Air Embolism Prevention in ECMO Systems: An in Vitro Study on CVC Lumen Protection

Air embolism can complicate extracorporeal membrane oxygenation (ECMO), as the negative pressure in the venous system can unintentionally draw in air. This air can disrupt pump function or enter the patient through the oxygenator, resulting in systemic air embolism. To examine this risk, a circuit model was created to study air entry through the central venous catheter (CVC) and its impact on ECMO performance at varying pump speeds in a veno-venous configuration. The research revealed that the unprotected lumen of the CVC is a potential air entry point. A closed three-way stopcock or clave effectively protects against this risk. Importantly, even small amounts of air produce a distinct hissing sound, serving as an early warning sign. At a pump speed of 4500 revolutions per minute (rpm), just 1 ml of air can pass through the oxygenator into the arterial portion, and 25 ml of air can halt the pump entirely. In conclusion, safeguarding the CVC with appropriate valves and being attentive to sounds in the circuit are critical measures to prevent air embolism during ECMO.