Progression of burn wound depth by systemical application of a vasoconstrictor: an experimental study with a new rabbit model

The final depth of a necrosis resulting from burn trauma is determined with in 3 days. The zone of stasis has the potential for complete regeneration o r there may be ischemic influences that lead to necrosis. In our model, we examined the dermal influence of vasoconstrictors with reference to the dev elopment of burn necrosis. On the backs of New Zealand white rabbits (4.0-4 .5 kg) standardized lesions were made with a heated aluminum stamp at 80 de grees C, 14 s in duration. The lesions were intradermal, whereby the border zone of the coagulated tis sue was found in the middle two quarters of the dermis in 100% of untreated animals after 72 h. For dermal vasoconstriction epinephrine in a dose of 0 .5 mu g/kg/min was used. There were two groups of seven animals each. One group received epinephrine and the dosage was dependent on the clinical state of the animal. Several cycles were administered within a 3-day period. The reduction of skin perfu sion was documented by Laser-Doppler-flowmetry. After 3 days, the skin with the lesions was excised and using a hematoxylin dye, a histological examin ation followed. The parameter used to determine the efficacy was the thickn ess of the uncoagulated part of the excised dermis. Over a period of 48 h, an average of 2.3 epinephrine cycles of average of 8 8 min per animal in duration resulted in an average reduction of skin diffu sion of 41%. The uncoagulated part of the dermis in the epinephrine group w as 28.6% average; in the control group, this was 43.5%. The statistical ana lysis revealed significant differences with a p-value of 0.0312 (significan t, when value is less than 0.05). The test results indicate that temporary reduction of skin perfusion through external administration of vasocontrict ors may lead to progression of burn necrosis in our animal model. Clinically, this result indicates that for patients with burn injuries and systemic inflammatory response syndrome who have insufficient volume therap y, the administration of vasocontrictors may produce similar results in the injured area. (C) 1999 Elsevier Science Ltd and ISBI. All rights reserved.