Posttraumatic respiratory distress syndrome and high-dose corticosteroids

Many authors have advocated glucocorticoids for prophylaxis against or treatment of Adult Respiratory Distress Syndrome (ARDS) or post-traumatic pulmonary microembolism. One of the theories underlying this advocacy is that the activation of the complement system possibly is preventable by pharmacologic doses of corticosteroids. Studies on traumatized patients are difficult to standardize, and clinical observations are correspondingly difficult to evaluate. Animal models for study of the microembolism syndrome have often comprised too short a time and most have greatly differed from the clinical situation. We have earlier evolved an experimental model by means of which changes identical to the microembolism syndrome can be induced from a reproducible musculo-skeletal trauma in pigs observed under long-term anesthesia under standardized conditions. In this study, early and long-term effects of corticosteroids on the course of post-traumatic microembolism was evaluated by following the pulmonary function and X-ray appearance, pulmonary trapping of platelets and fibrin and histologic changes in pigs, using this standardized trauma model. Methylprednisolone sodium succinate (30 mg/kg bw) was given to 9 pigs one hour after trauma and thereafter every 8th hour during a 72 hour observation period. Two other groups of animals were used for comparison, 13 traumatized, non-treated and 15 non-traumatized, non-treated pigs. Intrapulmonary microembolism was measured quantitatively by repeated external detection of labelled platelets (51Cr) and fibrinogen (125I), sequential chest X-rays and morphologic examination of the lungs post mortem.(ABSTRACT TRUNCATED AT 250 WORDS)