Ventilation and gas exchange lung functions were studied in 110 patients with severe closed chest trauma. In chest trauma that was not accompanied by intrapulmonary traumatic changes the main pathogenetic mechanism of gas exchange damage was marked pain syndrome. Such patients did not suffer from severe arterial hypoxemia and their intrapulmonary shunting did not exceed 15%. Analgesia and, if necessary, lung decompression improved considerably respiratory parameters and prevented the onset of severe pulmonary failure. Patients with intrapulmonary traumatic changes (lung contusion, intrapulmonary hematomas) were characterized by progressing arterial hypoxemia due to a considerable increase in intrapulmonary shunting. These patients are managed mainly by preventive therapy of pulmonary hyperhydration, thorough tracheobronchial cleansing, cough stimulation, prevention of pneumonia.