Background. Untreated immunization pain causes undue distress and contributes to underimmunization through physician, and possibly parental, resistance to multiple simultaneous injections.
Objective. To compare the efficacies of two pain management methods in reducing immediate immunization injection pain and distress in school-aged children.
Design. A randomized, controlled clinical trial of eutectic mixture of local anesthetics (EMLA) cream and vapocoolant spray.
Patients. Children aged 4 to 6 years and scheduled to receive diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) during health supervision visits.
Interventions. Enrolled children were randomized to one of three treatment groups: 1) EMLA cream + distraction; 2) vapocoolant spray + distraction; or 3) distraction alone (control). The specific pharmacologic pain control interventions consisted of EMLA cream (2.5% lidocaine, 2.5% prilocaine [Astra Pharmaceutical Products, Inc, Westborough, MA] $15.00/patient; applied 60 minutes before injection) and vapocoolant spray (Fluori-Methane [Gebauer Company, Cleveland, OH] $0.50/patient; applied via spray-saturated cotton ball for 15 seconds immediately before injection).
Main Outcome Measures. The blinded investigator (BI) measured (by edited videotape) cry duration and the number of pain behaviors using the Observational Scale of Behavioral Distress. Pain visual analog scales (linear and faces scales) were completed by the child, parent, nurse, and the BI.
Results. Sixty-two children, aged 4.5 ± 0.4 years (mean ± SD) were randomized. The three treatment groups had similar subject characteristics. All pain measures and cry duration were similar for EMLA and vapocoolant spray. Both EMLA and spray were significantly better than control. Results for spray vs control: cry duration (seconds): 8.5 ± 21.0 vs 38.6 ± 50.5; number of pain behaviors: 1.2 ± 1.9 vs. 3.1 ± 2.1; child-scored faces scale: 2.0 ± 2.4 vs. 4.1 ± 2.3; parent-scored faces scale: 1.6 ± 1.6 vs. 3.0 ± 1.7; nurse-scored faces scale: 1.6 ± 1.2 vs. 3.1 ± 1.4; and BI-scored faces scale: 1.0 ± 1.5 vs. 2.4 ± 1.4.
Conclusions. When combined with distraction, vapocoolant spray significantly reduces immediate injection pain compared with distraction alone, and is equally effective as, less expensive, and faster-acting than EMLA cream. As an effective, inexpensive, and convenient pain control method, vapocoolant spray may help overcome physician and parent resistance to multiple injections that leads to missed opportunities to immunize.