Phonomyographic measurements of neuromuscular blockade are similar to mechanomyography for hand muscles.
OBJECTIVE
Phonomyography consists of recording low frequency sounds created during muscle contraction. In this study, phonomyography of three regions of the hand was compared to mechanomyography of the adductor pollicis.


METHODS
In 12 patients, phonomyography was recorded via small condenser microphones taped over the thenar mass, the hypothenar eminence, and the dorsal groove between the first and second metacarpal bones to record the acoustic signals of adductor pollicis and the hypothenar and first dorsal interosseus muscles, respectively. Mechanomyography of the adductor pollicis was recorded simultaneously using a force transducer. After induction of anesthesia, the ulnar nerve was stimulated supramaximally using train-of-four (TOF) stimulation every 12 sec. Onset, maximum effect, and offset of neuromuscular block after rocuronium 0.6 mg x kg(-1) were measured using phonomyography and compared to mechanomyography using ANOVA and the Bland-Altman test.


RESULTS
Phonomyographic measurements of onset and maximum effect of neuromuscular blockade were not significantly different from mechanomyographic measurements. Phonomyographic measurements of offset (T25%, T75 %, TOF 0.8) of neuromuscular block at the thenar muscles and first dorsal interosseus muscles were not significantly different from mechanomyographic measurements at adductor pollicis; however, T50%, T75% and T90% phonomyographic measurements at the hypothenar muscle were significantly shorter than at any other muscle site.


CONCLUSIONS
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.
Neuromuscular Research Group, Department of Anesthesiology, Centre Hospitalier de l'Université de Montréal Hôtel-Dieu, Université de Montréal, Montréal, Québec, Canada. thomashemmerling@hotmail.com <thomashemmerling@hotmail.com>
Thomas M
TM
Hemmerling
Guillaume
G
Michaud
Guillaume
G
Trager
Stéphane
S
Deschamps
D000704:Analysis of Variance; D000732:Androstanols / Q000008:administration & dosage; D004558:Electric Stimulation; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D017214:Laryngeal Masks; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D009213:Myography / Q000379:methods; D019148:Neuromuscular Blockade / Q000379:methods*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage; D010812:Physical Stimulation; D000077123:Rocuronium; D013018:Sound Spectrography; D014459:Ulnar Nerve / Q000502:physiology
D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium