Experimental post-traumatic lung insufficiency in dogs. Gross and light microscopic lung lesions.

Post-traumatic lung insufficiency in dogs was induced by a combination of haemorrhagic hypotension and liver trauma. In one experimental group, lung biopsies were sampled every 4 h. This paper describes the development of gross and light microscopic lunig changes in these dogs, and the lung lesions 12 h after initiation of the trauma in another experimental group. Incipient changes were recognized as early as 4 h after initiation of the trauma. Perivascular and intraseptal oedema, scattered microthrombi, and trapping of leucocytes in lung microvessels were the most conspicuous morphological findings. These changes grew gradually more pronounced towards collapse, when also areas with interstitial haemorrhages, intra-alveolar protein-rich oedema fluid with strands of a fibrinoid material, and an increased number of partly degenerated leucocytes were found in addition to atelectasis. The morphological lung lesions in this experimental model are similar to post-traumatic shock lungs in human patients.