Mechanical Circulatory Support Flashcards
ECMO RPMs should be titrated to what goal index?
CI 2.2 - 2.4
What are some relative contraindications to mechanical circulatory support?
Known severe PVD that precludes access.
Devastating neurological injury.
DNR.
Relative to the inguinal ligament, where should you stick for a femoral cannula?
Below it.
If you access above, you may damage strictures in the canal.
Also, you can cause bleeding that would be difficult to hold pressure on and access.
In an ARDS/respiratory failure patient being considered for ECMO, what is a reasonable cutoff for initiation?
Failure of conventional care w/ PaO2/FiO2 <70. Refer in an early course of the disease.
Earlier may be better. Try not to limp along without it for too long.
In cardiac failure patients requiring HD, or have advanced HF, or have recovered from ARDS, compare ECMO to conventional therapy?
Long-term survivors of ECMO performed for cardiogenic shock have better general health, physical health, and social functioning than patients on conventional therapy who require chronic hemodialysis, have advanced heart failure, or have recovered from ARDS
Compare ECMO to conventional cardiopulmonary resuscitation for cardiac arrest.
Increased survival.
What would be a pH threshold to initiate ECMO in a patient with hypercapnic respiratory failure?
pH < 7.2.
Can ECMO be utilized for massive PE?
Yes
Can ECMO be used as a bridge to lung or heart transplant?
Yes
Outcomes for ECMO in patients with respiratory failure are better if initiated within how many days of intubation?
7 days
Describe the ECMO circuit.
Blood is drained from the vascular system, circulated outside the body via a mechanical heat pump, passes through an oxygenator (that also removes CO2) and heat exchanger, and reinfused into the circulation.
How is blood oxygenation and CO2 removal adjusted in an ECMO circuit?
Oxygenation is determined by flow rate.
CO2 is determined by the countercurrent gas flow (sweep).
What is VV ECMO used for? Where are the cannula?
How big are the cannula?
VV ECMO is used for respiratory failure in a patient that does not need circulatory support.
Drainage cannula is usually inserted into the CFV and the tip resides in the IVC or RA (ideally at the junction).
The infusion cannula has to be distal (deeper towards the RA) or else you will just be draining what you infuse. Usually inserted into the RIJ with the tip just distal to the SVC/RA junction.
Usually 31 Fr - accommodates most adults.
What is the main risk for VA ECMO (ie why don’t we always use VA and forego VV)?
What is the most common complication?
How do you prevent/tx this?
VA ECMO has arterial complications - ischemia of the LE is the main one. Dissection can also happen.
Prevent ischemia with distal infusion catheter.
What are the drawbacks and benefits of the different peripheral arterial cannulation sites for VA ECMO?
CFA, right common carotid, or subclavian artery can be used.
Femoral is usually favored since the cannulation is easiest.
R CCA or SCA are used when the femoral is not amenable (severe occlusive PAD, prior femoral recon).
SCA is advantageous because it allows patients to walk.
What is the ACT goal for ECMO?
180-210 w/ heparin.
(PTT >1,5x normal)
What are the ABG/lab goals for ECMO?
On VA ECMO, PAO2 should be >90%.
On VV ECMO, PAO2 should be >70%.
Venous O2 sat should be 20-25% lower than arterial. Lowest should be 50%.
Lactate should be normal.
What lab can be checked, if a high amount of heparin is being infused without much response in the ACT/PTT/anti-Xa?
AT3 levels. If <50% normal, give FFP or AT3 back.
What is the role of measure the platelet level during ECMO?
ECMO continuously activates platelets d/t exposure to the foreign surface.
It should be maintained >50K.
What is the ideal Hgb in patients on ECMO?
12 g/dL
ECMO circuit is often the only source of oxygen in patients with complete cardiac or pulmonary failure. Oxygen delivery depends on the amount of hemoglobin and blood flow. The risks of high blood flow outweigh the risk of transfusion.
Transfuse liberally in order to reduce flows.
Describe the different types of multi-cannula ECMO circuit configurations (femoral arterial return). What scenarios might they be useful?
VVA - bicaval drainage into femoral infusion (use if single cannula not providing drainage to the other system; superior or inferior congestion).
VAV - RA drainage with more distal RA infusion in addition femoral infusion (send some oxygenated blood through to the LVOT in pts w/ low radial arterial oxygenation despite good femoral infusion flow and lower body oxygenation).
VVAV - SVC and femoral drainage with femoral and RA infusion (VAV circuit causes poor SVC drainage, so you drain SVC and infuse RA via femoral, but now IVC has poor drainage, so the contralateral CFV is cannulated and drained).
VVVA - SVC, IVC, contralateral CFV drainage with femoral infusion (your VVA setup causes poor contralateral CFV drainage, so you insert another cannula to drain it).
You go on VA ECMO via femorals, but notice head and arm swelling. Saturations to the arm and lower extremity are fine. What do you do?
VVA - add RIJ in addition to the CFV for drainage of the SVC and IVC. Continue femoral infusion since the saturations in the upper and lower arterial systems are fine.
You go on VA ECMO via femorals, but poor saturations to the arm despite lower extremity saturations being ok. What do you do?
VAV - RA drainage with more distal RA infusion in addition to femoral infusion (send some oxygenated blood through to the LVOT in pts w/ low radial arterial oxygenation despite good femoral infusion flow and lower body oxygenation).
You go on VA ECMO via femorals, but poor saturations to the arm despite lower extremity saturations being ok.
You then go on VAV with CFV drainage into RIJ RA infusion and CFA infusion. Head and arms start to swell. What do you do?
VVAV - SVC and femoral drainage with femoral and RA infusion. You have to improve SVC drainage (treat head swelling) in addition to IVC drainage, but you still need LVOT to get oxygenated blood (known mismatch in measured radial and femoral oxygenation).
You go on VA ECMO via RIJ and CFA, but notice lower extremity swelling and rising LFTs, saturations to the arm and lower extremity are fine.
You start VVA ECMO to improve drainage via RIJ and CFV (now added) for drainage, and CFA infusion.
The contralateral lower extremity remains swollen, and there are not DVTs.
What can you do?
VVVA - SVC, IVC, contralateral CFV drainage with femoral infusion (your VVA setup causes poor contralateral CFV drainage, so you insert another cannula to drain it).
You go on VA ECMO via femorals, but poor saturations to the arm despite lower extremity saturations being ok.
You then go on VAV with CFV drainage into RIJ RA infusion and CFA infusion. Head and arms start to swell. What do you do?
VVAV - SVC and femoral drainage with femoral and RA infusion. You have to improve SVC drainage (treat head swelling) in addition to IVC drainage, but you still need LVOT to get oxygenated blood (known mismatch in measured radial and femoral oxygenation).
