ECMO

Question 1

Disadvantage of femoral-femoral VA ECMO circuit?

Answer 1

It can be effective in supporting cardiac/lung function however, it dumps oxygenated blood in the thoracic aorta via retrograde flow

This retrograde flow affects the normal body hemodynamics

You see increased LV after load, causes difficulty opening aortic valve

Increases LV wall stress and myocardial oxygen demand

***IABP have been used in combo with ECMO to help myocardial oxygen demand and LV function with good results

Question 2

VV ECMO?

Answer 2

Used for respiratory support
Used for hypercapnia or hypoxia with preserved cardiac function

Blood is drained from venous system, sent to the pump and oxygenation and sent back to venous system

Question 3

CESAR trial?

Answer 3

Pts with ARDS were put on ECMO vs traditional vent support
Showed improved survival in pts who were treated at ECMO referral centers
Did not show a direct benefit from ECMO but rekindled ECMO interest

Question 4

Basic ECMO circuit?

Answer 4

Blood is removed from venous side

Sent to a pump and oxygenation and returned to the arterial side

Similar to a HD circuit except the rates of an ECMO circuit run at 5L/min which increase risk of shear related hemolysis

Question 5

VV ECMO:

Answer 5

Blood is taken from venous circulation and returned to venous circulation

Requires intact cardiac function to pump new oxygenated and mixed blood to rest of circulation

Question 6

Indications for ECMO?

Answer 6

Sepsis w/ARDS
Chest trauma
Bridge to transplant
Influenza burn/inhalational injury
Air leak syndrome

Cardiac arrest
PE
Bridge to transplant
Bridge to ventricular assist device

Question 7

Absolute contraindications of ECMO?

Answer 7

Terminal malignancy
Severe and irreversible TBI

Question 8

Recirculation during ECMO?

Answer 8

The cannulas are too close to each other, so the returned oxygenated blood in the patient is sucked back out into the inflow cannula and circuit and bypasses systemic circulation

This can also occur when the EMCO flow rate is too high and higher than the CO

Question 9

How does multi lumen Avalon cannula work?

Answer 9

Single injection site

You get deoxygenated blood from IVC and SVC at either end of the cannula and you return the oxygenated blood via a middle port into the heart and tricuspid valve

Must be placed under flouro or TEE

Question 10

One advantage of the AVALOn single cannula?

Answer 10

Allows for greater patient mobility

But its a large cannula and positioning has to be perfect

Question 11

Oxygen delivery equation;

Answer 11

DO2 = CO x (1.34 x hgb x O2 Sat) + (0.003 x PaO2)

Hemoglobin is one of the most important components of oxygen delivery (DO2)
Goal is to keep hemoglobin around 14-15

Question 12

This can be used to project a patient’s expected outcome on ECMO’;

Answer 12

RESP calculator

Question 13

This is an absolute contraindication to ECMO:

Answer 13

End organ dysfunction with no exit strategy (such as transplant in a liver cirrhotic who still drinks)

Question 14

Most common strategy for a VV ECMO circuit is cannulation where?

Answer 14

Femoral vein drainage

Internal jugular vein reinfusion

Most adults need 4-6 L/M flow of gas exchange on VV ECMO

Question 15

What is a problem with a femoral-femoral VV ECMO circuit?

Answer 15

Recirculation is an issue when the two cannulae are too close together

Question 16

What is LV venting during ECMO?

Answer 16

Commonly used in pts on peripheral VA ECMO when the native cardiac function is not strong enough to overcome the increased afterload generated by the VA ECMO circuit; which leads to LV distention

Question 17

While of VV ECMO, what ventilator strategies should we use?

Answer 17

EOLIA trial recommendations:
Limit plateau pressure to 24 cm H20
PEEP >10 (driving pressure of 14)
RR 10-30
Fio2; 0.3-0.5

Question 18

What’s a common anticoagulation strategy during VV ECMO?

Answer 18

Heparin bolus upon cannula insertion followed by a continuous heparin infusion

ACT has been used to follow appopriate anticoagulation (goals 180-220)

Question 19

MC indication for RRT in both adult and pediatric ECMO pts is?

Answer 19

Fluid overload

Question 20

Harlequin syndrome?

Answer 20

During VA ECMO, when the heart starts to work again, a PaO2 from an radial artery may go from 400 to 150 in a few days indication, less work of the ECMO circuit and more native cardiac function regaining

Question 21

MC location of bleeding from ECMO?

Answer 21

Cannula site

Question 22

Venous thromboembolism after VV ECMO?

Answer 22

Occurs in 20-30% of pts despite adequate anticoagulation

Question 23

When do we do a trial off of ECMO?

Answer 23

When ECMO provides less than 30% of native cardiac or lung function then a trial off of ECMO should be considered

Question 24

Why do we screen pts for DVT 48-72 hrs after decnnulation?

Answer 24

30-50% have DVTs

Question 25

Oxygen index?

Answer 25

Measure of oxygenation

1/ (P/F ratio) x 100 x Mean airway pressure

Oxygen index >40 predicts high mortality and ECMO indicated

Question 26

VA ECMO cannulation for neonates <15 kg?

Answer 26

Right IJ for venous drainage

Right common carotid for reinfusion