Neuromuscular monitoring

The effect of muscle relaxants varies among people and the extent, the duration and recovery from the neuromuscular block varies. Clinical tests cannot determine the effect of muscle relaxants which is only possible with neuromuscular monitoring. The relaxometry procedure measures the muscular response to electrical stimulation of the corresponding motor nerve and the adductor pollicis muscle is mostly used; however, this muscle is not representative for other muscle groups, such as the muscles of the larynx and diaphragm. The muscles of the larynx and diaphragm are more resistant against nondepolarizing muscle relaxants than the adductor pollicis muscle. The train of four (TOF) is used at the beginning of surgery for monitoring of the optimal time for tracheal intubation; moreover, the TOF is used during surgery for monitoring of the muscle blockade and at the end of surgery for monitoring recovery. Monitoring of deep muscular blockades, however, is only possible with the posttetanic count (PTC) when there are no TOF counts. The PTC allows repetition and higher doses of muscle relaxants during abdominal surgery; therefore, conditions for surgery are optimal and cumulation of muscle relaxants is avoided.