Pulmonary insufficiency after long bone fractures. Absence of circulating fat or significant immunodepression

Twenty young men with displaced fractures of one or more long bones in the lower limb, but with no evidence of cranial, thoracic or abdominal injury, were studied prospectively. Although all the patients became hypoxaemic, the six who developed signs of respiratory distress (Group 1) were found to have a significantly lower arterial oxygen tension and a significantly higher rate of urinary urea excretion than the remaining 14 patients whose pulmonary function appeared to be clinically normal (Group 2). Circulating fat macroglobules were identified in three cases, only one of whom was in Group 1, and hence the tests for fat embolism were not of prognostic value. Although an immunodeficient state is considered to contribute to the pulmonary insufficiency which occurs after major trauma, convincing evidence of a lymphocyte-suppressive agent was found in only one patient.