In patients with severe adult respiratory distress syndrome, mechanical ventilation may not be able to ensure gas exchange sufficient to sustain life. We report the use of an intravenous oxygenator (IVOX) in five patients who were suffering from severe adult respiratory distress syndrome as a result of aspiration, fat embolism, or pneumonia. IVOX was used in an attempt to provide supplemental transfer of CO2 and O2 and thereby reduce O2 toxicity and barotrauma. All patients were tracheally intubated, sedated, and chemically paralyzed and had a PaO2 < 60 mmHg when the lungs were ventilated with an FIO2 = 1.0 and a positive end expiratory pressure of > or = 5 cmH2O. The right common femoral vein was located surgically, and the patient was systemically anticoagulated with heparin. A hollow introducer tube was inserted into the right common femoral vein, and the furled IVOX was passed into the inferior vena cava and advanced until the tip was in the lower portion of the superior vena cava. IVOX use ranged from 2 h to 4 days. In this group of patients, IVOX gas exchange ranged from 21 to 87 ml x min-1 of CO2 and from 28 to 85 ml x min-1 of O2. One of the five patients survived and was discharged from the hospital. The IVOX transferred up to 28% of metabolic gas-exchange requirements. One patient with a small vena cava showed signs of caval obstruction. Three other patients demonstrated signs of a septic syndrome after the device was inserted.(ABSTRACT TRUNCATED AT 250 WORDS)