The latest guidelines from the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology and Intensive Care Medicine (ESAIC) provide important recommendations for quantitative monitoring and antagonism of neuromuscular blockade. These guidelines are based on recent evidence-based research, and they place particular emphasis on using quantitative monitoring. Let’s look at the four main aspects of the recommendations and the differences and similarities between the two guidelines.
When should we monitor?
Both guidelines agree that any situation where a muscle relaxant is used, irrespective of the relaxant, and irrespective of the reversal agent, should be monitored quantitatively. Non-depolarising muscle relaxants (rocuronium, vecuronium etc.) have historically been the focus of quantitative monitoring. The ASA guidelines also address depolarising muscle relaxants (succinylcholine) in the following statement “..the task force suggests using neuromuscular monitoring to guide extubation when there are clinical signs of delayed recovery from succinylcholine.” The ESAIC guideline is a bit more direct in its clinical practice statement: “Recovery from succinylcholine-induced neuromuscular blockade should also be monitored quantitatively.” This recommendation follows the recommendation from the Association of Anaesthetists of Great Britain and Ireland (AAGBI) guidelines in 2021, also calling for monitoring of depolarising muscle relaxants.
Depolarising muscle relaxants are monitored differently than non-depolarising muscle relaxants, and it is important that the Objective NMT Monitor that is used has a dedicated mode to monitor these relaxants.
How should we monitor?
The evidence concerning the comparative diagnostic performance of different device types suggests that the preferred device is the one that a clinician uses appropriately.
Both the ASA and ESAIC guidelines strongly recommend quantitative monitoring of neuromuscular blockade, and strongly recommend against clinical assessment alone or qualitative monitoring. The quantitative approach is more accurate as it takes into account all relevant factors such as body weight, drug dose and individual patient variability.
A TOF Ratio equal to and above 90% (or 0.9) is also strongly recommended for all technologies. However, the ESAIC guidelines, although not stated in one of its recommendations, do offer an alternative level for raw (uncalibrated and non-normalised) acceleromyography readings of above 100% (or 1.0).
At which sites should we monitor?
Both guidelines state that quantitative measurement of neuromuscular blockade should be performed at the adductor pollicis muscle (AP). The ASA guidelines add an additional comment, strongly recommending against using facial muscles. It has been proven1 that there is a 5-fold increase in the incidence of residual neuromuscular block when using the facial muscle to determine the level of residual block.
Although neither of the guidelines makes a recommendation for a particular technology, following this recommendation on the recommended stimulation site, will highlight the shortcomings of some technologies when the patients’ arms are tucked i.e. robotic surgeries. A combination of technologies (i.e. AMG and EMG in a single device) will be the ideal solution from a best practices and cost point of view.
How should we antagonise?
The ASA and ESAIC guidelines are in agreement about the importance of quantitative neuromuscular monitoring when using reversal agents. Both recommend using a quantitative approach to accurately assess the degree of neuromuscular block, irrespective of the reversal agent used. A cohort of 5 studies (ASA supplemental tables S13 and S14 (http://links.lww.com/ALN/C928) show incidence levels of residual neuromuscular block as high as 16% when qualitatively or clinical assessments were used with Sugammadex. It is recommended by both guidelines that Sugammadex should be used to antagonise deep, moderate and shallow neuromuscular blockade induced by aminosteroidal agents (rocuronium, vecuronium), and Neostigmine should only be administered when a patient reaches a minimal level of block or a TOF ratio of 40%. The ESAIC guideline defines this level a bit differently, referring to spontaneous recovery (i.e. TOF > 0.2). This is however still significantly higher than previous recommendations when Neostigmine was administered during moderate levels of block.
Finally, both guidelines recommend that Neostigmine should only be applied 10 min (ASA) to 15 min (ESAIC) before emergence and extubation, and only after spontaneous recovery levels have been achieved, as the antagonist effect of Neostigmine is maximal within approximately 10 min. However, both guidelines are clear that this reversal should still be monitored quantitatively.
In summary, the following factors should be considered when choosing the neuromuscular antagonist drug:
- The type of neuromuscular blocking drug used
- Depth of neuromuscular blockade
- Efficacy of the antagonist drug for the class of neuromuscular blocking drug
- Any ceiling effect of the antagonist drug
- Time required to attain full antagonism.
Conclusion
Quantitative monitoring and antagonism of neuromuscular blockade is of paramount importance for the safety and efficacy of anaesthetic procedures. The recent ASA and ESAIC guidelines have provided further evidence-based recommendations on quantitative monitoring and antagonism, which should be followed in order to ensure patient safety. Quantitative monitoring should always be used when assessing the level of neuromuscular block, and the correct site and reversal agent chosen in accordance with the class of neuromuscular blocking drug used. Furthermore, quantitative monitoring should also be applied when administering antagonist drugs such as Neostigmine or Sugammadex, in order to ensure that optimal levels have been achieved prior to emergence and extubation. Following these guidelines will help ensure patient safety and improve the outcome of anaesthetic procedures. #eliminateRNB2025
References
- Intraoperative neuromuscular monitoring site and residual paralysis. Thilen SR, Hansen BE, Ramaiah R, Kent CD, Treggiari MM, Bhananker SM. Anesthesiology. 2012 Nov; 117(5):964-72.
About Xavant Technology
At Xavant Technology, we’re on a mission to reduce drug-related complications and the associated healthcare costs. At the moment we are laser focused on eliminating residual neuromuscular block by 2025. Our teams are committed to making this happen, and we know that with your help, we can make a difference.
About STIMPOD NMS450X
The STIMPOD NMS450X is the optimal Objective NMT Monitoring to help you monitor for and eliminate residual neuromuscular block in your practice. As the only handheld FDA and CE approved device that can perform both AMG and EMG in a single device, the STIMPOD is your perfect companion to eliminate RNB in all your procedures, in all anaesthesia locations, and for all muscle relaxants.
