3 The procedure
3.1 The aim of extracorporeal carbon dioxide removal (ECCO2R) is to reduce blood CO2 levels in acute respiratory failure, independently of the lungs. It can be used in cases of acute respiratory failure when a reduction in ventilator settings is needed to minimise the risk of ventilator-induced lung injury, but when such reductions (for example, airway pressures and tidal volume) result in severe hypercapnia. By allowing a reduction in ventilator settings, ECCO2R may help to improve the likelihood and speed of lung recovery. The technique may also increase blood oxygen levels.
3.2 There are 2 main types of ECCO2R: venovenous (VV) and arteriovenous (AV). In both types, cannulae are connected to a low‑resistance synthetic membrane device where exchange of CO2 occurs. In VV‑ECCO2R, either a single‑access double lumen catheter or a dual-access system using 2 venous catheters is inserted into a large vein or veins (typically the femoral or internal jugular veins) and connected to a venovenous circuit. Flow across the membrane is maintained using a pump. In AV‑ECCO2R, an artery and a vein are cannulated (typically the femoral artery and femoral vein). Arterial blood pressure drives blood continuously through the device and it is returned through the vein.
3.3 ECCO2R can be done using either a true ECCO2R system or a modified extracorporeal membrane oxygenation system.
3.4 Patients may be treated with ECCO2R support for several weeks, depending on clinical need.