Methodological limitations in acceleromyographic monitoring: a comment on the study by Piccioni et al

To the Editor,

I read with great interest the article by Piccioni et al., titled “Decurarization After Thoracic Anesthesia using sugammadex compared to neostigmine (DATA trial) a multicenter randomized double-blinded controlled trial” published in the Journal of Anesthesia, Analgesia and Critical Care [1]. The authors’ comparison of the efficacy of sugammadex and neostigmine in antagonizing neuromuscular blockade after thoracic surgery provides important contributions to clinical practice. However, I would like to highlight a critical methodological concern regarding the lack of normalized train-of-four ratio (TOFR) measurements, which may compromise the reliability of the reported neuromuscular recovery times.

Acceleromyography (AMG) is prone to artifacts such as overshooting or inverse fade, particularly when TOFR values are not normalized to pre-neuromuscular blocker baseline measurements [2, 3]. Non-normalized TOFR can overestimate recovery, leading to ratios > 1.0 even in the absence of neuromuscular blocking agents. For instance, Wedemeyer et al. demonstrated that 42% of non-normalized AMG readings exceeded 1.1, risking the misinterpretation of residual neuromuscular blockade [4]. In thoracic surgery, where residual paralysis is strongly associated with postoperative pulmonary complications, this methodological gap raises concerns about the validity of the primary endpoint of the study.

The authors reported a median recovery time of 88 s to TOFR 0.9 in the sugammadex group. However, without normalization, a TOFR of 0.9 could correspond to a true ratio as low as 0.75 (if the baseline was 1.2), indicating clinically significant residual blockade [3]. This discrepancy directly impacts the study’s conclusion that sugammadex ensures “faster recovery.” Normalized TOFR values could have strengthen the findings. It would be valuable for readers to discuss how this methodological deficiency may affect the study’s conclusions and clinical recommendations. Additionally, future studies in thoracic anesthesia should adopt electromyography (EMG)-based monitoring, which is unaffected by inverse fade and provides higher precision. EMG’s feasibility in complex surgeries has been validated, even in populations requiring precise neuromuscular control [5, 6].

Given the high stakes of residual paralysis in thoracic surgery, standardized monitoring is imperative to ensure patient safety and data comparability. I strongly recommend that future studies supplement TOFR measurements with normalized data.The authors’ contribution to thoracic anesthesia is commendable. Addressing this limitation would further solidify their conclusions and advance perioperative care standards.