Veno-arterial extracorporeal membrane oxygenation (VA ECMO) provides both respiratory and circulatory support for patients with heart and lung failure. It works by draining venous blood, oxygenating it, and returning it to the arterial system. The document discusses cannulation techniques and considerations for VA ECMO, as well as physiological effects and important monitoring parameters to optimize patient care and outcomes.

1. PHYSIOLOGY ,CANNULATION
AND
MONITORING OF
VENO-ARTERIAL ECMO
Dr.Manoj.P.
Lead Consultant Cardiovascular and Thoracic
Surgeon
Aster Medcity

2. Extra corporeal Life Support is achieved by
- Draining venous blood
- Removing CO2
- Adding oxygen
- Returning to circulation
- Through either a vein or artery

3. Types of ECMO
ECMO can be categorised according to the
circuit used
• Veno-arterial - VA ECMO provides both gas
exchange and circulatory support (Heart &
Lung failure)
• Veno-venous –VAECMO allows gas exchange
only (Isolated Lung failure)

4. Modes of ECMO
Veno -arterial (VA)ECMO
•Provides both respiratory and cardiac support
•Blood is drained from venous system and given to
arterial system.
Low flow veno-arterial ECMO is a transitory form of ECMO
support in which small cannulae (quicker to insert) are
inserted. It is an emergent resuscitative intervention, (Ecmo
CPR)

5. VA ECMO – Technical Specifications
 Peripheral-FA, pump outflow is retrograde,
admixing at arch level.
 If Respiratory failure co exists, heart pumps
poorly oxygenated blood to coronaries and
brain, while ECMO supports body distal to
Aortic arch.
 For this reason R Radial line is prudent
 Mechanical ventilation continued to
maintain Sao2 of blood ejected from LV at
90%

6. First successful ECMO patient,
1971
J Donald Hill MD and Maury Bramson BME, Santa
Barbara, Ca, 1971. (Courtesy of Robert Bartlett, MD)

7. First Neonatal ECMO
survivor..
Esperanza, Age 1 day 1975

8. Esperanza, age 21

9. FROM THIS
TO THIS

10. Advantages and
Disadvantages
Advantages Disadvantages
Both cardiac and pulmonary support Cannulation of major artery and sacrifice
of one carotid in newborn
More experience Poor coronary and pulmonary perfusion
Instant hemodynamic support Systemic thromboembolism
No recirculation Nonpulsatile flow
Right and left heart Myocardial stunning and LV distension
Increased incidence of neurological
events

11. ECMO ??????
• Several considerations must be weighed
- Likelihood of organ recovery
- Cardiac re-recovery
- Disseminated malignancy
- Advanced age
- Graft vs . Host disease
- Known severe brain injury
- Unwitnessed cardiac arrest
- Aortic dissection or aortic incompetence

12. • The physiologic goal is to improve tissue oxygen
delivery , remove CO2 and allow normal aerobic
metabolism whilst the lung rests
• ECMO circulation:
- Dual circulation
- Nonpulsatile flow

13. Dual
circulation
• Native circulation + ECMO circulation
• Sometimes Results in North South syndrome if the
return cannula is in femoral artery
• In most cases ECMO provides 60-80 % of CO
resulting in a discernible pulse contour

14. • Reduces preload
• Increases afterload Myocardial
stunning
• Left sided decompression
• Use of inodilators

15. In Veno Arterial
ECMO
• Perfusate saturation is 100%
• Without lung function LV saturation=RV saturation
• ABG reflects Perfusate+RV saturation
• If 50% blood flows through lungs,50% through
oxygenator –O2 saturation of arterial blood
becomes 90%

16. Increase in Systemic PO2 may
result from..
•Improved lung function at constant
flow
•Increased ECC flow at constant CO

17. CO2
removal..
• Mainly depends on oxygenator surface
area and sweep gas flow rate
• Independent of blood flow
• Moderately depends on inlet CO2

18. During Veno arterial
ECMO..
• O2 consumption decreases ( catecholamines
reduced,less metabolic stress)
• Arterial saturation >95 % and flow adjusted to maintain
arterial/venous saturation
• Bleeding Decreased venous return
Decrease in flow Transfusion
• Without lung function and ejection of heart arterial
saturation decreases

19. • Knowledge of the physiology of ECMO support
the management of ECMO patient
• O2 content is of utmost importance in the
physiologic management of critically ill patients
• DO2/VO2 ratio is reflected by mixed venous
saturation - most important monitor in critically
ill patients

20. CANNULATIO
N
The establishment and maintenance of
adequate vascular access is essential
for ECMO

21. CANNULATION
- Patient age and size
- Underlying disease & condition
- Cause of the cardiorespiratory compromise
- Type of support:
• Veno-venous (VV) ECMO
• Veno-arterial (VA) ECMO
- Time of the event in relation to the peri-
operative period
- Location

22. CANNULATI
ON
• For each modality, there are different
kinds and sizes of cannulae that can be
used
• Target ACTshould be accomplished
before ECMO (heparin 100 units/kg)
3 minutes before cannulation.

23. Cannula
Consideration
• Venous cannula should be with the largest
lumen and shortest length possible.
• Venous cannula should have side holes.
• M-number
• Resist kinking
• Smallest double lumen cannula is size 12 Fr
( for V V ecmo in neonate)

26. Veno-Arterial (VA) ECMO
Provides cardiac as well as
respiratory support and is
mainly used for post op cardiac
case

27. Cannulation can
either be..
• Through neck vessels(RCC artery and RIJV
and or an additional vein)
• Central cannulation
or
• Cannulation of groin vessels

28. Access and return cannula
sites
Access Return
RA Aorta
Femoral Vein Femoral Artery
Subclavian Vein Axillary artery
Internal Jugular Vein Carotid artery

29. CANNULATION
TECHNIQUE
• Open
• Semi-open
• Percutaneous

30. CANNULATION
• In central cannulation Aorta and RA are
cannulated
• LV decompression is important
:Can be done either by creating an
atrial communication or by a Left atrial
vent

31. CANNULATIO
N
Right atrium
and
Ascending aorta

32. CANNULATION
A Left atrial vent
line can be utilized
to monitor the LA
pressure

33. CANNULATIO
N
Internal jugular vein
and the common
carotid artery

34. Veno arterial access via the neck
vessels

35. CANNULATI
ON
Femoral vein
and
Femoral artery

36. Venoarterial access via the femoral
vessels

37. Peripheral Femoral Cannulation – VA ECMO

39. Femoral artery cannulation:
•Chances of distal limb ischemia
•Distal perfusion catheter is commonly
used

40. Distal Leg Perfusion 7/9 Fr Cannula

41. CANNULATIO
N
-In situations where ECMO
support is anticipated
-Chest will be left open and
covered by a Silastic
patch
-Purse-string sutures will be
left snared in place

42. CANNULATION
PROBLEMS
• Threading the venous catheter
• Vein division
• Proximal vein lost in
mediastinum
• Lack of venous return
• Intrathoracic vein perforation

43. Complicatio
ns
• Vascular injury( tear,
intimal dissection,
perforation).
• Obstruction (kinking,
positional).
• Misplacement( AI,
afterload LV failure).
• Bleeding.

44. Monitorin
g
• Success lies with vigilant monitoring which helps in early
recognition and diagnosis of problems and timely and
accurate action
• Monitoring includes:
-Clinical parameters
-Biochemical and
Laboratory parameters
-Radiologic monitoring
-Circuit monitoring

45. Clinical
parameters
• Vital parameters(ECG rhythm,Pulse rate,Blood
Pressure ,Temperature , and respiratory rate)
• Arterial and venous saturation(MAP and mixed
venous saturation)
• Daily Echocardiography
• Right hand saturation gives hints regarding
coronary perfusion

46. • Hematological parameters(CBC,HCT 35-
40%,Plasma Free Hemoglobin <0.1g/dl)
• If possible cerebral oxygenation with NIRS
• EtCO2
• RBS : 80-140 mg/dl
• ABG and RBS to be done every 4-6 hours
• Vascular and neurological status
• Urine output and urine colour

47. Coagulation
Monitoring
•Pre ECMO ACT 300 seconds
•On ECMO –Check ACT 2 hourly till
ACT drops to 200 seconds
•Maintenance with ACT 160-200 seconds
•ACT to be repeated every 6-8 hours
•aPTT : 60-70 seconds

48. Circuit
monitoring..
• Circuit blood flow
• Circuit gas flow
• Circuit pressure
• Circuit integrity
These variables should be monitored
continuosly

49. Factors affecting Circuit Blood
flow
Increased Blood flow Decreased Blood flow
Increased RPM Decreased RPM
Decreased Resistance
:Vasodilation
:Improved arterial cannula position
Increased Resistance
:vasoconstriction
:Kinking of tubing
:Improper cannula position
Increased preload
:Increased filling
:Improved venous cannula position
Decreased preload
:Hypovolemia
:Improper cannula position
:Kinking of tubing

50. Circuit
Pressure
• Pre pump pressure: too much negative pressure
results in Hemolysis, cavitation, endothelial
damage of Right atrium and vena cava
• Reasons : Hypovolemia,
Improper catheter placement,
Inadequate cannula size.

51. •Pre membrane pressure
•Post membrane pressure
•Transmembrane pressure

52. Circuit
integrity
• Check for : Clot
: Air
: Leak
• Pump is checked for abnormal noise or crack

53. Clot in the oxygenator

54. Other things to be checked
regularly.
•Insertion site/dressing security
•Functioning of heat exchanger
•Access line for kinking/movement

55. Thank You