Peripheral high-energy missile hits cause pressure changes and damage to the nervous system: experimental studies on pigs

The aim of the present study was to investigate pressure changes and possible damage to the central and peripheral nervous system induced by a high-energy missile striking a peripheral extremity. Anesthetized pigs were shot with a high-velocity missile (1,500 ms-1) in their left thigh. Transducers placed in the abdomen and brain recorded short-lasting bursts (1.0 to 1.5 ms) of oscillating pressure waves of high frequency. The amplitude of the pressure waves within the brain was about 125 KPa, and in the abdomen about 270 KPa, with a mean value of transferred energy from the missile of about 700 joules. Concomitantly, there were one or two apneic periods with a duration of a few seconds during the first minute after the shot. No significant changes in the heart rate, blood pressure, or other circulatory parameters were detected. Minor blood-brain and blood-nerve barrier damage occurred. It is concluded that the pressure waves caused by hits of peripheral parts of the body by high-energy missiles may be of such a large magnitude that distant damage to nervous tissue may result.