NEUROMUSCULAR MONITORING - DOES IT MAKE A DIFFERENCE

Purpose: The objective of the present prospective study was to evaluat e the influence of neuromuscular monitoring on the level of neuromuscu lar blockade from induction of anaesthesia until extubation of the tra chea. Methods: Forty-two patients aged between 18 and 73 yr undergoing a range of surgical procedures under general anaesthesia were randoml y distributed into two groups of 21 patients each. In both groups a Da tex NMT Monitor(R) was used and electromyographic responses of the the ulnar muscles to supramaximal stimulation of the ulnar nerve were rec orded. In Group 1, the anaesthetist could see the movements of the sti mulated hand, but not the monitor. In Group 2, the anaesthetist could see neither the stimulated hand nor the monitor. The same anaesthetist administered the neuromuscular relaxants which were succinylcholine 1 .5 mg . kg(-1) for tracheal intubation and vecuronium 0.1 mg . kg(-1) for neuromuscular relaxation during surgery, followed by 1 to 2 mg mai ntenance injections. Possible residual curarization was evaluated in t he recovery room by head lift tests and pulse oximetry. Results: Patie nts in Group 1 had deeper neuromuscular block throughout surgery, desp ite the use of a comparable dose of vecuronium (10.1 mg for G1 vs 11.2 mg for G2). The EMG values of T-1 and train-of-four values were not d ifferent at tracheal intubation or at extubation. No patients presente d signs of residual curarization in the recovery room. Conclusion: The study demonstrates that with the same amount of vecuronium the neurom uscular relaxation was deeper with the use of a simple neuromuscular m onitoring (visual evaluation of the thumb movements). Despite the deep er neuromuscular block in the monitored group, there was no residual c urarization in the recovery room.