Extracorporeal Life Support (ECLS) Anupol Panitchote, MD. Division of Critical Care Medicine, Department of Medicine Faculty of Medicine, Khon Kaen university, Thailand

ปอดจริง ปอดเทียม Oxygenator

หัวใจจริง หัวใจเทียม Blood pump

VA ECMO (venoarterial) Cardiopulmonary failure: for instance Acute myocarditis Cardiogenic shock ECMO CPR Drainage at venous site: femoral vein Return at arterial site: femoral artery

VV ECMO (venovenous) Pulmonary failure: for instance ARDS Drainage at venous site: femoral vein Return at venous site: internal jugular vein

VA ECMO

VV ECMO

Compare natural lung VS membrane lung Natural lung (NL) Membrane lung (ML) Exchange surface (m2) 150 4 Interface (m) 1-3 10-30 Surface blood volume ratio (cm-1) 300 30

VV access via double lumens Recirculation VV access via double lumens

Oxygenation during VV ECMO Recirculation Shunt

𝑉𝑂2𝑀𝐿=𝐵𝐹×(𝐶𝑜𝑢𝑡𝑂2−𝐶𝑖𝑛𝑂2) 𝑉𝑂2𝑁𝐿=𝐶𝑂×(𝐶𝑎𝑂2−𝐶𝑣𝑚𝑖𝑥𝑂2) 𝑉𝑂2𝑇𝑜𝑡=𝑉𝑂2𝑀𝐿+𝑉𝑂2𝑁𝐿 Factors affect to VO2ML Intrinsic properties of ML FiO2 in sweep gases Recirculation ECMO blood flow

Factors affect to SvmixO2 SvO2 that leaving tissues BF/CO Recirculation

Severity of lung disease (shunt) Ventilator set up (FiO2) Cannula size Factors affect to VO2NL Severity of lung disease (shunt) Ventilator set up (FiO2) Cannula size FiO2

Oxygenation during VA ECMO Mixing blood b/t ECMO flow and blood pass heart and lungs Hypoxic Harlequin syndrome VA access via femoral vessels

CO2 removal during ECMO Easier than oxygenation CO2 clearance is more efficient than oxygen delivery Lower ECMO blood flow Sweep gas flow determine CO2 removal

Hemodynamics during VV ECMO Hemodynamically neutral support

Hemodynamics during VA ECMO Extracorporeal pump works in parallel with patient’s heart Different arterial cannulation sites have some advantages and disadvantages

General hemodynamic changes Loss of arterial flow pulsatility (flat arterial line) Patient’s circulation is fully supported Pulsatile > non-pulsatile Pulsatility is the index of LV ejection Reduction of preload: divert blood to ECMO circuit Resting RV Coronary arteries were perfused by deoxygenated blood Increase in LV afterload LV distension

Indication for Respiratory ECMO Hypoxemic respiratory failure 50% mortality risk: PaO2/FiO2 < 150 on FiO2 > 90% and/or Murray score 2-3 80% mortality risk: PaO2/FiO2 < 100 on FiO2 > 90% and/or Murray score 3-4 CO2 retention despite of high Pplat (>30 cmH2O) Severe air leak syndromes Need for intubation in a patient on lung transplant list Immediate cardiac or respiratory collapse.

Contraindications for Respiratory ECMO MV at high settings ≥ 7 days (FiO2 > 0.9, Pplat > 30) Major pharmacologic immunosuppression (ANC < 400) CNS hemorrhage Non recoverable co-mobidity such as terminal malignancy Underlying diseases: Charlson score ≥ 7 Current condition: SOFA ≥ 18 (w/ GCS), ≥ 16 (w/o GCS)

Indication for ECMO in adult cardiac failure Inadequate tissue perfusion despite adequate intravascular volume Shock persists despite volume administration, inotropes and vasopressors and IABP Typical causes: Acute MI, myocarditis, Peripartum cardiomyopathy, decompensated chronic heart failure, post cardiotomy shock Septic shock is an indication in some centers

Complications Circuit related complications Blood clots in circuits and thromboembolism Gas embolism Circuit fractures Plasma leak Patient related complications Vascular complication: perforation, dissection, fistula, aneurysm Leg ischemia: VA femoral a. cannulation Bleeding, coagulopathy, ICH Cardiac complications: tamponade, LV distension, pneumothorax

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