Several years ago, largely due to the influence of our colleague Dr. Stephan Thilen, we became interested in the quantitative twitch monitoring of neuromuscular blockade.  We were convinced that quantitative twitch monitoring is necessary to prevent the patient harm that comes from residual neuromuscular blockade, and also to manage the costs of reversal of neuromuscular blockade with the advent of sugammadex (a drug that is highly effective, but also relatively expensive). We discovered that the existing quantitative twitch monitors were inadequate and so we embarked on a collaboration with Justin Hulvershorn to develop electromyography (EMG)-based twitch monitor that would address the inadequacies of existing monitors. This resulted in TwitchView, which is currently the only FDA approved EMG-based monitor.

An essential step in the development of TwitchView was to validate twitch monitors to mechanomyography, which is the “gold standard” of twitch monitoring. Because mechanomyography is not commercially available, we were required to design and build a mechanomyography monitor. Kelly Michaelsen, who is an anesthesia resident and a bioengineer, did most of the work to create our mechanomyography monitor. We have now compared several commercially available twitch monitors, including TwitchView, to mechanomyography. Other monitors included Stimpod, Tetragraph, and GE NMT module.

                Kelly’s mechanomyograph                                  1970’s mechanomyograph

Examples of acceleromyograph, electromyograph and mechanomyograph.

A comparison of a prototype electromyograph vs. a mechanomyograph and an acceleromyograph for assessment of neuromuscular blockade.

Awards

BEST Late-Breaking Abstract International Anesthesia Research Society Annual Meeting May 16–20, 2019 Montreal, Quebec, Canada

Publications

Bowdle A, Jelacic S. Progress towards a standard of quantitative twitch monitoring. Anaesthesia. 2020 Sep;75(9):1133-1135.        Bowdle A, Bussey L, Michaelsen K, Jelacic S, Nair B, Togashi K, Hulvershorn J. Counting train-of-four twitch response: comparison of palpation to mechanomyography, acceleromyography, and electromyography. Br J Anaesth. 2020 Jun;124(6):712-717.    Bowdle A, Bussey L, Michaelsen K, Jelacic S, Nair B, Togashi K, Hulvershorn J. A comparison of a prototype electromyograph vs. a mechanomyograph and an acceleromyograph for assessment of neuromuscular blockade. Anaesthesia. 2020 Feb;75(2):187-195.