Évaluation de la force musculaire au cours de la chirurgie

The electrical activity of a resting skeletal muscle is zero, but the motor drive to skeletal muscles may be high as a consequence of surgical stimulation of nociceptors and muscle spindles. Muscle relaxation can be accomplished by systemic administration of hypnotics and opioids, or regional anesthesia. Neuromuscular blocking drugs (NBD) induce dose-dependent muscle relaxation, which optimizes surgical conditions. The flip side of the coin relates to the fact that NBD effects vary widely between individuals, such that postoperative residual neuromuscular blockade occurs frequently (incidence: 20-30% depending on the criteria used for making the diagnosis). Residual neuromuscular blockade is associated with impaired postoperative respiratory function and delayed recovery. We recommend a multimodal approach to accomplish muscle relaxation where low doses of NBD are being used whenever possible, effects be monitored quantitatively, and residual neuromuscular block be reversed. Acetylcholinesterase inhibitor reversal can cause many side-effects, so the lowest efficacious dose should be used: as little as 0.015-0.025 mg/kg of neostigmine is typically sufficient to reverse NBD effects at a train-of-four count of four with minimal fade. Sugammadex reversal is a viable approach to rapidly antagonize deep and shallow levels of neuromuscular block. We propose a multimodal approach to optimize muscle relaxation during surgery: optimized positioning, as well as hypnotics, regional anesthesia, opioids, and low-doses of NBD should be combined creatively taking into account the pharmacokinetics of the drugs as well as the target time of recovery of the muscle strength. Effects of NBD should be monitored quantitatively, and reversed appropriately.