EC₅₀and EC₉₅of remifentanil to prevent rocuronium-induced withdrawal movements in children

Abstract

BackgroundIntravenous administration of rocuronium induces intense pain in most patients (60-100%). This could be harmful during anesthesia induction because of the unintended reflex movement of an unconscious patient in response to the pain. Previous studies have reported that remifentanil effectively reduces rocuronium-induced pain and withdrawal movements. This study was designed to evaluate the EC50 and EC95 of remifentanil to prevent withdrawal movements in children.MethodsWe enrolled a total of 171 pediatric patients scheduled for general anesthesia in this study. Remifentanil was administrated by target-controlled infusion. Effect-site target concentrations ranged from 0.5 to 3.0 ng/ml. At each concentration, experiments were repeated in 10-20 patients. Propofol 2 mg/kg and rocuronium 0.9 mg/kg were administrated after equilibration of plasma and effect-site target remifentanil concentration. The withdrawal movements were graded on a 4-point scale. The EC50 and EC95 of remifentanil to prevent rocuronium-induced withdrawal movements were determined by using a logistic regression model.ResultsThe logistic regression model showed that the probability of preventing rocuronium-induced withdrawal movement was as follows: exp (-3.49 + 2.07 × remifentanil concentration) / (1 + exp [-3.49 + 2.07 × remifentanil concentration]). EC50 and EC95 were 1.69 ng/ml (95% confidence intervals [CIs], 1.42-1.87) and 3.11 ng/ml (95% CIs, 2.79-3.72), respectively.ConclusionsAdministration of remifentanil at an effect-site target concentration of 3.1 ng/ml could effectively prevent rocuronium-induced withdrawal movements.

Rocuronium Bromide Inhibits Inflammation and Pain by Suppressing Nitric Oxide Production and Enhancing Prostaglandin E₂ Synthesis in Endothelial Cells

“…Local mediators, such as kinins that directly irritate the venous nociceptors and the allogenic effect of aminosteroid neuromuscular blocking drugs were suggested as the possible mechanisms of rocuronium bromide-induced injection pain [16]. Park et al [17] demonstrated that remifentanil effectively prevents rocuronium-induced injection pain or withdrawal movement. Zhang et al [18] reported that the incidence and severity of rocuronium-induced injection pain were significantly alleviated by use of a large vein.…”

Looking back on your statistical tool

“…In the first article, Park et al [ 1 ] stated that some previously reported confidence intervals for 95% thresholds estimated with the up-and-down sequential (UDS) design were so large that they demonstrated a fixed-concentration design. While the text comprises a matter-of-fact description, those are also intriguing me to regard as their confession, in a sense.…”