ECMO, DEFINITION, ETIOLOGY, INDICATION, CONTRAINDICATION, TYPES OF ECMO, VENOVENOUS ECMO, VENO ARTERIAL ECMO, NURSING CARE OF PATIENT ON ECMO, WEANING FROM ECMO,

1. ECMO (Extracorporeal
Membrane Oxygenation )
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2. When I think about Ecmo, I think …
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3. Introduction
ECMO is instituted for the management of life
threatening pulmonary or cardiac failure (or both),
when no other form of treatment has been or is likely
to be successful.
ECMO is essentially a modification of the
cardiopulmonary bypass circuit which is used
routinely in cardiac surgery.
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4. Introduction
Instituted in an emergency or urgent situation after
failure of other treatment modalities.
It is used as temporary support, usually awaiting
recovery of organs.
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5. History
In 1965, Rashkind and coworkers were the first to
use a bubble oxygenator as support in a neonate
dying of respiratory failure. In 1969, Dorson and
colleagues reported the use of a membrane
oxygenator for cardiopulmonary bypass in infants.
In 1970, Baffes et al reported the successful use of
extracorporeal membrane oxygenation as support in
infants with congenital heart defects who were
undergoing cardiac surgery. In 1975, Bartlett et al
were the first to successfully use ECMO in neonates
with severe respiratory distress.
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6. Parts of ECMO
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7. Definition
 ECMO or Extra Corporeal Membrane Oxygenation
is a form of extracorporeal life support where an
external artificial circuit carries venous blood from
the patient to a gas exchange device (oxygenator)
where blood becomes enriched with oxygen and
has carbon dioxide removed. This blood then
reenters the patient circulation.
 ECMO circuit blood flow is optimised to provide
adequate patient support in the absence of native
lung or heart function.
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8. Configurations for ECMO
ECMO can be inserted in 2 configurations:
 Veno-venous
 Veno-arterial
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9. The Mode of ECMO is defined by the position of the
access and return cannulae.
There are three modes of ECMO:
Veno-Venous (VV)
Veno-Arterial (VA) and
Veno-Pulmonary Artery (V-PA)
VV and VA modes of ECMO have a number of
configurations to best suit patient needs.
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10. Veno-arterial (VA) configuration
 Blood being drained from the venous system and returned to
the arterial system.
 Provides both cardiac and respiratory support.
 Achieved by either peripheral or central cannulation
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11. Peripheral ECMO Cannulation
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12. Veno-Venous (VV) configuration
 Provides oxygenation
 Blood being drained from venous system and returned to
venous system.
 Only provides respiratory support
 Achieved by peripheral cannulation, usually of both femoral
veins.
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13. a. Veno-Venous ECMO:
Venous blood is accessed from the large central veins,
pumped through the oxygenator and returned to the venous
system near the right atrium. It provides support for severe
respiratory failure.
There are 4 configurations of VV ECMO
i. Femoro-Femoral (Fem/Fem)
ii. High-Flow
iii. Femoro-Jugular
iv. Dual lumen/Two stage single cannula (Avalon)
In all cases, ECMO blood flow travels from the vena cavae to
the atria (Cavo-Atrial Flow) to minimise recirculationAVELIN D'SOUZA

14. a.Femoro-Femoral:
i. Two long “venous” cannulae are used
ii. Direction of flow is cavo-atrial
iii. Access cannula (single stage, or multistage) is inserted via the femoral
vein. Usual sizes 21-25 F
iv. Return cannula (single stage) is inserted via the contralateral femoral
vein with the tip sited within the right atrium. If the tip is advanced too
far it will impinge on the inter-atrial septum.
Usual sizes 21-25 F
v. The tip of the access cannula is positioned 10-15cm lower than the tip
of the return cannula to minimise recirculation.
Advantages: Quick and safe to insert; easy to secure cannulae;
Disadvantages:
Limited maximum flow rates so often requires conversion to a high-flow
configuration. Patient remains bed bound
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16. b. High-flow:
i. Uses the same bi-femoral cannulation as femoro-femoral
ii. An additional short access cannula (“arterial”) is inserted via the right
internal jugular vein with the tip sited in the superior vena cava. The
optimal position of the tip is established after commencing full circuit
blood flow. The tip is withdrawn sufficiently to prevent visible
recirculation. Usual size 17-19 F
iii. Direction of flow is bi-cavo-atrial to minimise recirculation
Advantages:
Allows higher circuit blood flows as two access cannulae draw patient
blood from the great veins .
Can provide maximal oxygen delivery if configured correctly
Disadvantages: Occupies 3 veins. Relatively complex to secure and
dress the jugular
cannula. Patient remains bed bound.
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17. c. Femoro-Jugular:
i. Direction of flow is cavo-atrial to minimise recirculation
ii. Access cannula (multi-stage) is inserted via the femoral vein with the
tip sited just below the inferior cavo-atrial junction. Usual size 21-25 F
iii. Return short cannula (“arterial”) is inserted into the right internal
jugular vein with the tip sited in the lower superior vena cava. Blood
returning in this direction preferentially flows towards the tricuspid valve
and right ventricle, which minimises recirculation. Usual sizes 19-23 F
iv. Advantages: Nearly always can provide adequate support (5-7 L/min)
without large recirculation, only two veins occupied
Disadvantages: Relatively difficult to secure and dress the jugular return
cannula. Requires two sterile fields to be during ECMO cannulation.
Access insufficiency can be more difficult to identifyin the early stages
without negative pressure monitoring Patient remains bed bound
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18. d. Dual lumen/Two stage single cannula (Avalon):
i. Direction of flow is bi-cavo-atrial to minimise recirculation
ii. Single cannula with two lumens for access and return inserted via the
right internal Jugular vein.
iii. Two access stages (SVC and IVC)
iv. Return port emerges between the two access ports and is positioned at
the level of the tricuspid valve.
Advantages: Single vein cannulation. Allows movement from bed and
potentially ambulation
Disadvantages: Care on insertion to avoid right ventricular
placement/rupture and hepatic vein cannulation.Large cannula to insert
(27F or 31F for adults). Difficult to position return port towards the
tricuspid valve.
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20. a. Standard Femoro-Femoral
i. Access Cannula (multistage) is inserted via the femoral vein
with the tip sited within the right atriumwithout impinging
on the interatrial septum.
Usual size 21-25 F
ii. Return cannula is a short arterial cannula inserted via the
common femoral artery. Usual size 17-21 F
Advantages: Provides full or partial cardiac support.
Disadvantages: Risk of differential hypoxia may need
conversion to high flow configuration if native cardiac
function improves in the setting of significant respiratory
failure
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21. Central: Specialised cannulae
i. Uses specialised surgical cannulae. Access cannula is wire reinforced and
malleable and is sited within the right atrium via the atrial appendage. Cannula is
then tunnelled out of the chest and t he sternum closed. Usual size >30 F
ii. Return cannula is Dacron tipped and sewn directly onto the proximal aorta.
Cannula is then tunnelled out of the chest and the sternum closed. Usual size >30
F
iii. Advantages: Can provide full cardiac and respiratory support and is not
associated with differential hypoxia in the setting of combined cardiac and
respiratory failure. Optimal support for severe cardiac and respiratory failure in
the immediate post cardiotomy setting.
Allows sternum to be closed and facilitates standard patient pressure area care.
Can provide support for upto 2 weeks
iv.Disadvantages Requires sternotomy for institution and re-sternotomy for
decannulation. Bleedingmore common than in femoro-femoral configuration
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22. Central ECMO Cannulation
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24. Central vs. Peripheral Cannulation
Advantages
 Flow from Central ECMO is directly from the outflow cannula
into the aorta provides antegrade flow to the arch vessels,
coronaries and the rest of the body
 In contrast, the retrograde aortic flow provided by peripheral
leads to mixing in the arch.
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25. Disadvantages
 Previously insertion of central ECMO required leaving chest
open to allow the cannulae to exit.
 Increased the risk of bleeding and infection
 Newer cannulae are designed to be tunneled through the subcostal
abdominal wall allowing the chest to be completely closed.
 Central cannula are costly (approximately 4 times as much as
peripheral)
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26. The Configuration of ECMO refers to the cannula insertion
site, type, tip position and size used in a particular mode.
Cannulae Definitions:
Access Cannulae: drain blood from the venous system
into the ECMO circuit.
Single stage access cannulae drain blood via a short region
near the tip only
Multi-stage access cannulae drain blood through side holes
over a long length of the cannula in addition to the tip.
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28. b) Return Cannulae: deliver blood back to the patient
from the ECMO circuit and only ever expel blood at
the cannula tip (single stage).
c) Distal Perfusion Cannula: Deliver blood
antegradely into the femoral artery distal to the
ECMO return cannula to maintain perfusion to the
leg.
d) d. Double-lumen Cannulae single cannula
partitioned into two lumens with both access blood
flow and return blood flow, similar to vascular
access cannulae used in renal replacement therapy.
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29. e) Cannula Length
i. Long cannulae (55 cm) are labelled by manufacturers
as “venous” and are designed for use in the venous
system.
ii. Short cannulae (15-25cm) are labelled by
manufacturers as “arterial”. They are used to return
blood in both VA ECMO and some VV ECMO
configurations
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30. Dynamics of ECMO
Blood is removed from the venous system either
peripherally via cannulation of a femoral vein or
centrally via cannulation of the right atrium,
 Oxygenate
 Extract carbon dioxide
Blood is then returned back to the body either
peripherally via a femoral artery or centrally via the
ascending aorta.
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31. Indications for ECMO
Divided into two type
 Cardiac Failure
 Respiratory Failure
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32. Indications – Cardiac Failure
Post-cardiotomy
 when unable to get pt off cardiopulmonary bypass following
cardiac surgery
Post-heart transplant
 usually due to primary graft failure
Severe cardiac failure due to almost any other cause
 Decompensated cardiomyopathy
 Myocarditis
 Acute coronary syndrome with cardiogenic shock
 Profound cardiac depression due to drug overdose or sepsis
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33. Indications – Respiratory Failure
Adult respiratory distress syndrome (ARDS)
Pneumonia
Trauma
Primary graft failure following lung transplantation.
ECMO is also used for neonatal and pediatric
respiratory support
 This is where most of the research on ECMO has been done
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34. Decision to Institute ECMO
Several considerations must be weighed:
 Likelihood of organ recovery.: only appropriate if disease process is
reversible with therapy and rest on ECMO
 Cardiac recovery: to either wait for further cardiac recovery to allow
implant of device (LVAD) or to list for transplantation.
 Disseminated malignancy
 Advanced age
 Graft vs. host disease
 Known severe brain injury
 Unwitnessed cardiac arrest or cardiac arrest of prolonged duration.
 Technical contraindications to consider: aortic dissection or aortic
incompetence
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37. Things to Think About
Mechanical ventilation must be continued during ECMO
support to try to maintain oxygen saturation of blood
ejected from the left ventricle to at least above 90%.
ECMO flow can be very volume dependent
ECMO flow will drop:
 Hypovolemia
 Cannula malposition
 Pneumothorax
 Pericardial tamponade.
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38. Weaning of ECMO – VV ECMO
Actual ECMO flows do not need to be altered to assess
native respiratory function
 Done by altering gas flow through the ECMO circuit
Pt may be weanable:
 Gas exchange is able to be maintained with a low FiO2 (<30%)
 Low fresh gas flow rates into the circuit (<2 L/min)
Caveat: RR and PEEP set on ventilator are not too high
(e.g. <25 breaths/min and <15cmH2O, respectively).
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39. Weaning of ECMO – VA ECMO
Depends on cardiac recovery, Factors:
 Increasing blood pressure
 Return or increasing pulsatility on the arterial pressure waveform
 Falling pO2 by a right radial arterial line
 indicating more blood is being pumped through the heart which may
be less well oxygenated,
 Falling central venous and/or pulmonary pressures.
It is important to note that cardiac outputs from
pulmonary artery catheter are inaccurate on ECMO
 Most of the circulating blood volume is bypassing the pulmonary
circulation
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40. Complications
Falls into one of three major categories
1) Bleeding associated with heparinization
2) technical failure
3) neurologic sequelae
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41. Complications of ECMO
Bleeding/Hemolysis
 Out of proportion to the degree of coagulopathy and patient
platelet count
Coagulopathy
 Continuous activation of contact and fibrinolytic systems by the
circuit
 Consumption and dilution of factors within minutes of initiation
of ECMO
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42. Complications of ECMO
Thrombocytopenia
 Platelets adhere to surface fibrinogen and are activated
 Resultant platelet aggregation and clumping causes numbers to
drop
Non-pulsatile perfusion to end organs
 Kidneys
 Splanchnic circulation seems to be particularly susceptible
 GI bleeding, ulceration and perforation
 Liver impairment
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43. Complications of ECMO
Mechanical Complications
 Tubing rupture
 Pump malfunction
 Cannula related problems
Local complications: Leg ischemia
 Particularly at peripheral insertion site of VA
Air embolism/Thromboembolism
Neurological: Intracerebral bleeds
 Largely associated with sepsis
 Manifest as seizures or brain death
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44. Management of Complications
Regular measurements of blood tests (Q6-Q8h)
 Coagulation Profile
 Platelet Count
 Hemoglobin
 Creatinine to evaluate for renal insufficiency
Aggressive replacement of clotting factors,
electrolytes, PRBC
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45. Outcomes of ECMO
Good quality RCT of ECMO outcomes in adult
population are lacking
There are very promising studies in the Pediatric
populations, however it is hard to know if this
translates into the adult population.
Completed yet unpublished CESAR Trial shows
some potential impact in ECMO research
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46. ECMO Observations and Documentation
Distal Perfusion (“Backflow”) cannula and leg vascular
observations must also be performed each hour for patients
on peripheral VA ECMO. In the event that blood flow through
the distal perfusion circuit is occluded, blood within the back
flow tubing will separate into plasma and cells, which is
obvious on inspection. Normal blood flow can be seen under
torchlight.
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47. ECMO dressings and line position
monitoring
The bedside nurse is responsible for maintaining cannula
dressings and redressing soiled or inadequate dressings.
Line position monitoring is performed at least once per shift
for patients with peripheral cannulae skin markings.
Pressure area care:
Patient Arterial Blood Gas (ABG)
Ensure that heater water level is approximately 75-80% full
Routine Investigations: CXR, Mg; PO4; LFT; APTT, INR,
Fibrinogen and D-dimers
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48. APTT is measured 6 hourly while the patient is on
ECMO if they are receiving systemic anticoagulation.
Peripheral VA ECMO patients require vascular
ultrasound studies to be performed on lower limbs
on day 1 and additionally as clinically indicated.
For VV ECMO target blood flows must provide
adequate arterial oxygenation while allowing non-
injurious lung ventilation.
Anticoagulation and prevention of bleeding.
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49. All ECMO lines must be secured at 2 points with
properly adherent skin dressings.
Sterility must be maintained and insertion sites kept
unsoiled.
A designated staff member must secure ECMO
circuit lines to prevent tension or torsion during
patient moves.
Do not allow water to enter the ECMO drive unit
Alcohol Containing Cleaning solutions (including
triclosan) should not come in to contact with the
ECMO circuit as they may cause cracking of some
circuit componentsAVELIN D'SOUZA

50. WEANING
VV ECMO weaning:
i. Circuit flow need not be reduced at any stage for weaning
and therefore, no additional heparin is required
ii. Weaning VV ECMO is achieved by progressively reducing
the Fresh Gas Flow to the oxygenator. An increase in lung
ventilation is required to ensure adequate CO2 clearance.
iii. In normal circumstances there is no requirement to wean
the blender FiO2 as part of the weaning process
iv. It is usual to observe the patient to be stable for 4-24 hours
with the Fresh Gas Flow to the ECMO circuit at 0 L/min .
v. Echocardiography is not required
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51. VA ECMO weaning:
Formal weaning studies must be performed to assess the heart’s ability to
manage the circulation without VA ECMO support. Circuit flow must be
reduced to assess native heart function in the setting of an increased
venous return. Flow is reduced from 2.5 L/min in a series of 0.5 L/min
increments while haemodynamic and echocardiographic data are
collected
ii. Lung ventilation must be increased and oxygenator Fresh Gas Flow
reduced during the weaning study
iii. The reduced flow during the VA weaning process increases the risk of
stasis and clotting within the circuit. Additional heparin is required to
reduce the risk of clotting in this setting
iv. Echocardiography is essential to assessing cardiac function during
weaning from ECMO
v. Once cardiac function has improved and ECMO decannulation is
planned, ECMO flows should be maintained above 2.5L until
decannulation takes place.AVELIN D'SOUZA

52. Cannula Removal and Circuit Disposal
Cannula Removal: Heparin should be ceased for at least 2
hours prior to decannulation. The patient should be
adequately sedated or have received an explanation of the
procedure prior to commencement. After dressings are
removed, all access and return lines are clamped, the ECMO
console powered off and the cannulae removed
simultaneously with immediate adequate pressure applied to
the vessel puncture sites with sterile gauze.
Returning the blood held within the ECMO circuit to the
patient prior to cannula removal carries additional risk of air
and thrombus entering the patient’s circulation and volume
overload. It should only be performed if there is a clinical
imperative to conserve blood.
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53. Cannula Removal and Circuit Disposal
Bleeding control: After percutaneously placed venous
cannulae are removed the venous puncture site is
compressed for 20 minutes by ECMO trained medical staff.
The patient must remain supine and still for approximately 4
hours post cannula removal and the site monitored for re-
bleeding
d.
Circuit disposal: The circuit should be disposed of in a
biohazard bag/bin with cytotoxic precautions where
appropriate. Reusable (metal) ECMO Clamps MUST not be
discarded.
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54. Summary
ECMO is instituted for the management of life
threatening pulmonary or cardiac failure (or both),
when no other form of treatment has been or is likely
to be successful.
ECMO is essentially a modification of the
cardiopulmonary bypass circuit which is used
routinely in cardiac surgery.
ECMO can be inserted in 2 configurations: Veno-
venous & Veno-arterial
Completed yet unpublished CESAR Trial shows
some potential impact in ECMO research
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55. Questions??
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56. AVELIN D'SOUZA