Paired assessment of two electromyographic neuromuscular monitors: stimpod NMX450X versus Datex-Ohmeda E-NMT

Quantitative neuromuscular monitoring (NMM) is widely recommended, yet its clinical adoption remains limited, partly due to usability issues. This study aimed to compare the clinical performance of two electromyography (EMG)-based NMM devices—the Datex-Ohmeda E-NMT module and the Stimpod NMS450X—under real-world operating room conditions. Twenty-four adult patients undergoing elective non-cardiac surgery were monitored simultaneously with both devices, applied contralaterally. Train-of-four (TOF) counts and TOF ratios were recorded at one-minute intervals. Agreement between devices was assessed using Bland–Altman analysis, repeatability coefficients, and the concordance correlation coefficient (CCC). The Datex-Ohmeda recorded an average of 121 TOF-count and 71 TOF-ratio values per patient, compared with 56 and 39, respectively, for the Stimpod. Inter-device correspondence was low, with numerous missing or physiologically implausible values on the Stimpod stream. The repeatability coefficient was 0.81 (95% CI: 0.80–0.83), indicating poor precision. The CCC was 0.662, consistent with weak agreement. In routine clinical use, the Stimpod NMS450X and Datex-Ohmeda E-NMT demonstrated poor concordance and high variability, likelyinfluenced by device-specific artifacts, connectivity limitations and electrode sensitivity.These findings highlight the need for device-specific validation of EMG NMM, both for clinical practice and for research purposes.