Post-traumatic-shock lung: postmortem microangiographic and pathologic correlation.

In post-traumatic-shock lung, increased pulmonary vascular resistance and pulmonary hypertension are prominent features. The explanation for them was sought by postmortem microangiography of the lungs of 17 patients dying of respiratory failure after trauma. The 10 patients with thoracic injury died earlier (1-8 days). Extravasation of contrast material due to alveolar capillary rupture was present in all but one specimen and occupied 20% of the sampled area. Pulmonary artery thrombi lay proximal to these extravasations. Hypovascular areas due to infection and hemorrhagic alveolitis were found in all patients and involved 40% of the surface area. The small pulmonary arteries were poorly filled and contained many microthrombi. Some patients had hematomas, cavities, and areas of interstitial edema occupying about 5% of the lung area and associated with compressed or occluded vessels. Several mechanisms including pulmonary trauma may be responsible for the antemortem rupture and obstruction of small blood vessels. In the post-traumatic-shock lung, small artery occlusion and compression are associated with pulmonary hemorrhage, infarction, and infection and are important contributors to perfusion abnormalities and respiratory failure.