Lung, Artificial: Current Research and Future Directions

Artificial lungs are medical devices designed to take over or supplement the respiratory function of the lung: oxygenating the blood and removing carbon dioxide. They are generally classified as extracorporeal, paracorporeal, intravascular, or intrathoracic devices (Fig. 1). The artificial lungs used clinically today are extracorporeal blood oxygenators, primarily used in operations requiring cardiopulmonary bypass, but also used less frequently for support of patients with respiratory failure. The growing incidence of lung disease associated with the aging population has spurred recent work toward nextgeneration artificial lungs that may be used to successfully treat patients with a variety of respiratory failures. Nextgeneration artificial lungs include 1) paracorporeal approaches (wearable devices that will be attached directly to patients); 2) intravascular approaches (respiratory catheters placed within the vena cava through a peripheral vein); and 3) intrathoracic approaches (devices that will be placed internally within the thoracic or abdominal cavities). Intravascular artificial lungs are aimed primarily at treatment of acute respiratory failures, whereas paracorporeal and intrathoracic artificial lungs are aimed primarily at bridge-to-transplant respiratory support because of the more invasive procedures required to implement them. This article reviews the current state of research on next-generation artificial lungs for support of patients with failing lungs. The basic operational principles of artificial lungs and the current clinical applications of standard blood oxygenators are reviewed in a companion article (Lung, Artificial: Basic Principles and Current Applications).