What is the ED95 of prilocaine for femoral nerve block using ultrasound?

Abstract

BackgroundOur aim was to estimate the ED95 of prilocaine 1% w/v for femoral nerve block.MethodsThis two-stage dose-finding sequential clinical trial followed an adaptive design based on the continual reassessment method (CRM). Adult patients undergoing Vastus medialis muscle biopsy under ultrasound-guided femoral nerve block were recruited. Data from previously published studies and our own previous experience were used to set the dose levels and their guesstimate probabilities of response.ResultsForty patients were recruited in the trial (n=26 in the first stage and n=14 in the second stage). Using the CRM, the estimated response probabilities with 13 and 17 ml prilocaine 1% w/v were 90.4% (95% credibility interval: 68-98%) and 99.1% (95% credibility interval: 89-100%), respectively.ConclusionOur study demonstrates that the dose closest to the ED95 of prilocaine 1% w/v for ultrasound-guided femoral nerve block is 17 ml. The study also illustrates the value of CRM in dose-finding experiments. © 2013 Author.