Age-Related Response to Lidocaine-Prilocaine (EMLA) Emulsion and Effect of Music Distraction on the Pain of Intravenous Cannulation

Abstract

Objective. To compare the efficacy of a local anesthetic cream and music distraction in reducing or preventing pain from needle puncture (intravenous cannulation) in children. A secondary aim was to examine the influence of age on the pain report and behavior and on the therapeutic outcome. Methodology. Children aged 4 to 16 years (N = 180) who were to undergo surgery under general anesthesia via intravenous cannulation were randomly allocated to one of three interventions. The comparison of lidocaine-prilocaine emulsion (EMLA, Astra) and a placebo emulsion was double-blind. Stratification by age group (4 to 6, 7 to 11, 12 to 16) ensured an equal number of children (20) in each intervention/age group category. A global assessment of the behavioral reaction to the procedure was made by the principal investigator, taking into account vocal, verbal, facial, and motor responses. The child was asked to assess pain severity on the Faces Pain Scale (FPS) and a visual analogue toy (VAT). The scales were applied conservatively as ordinal scales: FPS 0 to 6; VAT 0 to 10. Results. Children who received lidocaine-prilocaine emulsion reported less pain (mean FF5 score = 1.42) compared with placebo emulsion (mean FPS score = 2.58) and with music distraction (mean FPS = 2.62). There was a highly significant therapeutic effect (P < .001) on the self-report and behavioral scores. Younger children, regardless of intervention, reported significantly more pain than the older children (mean FPS scores: 2.85, 2.33, 1.43 for age groups 4 to 6, 7 to 11, and 12 to 16 respectively; P < .001). The superiority of the local anesthetic emulsion was maximal in the youngest age group (4 to 6) almost eliminating pain-related behavior, and multiple regression analysis confirmed significant age and treatment effects and revealed interaction between therapeutic effect and age. Although a trend favoring the active emulsion was evident in the older children (7 to 11, 12 to 16) the differences were not significant. The pain scores were influenced by the type (gauge) of cannula, but this did not affect the conclusion regarding therapeutic and age effects. There was no influence of sex, experience with venipuncture, or whether the child was anxious on arrival in the operating room. Conclusions. The results show that lidocaine-prilocaine emulsion is highly effective in preventing pain from venipunctures in young children the group in most need of prevention.