Impact of the intubation model on the efficacy of rocuronium during rapid sequence intubation: systematic review of randomized trials

Background:  Propofol–rocuronium is thought to be superior to thiopental–rocuronium for rapid sequence intubation (RSI). The role of the intubation model per se has never been investigated. Methods:  Randomized comparisons of rocuronium with succinylcholine for true RSI (administration of muscle relaxant immediately after the hypnotic, intubation within 60 s) or modified RSI (delay between administration of the hypnotic and the muscle relaxant, intubation within 60 s) were sought. Good or excellent intubation conditions were expressed as relative risks (RR) with 95% confidence intervals (CI). Results:  Twelve trials (1471 patients) used a true RSI. With propofol for induction, RR for good or excellent intubation conditions with conventional rocuronium doses (0.6–0.7 mg/kg) was 0.95 (95%CI, 0.90–1.00), with high doses (0.9–1.2 mg/kg) was 0.96 (0.92–1.01) compared with succinylcholine. With thiopental for induction, RR with conventional rocuronium doses was 0.69 (0.61–0.78) and with high doses was 0.99 (0.95–1.03). Nine trials (340 patients) used a modified RSI. With propofol for induction, RR with conventional rocuronium doses was 0.98 (0.91–1.06); data on high rocuronium doses were lacking. With thiopental for induction, RR with conventional rocuronium doses was 0.97 (0.92–1.02) and with high doses was 1.0. There was no evidence that concomitantly used opioids or the dose of the induction agent had an impact on intubation conditions, independent of the intubation model. Conclusion:  The efficacy of rocuronium for RSI is influenced by both, the induction agent and the intubation model. To test the clinical usefulness of alternatives to succinylcholine for RSI, a true RSI model should be used.