| Objective: To explore the detrimental effects of the compound factors of hot and humid environment and trauma on rabbit's wounds and the whole physiological responses of rabbits, and the protective function of immediate topical negative pressure wound therapy (TNP) under the influence of the above compound factors, estimate the degree of wounds healing, compared with the traditional therapy. The study offers theoretical basis to select the therapy of wound nursing in hot and humid environment.Methods: Twenty-four New Zealan white rabbits, six for each, were divided randomly into four groups: normal environment control group (NEC), normal environment topical negative pressure wound therapy group (NEE), hot and humid environment control group (HHC), hot and humid environment topical negative pressure wound therapy group (HHE). After the acute whole-skin-loss wounds model of rabbits' backside were established, the rabbits of HHC and HHE groups were put into the controlled climate room. The rabbits of HHC and HHE groups were in condition of Tdb (36.00 ± 0.20)℃, Twb (32.00 ±0.50)℃, Rh (68.00±2.50)% for 6 hours then continued to be treated into normal environment, and those of NEC and NEE groups were in condition of Tdb (25.00 ± 0.50)℃, Twb (20.00±1.10)℃, Rh(50.00±2.50)%. The rabbits of HHE and NEE were treated with the topical negative pressure wound therapy (TNP)(experiment group). The technique entails placing an open-cell foam into the wound sealing the site with an adhesive drape and applying subatmospheric pressure (-12kPa) that is transmitted to the wound in a controlled manner. The rabbits of HHC and NEC were treated with normal dressing (control group). The study was divided into 3 parts: In section I ,(1)Tr, HR, and RF served as observing indexes. During the test, the physiological indexes were recorded once per 1 hours; (2)The quantity changes of bacteria in wound tract: the bacteria in the tissue from wound tract at various time were cultivated. In section II, all rabbits were sampled to observe the pathological morphology of rabbits' muscle of wound under optical microscope at Oh, 6h after trauma, total tissue water content in wound was measured by method of wet-dry subtraction at Oh, 4h, 6h after trauma. In section III, gross tissue change, wound healing time and the percent of wound healing at 7d after trauma were estimated.Result: (1) Changes of physiological response: Compared with the normal environment (NEC, NEE), the Tr, HR, RF in hot and humid environment (HHC, HHE) increased significantly at every hours after trauma (p<0.05), and raised straightly with the time prolonged. Compared with HHC, the Tr, HR, RF of HHE decreased significantly in 3 to 6 hours after trauma (p<0.05); (2) Changes of bacteriological quantity: The quantity of bacteria in wound tract in four groups at 4h, 6h after trauma were all higher than Oh (p<0.05), and increased with the time prolonged. Compared with the normal environment (NEC, NEE), the quantity of bacteria in hot and humid environment control (HHC) increased significantly (p<0.01). Compared with HHC, the quantity of bacteria of HHE decreased significantly at 4h, 6h after trauma (p<0.01) ;(3) Changes of pathological morphology: In these rabbits, we can sawdropsical muscle fibers and disorganized myofibrillae with some loss of myofibrillae, the damage of muscle fibers in HHE was better than that in HHC. The damage of muscle cells in NEC was slighter than that in HHC, the muscle cells in NEE were all normal on the whole;(4) Changes of the containing water percent in wound tissue: The containing water percent in wound tissue in four groups at 4h, 6h after trauma were all higher than Oh (p<0.05), and increased with the time prolonged. Compared with the normal environment (NEC, NEE), the content of tissue water in the hot and humid environment (HHC, HHE) increased significantly after 4, 6 hours trauma (p<0.01). Compared with HHC, the containing water percent in wound tissue of HHE decreased significantly at 4h, 6h after trauma (p<0.05); and Compared with NEC, the containing water percent in wound tissue of NEE decreased significantly at 4h, 6h after trauma (p<0.05);(5) Condition of wound healing: seven wounds were infected on all rabbits' wound, and general infection rate was 29.17%. NEC infection rate was 8.33%, NEE was none, and HHC, HHE group respectively was 16.67%, 4.17%. The wound healing time in HHC was longest, and that in NEE is shortest of four groups. The percent of wound healing at 7d after trauma between NEC and NEE was higher than that in HHC (p<0.01). Compared with the HHC, the percent of wound healing at 7d after trauma of HHE increased significantly (p<0.01), Compared with the NEC, the percent of wound healing at 7d after trauma of NEE also increased significantlyConclusion: (1) The compounded function of hot and humid environment and trauma is more serious than that of each single factor on rabbits' acute wound and physiological response;(2) In hot and humid environment, topical negative pressure wound therapy can efficiently lowered rabbit's Tr, HR, RF, and lightened the body stress reaction, it can effectively prevent hot injury from farther hurting the traumawound and the body;(3) In hot and humid environment, pathological effects induced by hot humid factor to rabbits and the degree of injury and edema of muscle tissue in wound is more serious than that in normal environment;(4) Compared with the traditional therapy, the topical negative pressure wound therapy has the function of effective educing of secretion and protecting of wound and stimulating growth of tissue, on the one hand, it can efficiently abirritate harmful pathological influence and edema of muscle tissue on wound restrain injury progress, on the other hand, it can effectively inhibit the growth of bacteria in the wound and decrease wound infection rate, in addition it can eliminate the disadvantage factors to hasten the processes of healing;(5) The advantages of TNP include operating simple, low cost, and no side-effect, topical negative pressure wound therapy is a kind of simple and effective therapy on wound nursing in hot and humid environment. It is not only suitable to wartime but also to peacetime.
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