The "intubating dose" of succinylcholine: the effect of decreasing doses on recovery time.
BACKGROUND
The usually cited "intubation dose" of succinylcholine is 1.0 mg/kg. In the majority of patients, this dose will produce apnea of sufficient duration that significant hemoglobin desaturation may occur before neuromuscular recovery takes place in those whose ventilation is not assisted. This study was undertaken to examine the extent to which reducing this dose would decrease the duration of action of succinylcholine.


METHODS
During stable desflurane/oxygen/opioid anesthesia and after adequate twitch stabilization, neuromuscular function was recorded with an acceleromyographic monitor. Supramaximal stimuli were delivered at 0.10 Hz. Patients received 0.40, 0.60, or 1.0 mg/kg succinylcholine, and twitch height was monitored for at least 20 min thereafter.


RESULTS
The onset times to maximal effect were 105 +/- 23 s, 81 +/- 19 s, and 71 +/- 22 s, respectively. The lowest dose (0.40 mg/kg) did not reliably produce 100% twitch depression. The times to 90% twitch recovery at the adductor pollicis in the three groups were 6.6 +/- 1.5 min, 7.6 +/- 1.6 min, and 9.3 +/- 1.2 min, respectively.


CONCLUSIONS
Reducing the dose of succinylcholine from 1.0 mg/kg to 0.60 mg/kg shortens the duration of effect at the adductor pollicis by more than 90 s. The authors believe that even this modest decrease in the duration of drug-induced paralysis is often worth pursuing.
Kopman
Aaron F
AF
Professor of Anesthesiology, New York Medical College, Valhalla, New York, USA. akopman@rcn.com
Zhaku
Bledi
B
Lai
Kane S
KS
D000328:Adult; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D000077335:Desflurane; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D007530:Isoflurane / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D009467:Neuromuscular Depolarizing Agents / Q000008:administration & dosage*; D013390:Succinylcholine / Q000008:administration & dosage*; D014459:Ulnar Nerve / Q000502:physiology
D018685:Anesthetics, Inhalation; D009467:Neuromuscular Depolarizing Agents; D000077335:Desflurane; D007530:Isoflurane; D013390:Succinylcholine