Role of extracorporeal lung assist in the treatment of acute respiratory failure.

For patients with most severe acute respiratory distress syndrome (ARDS) conservative treatment with lung protective ventilation is often not sufficient to prevent life-threatening hypoxemia and additional strategies are necessary. Extracorporeal lung assist (ECLA) or extracorporeal membrane oxygenation (ECMO) using capillary membrane oxygenators can provide sufficient gas exchange and lung rest. In 2 randomized trials mortality was unchanged for ECMO. Today an technically enhanced ECMO is used for most severe ARDS using clinical algorithm and different case studies demonstrated a survival rate about 56%. Today miniaturized ECMO with optimized blood pumps and oxygenators are available and could enhance safety and clinical management. Another approach is an arterio-venous pumpless interventional lung assist (ILA) with a low resistance oxygenator. Advantages seem a simplified clinical management and less blood trauma. At present new devices are developed for chronic respiratory failure or bridge to lung transplant. Oxygenators with even less flow resistance could be implanted paracorporeal using the right ventricle as driving force. An intravascular oxygenator has been developed using the combination of a miniaturized blood pump and an oxygenator for implantation in the vena cava. Well designed clinical trials are necessary to demonstrate a clinical benefit for these experimental devices.