Comparison of phonomyography with balloon pressure mechanomyography to measure contractile force at the corrugator supercilii muscle.
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Hemmerling
Thomas M
TM
Neuromuscular Research Group, Department of Anesthesiology, Centre hospitalier de l'université de Montréal, Hôtel-Dieu, Université de Montréal, Montréal, Québec, Canada. thomashemmerling@hotmail.com
Michaud
Guillaume
G
Babin
Denis
D
Trager
Guillaume
G
Donati
François
F
D000328:Adult; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D004558:Electric Stimulation / Q000379:methods; D005152:Facial Muscles / Q000187:drug effects / Q000502:physiology*; D005154:Facial Nerve / Q000502:physiology; D005260:Female; D006801:Humans; D007546:Isoquinolines / Q000008:administration & dosage; D017214:Laryngeal Masks; D008297:Male; D000077590:Mivacurium; D016343:Monitoring, Intraoperative / Q000379:methods*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009213:Myography / Q000379:methods; D019148:Neuromuscular Blockade / Q000379:methods; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage; D010880:Piperidines / Q000008:administration & dosage; D011312:Pressure; D015742:Propofol / Q000008:administration & dosage; D000077208:Remifentanil; D013016:Sound; D013997:Time Factors
D018686:Anesthetics, Intravenous; D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D010880:Piperidines; D000077590:Mivacurium; D000077208:Remifentanil; D015742:Propofol