Observational Cohort Study of TetraGraph Electromyography Compared to Standard Acceleromyography Monitoring.

: Current guidelines recommend objective neuromuscular monitoring to ensure patient safety during neuromuscular blockade. Acceleromyography using train-of-four (TOF) stimulation is most commonly used to assess neuromuscular function. This study compares a new electromyography-based monitor with an established acceleromyography device for neuromuscular monitoring when mounted on a restricted arm. : This prospective, controlled observational study enrolled patients undergoing surgery with general anesthesia requiring neuromuscular blockade. Two neuromuscular monitoring systems were used simultaneously: the standard acceleromyography device (Philips IntelliVue MX550) and the electromyography-based TetraGraph monitor on the opposite arm. Atracurium was administered as the neuromuscular blocking agent. The TetraGraph arm was restricted during surgery. The primary outcome was the time for the TOF ratio to return to ≥90%. Secondary endpoints included the time to reach a TOF count of 0 during induction. Data were analyzed using Bland-Altman plots and a paired -test. : Mean time to recovery to TOF ratio ≥ 90% was 67 min (±21.4) for IntelliVue MX 550 and 75.8 min (±22.3) for TetraGraph ( = 0.0001; mean bias 8.9 min, 95% confidence intervals (CIs) 5.99-11.8). The mean time to reach a TOF count of 0 was 180.6 s (±7.8) for IntelliVue and 200 s (±8.2) for TetraGraph ( = 0.0217; mean bias 19 s, 95% CI 2.96-35.8). : TetraGraph consistently recorded the endpoints later than IntelliVue, reflecting slower onset and recovery times. However, substantial intra-individual variability was observed with both devices during recovery from neuromuscular block. The observed differences may have clinical implications, such as when assessing readiness for extubation.