Ambulatory Oxygenator Right Ventricular Assist Device for Total Right Heart and Respiratory Support

Background: Our goal is ambulatory total respiratory and right heart assistance allowing a bridge to lung transplant. To that end, we have coupled a compact paracorporeal gas exchange device with a right ventricular assist device (RVAD) to create an "OxyRVAD.". Methods: Through a limited left thoracotomy, the main pulmonary artery (PA) and right atrium (RA) were exposed in 5 anesthetized sheep. After a systemic heparin bolus, a 12-mm outer diameter crimped graft glued to tubing was anastomosed (end to side) to the main PA and a VAD atrial cannula was placed through the RA appendage. The chest was drained and closed, then the PA graft flowed at 1 to 2 L/min as a shunt to the RA overnight. The next day, the animal was reanticoagulated, and the shunt cannulae clamped and divided. The OxyRVAD unit, consisting of commercially available components including an axial flow pump and low-resistance cardiopulmonary bypass gas exchange device, was interposed. Pumping from RA to PA was maintained at 3 L/min. Results: Five consecutive sheep survived the implant, and stood and ate normally after initiation of the OxyRVAD. Three survived the full 2-week study, and a fourth was sacrificed on day 13 owing to a storm-related power failure. For these 4 sheep, pump flow was stable at 3 L/min. Carbon dioxide removal was constant and total during the experiment at 200 ± 19 mL/min. Oxygen transfer was 144 ± 44 mL/min. One sheep had progressive thrombocytopenia and was sacrificed on day 5 after implant. Conclusions: Our ambulatory OxyRVAD can provide total assistance for the right heart and lungs in normal awake sheep for 14 days.