Branched vascular network architecture: A new approach to lung assist device technology

Objective: A lung assist device would serve an important clinical need as a bridge to transplant or destination therapy for patients with end-stage lung disease. A new lung assist device has been developed that incorporates a branched network of vascular channels adjacent to a gas chamber, separated by a thin, gas-permeable membrane. This study investigated 2 potential gas exchange membranes within this new architecture. Methods: Oxygen and carbon dioxide exchange within the device was tested in vitro using 3 gas-permeable membranes. Two of the membranes, silicone only and silicone-coated microporous polymer, were plasma impermeable. The third, a microporous polymer, was used as a control. Gas exchange testing was done using anticoagulated porcine blood over a range of flow rates. Results: Oxygen and carbon dioxide transfer was demonstrated in the device and increased nearly linearly from 0.6 to 8.0 mL/min blood flow for all of the membranes. There was no significant difference in the gas transfer between the silicone and the silicone-coated microporous polymer membranes. The transfer of oxygen and carbon dioxide in the device was similar to existing hollow fiber oxygenators controlling for surface area. Conclusions: The silicone and silicone-coated microporous polymer membranes both show promise as gas-permeable membranes in a new lung assist device design. Further optimization of the device by improving the membranes and reducing the channel diameter in the vascular network will improve gas transfer. The current device may be scaled up to function as an adult lung assist device. (J Thorac Cardiovasc Surg 2010;140:990-5)