Intravenacaval Membrane Oxygenation

Study objective: To characterize the physiologic response to, and safety of, intravenacaval membrane oxygenation and carbon dioxide removal. Design: Interventional before-after study. Setting: University teaching hospital ICU. Patients: Twenty-two patients with severe acute respiratory distress syndrome (ARDS). Interventions: Implantation of a hollow-fiber membrane oxygenator (IVOX; CardioPulmonies; Salt Lake City, Utah) into the superior and inferior venae cavae by venotomy of the right femoral or right internal jugular vein for a duration of up to 20 days. Measurements: Hemodynamic measurements using pulmonary artery and systemic artery catheters, ventilator settings (FIo2, minute ventilation, peak inspiratory pressure, and positive end-expiratory pressure), arterial and mixed venous blood gases (pH, Pco2, Po2, and measured saturation), and clinical laboratory determinations (CBC, fibrinogen, plasma hemoglobin, complement C3 and C5) were obtained. Calculations of PaO2/ FIo2 ratio and PaCO2-VE product were used to assess gas exchange efficacy. Microbiologic cultures were obtained from the device and wound following explantation. Survival to ICU discharge and hospital discharge were recorded. Results: Implantation was successful in 20 of 22 patients. Gas exchange rates averaged 50.4 + 15.8 mL min-' for carbon dioxide and 71.1 ± 20.2 mL min-' for oxygen. A reduction in FIo2 from 0.78 ± 0.16 to 0.63 ±0.21 and in VE from 177± 94 mL -kgmin' to 127 ± 58 mL kg' min-t was possible within 4 h postimplantation. By 12 h, FIo2 was reduced to 0.57 ± 0.18. Indices of gas exchange improved significantly after