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The influence of the duration of isoflurane anaesthesia on neuromuscular effects of mivacurium
Author(s) -
JALKANEN L.,
MERETOJA O. A.
Publication year - 1997
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1997.tb04674.x
Subject(s) - isoflurane , medicine , anesthesia , pharmacodynamics , nitrous oxide , neuromuscular transmission , adductor pollicis muscle , neuromuscular monitoring , pharmacokinetics , neuromuscular blockade , surgery , elbow , ulnar nerve
Background: The pharmacodynamic profile of muscle relax‐ants is usually changed by volatile anaesthetics. These changes seem to be time‐dependent, even though few data are available to substantiate this. Methods: We studied neuromuscular effects of a single dose of mivacurium (0.2 mg·kg ‐1 ) during short and intermediate duration of isoflurane anaesthesia. Forty‐five children 1–10 years of age were randomized to receive 1.5% end‐tidal concentration of isoflurane in N 2 O/O 2 for 10 or 30 min (groups Iso‐10 and Iso‐30, respectively) or to receive nitrous oxide in oxygen for 10 min (Group N 2 O) before 0.2 mg · kg ‐1 of mivacurium was given. Neuromuscular response was recorded by adductor pollicis electromyogram. Results: The onset time of mivacurium was shorter in Group Iso‐30, 1.7 (1.0–2.3) min than in Group Iso‐10, 2.3 (1.7‐3.3) rnin or Group N 2 O, 2.3 (1.7‐3.3) min (median with 10–90% percen‐tiles) ( P <0.05). In Group Iso‐30 the recovery time of the first EMG response was significantly longer than in groups Iso‐10 and N 2 O ( P <0.0001). Groups Iso‐10 and N 2 O did not differ from each other. Conclusions: Our results indicate that the duration of a constant concentration of isoflurane anaesthesia influences significantly the pharmacodynamics of mivacurium. The duration of a volatile anaesthesia is critical when potentiation of NMB is evaluated or compared in neuromuscular studies.