Topical anesthesia before vascular access in children: Comparison of a warmth-producing lidocaine-tetracaine patch with a lidocaine-prilocaine patch

Background: Venepuncture is one of the most stressful situations for children during induction of general anesthesia. Therefore, many clinicians use a local anesthesia patch (EMLA®) containing a mixture of lidocaine and prilocaine in order to reduce the stress for pediatric patients. This study compared the effect of a new heated topical anesthesia delivery system containing lidocaine and tetracaine (Rapydan®) with the lidocaine/prilocaine patch EMLA®. Methods: The study design was prospective, randomized, single-blinded and monocenter. A total of 200 children aged from 3 to 13 years were randomized into group E (EMLA®) or group R (Rapydan®). The primary endpoint of the study was the overall incidence of pain. Additionally, the intensity of pain during venous puncture was evaluated by means of an investigator-based 4 point pain score: 0 no reaction, 1 gentle movement/grimacing, 2 moderate withdrawal of the arm/crying and 3 strong withdrawal/screaming. Furthermore, erythema of the skin, visibility of the veins and success rate of the punctures were assessed. Results: Mean contact time of the patch with the skin was 35 min in both groups. The overall incidence of pain was 46% in group E and 12% in group R (p<0.001). The intensity of pain also differed significantly between the groups. A pain score of 1 was observed in 24% (group E) versus 10% (group R), a score of 2 was documented in 13% (group E) versus 1% (group R) and a score of 3 was observed in 9% (group E) versus 1% (group R; p<0.001). Erythema of the skin was observed more frequently in group R (p<0.001). Visibility of the veins and success rate of venous puncture did not differ significantly. Conclusions: After a contact time of 35 min the Rapydan® patch led to superior analgesia during venous puncture than the EMLA® patch. With regard to visibility of the veins and success rate of the punctures, differences between the two patches were not observed. © 2010 Springer-Verlag.