Effects of peripheral high energy missile trauma on the oxygenation of lung tissue in the pig.
The purpose of this paper was to study the effect of peripheral high energy missile trauma on oxygenation of the lung tissue. Eleven pigs were randomised to either high energy gunshot wound of the soft tissues of the thigh or sham exposure. Under anaesthesia and controlled ventilation, the carotid artery and the jugular vein were catheterised and a thoracotomy was performed. A Clark-type multiwire electrode was placed on the surface of the middle lung lobe for registration of the oxygen pressure fields of the lung tissue (PtO2). In animals subjected to missile trauma, an increased heterogeneity was seen in PtO2 1 and 2 hours after exposure, specially under hypoventilatory provocation. Furthermore, PtO2 values did not return to baseline when hypoventilation was followed by normoventilation, in contrast to what was seen in the sham exposed animals. No differences between groups were found in arterial PO2, O2-saturation, PCO2, pH or in pulse frequency. These findings of disturbance in oxygenation of pulmonary tissue, may represent an early phase in the development of a lung injury resembling the post-traumatic adult respiratory distress syndrome seen in man. The initiating events could be release of mediators from traumatised tissue and/or direct effects of the shock waves from missile impact, passing through the body.