Does a lidocaine patch reduce the pain at venous cannulation in adults?

Abstract

In this study we evaluated whether a lidocaine patch reduces the pain relating to a venous cannulation in adults. The patch is consisted of the base containing 50% lidocaine on a thin polyester membrane. Its surface area is 15 cm². Twenty-six adult patients scheduled for elective surgery (11 males and 15 females) were randomly divided into two groups according to application periods: Group A for 15 min and Group B for 30 min. Either the dorsal part of the hand or the radial side of the wrist was chosen and covered with the patch. Pain assessment was made by patients using a 0–100 point visual analog scale (VAS). In 7 patients of Group A, plasma lidocaine levels were measured 15 min after application by homogeneous enzyme immunoassay. The levels were further measured 30 and 60 min after application in 3 of those patients. The mean VAS score was 28.4±13.1 (mean ± SD) for Group A and 51.8±15.9 for Group B, and the difference was statistically significant (P<0.05). Plasma lidocaine levels were always below 0.2 μg·m⁻¹. The results indicate that the skin was partially anesthetized by the lidocaine patch. A lidocaine patch may be useful and safely applicable for venous cannulation in adult patients.