Long awaited, the official ASA “practice guidelines” (distinct from the original “standards” in the late 1980’s that were specifically intended to mandate practice, but guidelines which, nonetheless, still have potential medical-legal implications for practitioners) on neuromuscular monitoring of and reversal of nondepolarizing blockers (NMB) are published. Avoiding postoperative residual NMB weakness with its significant patient safety risks is the main goal. The descriptive article outlining the extensive methodology and effort, evidence (of varying strengths) considered, and the actual guidelines is long and complex, including 277 references.
- Rather than qualitative clinical assessment, even with a traditional “nerve stimulator,” during and after NMB administration, quantitative monitoring using an electronic device that displays a measured train-of-four ratio (TOF) is listed as the principle “recommendation.”
- Specifically recommended is an electromyograph employing a single-use set of proximal and distal electrodes measuring transmission of nerve impulses to muscle (costing perhaps $15-20) rather than a less reliable and more difficult to use accelerometer employing crystals to sense motion of the thumb from ulnar nerve stimulation – see APSF Newsletter, October, 2021.
- The adductor pollicis (and not any periocular) muscle should be monitored.
- The TOF should be 0.9 prior to extubation after NMB use. This is the key factor in preventing dangerous residual weakness.
- Using rocuronium or vecuronium, with TOF < 0.4, sugammadex and specifically not neostigmine is recommended to reverse NMB, but neostigmine is a “reasonable alternative” with TOF 0.4-0.9.
- Using atracurium or cisatracurium, neostigmine should be administered to achieve TOF 0.9.
The accompanying editorial (which, interestingly, includes a picture of an accelerometer rather than an electromyograph) chronicles the history of resistance to the idea of quantitative NMB monitoring and the importance of studies demonstrating adverse postoperative respiratory events from residual weakness. It emphasizes that these ASA guidelines represent “evidence-based medicine” that should overcome old prejudices and be “internalized” by all.