Physiology of extracorporeal circulatory support and blood gas monitoring

Extracorporeal life support encompasses devices that mechanically assist cardiac and/or pulmonary function. Extracorporeal membrane oxygenation (ECMO) began in the 1970s as a respiratory support option, but today it assists patients with refractory respiratory and circulatory failure. ECMO allows adjustments in treatment to minimize additional patient harm, such as reducing vasopressors and modifying mechanical ventilation parameters to protect the lungs. Managing patients on ECMO requires a deep understanding of cardiopulmonary physiology and ECMO physiology. It is crucial to maintain the balance between oxygen delivery and consumption (DO2 and VO2 ) to ensure organ perfusion and promote recovery. Blood oxygen content is measured through gas analyses, which help tailor treatment based on the patient’s metabolic needs. In ECMO, blood is drained, artificially oxygenated, and then returned to the circulation, temporarily providing respiratory and cardiac function. Continuous monitoring is required to adjust blood and gas flow, optimizing oxygenation and carbon dioxide removal. Calculating cardiac output and other critical parameters allows for the evaluation and adjustment of therapy to improve patient perfusion and oxygenation.