Randomised double-blind comparison of fentanyl, mivacurium or placebo to facilitate laryngeal mask airway insertion

In a double-blind randomised study, we compared conditions during insertion of the: laryngeal mask airway in 150 patients who received either fentanyl 1 mu g.kg(-1), mivacurium 0.04 mg.kg(-1) or normal saline, before inductio n of anaesthesia with propofol 2 mg.kg(-1). Insertion conditions, including mouth opening, swallowing, gagging or coughing, head or Limb movement and ease of insertion, were each graded using a three-point scale. The median ( interquartile range) summed insertion scores were more favourable with the use of fentanyl [8.0 (7.0-9.0)] and mivacurium [7.5 (6.8-8.3)] than with no rmal saline [9.0 (7.8-10.3); p<0.01]. Fentanyl and mivacurium decreased swa llowing and head or limb movement, and mivacurium improved mouth opening. I nsertion conditions were similar between fentanyl and mivacurium, while bot h prolonged apnoea. Fentanyl and mivacurium are equally effective in facili tating insertion of the laryngeal mask airway following anaesthetic inducti on with propofol.