Neuromuscular monitoring

Patterns of nerve stimulation

Various nerve stimulation patterns may be used in neuromuscular function monitoring and the response to these stimulation patterns is used to assess the depth of neuromuscular blockade.

Some patterns of stimulation used today include, single twitch (ST), train-of four (TOF), double burst stimulation (DBS), tetanic stimulation

and the post tetanic count.

Monitoring the response of the muscle to nerve stimulation

The response of the muscle to stimulation of the nerve supplying it can be assessed by subjective (visual or tactile) techniques or quantitative (objective) devices that provide a numeric value relating to the depth of neuromuscular blockade.

Quantitative (objective) neuromuscular monitors

Quantitative neuromuscular monitors can be subdivided into monitors that measure the electrical response, the compound evoked muscle action potential, and those that monitor the contractile response to stimulation. The measurement of the electrical response to muscle stimulation is called electromyography. The mechanical response to stimulation of the muscle can be measured by mechanomyography, kinemyography and acceleromyography

Consensus Statement on Perioperative Use of Neuromuscular Monitoring

In 2018 recommendations by an international panel of experts on neuromuscular monitoring to assist anaesthesia care providers and professional organisations that develop practice advisories and guidelines regarding the minimum standards for monitoring patients that receive neuromuscular blockade (NMB) during anaesthesia. The recommendations include the following:

1. "Quantitative (objective) NMB monitoring should be used whenever non-depolarising neuromuscular blocking drug is administered."
2. "Subjective or clinical tests of NMB are not predictive of adequate neuromuscular recovery and are not sensitive to detect residual weakness; their use should be abandoned in favour of quantitative (objective) monitoring."
3. "Professional organisations should develop practice standards and guidelines detailing how best to monitor and manage perioperative administration of NMBDs."
4. "Terms that describe the levels of NMB should be standardised. New proposed definitions are published in the consensus statement based on quantitative NMB monitoring criteria."

Anaesthetic organisations with guidelines or professional standards on neuromuscular monitoring

The Association of Anaesthetists of Great Britain and Ireland published recommendations for standards of monitoring during anaesthesia and recovery in 2015. These included that a peripheral nerve stimulator is mandatory for all patients receiving neuromuscular blocking drugs and that they should be applied and used from induction (to confirm adequate muscle relaxation before intubation) until recovery from blockade and return of consciousness. They state that a more reliable guarantee of return of safe motor function is a train of four ratio of greater than 0.9. A quantitative neuromuscular monitor is required to accurately assess the train of four ratio.

The Australian and New Zealand College of Anaesthetists also publishes professional standards and guidelines on monitoring during anaesthesia. In respect to neuromuscular function monitoring - They state " Neuromuscular function monitoring, preferably quantitative, must be available for every patient in whom neuromuscular blockade is induced and should be used whenever the anaesthetist is considering extubation following the use of non-depolarising neuromuscular blockade."

References

References

1. (January 2018). "Monitoring Neuromuscular Function". The New England Journal of Medicine.
2. (January 2017). "Conceptual and technical insights into the basis of neuromuscular monitoring". Anaesthesia.
3. (January 2016). "Recommendations for standards of monitoring during anaesthesia and recovery 2015: Association of Anaesthetists of Great Britain and Ireland". Anaesthesia.
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14. (July 2018). "Consensus Statement on Perioperative Use of Neuromuscular Monitoring". Anesthesia & Analgesia.
15. (2016). "Recommendations for standards of monitoring during anaesthesia and recovery 2015 : Association of Anaesthetists of Great Britain and Ireland". Anaesthesia.
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