title: Optimal stimulating current for train-of-four stimulation in conscious subjects.
abstract: The purpose of this study was to determine the optimal stimulating current for train-of-four (TOF) monitoring with regard to the return of TOF response and the discomfort associated with TOF. Two variables were examined at 60, 50, 40, 30, and 20 mA: (1) times from administration of vecuronium 80 micrograms.kg-1 to returns of responses to TOF determined accelographically in 75 anaesthetised patients and (2) discomfort associated with TOF in 15 awake volunteers using visual analogue scale (VAS). Times to return of the first response to stimulation at 60, 50, 40, and 30 mA were not different (29.1 +/- 11.2, 30.1 +/- 12.0, 31.9 +/- 12.6, and 35.4 +/- 14.2 min, respectively, mean +/- SD). However, time to the return of the first response elicited at 20 mA (53.7 +/- 21.6) was longer than at higher currents (P < 0.05). Similarly, with regard to the second, third, and fourth responses, the time to the return at 20 mA was longer than at the other currents (P < 0.05). The VAS associated with TOF at 60, 50, 40, 30, and 20 mA were 7.3 +/- 1.9, 6.7 +/- 1.8, 6.0 +/- 2.0, 4.1 +/- 2.1, and 2.7 +/- 2.3, respectively. The VAS at 30 mA was less than at 60 and 50 mA (P < 0.05), and at 20 mA was less than at 60, 50, and 40 mA (P < 0.05). In conclusion it is suggested that, when testing conscious patients, 30 mA is the optimal stimulating current for TOF monitoring because it represents the best compromise of neuromuscular monitoring and patient discomfort.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Saitoh
authors.forename: K
authors.initials: K
authors.lastname: Nakazawa
authors.forename: H
authors.initials: H
authors.lastname: Toyooka
authors.forename: K
authors.initials: K
authors.lastname: Amaha
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D003243:Consciousness; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D009119:Muscle Contraction; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D016037:Single-Blind Method; D013997:Time Factors; D014459:Ulnar Nerve / Q000187:drug effects / Q000502:physiology*; D014673:Vecuronium Bromide / Q000008:administration & dosage
chemical_list: D003473:Neuromuscular Nondepolarizing Agents; D014673:Vecuronium Bromide