Intravenous lidocaine infusion in the treatment of experimental human skinburns - digital colour image analysis of erythema development

Previous studies have shown that local anaesthetics possess a wide range of effects on the pathophysiology of burns, including inhibition of burn oede ma and inhibition of progressive burn ischemia. The present randomised doub le-blind cross-over study in six volunteers investigated the effects of int ravenous lidocaine infusion on partial thickness skin burns. A thermoprobe was used to induce a standardised thermal injury (1 cm(2)) on the flexor si de of one forearm and was repeated on the opposite side 1 week later. Subje cts received either an intravenous bolus dose of lidocaine (1 mg kg(-1)) im mediately after the thermal trauma followed by continuous intravenous infus ion of lidocaine (40 mug kg(-1) min(-1)) during 4 h or equal volumes of iso tonic saline. Macrophotographs of the experimental skin area were taken pre burn and 1, 2, 3, 4, and 12 h postburn and evaluated by computerised image colour analysis using normalised rgb (n-rgb) and Hue-Saturation-Intensity ( HSI) colour systems as a quantitative measure of pathophysiological events, Maximum erythema occurred 2-3 h postburn. Differences between lidocaine- a nd placebo-treated burns were not significant during the first 4 h postburn . At 12 h postburn, the lidocaine-treated burn demonstrated a significantly faster restitution of residual erythema compared to control sites. The pre sent study shows that intravenous lidocaine significantly inhibits the long -term inflammation-induced tissue responses to thermal trauma. (C) 2000 Els evier Science Ltd and ISBI. All rights reserved.