Mivacurium infusion during nitrous oxide-isoflurane anesthesia: a comparison with nitrous oxide-opioid anesthesia.
OBJECTIVE
To determine the potentiation of the neuromuscular blockade induced by a titrated infusion of mivacurium in the presence of isoflurane versus a nitrous oxide (N2O)-opioid anesthesia.


METHODS
An open-label, controlled study.


METHODS
The inpatient anesthesia service of two university medical centers.


METHODS
Thirty adults divided into two groups.


METHODS
An intravenous infusion of mivacurium during anesthesia with N2O-opioid or N2O-isoflurane.


RESULTS
A neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation at the ulnar nerve at 2 Hz for 2 seconds at 10-second intervals. The mivacurium infusion rate was significantly less in the presence of isoflurane [4.0 +/- 0.8 micrograms/kg/min (mean +/- SEM)] than during N2O-opioid anesthesia (6.4 +/- 0.6 micrograms/kg/min). The recovery rates did not differ between anesthetic groups. After the termination of the infusion, spontaneous recovery to T4/T1 of at least 0.75 occurred in an average of 17.9 +/- 1.5 minutes, with a mean recovery index (T25-75) of 6.0 +/- 0.7 minutes.


CONCLUSIONS
Isoflurane anesthesia reduces the infusion rate of mivacurium required to produce about 95% depression of neuromuscular function.
Powers
D M
DM
Department of Anesthesiology and Critical Care Medicine, University of Pittsburgh School of Medicine, PA.
Brandom
B W
BW
Cook
D R
DR
Byers
R
R
Sarner
J B
JB
Simpson
K
K
Weber
S
S
Woelfel
S K
SK
Foster
V J
VJ
D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D004357:Drug Synergism; D005260:Female; D005283:Fentanyl; D006801:Humans; D007262:Infusions, Intravenous; D007530:Isoflurane; D007546:Isoquinolines; D008297:Male; D008875:Middle Aged; D000077590:Mivacurium; D009469:Neuromuscular Junction / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage*; D009609:Nitrous Oxide
D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D000077590:Mivacurium; D007530:Isoflurane; D009609:Nitrous Oxide; D005283:Fentanyl