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Department of Anesthesiology, University of Cologne, Cologne, Germany
Address correspondence and reprint requests to Michael H. Dueck, MD, DEAA, Department of Anesthesiology, University of Cologne, D-50924 Cologne, Germany. Address email to m.dueck{at}uni-koeln.de
We performed this study to assess the recovery period after neuromuscular blockade by electromyographic F-wave analysis, a method that supplies more information about more proximal parts of the motor system than conventionally used methods, e.g., mechanomyography (MMG). In 20 neurosurgical ASA physical status I or II patients anesthesia was induced and maintained with IV fentanyl and midazolam. Patients were randomly assigned to receive either 0.25 mg/kg mivacurium (MV group, n = 10) or 0.1 mg/kg pancuronium (PC group, n = 10) intraoperatively. MMG monitoring of the adductor pollicis muscle was performed continuously. F waves were recorded at the abductor pollicis muscle of the contralateral hand at train-of-four (TOF) ratios of 0.1, 0.25, 0.5, 0.7, 0.75, 0.8, 0.85, 0.9, and 0.95. Recovery of F-wave amplitudes after neuromuscular blockade with pancuronium was significantly slower compared with mivacurium (P = 0.004) during the clinically important recovery period defined by MMG TOF ratios from 0.7 to 0.95. This electrophysiologic finding suggests a differential recovery of the motor system after administration of pancuronium and mivacurium not detected by MMG.
IMPLICATIONS: Our findings using F-wave monitoring indicate a differential recovery of the whole motor system after administration of two different neuromuscular blocking drugs that was not detected by peripheral mechanomyography. This result may have been caused by different spinal effects of pancuronium compared with mivacurium.
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