optimal dose of succinylcholine revisited.
anesthesiology. 99(5):1045-1049, november 2003.
naguib, mohamed m.b., b.ch., m.sc., f.f.a.r.c.s.i., m.d. *; samarkandi, abdulhamid m.b., b.s., k.s.u.f., f.f.a.r.c.s.i. +; riad, waleed m.b., b.ch., m.sc., a.b., m.d. ++; alharby, saleh w. m.b., b.s., f.r.c.s. (glas) [s]
background: the authors reappraised the conventional wisdom that the intubating dose of succinylcholine must be 1.0 mg/kg and attempted to define the lower range of succinylcholine doses that provide acceptable intubation conditions in 95% of patients within 60 s.
methods: this prospective, randomized, double-blind study involved 200 patients. anesthesia was induced with 2 [mu]g/kg fentanyl and 2 mg/kg propofol. after loss of consciousness, patients were randomly allocated to receive 0.3, 0.5, or 1.0 mg/kg succinylcholine or saline (control group). tracheal intubation was performed 60 s later. a blinded investigator performed all laryngoscopies and also graded intubating conditions.
results: intubating conditions were acceptable (excellent plus good grade combined) in 30%, 92%, 94%, and 98% of patients after 0.0, 0.3, 0.5, and 1.0 mg/kg succinylcholine, respectively. the incidence of acceptable intubating conditions was significantly greater (p < 0.05) in patients receiving succinylcholine compared with those in the control group but was not different among the different succinylcholine dose groups. the calculated doses of succinylcholine (and their 95% confidence intervals) that were required to achieve acceptable intubating conditions in 90% and 95% of patients at 60 s were 0.24 (0.19-0.31) mg/kg and 0.56 (0.43-0.73) mg/kg, respectively. conclusions: the use of 1.0 mg/kg of succinylcholine may be excessive if the goal is to achieve acceptable intubating conditions within 60 s. comparable intubating conditions were achieved after 0.3, 0.5, or 1.0 mg/kg succinylcholine. in a rapid-sequence induction, 95% of patients with normal airway anatomy anesthetized with 2 [mu]g/kg fentanyl and 2 mg/kg propofol should have acceptable intubating conditions at 60 s after 0.56 mg/kg succinylcholine. reducing the dose of succinylcholine should allow a more rapid return of spontaneous respiration and airway reflexes.