Brief review: Neuromuscular monitoring: an update for the clinician

Abstract

Purpose:To review established techniques and to provide an update on new methods for clinical monitoring of neuromuscular function relevant to anesthesia.Source: A PubMed search of relevant article for the period 1985-2005 was undertaken, and bibliographies were scanned for additional sources. Principal findings:There is no substitute for objective neuromuscular monitoring; for research purposes, mechanomyography (MMG) is the gold standard; however, the most versatile method in the clinical setting is acceleromyography since it can be applied at various muscles and has a long track record of clinical utility. Kinemyography is valid to monitor recovery of neuromuscular transmission at the adductor pollicis muscle (AP), whereas phonomyography is easy to apply to various muscles and shows promising agreement with MMG. Monitoring of the corrugator supercilii muscle (CS) may be used to determine the earliest time for tracheal intubation as it reflects laryngeal relaxation better than monitoring at the AP. Recovery of neuromuscular transmission is best monitored at the AP, since it is the last muscle to recover from neuromuscular blockade (NMB). If train-of-four (TOF) stimulation is used, a TOF-ratio > 0.9 should be the target before awakening the patient. If surgery or the type of anesthesia necessitates NMB of a certain degree, e.g., TOF-ratio = 0.25, monitoring of muscles which best reflect the degree of NMB at the surgical site is preferable. Conclusion:Objective methods should be used to monitor neuromuscular function in clinical anesthesia. Acceleromyography offers the best compromise with respect to ease of use, practicality, versatility, precision and applicability at various muscles.The CS is the optimal muscle to determine the earliest time for intubation, e.g., for rapid sequence induction.

Recommendations for standards of monitoring during anaesthesia and recovery 2015 : Association of Anaesthetists of Great Britain and Ireland

“…Ideally the adductor pollicis muscle response to ulnar nerve stimulation at the wrist should be monitored. Where this is not possible, the facial or posterior tibial nerves may be monitored 34.There is variability in the duration of action of non‐depolarising neuromuscular blocking agents. Residual neuromuscular blockade can be detected in up to 40% patients for up to two hours after their administration 35, 36.…”

“…Residual neuromuscular blockade can be detected in up to 40% patients for up to two hours after their administration 35, 36. Patient harm may result from postoperative hypoxaemia in the post anaesthesia care unit 37, 38 and a risk of AAGA at extubation 13.The NAP5 project on AAGA reported on the role of neuromuscular blockade in contributing to AAGA, and how patients interpret unintended paralysis in extremely distressing ways.Recommendations: a peripheral nerve stimulator is mandatory for all patients receiving neuromuscular blockade drugsperipheral nerve stimulator monitors should be applied and used from induction (to confirm adequate muscle relaxation before endotracheal intubation) until recovery from blockade and return of consciousness;while a ‘simple’ peripheral nerve stimulator allows a qualitative assessment of the degree of neuromuscular blockade; a more reliable guarantee of return of safe motor function is evidence of a train‐of‐four ratio > 0.9.a quantitative peripheral nerve stimulator is required to accurately assess the train of four ratio 34, but other stimulation modalities (e.g. double burst or post tetanic count) can also be used for assessment.…”

“…Ideally the adductor pollicis muscle response to ulnar nerve stimulation at the wrist should be monitored. Where this is not possible, the facial or posterior tibial nerves may be monitored 34.…”

“…Recommendations: a peripheral nerve stimulator is mandatory for all patients receiving neuromuscular blockade drugsperipheral nerve stimulator monitors should be applied and used from induction (to confirm adequate muscle relaxation before endotracheal intubation) until recovery from blockade and return of consciousness;while a ‘simple’ peripheral nerve stimulator allows a qualitative assessment of the degree of neuromuscular blockade; a more reliable guarantee of return of safe motor function is evidence of a train‐of‐four ratio > 0.9.a quantitative peripheral nerve stimulator is required to accurately assess the train of four ratio 34, but other stimulation modalities (e.g. double burst or post tetanic count) can also be used for assessment.…”

“…a quantitative peripheral nerve stimulator is required to accurately assess the train of four ratio 34, but other stimulation modalities (e.g. double burst or post tetanic count) can also be used for assessment.…”