[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.