Extracorporeal organ support for critically ill patients: Overcoming the past, achieving the maximum at present, and redefining the future

Table 1 Available organ support systems and devices, with their main indications

Modality	Indications	Remarks
MARS	Liver support in ALF-ACLF/hepatic encephalopathy/hepatorenal syndrome/removal of toxins	Spares exogenous albumin by using a secondary circuit system, can lead to hemorrhagic complications, due to consumption of platelets and coagulation factors
Prometheus	Liver support in ALF-ACLF/hepatic encephalopathy/hepatorenal syndrome/removal of toxins	Recirculates patient’s endogenous albumin
SPAD	Liver support in ALF-ACLF/hepatic encephalopathy/hepatorenal syndrome/removal of toxins	Lack of cost-effectiveness due to albumin waste
Bioartificial systems	Liver support in ALF-ACLF/hepatic encephalopathy/hepatorenal syndrome/removal of toxins/enhancement of liver synthetic function	Research in progress, regulatory are safety issues need to be addressed, not yet widely available
(VV-) ECMO	Refractory respiratory failure – severe ARDS/severe respiratory acidosis Circulatory – cardiac failure/cardiac arrest/respiratory failure	Provides immediate and effective support for cardiac function and oxygenation, needs to be applied early during disease course when other supportive measures are insufficient or fail
(VA-) ECMO
SCUF	Acute or chronic heart failure/fluid overload	Controls balance of fluids, decreases preload or right heart chambers
LVAD	End stage heart failure	Assists left ventricle to deliver sufficient blood volume and maintain organ perfusion, serves as bridge to transplant
IABP	Cardiogenic shock	Increases cardiac output by reducing afterload, improves myocardial oxygen perfusion
ECCO2R	Hypercapnic respiratory failure at exacerbations of COPD/severe hypercapnia in setting of protective ventilation	Uses lower blood flows in comparison to ECMO
Hemoperfusion	Severe sepsis/septic shock/liver support	Acts as immunomodulator by restoring balance of pro- and anti-inflammatory molecules in sepsis/ALF/ACLF
Plasmapheresis/plasma exchange	Elimination of autoantibodies, endotoxins and other substances/liver support	Potential immunomodulatory effect on CRS. Replaces coagulation factors and other diminished plasma proteins in patients with ALF or ACLF and improves outcome

MARS: Molecular adsorbent recirculating system; ALF: Acute liver failure; ACLF: Acute-on-chronic liver failure; SPAD: Single-pass albumin dialysis; VV: Veno-venous; VA: Veno-arterial; ECMO: Extracorporeal membrane oxygenation; ARDS: Acute respiratory distress syndrome; SCUF: Slow continuous ultrafiltration; LVAD: Left ventricular assist device; IABP: Intra-aortic balloon pump; ECCO₂R: Extracorporeal CO₂ removal; COPD: Chronic obstructive pulmonary disease; CRS: Cytokine release syndrome.