犬冲烧复合伤合并海水浸泡的血流动力学研究

Hemodynamic responses in dogs exposed to blast-burn combined injuries followed by immersion in seawater

目的 建立犬冲击伤复合烧伤合并海水浸泡的实验模型 ,观察实验犬血流动力学特点并探讨相关机制。方法 将肺部轻度冲击伤合并 10 %Ⅱ度体表烧伤犬 17只随机分为浸泡组 (n =10 )和冲烧组 (n =7)。浸泡组实验犬浸泡于海水中 (水温 2 3℃ ,pH8 0 ,盐度 2 2～ 2 5 3) 4h后 ,观察伤前及浸泡出水后 2 4h内血流动力学变化 ,抽取静脉血测定丙二醛 (MDA) ,进行血细菌培养 ,实验结束后观察心、肺病理变化。冲烧组除不浸泡外 ,余处理同浸泡组。结果 浸泡组实验犬体温、心脏指数 (CI)、平均动脉压 (MAP)、心率(HR)较冲烧组明显下降 ,周围血管阻力指数 (SVRI)、肺血管阻力指数 (PVRI)明显升高 ,血浆MDA变化与CI呈负相关 ,在浸泡出水后6h内血流动力学紊乱最明显。浸泡组伤后血中出现肠道菌的时间较冲烧组提前。浸泡组的心、肺病理损伤程度重于冲烧组。结论 海水浸泡明显加重冲烧复合伤血流动力学紊乱 ,浸泡后 6h内为最明显时相段。这可能与浸泡后体温下降、炎症反应和脂质过氧化物反应增强有关。

Objective A dog model of blast-burn combined injuries followed by immersion in seawater was reproduced in dog to study hemodynamic responses and their mechanism. Methods The dogs which were exposed to blast injuries produced by primer explosion and 10% second degree burn were randomly divided into seawater immersion group and blast-burn only group. The dogs in immersion group were immersed in seawater under anesthesia for 4 hours. The hemodynamics of the dogs was monitored, and blood samples were collected to assay malondialdehyde (MDA), and cultured for bacteria. After the above procedures were completed, the pathological changes in the dogs′ hearts and lungs were observed. The dogs in blast-burn group underwent the same protocol in immersion group except immersion. Results The body temperature (T), cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) in dogs in the immersion group were remarkably decreased, while the mean pulmonary artery pressure (MPAAP), systemic vascular resistance index (SVRI), and pulmonary vascular resistance index (PVRI) were markedly increased compared with those in blast-burn group. These obvious hemo dynamic disorders occurred during 3h to 6h after the dogs leaving seawater. Plasma MDA level was negatively correlated with CI. The interval between positive blood calture for intestinal bacteria and injury was shorter in immersion group than that of blast-burn group. The gross and histopathological changes in dogs′ hearts and lungs in immersion group injuries were more severe in degree than in blast-burn group. Conclusions Seawater immersion markedly aggravates the hemodynamic disorders in dogs having had blast-burn combined injury. The changes became obvious during 3h to 6h after leaving seawater. The aggravating effect might be related with declination of body temperature, inflammatory response and lipid peroxidation.