What’s A Hemolung RAS?

The Hemolung Respiratory Assist System (RAS) is an investigative extracorporeal carbon dioxide (CO2) removal (ECCO2R) therapy. This system uses a centrifugal pump and blood gas exchanger to create respiratory dialysis – a form of low-flow VV-ECMO – where CO2 is removed, and oxygen (O2) is added to the blood through a network of hollow fiber membranes housed within the device cartridge.

A 15.5 French Hemolung dual lumen catheter is primed and inserted into the internal jugular or femoral vein using the Seldinger technique. The catheter is sutured and secured using gridlock devices. The Hemolung RAS blood tubing is then securely connected to the red and blue lumens using a wet-to-wet technique to ensure no air at the interface. During insertion, the patient is also systemically anticoagulated for a goal activated clotting time (ACT) of 150 – 180 seconds. By default, the Hemolung starts at a pump speed of 500 rpm (range 0 – 1500 cc/min) and a sweep gas flow rate of 1.0 L/min (up to 10 L/min). The resulting blood flow rate depends on the pump speed, volume status, cannula positioning, blood viscosity, etc.

Compared to traditional VV-ECMO, the flows on the Hemolung can be much lower because CO2 is 20-25x more soluble than O2 in the blood. This makes its removal much less dependent on the flow rate. Furthermore, by offloading much of the CO2 directly, Hemolung promotes lung-protective mechanical ventilation strategies in those already intubated.

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