AN INTRAPLEURAL LUNG PROSTHESIS - RATIONALE, DESIGN, AND TESTING

Extracorporeal life support (ECLS or ECMO) is standard treatment for s evere respiratory failure but poses many contraindications to future l ung transplantation. The solution to this dilemma is the implantable g as exchange device (IGED) or artificial lung. Preliminary efforts to c reate such an artificial lung have been made since 1970 and include de signs involving single devices, intravascular devices (i.e., IVOX), an d combination heart-lung devices, Stringent requirements govern the de sign of such a device, the most important of which are high gas exchan ge efficiency, low resistance to blood flow, and size. This paper desc ribes such a device. It incorporates large diameter inflow and outflow ports in close proximity and a low resistance wound hollow fiber core encapsulated in a compliant outer shell which conserves the work of t he right ventricle. In a large animal model (adult sheep) this device was connected in line with the main pulmonary artery in series with th e native lungs. This configuration has the advantages of using the lun gs as an embolic filter, perfusing the lungs with fully oxygenated blo od, and maintaining the integrity of the anatomy necessary for transpl ant. Laboratory experiments have run > 8 h. Preliminary data show that the animals have remained hemodynamically stable while the devices ha ve supported the animals completely by supplying 100% O2 saturation wi th PO2 values ranging from 250-350 mm Hg. Additionally, this model mak es possible the study of respiratory failure without introducing other variables such as extracorporeal circuits or pumps. The other metabol ic, endocrine, and reticuloendothelial functions of normal and injured lungs can now be studied more precisely by excluding these variables. Further studies are needed to evaluate this device in chronic (long-t erm implantation) experiments before clinical application.