RESUMEN
OBJECTIVE: We sought to investigate the safety and feasibility of obtaining total respiratory support during 72 hours using a pump-driven (Levitronix CentriMag; Levitronix LLC, Waltham, Mass) venous-venous extracorporeal lung membrane (Novalung; Novalung GmbH, Hechingen, Germany) attached through a single double-lumen cannula (Novalung) into the femoral or jugular vein in pigs. METHODS: Twelve pigs were initially mechanically ventilated for 2 hours (respiratory rate, 20-25 breaths/min; tidal volume, 10-12 mL/kg; fraction of inspired oxygen, 1.0; positive end-expiratory pressure, 5 cm H(2)O). Thereafter, the extracorporeal lung membrane was attached to the right femoral (n = 6, 26F) or jugular (n = 6, 22F) vein by using a single double-lumen cannula placed transcutaneously. Ventilatory settings were then reduced to near-apneic ventilation (respiratory rate, 4 breaths/min; tidal volume, 1-2 mL/kg; fraction of inspired oxygen, 0.21; positive end-expiratory pressure, 10 cm H(2)O), and pump flow was increased hourly until maximal efficacy. Blood gases and hemodynamics were measured hourly, and lung and plasma cytokine levels were measured every 4 hours. RESULTS: The device's mean blood flow was 2.16 +/- 0.43 L/min, permitting an oxygen transfer and carbon dioxide removal of 203.6 +/- 54.6 and 590.3 +/- 23.3 mL/min, respectively. Despite static ventilation, all pigs showed optimal respiratory support, with a PaO(2), PaCO(2), and mixed venous oxygen saturation of 226.2 +/- 56.4, 59.7 +/- 8.8, and 85.6 +/- 5.3 mm Hg, respectively. There were no significant inflammatory, cellular, or coagulatory responses; lung cytokine levels remained in the normal range. Route (femoral vs jugular) or size (22F vs 26F) of the cannula did not change hemodynamic or respiratory parameters significantly. CONCLUSIONS: This circuit provides total respiratory support over 72 hours without inducing significant hemodynamic, coagulatory, cellular, or inflammatory responses.