ECMO Flashcards
1
Q
VV EMCO and indications
A
Veno-venous ECMO
- drained from IVC returned to SVC
- does not bypass heart
- hemodynamics not completely dependent on ECMO
- oxygenating and ventilating
- “Pulmonary ECMO”- PNA, ARDS, massive aspiration, rib fractures, chest trauma, primary graft dysfunction after lung transplant, COVID
- PE?
2
Q
VA EMCO and indications
A
- veno arterial ECMO
- Venous drain and arterial return
- completely bypassing the heart and lungs, replaces cardiac function
- hemodynamics dependent on ECMO flow
- USES: cardiac arrest (known to cardiology?), EPS/Cath lab, end stage cardiomyopathy/ possible VAD/transplant candidate (acute decompensation, failure to wean from bypass, ?massive PE?
3
Q
Contraindications to ECMO
A
- severe peripheral vascular disease, aortic dissection, severe aortic valve insufficiency
- malignancy, severe brain injury
- advanced age >75
- cardiac arrest of prolonged duration
- mechanical ventilation >7 days
- pulmonary HTN (VV EMCO only)
- Obesity >125kg, BMI>40, very difficult to cannulate and keep clean
4
Q
Sweep
A
minute ventilation of ECMO
- Total amount of gas pushed through oxygenator in one minute L/min
sleep flow is increased or decreased based on CO2 (jusy like we increase or decrease the RR on the vent based on CO2)
-
5
Q
Peripheral VA ECMO
A
- the classic VA ECMO cannulation is RIGHT femoral VENOUS drain and LEFT femoral arterial return (better to have the cannulas in different spots
- Right venous drain cannula is very long 30-40inches the tip sitting in the IVC maybe in the right atrium
- sometimes may need a second venous drain because this is full hemodynamic support and need high flow — right IJ is “Y”ed into the venous cannula SVC completely decompressing the heart
6
Q
North/ south syndrome
A
- seen in VA ECMO
- As the heart starts to recover, the LV will start to eject and that blood will push out again the ECMO retrograde flow
- the area where the antegrade and the retrograde flow meets is called the “mixing cloud”
- The strong the heart gets the farther it will perfuse, if the lungs are normal, the LV output will adequately oxygenate/ventilate areas that it is perfusing
- if the lungs are compromised, the areas perfused by the LV may become hypoxic— north south syndrome
7
Q
VA central ECMO
A
usually patients who cannot come off bypass
- all antagrade so no risk of north south syndrome
- right atria venous drain
- ascending aorta arterial return
- skin may be closed but sternum cannot be wired unless the cannula are tunneled– risk for unstable sternum
8
Q
VA ECMO flow goals for full support
A
- ECMO flow= cardiac output
- “ECMO index”= 1.8-2.4l/min or better
- Take patients BSA and x2 for CO/ flow
- Increase RPMs util goal flow is achieved
- Indications for full support
- little to no native cardiac functio
- myocardial stunning– post cardiotomy/ STEMI
- goal is to rest the heart
9
Q
ECMO flow goals– low flow less than 3L/min
A
- allows for LV ejection
- decreases risk of clot formation
- unloads LV and reduces or prevents pulmonary congestion/edema
- lower flows may allow us to diuresis the patient and improve pulmonary congestion
10
Q
Dx of north south syndrome
A
draw a right radial and post ECMO oxygenator ABG and compare- a different in PaO2 indicates N/S syndrome especially if right radial ABG is hypoxic
11
Q
North. South syndrome treatment
A
- increase ECMO flow?? (careful.. it may worsen the problem by increasing LV distention and pulmonary congestion)
- Maximize vent settings
- impella to unload LV (will decrease pulm congestion)
- LV vent spliced into ECMO inflow lone
- Consider decannulation or switching to VAV or VV ECMO
12
Q
VV ECMO peripheral cannulation
A
- Right femoral vein tip of IVC drainage
- Right IJ SVC return
- maintains pulsality
- lower flos and PaO2 is not as high with VV (more mixing of native blood)
- When oxygenated blood from the outflow cannula mixes with the blood going into the inflow cannula can cause recirculation circle
- inflow and outflow lines same color, increased ECMO SvO2 with decreased patient oxygenation
13
Q
Goals of VV ECMO
A
- to support the patients oxygenation/ventilation needs and allow the lungs to heal/recover or to be transplanted
- VV ECMO does not replace the lungs, it adds to them -
- if the FI02 is too low, the patients sats drop, if the ECMO flow is too low, the sats drop.. higher flows to better oxygenate
14
Q
VV ECMO and Cardiac output
A
- VV ECMO flow is a portion of the patients total CO
- VV ECMO flow is fixed, CO is variable
- think of it as a percentage (2/3 of CO is going through the ECMO circuit, 1/3 is not)
- As CO increases that percentage of non ECMO blood gets larger, “awake” patients generally have high heart rate and BP— and thus will not oxygenate as well
- sedation/ analgesia decrease WOB but also decrease CO
- Beta blockers may be utilized- continuous infusions may work better than IVP– esmolol gtt
15
Q
What can compromise ECMO flow
A
- inadequate proload- bleeding 3rd space shift
- intra-thoracic/ intra-abdominal HTN ( Tamponade/domain issues, coughing, breathing)
- large patient, small cannula
- HTN (systemic and pulmonary) Afterload sensitive
