Background: Propofol is associated with a high incidence of injection pain in children, even if given together with lidocaine. A new lipid formulation of etomidate (Etomidate-Lipuro) has been found in adults to cause very little discomfort during i.v. injection. The aim of the present prospective, double-blind, randomized trial was to compare the incidence of injection pain during i.v. induction of anaesthesia between propofol with added lidocaine (previous standard) and this new etomidate formulation in paediatric patients.
Methods: A total of 110 paediatric patients, aged 2-16 years, scheduled for outpatient surgery were planned to be included in the study. The primary end point of the study was the incidence of injection pain during induction of anaesthesia as assessed by a four-point scale as described previously. The occurrence of myoclonic muscular activity was registered as a secondary end point (four-point scale). An interim analysis after 80 patients was requested by the Ethics' Committee.
Results: The study was stopped after the inclusion of 80 patients. A significantly lower incidence of injection pain was found in the Etomidate-Lipuro group as compared with the propofol-lidocaine group (5.0% vs 47.5%, P<0.001). The use of etomidate was associated with a significantly higher incidence of myoclonic activity compared with propofol-lidocaine (85.0% vs 15%, P<0.001).
Conclusions: The use of a new lipid formulation of etomidate is associated with significantly less injection pain than propofol with added lidocaine in children. This finding may warrant a change in clinical practice in order to avoid unnecessary pain in children.