INVOLVEMENT OF THE CENTRAL-NERVOUS-SYSTEM IN THE GENERAL RESPONSE TO PULMONARY BLAST INJURY

The local, general, and cerebral responses of rabbits exposed to pulmo nary blasts were examined to define the role of vagal afferentation in cardiorespiratory as well as metabolic control after a blast injury. Two series of experiments were conducted on rabbits to analyze the gen eral, local, and cerebral responses to pulmonary injury caused by blas t overpressure, and to evaluate the effects of bilateral vagotomy on t he general, local, and cerebral responses to local (pulmonary) blast i njury. The blast wave was generated in laboratory conditions using an air-driven shock tube that was able to cause moderate pulmonary blast injury, i.e., four pulmonary contusions characterized as confluent ecc hymoses involving 30 to 60% of the lungs. One group of animals was sub jected to pulmonary deafferentation, performed by bilateral transectio ns of the vagus, glossopharyngeal, and hypoglossal nerves. Numerous he modynamic as well as biochemical parameters were observed in systemic circulation and in lung and brain (medulla oblongata) tissues. After o bservation during the early posttraumatic period, rabbits were sacrifi ced by decapitation 30 minutes after the blast injury. On the basis of obtained results, it was concluded that vagal afferents have an impor tant role in the modification of general and local responses to a pulm onary blast injury. Furthermore, it was suggested that functional chan ges in medulla oblongata may be the consequences of afferent neural im pulses from the injured region (lungs) rather than consequences of isc hemia, energy transfer to the brain, or both.