Figure 1. A novel ultralong acting nondepolarizing neuromuscular blocker and corresponding cucurbituril (analogous to sugammadex) reversal agent from Yang et al.
Our patient safety lab has spent quite some effort over the past few years studying neuromuscular bock, reversal and monitoring. As we embark on 2026, it may be interesting to look back at a few notable publications on these topics from 2025. I am going to highlight some articles that I think are worth another look. My choice of these articles is subjective and is not meant to be all inclusive. Also, I have selected some of these articles not because they are excellent but because they are flawed. Recognizing the flaws is often as important or even more important than recognizing excellence.
There is growing interest in performing quantitative neuromuscular block monitoring with electromyography (EMG) in children, and small electrode arrays are available for this purpose (Figure 2). However, there is not much information available about monitoring in small children and whether or not it is possible to treat children as “small adults” for this purpose. I previously posted about a study by Kalli from 1989 showing that the “supramaximal” ulnar nerve stimulating current (see below for definition) was essentially the same in infants and young children as in adults. In my opinion, this gives us considerably more confidence that the quantitative twitch monitors that we use in adults should also work in children.
Figure 2. A tiny TwitchView electrode array for a tiny patient
In 2025, Chaney et al published an observational case series in which they used electromyographic twitch monitoring in 49 patients under the age of 1 year, ranging from 3.1 to 10.3 kg. This was not a scientific study with specific measured outcomes. They simply reported that electromyographic monitoring appeared to work in these children who received rocuronium and in most cases sugammadex. As far as it goes, that is good news. Interestingly, in 40 out of 49 patients, a peripheral nerve stimulator was also used, presumably to carry out subjective monitoring.
The reasons for using both objective and subjective monitoring were not explained, and no data from the subjective monitoring were provided. They did not report the current (measured in mA) used for ulnar nerve stimulation. Baseline determination of the train-of-four ratio was not always determined prior to administration of rocuronium. Among the patients in whom the baseline train-of-four ratio was determined, 4 patients had a train-of-four ratio <0.9. This is unexpected, since the baseline train-of-four ratio should be close to 1.0. This finding was unexplained. This study tells us that monitoring small children is feasible, but not much else.
Iwasaki et al published a study in 2025 that determined the supramaximal ulnar nerve stimulation current for patients 2-11 years of age for the TOF-Watch acceleromyograph twitch monitor and the Nihon-Kohden electromyograph twitch monitor placed on opposite arms. The supramaximal current for the electromyograph monitor averaged 27 mA, whereas for the acceleromyograph monitor the current averaged 54 mA. Interestingly, the Nihon-Kohden electromyograph had previously been shown to have quite a low average supramaximal current in adults as well, 32 mA in a study by the same group of investigators. I don’t know why the supramaximal current is on the low side with the Nihon-Kohden monitor, but there appears to be little difference between children and adults, reinforcing the earlier results from Kalli’s 1989 paper mentioned above.
In 2025 Asztalos et al published a prospective case series suggesting that pipecuronium, an aminosteroid neuromuscular blocking drug that is not available in many places, is reversed very efficiently by sugammadex. Stephan Thilen and I wrote an editorial to accompany this article in which we highlighted other work by this same group demonstrating that not all aminosteroid neuromuscular blocking drugs are reversed by sugammadex with the same effectiveness. In particular, vecuronium is least effectively bound by sugammadex, so much so that I would recommend exercising quite some caution in attempting to reverse vecuronium, as Asztalos et al found an alarming incidence of recurrent neuromuscular block in the post anesthetic care unit in patients whose vecuronium had been adequately reversed with sugammadex in the operating room. Sugammadex binds most avidly to pipecuronium, with rocuronium being intermediate, and vecuronium being least avidly bound.
Scheffenibichler et al published an article in 2025 that illustrates one of the enduring misconceptions about neuromuscular blockade monitoring. The study claimed to examine how “calibration” of an electromyograph affects the precision (repeatability) of train-of-four measurement. In my opinion, this is complete nonsense. Calibration means to adjust a measuring device to a known standard. This is not possible for any commercially available twitch monitor, and the importance of this is not just a semantic nicety. What twitch monitors actually are capable of doing, is to determine the supramaximal current for stimulating the ulnar nerve. As I explained in a previous post—” All of the quantitative neuromuscular block monitors that I know of determine the “supramaximal” current by administering a stepwise series of increasing currents until the amplitude of the twitch response becomes maximal. Then an additional amount of current is added (supramaximal) as a safety margin, to be sure that the ulnar nerve is being adequately stimulated. This procedure has to be carried out after the patient is asleep but BEFORE administering a neuromuscular blocking drug. Alternatively, the operator may simply select the highest possible current, which is usually in the range of 60-80 mA, depending upon the particular monitor.”
Note that last sentence. Effective use of a neuromuscular block monitor does not even require determining the supramaximal current. Just turn the current up “all the way” (60-80 mA), ensuring that a supramaximal current will be administered.
Let’s make a New Year’s Resolution for 2026. Let’s stop talking about “calibrating” neuromuscular block monitors and instead describe what they actually do, which is to determine the supramaximal current for ulnar nerve stimulation.
While we are at it, let’s make another New Year’s Resolution. Let’s say goodbye to acceleromography.
In 2025 we published an editorial by the title, “Let’s say goodbye to acceleromyographic twitch monitoring”, and I also took up this topic on Substack. Acceleromyography has two big problems. The first is overshoot in the baseline train-of-four ratio, and the second is a relative lack of precision (repeatability). I won’t belabor these points, since you can read the editorial or the previous Substack post. I would clarify one point. If you have acceleromyography as your only method of quantitative neuromuscular block monitoring, keep using it. As my friend and colleague Dr. Mike Todd says (to paraphrase), “It’s better than no monitoring”. But in my opinion, you shouldn’t buy any more acceleromyographs when you need new monitors. Buy electromyography instead.
Yang et al announced the discovery of a novel, very long acting non-depolarizing neuromuscular blocker and a corresponding cucurbituril antagonist, illustrated in Figure 1 above. Cucurbituril refers to a family of rigid, barrel shaped macrocycles made from glycoluril units. These demonstrate “host-guest” binding that is very strong, analogous to the host-guest behavior of sugammadex towards aminosteroid neuromuscular blocking drugs. The rationale for this drug candidate is that a single dose could be administered to cover an entire surgery, obviating the need for repeated doses or infusion of shorter acting drugs. Normally, we would consider very long acting drugs to be disadvantageous, but the availability of a highly effective cucurbituril antagonist might change the equation, assuming that the antagonist is extremely reliable. It’s at least nice to know that there are medicinal chemists out there working on anesthetic drug candidates.
Late in 2025, Wachtendorf et al published a database study confirming what many of us already “knew”. The availability of sugammadex in the authors’ hospitals had resulted in a 45% increase in rocuronium dosing. When patients were reversed with sugammadex, the risk of respiratory complications from residual neuromuscular blockade were reduced (compared to neostigmine), but these complications could only be abolished by the use of quantitative neuromuscular block monitoring. The results of this study verify and amplify many other earlier studies. The message is clear. Go forth in 2026 and monitor quantitatively.