A series of models of non-thermal high voltage electrical injuries.

Although many models of electrical injury have been established, none of them are completely typical of the clinical features of electrical injury. As a result, research based on these models were incapable of explaining many clinical phenomena such as continuous tissue necrosis and also were unable to cope with high ratio of amputation of extremities. In order to investigate the mechanism of electrical injuries and better model the condition with similar clinical characteristics we developed a new model. Seventy-five New Zealand rabbits were employed in this study, of them 45 were used in a preliminary experiment including the selection of the size of electrode plate area, damaged extent, time length of electrical injury and interval length between two injuries and so on. Another 30 rabbits were equally divided into five groups with electrical injury times of 6, 12, 18, 24 and 30 cycles, respectively. Observations were made using clinical anatomical exploration, with quantification using an IDBI scale on the 2nd, 8th, 24th, 48th hours and 5th, 15th days, and TC-99m-DMP isotope scanning and gamma photography at 2nd hour and 5th day in post-injury, respectively. The results showed the effective electric field strength was 17,000 V/m, mean current intensity was 554 mA, average current density was 137 mA/cm(2) beneath the small electrode plate with 21 mA/cm(2) beneath big one, and average increase of tissue temperature was 1.73 degrees C during injury process which excluded the possibility of thermal injury. One single wound injury beneath the small plate of the experimental rabbits with loss of injured extremities from 5th to 15th post-injury days in groups 3-5 and obviously progressive tissue necrosis in and outside the wounds were obtained. A series of electrical injured models from mild, moderate, severe, extra severe, and destructive which was exactly similar to the clinical features of electrical injury cases was established.

[Preventing scarring in split-thickness skin donor sites with epidermal grafting].

OBJECTIVE: Introducing a new technique for preventing the scar growthing in split thickness skin donor sites using the great sheets of epidermis covering. METHODS: The donor sites of split thickness skin were grafting with the great sheets of the epidermis, of the thickness about 0.07 approximately 0.12 mm, harvested by electrical power dermatome and fixed the edges of the epidermal sheet with the verges of donor wound together using the nanoparticles-Ag-gauze stripes adding the sutures or skin stapler, dressing the wounds with the nanoparticles-Ag-gauze using the tie-over technique, left the dressing entire for a 5-day period. RESULTS: This method were used in a total of 209 donor sites of both the split-thickness skin and epidermis for 133 reconstructed sites of 118 cases from November 1999 to November 2003, and the smooth, near normal skin appearance without scarring were obtained in the split thickness skin donor sites, and the epidermal donor sites healed good enough 5 days after surgery, and skin appearance is near normal in 3 months later. CONCLUSIONS: Covering the donor sites of split thickness skin with the large sheets of epidermis is an effective and useful method for preventing the scarring in the split thickness skin donor sites.