Quantitative Neuromuscular Monitoring in Clinical Practice: A Professional Practice Change Initiative

Quantitative Neuromuscular Monitoring in Clinical Practice: A Professional Practice Change Initiative.  Wade Weigel, MD at Virginia Mason Medical Center, Seattle, WA


Key Takeaways


Virginia Mason Medical Center has 28 anesthetizing locations.  A total of 20,181 electronic charts and 2,807 manually reviewed charts were examined over a 4 year period (2016-2020) 

History of Nerve Stimulator installations at Virginia Mason MC

In 2016, every operating room contained a peripheral nerve stimulator

– Digistim II (Neuro Technologies)

– EZ Stim II (LifeTech)

– TOF-Watch SX (Organon)

– Intellivue NMT (Philips)

In 2017, the STIMPOD NMS450X was introduced in 24 locations, replacing the previously installed stimulators

In 2018, Twtichview monitors were introduced in 4 locations, primarily to cover tucked-arm procedures (robotic, cardiac etc). There was a significant cost implication, estimated at $9600 per annum for the EMG electrodes per Twitchview monitor. 

Great example of only using EMG where it is needed. If Virginia Mason had to standardize on Twitchview monitors for all their locations, this would have incurred an additional cost of $230,400 per annum, compared to the $38,400 when using it in only select locations – a great saving for the hospital. Also note that only 4 Twitchview monitors (14% of total sites) were needed to cover tucked-arm procedures.

Key Outcomes:

PACU length of stay was reduced by 7% (p<0.001)

Pulmonary complications overall reduced by 42% (p = 0.011) 

Average Sugammadex dosage decreased by 14% (p < 0.001)

Subjective assessment decreased from 82% of cases (pre-implementation) to 5% of cases (post-implementation)

TOF Ratios > 90% increased from 3% of cases (pre-implementation) to 92% of cases (post-implementation)

Continued on next page:

Discussion Quotes:

“Frequent error messages and inability to attain measurements historically impeded uniaxial acceleromyography enthusiasm. Introduction of the triaxial monitor (STIMPOD NMS450X), which measured three dimensions of movement, worked more reliably, which facilitated acceleromyography monitor use.”

“In contrast, TwitchView array failures that included failed current delivery, failed signal return, poor-quality signal, and inaccurate readings (e.g., train-of-four count 0 with four visible thumb movements) demotivated providers from using the TwitchView given the cost of each array.”

The takeaway here is not that Twitchview is necessarily bad, but that EMG is difficult. AMG is still the most reliable, consistent and cheapest method of monitoring NMBA’s. Xavant continues to invest in both technologies, as we believe both of these technologies are needed to drive adoption of Objective NMT Monitoring.

Closing statement:  “Achieving and documenting a train-of-four ratio greater than or equal to 0.9 after administration of a nondepolarizing neuromuscular blocker is not a quixotic goal. This result was achieved in a busy tertiary hospital. However, attaining this endpoint requires more than just placing a quantitative monitor at each anesthetizing location. Ongoing educational effort and follow-up are required. We think our experience provides a useful road map to this end. Anesthesia providers are solely responsible for properly rescuing patients from the states of paralyses they initiate. This should occur for all patients as verified by quantitative measurement and documentation of train-of-four ratios greater than or equal to 0.9.”

For more information on QTOF monitoring and the Stimpod 450X please contact Bell Medical at [email protected]


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