Neuromuscular monitoring

Abstract

In patients receiving a neuromuscular blocking agent, quantitative monitoring of neuromuscular function is essential. For this purpose, neuromuscular monitoring devices which provide train-of-four ratio values are necessary. In the absence of a quantitative monitoring device, neuromuscular function may be evaluated with the use of a nerve stimulator. Muscle responses can be monitored either using the mechanomyography, electromyography, acceleromyography, or phonomyography. Although, mechanomyography is still considred the gold standard for assessing the neuromuscular function, mechanomyography is not easy to set up and use in a routine clinical setting. At present we have only two commercially available devices which are easy to set up and useful in daily clinical practice. One is MNMT monitor which comes with Datex AS 3 or S 5 monitor. The other is TOF-Watch acceleromyographic monitor. In clinical anesthesia, sites of monitoring can be any superficially located peripheral nerves and innervated muscles. Since different muscle groups have different sensitivity to neuromuscular blocking agents, results obtained for one muscle cannot be extrapolated to other muscles. Also, results from one monitoring method cannot be extrapolated to other methods. Anesthesiologists should be aware of these differences. In this article, the basics of neuromuscular monitoring are summarized.