Pathology scoring system for blast injuries.

A pathology scoring system, initially developed by the Walter Reed Army Institute of Research in collaboration with the Lovelace Biomedical and Environmental Research Institute and currently used in the Jaycor Pathos data base program, was modified to arrive at a severity of injury index for individual animals. With this approach, an animal was assessed for injuries by using an alphanumeric code. External lesions, fractures, and trauma to pharynx/larynx, trachea, lungs, heart, hollow abdominal organs, and solid abdominal organs were assigned individual numerical scores based on the severity of the lesion. The various lesions also were graded as trace, slight, moderate, or extensive, depending upon their severity. Each individual score was divided by its preassigned maximum possible score to arrive at a severity of injury ratio for that organ or system. The presence or absence, and the extent of a pneumothorax, hemothorax, hemoperitoneum, coronary air, or cerebral air were summed and added to the sum of the ratios. The resulting value was then multiplied by 1 or 2, depending upon whether the subject was a survivor or a fatality, to arrive at an adjusted severity of injury index by excluding ear damage values from the sum of the ratios. The severity of injury index was used in conjunction with a single degree of freedom blast model to develop damage risk criteria for blast injury.