Continuous intravenous infusion of rocuronium (ORG 9426) in patients receiving balanced, enflurane, or isoflurane anesthesia.
BACKGROUND
Rocuronium (ORG 9426) is a new nondepolarizing neuromuscular blocking agent with a rapid onset and an intermediate duration of action. This study obtains the infusion requirements of rocuronium in 30 patients in whom anesthesia was maintained with barbiturate-nitrous oxide-opioid, nitrous oxide and enflurane, or nitrous oxide and isoflurane.


METHODS
For all 30 patients, anesthesia was induced with intravenous thiopental and fentanyl, followed by 0.45 mg/kg rocuronium. Patients were randomly allocated to receive either: 1) nitrous oxide in 40% oxygen supplemented with fentanyl, thiopental, and droperidol (balanced anesthesia), 2) 1.25 MAC enflurane-nitrous oxide, or 3) 1.25 MAC isoflurane-nitrous oxide. Once blockade had recovered to 95% depression of twitch height, muscle relaxation was maintained by continuous infusion of rocuronium, adjusted to maintain mechanical twitch response at 95% depression.


RESULTS
At 90 and 120 min, the enflurane and isoflurane groups had lower infusion requirements than those receiving barbiturate-nitrous oxide-opioid anesthesia (P < 0.02), but these did not differ significantly between the two volatile agents. Final infusion requirements (mean +/- SD) were 9.8 +/- 3.7, 5.9 +/- 3.1, and 6.1 +/- 2.7 micrograms.kg-1.min-1 for the groups receiving barbiturate-nitrous oxide-opioid, enflurane, and isoflurane anesthesia, respectively. Spontaneous recovery began soon after termination of the infusion; in all patients, twitch tension equaled 10% of control within 5 min.


CONCLUSIONS
The infusion requirements to maintain 95% twitch depression approximated 10 micrograms.kg-1.min-1 during barbiturate-nitrous oxide-opioid anesthesia. These requirements were reduced by 40% during anesthesia involving enflurane or isoflurane.
Shanks
C A
CA
Department of Anesthesia, Northwestern University, Chicago, Illinois 60611.
Fragen
R J
RJ
Ling
D
D
D000328:Adult; D000368:Aged; D000732:Androstanols / Q000008:administration & dosage / Q000494:pharmacology*; D000758:Anesthesia; D001463:Barbiturates; D004357:Drug Synergism; D004737:Enflurane / Q000494:pharmacology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007530:Isoflurane / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009294:Narcotics; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D009609:Nitrous Oxide; D000077123:Rocuronium
D000732:Androstanols; D001463:Barbiturates; D009294:Narcotics; D003473:Neuromuscular Nondepolarizing Agents; D004737:Enflurane; D007530:Isoflurane; D009609:Nitrous Oxide; D000077123:Rocuronium