Shock lung: a distinctive nonentity.

B Y THE CLOSE of World War II, a syndrome of "wet lung" had been identified in which life-threatening respiratory distress unexpectedly interrupted convalescence from hemorrhagic and traumatic shock incurred during combat. During the recent war in Vietnam, as the salvage rate after circulatory collapse on the battlefield increased, the syndrome became even more familiar, but under new eponyms. Thus, "wet lung," "shock lung," or "DaNang lung" became synonyms for lung failure that followed successful resuscitation from circulatory collapse. But no matter what it was called, the sequence was the same: severe nonthoracic injury, blood loss, and hypotension during combat; successful resuscitation using tourniquets, transfusions, and opiates on the battlefield; prompt evacuation to a sophisticated medical facility for more deliberate management; and then, a few days later, the calamitous interruption of convalescence by progressive respiratory distress and failure. Only a few who reached the hospital developed shock lung, but in those who did, the pattern of evolution was consistent: insidious onset of rapid shallow breathing, breathlessness, and productive cough; rales and wheezes; refractory cyanosis. Xray appearance of enlarging interstitial and alveolar infiltrates continued to extend and to coalesce until the entire lung was enveloped in a diffuse haze. Enriched oxygen mixtures and assisted ventilation became less and less effective in achieving tolerable levels of oxygenation. Finally, death resulted from respiratory insufficiency often complicated by the recurrence of circulatory collapse. And, at autopsy, a stereotyped morbid anatomy: vascular congestion,