for medical students

1. Extracorporeal membrane
oxygenation
in Adults
GUILLERMO MARTINEZ MD
ALAIN VUYLSTEKE MD FRCA FFICM
CONTINUING EDUCATION IN ANAESTHESIA,
CRITICAL CARE & PAIN| VOLUME 12 NUMBER 2 2012

2. ECMO
 Extracorporeal membrane oxygenation (ECMO) uses technology derived from
cardiopulmonary bypass (CPB) that allows gas exchange outside the body.

 The benefits of ECMO in adult patients with cardiac failure or refractory acute respiratory
distress syndrome (ARDS) are still debated, as ECMO was initially associated with poor
survival rates.
 However, recent technological advances in the ECMO circuit have led to a reduction in the
rate of technical issues and complications.
ECMO has emerged from its widespread use as a rescue therapy for patients with ARDS
and refractory hypoxaemia associated with H1N1/2009 infection (‘swine flu’).

3. Types:
An ECMO circuit can be set up in three ways:
I. Veno-Arterial ECMO (VA-ECMO):
II. Veno-Venous (VV-ECMO):
III. Arterio-Venous ECMO (AV-ECMO):

4. Description:
 The circuit for VA or VV is almost identical. Blood movement is facilitated by external pump
through the membrane allowing gas exchange
 The gas exchanger (oxygenator) allows more efficient CO2 removal than O2 addition
because of the solubility and better diffusion properties of CO2 relative to O2.
 The most recent models (hollow fibre non-micropore membrane) present less resistance to
blood flow and are less traumatic to blood components than previous designs.¥
 Centrifugal pumps are better reliable and easy to care for.

5. Cannulae
 Indwelling cannulae
 Venous
 Arterial
 Placed under
 Direct vision
 Percutaneous should be done ideally under ultrasound or fluoroscospy

6. Veno-Arterial ECMO:
 VA-ECMO bypasses pt heart and lung
 The drainage cannula is commonly placed in the inferior vena cava or rt atrium
 Done by sternotomy or percutaneously by inserting the cannula via the internal jugular or the
femoral vein.
 The bloods returns by cannula inserted in either
 Ascending aorta(central ECMO) or (preferred esp immediately after CPB as cannula same)
 Femoral Artery(peripheral ECMO)
 VA-ECMO reduces cardiac work and oxygen consumption
 VA-ECMO provides adequate organ perfusion

8. Veno-venous ECMO
 When cardiac function preserved to improve O2
 Insertion of at least two cannulae in large veins
 Decreases incidence of
 Recirculation
 Bleeding issues
 Allows greater mobilization

9. AV pumpless Device:
 Characterized by membrane gas exchange device integrated into a pumpless AV circuit
 Cannulation of femoral artery and vein
 Predominantly CO2 removal more than oxygenation
 AV ECMO requires cardiac index at least 2.5 Lmin before insertion

10. Clinical indications for institution of
ECMO support:
VA-ECMO VV-ECMO
Weaning from cardiopulmonary bypass after cardiac
surgery
Any potentially reversible acute
respiratory failure
Bridge to cardiac transplantation ARDS. Associated with pneumonia (viral or bacterial)
Acute myocarditis Failed lung transplant graft
Intractable arrhythmia Trauma (pulmonary contusion)
Post-cardiac arrest (as part of Advance Life Support) Pulmonary embolism (if acceptable cardiac function)
Local anaesthetic toxicity
Pulmonary hypertension (after pulmonary
endarterectomy

11. Parameters:
 VA-ECMO considered
 SAP lower than 85mmHg
 Cardiac Index less than 1.2L/min despite adequate preload
 More than ≥two inotropes in use
 Intra-aortic balloon counterpulsation
 Systemic signs of low cardiac output
 AV-ECMO useful in Severe hypercapnia, respiratory acidosis and moderate
hypoxemia with advantage of easier transportation no pump requirement

12. Indications:
 Aim of VV-ECMO
 Provide oxygenation and rest the lungs
 Decrease insult by mechanical ventilation
 Advantage of VV
 Lowers thromboembolic complications
 Lung perfusion allows endocrine function in comparison with VA-ECMO
 Best survival rates are observed in pt with
 Non-necrotizing viral pneumonia associated with respiratory failure
Cesar Trial compared survival at 6months in absence of severe disability in pt who developed
ARDS and has been randomized to be treated in their original or ECMO centre. The trial showed that
pt treated in ECMO centre had better outcome and approach is cost-effective

13. ECMO Contraindication:
 Patients with
 Irreversible organ damage
 Multiorgan failure
 Those who are not candidates of transplantation
 Those who cannot be coagulated
 Severe aortic regurgitation and aortic dissection – VA-ECMO

14. Complications:
 Haemorrhage due to continuous anti-coagulation
 Infection due indwelling catheters or Primary pathology
 Thromboembolism pathogenesis is multifactorial
 blood activation after contact with foreign surfaces
 blood stasis in the cardiac chambers and the systemic veins
 DIC
 Thrombus in the circuit effect pump func. And in VA-ECMO can lead leg ischaemia
 Cannula displacement or malposition and circuit failure = catastrophic affect

15. Blood Component Protocols for ECMO
Clinical Scenario Urgency Components Blood Groups Storage
Cardiac arrest 5-10 min 2 units RBCs O-neg RBCs <14 days, AS
ECMO circuit
disruption
5-10 min 2 units RBCs O-neg RBCs <14 days, AS
Progressive septic
shock(nonneonate)
30 min 2 units RBCs O-neg RBCs or
type specific
<10 days,
any preservative
Neonate transferred
for ECMO
1-2 hours 2 units RBCs
1 unit FFP
1 unit platelets
O-neg RBCs
AB plasma
<10 days,
CPD or CPDA
Cardiac ICU 30-60 min 2 units RBCs Type specific <7 days, AS
Gradual respiratory or
cardiac failure on
conventional support
Hours to days 2 units RBCs Type specific <10 days, CPD
AABB

16. Platelet Transfusion thresholds for
ECMO in paediatric patients:
 Platelet Transfusion in neonate Patient undergoing ECMO with:
 A platelet count of <100,000/μL(AABB), or 50,000-100,000/μL(ROSSI)
 Higher platelet counts if bleeding

17. Paediatric Plasma Transfusion in ECMO
Patients:
 ECMO is increasingly being utilized to treat a number of paediatric conditions nonresponsive to
traditional ventilatory support
 As institutions use Albumin, RBC and other additives to prime the circuit, coagulopathy is
complicated
 Plasma transfusion in children in ECMO, protocol includes
 Factor Xa monitoring
 Thromboelastography
 Anti-Thrombin monitoring
 Plasma to be transfused
 ABO compatible but Rh matching not required
 No irradiation required
 10-15ml/kg plasma raises INR by 30% approx.
Rossi

18. Transfusion Guidelines for Adult in
ECMO
ELSO(Extracorporeal Life Support Organisation) has no specific guidelines for transfusion in Adults,
 Although ELSO recommends 12-14g/dl. Restrictive transfusion is better outcome with
Transfusion threshold at ≤ 7g/dl(Voelker et al) whereas TRICS III showed threshold 7.5-8g/dl
reasonably good regarding composite outcome of mortality, Myocardial ischaemia etc.
 Decrease Anticoagulant(Heparin) or transfuse FFP till Activated Clotting Time or PTT is 1.4 to 1.5
times normal (target aPTT 40-60 secs)
 Since procedure itself results in Thrombocytopenia so it is wise to maintain the platelet count
above 100,000/μL by platelet transfusion. ELSO recommends plt above 75,000/μL
 Giving Antifibrinolytics
ELSO Guidelines for Adult Respiratory Failure, August 2017

19. Thank You
HAVE A NICE DAY!