Extracorporeal Membrane-Gas Exchange

Abstract

For patients with severe acute respiratory failure whose pulmonary gas exchange cannot be improved sufficiently by means of advanced intensive care, extracorporeal membrane oxygenation may be established as an additional therapeutic option during the acute phase. Extracorporeal membrane oxygenation is able to partly take over oxygenation and carbon dioxide removal and thereby allow respirator settings to be adjusted to the aims of lung protective mechanical ventilation. The key features of an extracorporeal circuit are catheters for vascular access, tubing for blood drainage and return, pump, membrane lung, heat exchanger, and monitoring unit. Venovenous circuits are established if the major goal is respiratory support while venoarterial techniques are considered if combined cardiac and respiratory failure is an issue. Bleeding remains the most prevailing complication in adult patients with acute respiratory distress syndrome (ARDS) undergoing extracorporeal gas exchange, and seems partly related to anticoagulation. Surface-heparinized extracorporeal circuits and membranes markedly reduce the daily blood loss and survival rates are higher than in patients treated with nonheparinized systems. Survival rates of adult ARDS patients treated with extracorporeal gas exchange are 33–50%. In neonates with severe respiratory failure, survival rates of 68% and higher are reported.