Experimental Researches of Time Selection of Excision of Eschar and Skin Grafting after Alkali Burn

Objective To explorie the time of excision of eschar and skin grafting after alkali burn,improving the surviving rate of skin grafting.Methods 90 healthy Wistar rats were divided into 2 groups(A、B) averagely,each group 45 rats.A group's rats were treated by excision of eschar and instantly skin grafting,and B group's rats were treated by excision of eschar and skin grafting after 48 hours.The grafting time was separated into 9 segments(1、2、4、8、12、24、48、72、96h),and every time segments was presented 5 rats.The wound surfaces of 2 groups animals were tested pH value and were made pathology slicings to observe the damage degree and the information of inflammation cells soakaging at the time of the operation.Results The wound surface of A group animals pH value was(10.5±0.5) after excision of eschar,and the pH value of the wound surface was(7.6±0.2) after treating.The pathology observation of the tissue of excision of eschar before 8 hours showed that except the full skin necrosis,the striated muscle was feculent and tumid,but there were not inflammation cell soakaging.The surviving rate of skin grafting was 98.66%;the pathology observation of the tissue of excision of eschar during 12~48 hours indicated that not only the full skin had necrosis,but also had obvious inflammation.There were amount of PMNs soakaging in the muscle tissue,and the surviving rate(79.65%) of the skin decreased distinctively,the difference had statistical meaning(P0.001).The wound surface of B group animals pH value was equal to the A group,and after 48 hours pH value(9.5±0.5) decreased but not evidently.The pH value of the wound surface was equal to A group after treating.The surviving rate of skin grafting was 98.47%.The difference of surviving rate of the 2 groups had no significance(F=0.002,P0.05),but the surviving rate of the 2 groups had crossing effect(P0.001).That is, the effect of different treatments to the surviving rate had the change along with the change of the time.Conclusion The different time of the early patholo-histological observation of the wound surface of rat skin alkali burn,the wound surface of excision of eschar before 8 hours suited early skin grafting;the wound surface of excision of eschar after 8 hours suited delayed skin grafting.