ECMO (Extracorporeal Membrane Oxygenation )
ECMO (Extracorporeal Membrane Oxygenation )
ECMO in Adults? Isnt this a Peds thing?
1000 patients supported on ECMO at the University of Michigan
were reviewed (retrospectively)
VV-ECMO for respiratory failure provided survival to
discharge:
88% of 586 cases of respiratory failure in neonates
70% for 132 cases of respiratory failure in children
56% for 146 cases of respiratory failure in adults
Introduction
Mechanical circulatory support has evolved markedly over recent
years.
ECMO (extra corporeal membrane oxygenation) has become more
reliable with improving equipment, and increased experience, which
is reflected in improving results.
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.
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.
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.
Indications for ECMO
Divided into two type
Cardiac Failure
Respiratory Failure
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
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
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
Configurations for ECMO
ECMO can be inserted in 2 configurations:
Veno-venous
Veno-arterial
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
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.
Peripheral ECMO Cannulation
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.
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)
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.
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 (
