Gastrointestinal Lesions in Lambs Due to Multiple Low-Level Blast Overpressure Exposure

Abstract

Previous studies of non-auditory injuries due to blast overpressure (BOP), or “concussion”, generated by explosives have dealt with high intensity—high mortality single exposures. This study explored non-auditory lesions in lambs due to 50 repetitions of 3.5, 7.5, or 15 psi, far below the 1% mortality dose for a single exposure. Severe hemorrhage in the 15 psi group was noted in 12 of 15 animals in the rumen, 9 of 15 in the small intestine, and 9 of 15 in the large intestine. Pulmonary hemorrhage, the most frequent major non-auditory lesion observed with a single high intensity BOP exposure, did not increase in incidence or severity in exposed lambs over control lambs. These results indicate that the number of BOP exposures, as well as the intensity, plays a role in determining the pattern of BOP injury produced, and that increasing numbers of exposures significantly lower the threshold for potentially disastrous non-auditory injury.