Hemodynamic responses in dogs exposed to blast-burn combined injuries followed by immersion in seawater / 解放军医学杂志

ABSTRACT

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.