[Comparative study on physical parameters and biological effects of blast wave on plateau and on plain].

Objective: To compare the physical parameters and biological effects of blast wave on plateau and on plain.

Methods: Twenty-five pigs were divided into two groups: plateau group (n=15) and plain group (n=10). They were placed either 5 meters or 6 meters away from the site of explosion. Ten kilogram of TNT was detonated to produce blast injury. Physical parameters were measured with pressure transducers. The survival rate and gross morphological changes were carefully observed 28 hours later.

Results: There was no significant difference in propagation speed of blast wave between the two groups. Compared with plain group, the over-pressure value measured in plateau group was a slightly lower, however, the duration of positive pressure was more lengthy and impulse stronger compared with that of plain group. The survival rate was 12/15 and 8/10 respectively for plateau and plain groups 28 hours after injury. The morphological changes were mainly lung hemorrhage and edema. Intestinal subserosal hemorrhage and subendocardial hemorrhage were found in some animals. The lung injury severity in plateau group was one scale severer than that of plain group.

Conclusion: Plateau blast wave is characterized by slightly higher impulse, longer duration, and lower over-pressure value, although the propagation speed of the wave is not different from that of plain environment. The blast injury in plateau environment is also severer, its underlying mechanisms need to be further explored.