Improved right heart function with a compliant inflow artificial lung in series with the pulmonary circulation

Background. We previously reported a 50% incidence of immediate right heart failure using a rigidly housed, noncompliant inflow artificial lung in ser ies with the pulmonary circulation in a healthy ovine survival model. Three device modifications resulted: (1) an inflow cannula compliance chamber, ( 2) an inlet blood flow separator, and (3) modification of the artificial lu ng outlet geometry, all to reduce resistance and mimic the compliance of th e pulmonary vascular bed. Methods. In 7 sheep, arterial grafts were anastomosed end-to-side to the pr oximal and distal main pulmonary artery, with the paracorporeal artificial lung interposed. A pulmonary artery snare between anastomoses diverted full pulmonary blood flow through the artificial lung for up to 72 hours. Results. Six of 7 sheep exhibited good cardiac function throughout the test period: mean central venous pressure was 6.8 mm Hg (range, 4 to 11 mm Hg), mean cardiac output, 4.17 +/- 0.12 L/min (range, 2.4 to 6.3 L/min); before and after device mean pulmonary arterial pressure, 21.8 and 18.5 min Hg, a nd left atrial pressure, 10.8 mm Hg. Conclusions. This modified artificial lung prototype with an inflow complia nce chamber, blood flow separator, and modified outlet geometry has greatly improved cardiac function and initial survival in our healthy ovine model. (C) 2001 by The Society of Thoracic Surgeons.