Authors: Motamed C et al.
Source: Anesthesia & Analgesia, 142(2):261–263, February 2026.
Summary
This editorial explores phonomyography (PMG), also referred to as acoustic myography, as a renewed approach to quantitative perioperative neuromuscular blockade monitoring. Prompted by a study from Dong et al evaluating a new PMG prototype, the authors place this technology within the broader landscape of neuromuscular monitoring and assess its potential advantages and limitations compared with established methods.
Accurate monitoring of neuromuscular blockade is essential to avoid residual neuromuscular blockade (RNMB), a clinically significant complication of non-depolarizing neuromuscular blocking drugs associated with postoperative respiratory weakness and pulmonary complications. Quantitative, objective monitoring is strongly recommended by multiple professional societies, as clinical assessment and qualitative nerve stimulation are insufficient for reliably detecting RNMB.
Mechanomyography (MMG) remains the reference standard but is impractical for routine clinical use due to its complex setup. Acceleromyography (AMG), while widely used, has known limitations including the staircase phenomenon, need for preload or normalization, and positioning constraints. Other techniques such as electromyography (EMG) and kinemyography (KMG) offer alternatives but introduce their own challenges related to invasiveness, stabilization time, availability, accuracy, and integration into clinical workflows.
PMG detects low-frequency sound waves generated by muscle contraction using a sensitive microphone. Although described and validated decades ago, it has not previously been commercialized. Advances in sensor technology have renewed interest in PMG, and the prototype evaluated by Dong et al demonstrated good correlation with AMG when assessing neuromuscular blockade from several agents, including vecuronium, cisatracurium, and succinylcholine. However, the devices were not interchangeable: PMG showed a slower onset response and faster recovery compared with AMG.
The editorial emphasizes that PMG’s main potential advantages include its noninvasive nature, lack of need for arm immobilization or preload, and possible applicability to muscles beyond the adductor pollicis, such as periocular muscles. Nonetheless, important gaps remain, including the absence of comparison with EMG, lack of MMG benchmarking, and limited validation across muscle groups and clinical scenarios.
Ultimately, the authors argue that PMG represents a promising addition to the neuromuscular monitoring toolkit but is not yet ready to replace existing technologies. The future of neuromuscular monitoring is likely to involve multiple complementary techniques, with adoption driven not only by accuracy but also by ease of use, cost, and integration with anesthesia information management systems for automated data capture and quality assurance.
Key Points
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Residual neuromuscular blockade remains common and clinically significant without quantitative monitoring
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MMG is the reference standard but impractical for routine use
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PMG offers a noninvasive alternative without preload or limb immobilization
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PMG correlates with AMG but is not interchangeable
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Further validation against EMG and across different muscles is needed
What You Should Know
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Quantitative neuromuscular monitoring is essential whenever muscle relaxants are used
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No current technology is ideal for all clinical settings
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PMG may simplify monitoring and expand usable muscle sites
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Clinical adoption will depend on accuracy, usability, price, and workflow integration
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Neuromuscular monitoring technology is likely to remain multimodal rather than singular
Thank you for allowing us to highlight and summarize this forward-looking editorial from Anesthesia & Analgesia, which examines emerging technologies shaping the future of quantitative neuromuscular monitoring in anesthesia practice.