The lung parenchyma in burns

A clinicopathological correlation of the lungs on 68 cases dying from burns was carried out. The patients were divided into two main groups. Those in which the burns were the main cause of death (30 cases) and the others that had other serious underlying pathology as well as burns (38 cases). The cases were analysed sequentially in order that the evolution of the pulmonary changes could be studied. Note was made of the level of inspired oxygen received by the patient. The pulmonary changes were similar in both cases. In the first 48 h there was congestion of the alveolar walls, capillary proliferation, interstitial and intra-alveolar oedema and intra-alveolar haemorrhage. 'Giant endothelial cells' appeared at 24 h. After 48 h there were many of these structures along with intravascular microthrombi denoting disseminated intravascular coagulation. Pneumonia and septicaemia were common findings after 48 h. In some of the septicaemic patients there was basophilic staining both in the blood vessel wall as well as inside the lumen. Hyaline membranes were uncommon, being found in only four cases. Similarly interstitial and intra-alveolar fibrosis were uncommon. Interstitial fibrosis was present in only 8/30 cases where burns were the main cause of death, and in some of these there were other causes for the fibrosis. No correlation was found between the presence of hyaline membranes, interstitial fibrosis and the percentage or duration of oxygen therapy. These findings once again question the validity of the concept of oxygen toxicity in man.