Purpose:The gold standard of neuromuscular monitoring is mechanomyography (MMG). Phonomyography (PMG) and kinemyography (KMG) are new methods of neuromuscular monitoring. In this study, all three methods were compared to determine neuromuscular blockade at the adductor pollicis muscle.Methods: In 14 patients, phonomyography was recorded via a microphone taped to the thenar region. A standard mechanomyographic device was applied to the same thumb, and attached to the force transducer. On the contralateral side, a NMT-Mechanosensor® probe was attached to the thumb and forefinger (KMG). After induction of general anaesthesia, the ulnar nerves were stimulated supramaximally using superficial electrodes at the wrists using train-of-four (TOF) stimulation every 12 sec. Onset and recovery indices measured by the three methods after mivacurium 0.2 mg·kg -1 iv were compared using ANOVA-multiple group comparisons. Agreement between methods was determined using Lin's concordance correlation coefficient.Results: Onset time and peak effect measured via MMG and PMG were similar. Recovery times from neuromuscular blockade (NMB) as measured via the three methods were not different. Agreement between PMG and MMG was excellent for onset and offset of NMB but unsatisfactory for peak effect. Agreement between MMG and KMG was satisfactory for TOF 0.25 and 0.50, and excellent for TOF 0.75 and 0.90 (onset and peak effect not determined for KMG). Agreement between PMG and KMG was satisfactory for TOF 0.25, 0.50 and 0.75, and excellent for TOF 0.90. Conclusion:Mechanomyography, PMG and KMG show satisfactory agreement for determination of recovery of NMB for clinical purposes. Objectif : La référence en monitorage neuromusculaire est la mécanomyographie (MMG). La phonomyographie (PMG) et la cinémyographie (CMG) sont de nouvelles méthodes. Nous comparons les trois méthodes pour qualifier le blocage neuromusculaire à l'adducteur du pouce. Méthode : La phonomyographie a été enregistrée par un microphone fixé à la région thénar chez 14 patients. Un appareil de mécanographie standard, au même pouce, a été fixé au transducteur de force. Au côté opposé, une sonde de NMTMechanosensor® a été fixée au pouce et à l'index (CMG). Après l'induction de l'anesthésie, les nerfs cubitaux ont reçu une stimulation supramaximale, utilisant un train-de-quatre (TDQ) toutes les 12 sec, produite par des électrodes superficielles aux poignets. Les indices du début et de la fin du bloc, mesurés par les trois méthodes après l'administration iv de

Mechanomyography and phonomyography (PMG), a novel method of monitoring neuromuscular blockade (NMB) by recording low-frequency sounds emitted by muscle contraction, can be used interchangeably to determine NMB at the adductor pollicis muscle. PMG is easier to apply, does not need a special monitoring board and could be a reliable monitor to determine NMB in daily routine.

P Pu ur rp po os se e: : Phonomyography is based on the creation of low frequency sounds during muscle contraction, which can be recorded and used for neuromuscular monitoring. In this study, balloon pressure mechanomyography, a novel method to measure the force of contraction via pressure changes in an air-filled balloon, was compared with phonomyography to determine neuromuscular blockade at the corrugator supercilii muscle. M Me et th ho od d: :After approval of the Ethics Committee and informed consent, 15 patients were studied. A small condenser microphone was taped to the area just above the eyebrow for phonomyography; an air-filled balloon was taped to the area just above the opposite eyebrow. After induction of anesthesia using remifentanil and propofol, a laryngeal mask airway was inserted without the aid of neuromuscular blocking agents. The facial nerve was stimulated supramaximally with single-twitch stimulation (0.1 Hz) using superficial electrodes placed on both temporal areas for onset and train-of-four stimulation every 12 sec during offset of neuromuscular blockade produced by mivacurium 0.1 mg·kg -1 . Onset and recovery measured by the two methods were compared using the t test and agreement between phonomyography and balloon pressure mechanomyography was examined using the Bland-Altman method.R Re es su ul lt ts s: : Onset, peak effect, and time to reach 25%, 75%, and 90% of control twitch response for phonomyography vs balloon pressure method were 83 ± 16 sec vs 81 ± 15 sec, 80 ± 15% vs 82 ± 17%, 7.7 ± 2.3 min vs 7.5 ± 2.4 min, 9.9 ± 4.1 min vs 10.5 ± 4 min, and 12.6 ± 4.3 min vs 13.1 ± 4.5 min respectively without being significantly different. Mean bias was 1% with limits of agreement of -9 and +9% of twitch height (T1).C Co on nc cl lu us si io on n: : We applied a balloon pressure method to measure the force at the corrugator supercilii. Phonomyography at the corrugator supercilii shows good agreement with this modified version of mechanomyography. Objectif

There was good agreement between mechanomyographic measurements at the adductor pollicis muscle and phonomyographic measurements at the thenar and the first dorsal interosseus muscles. Phonomyography of those two muscles could be used interchangeably with mechanomyography of adductor pollicis for clinical purposes.