparatus. Furthermore, with regard to detection of residual curarization the sensitivity of TOF stimulation is greater than that of twitch or tetanus with 50 Hz in 5 seconds. The neuromuscular response can be evaluated in different ways: visually, tactillaly, mechanically or electrically. Routinely, visual and tactile impressions are combined to evaluate the degree of curarization; with TOF stimulation of the ulnar nerve for example, the number of visible contractions of the thumb correlates with the degree of curarization. To refine the evaluation of the muscular contraction it is possible to connect the thumb to a recorder. Use of a nerve stimulator facilitates more appropriate and individualized dosage of the neuromuscular blocking agents. In this way one may achieve an optimal level of surgical relaxation, avoid overdosage of the neuromuscular blocking agents and diminish the risk of post-operative residual curarization.