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Mechanical Circulatory Support

Absolute  contraindications to VA ECMO

       •Aortic dissections

  • •Severe Aortic valve regurgitation

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Absolute contraindications to all forms of ECMO


  •        •>75 years

  • •>140 kg or BMI >35
    •Non recoverable cardiac, respiratory , or neurologic diseases.
    •Chronic severe pulmonary hypertension
    •Active malignancy
    •Failed transplants beyond 30 days
    •Advanced liver disease
    •AIDS
    •Unwitnessed arrest or CPR >30 minutes 

Peripheral ECMO cannulation

Kinked cannula

Inclusion / Exclusion

  • A: age > 70 (very few survivors > 70yrs old no matter what the reason)

  • A: ABG - how long have the PaO2's been low

  • A: Anaphylaxis

  • B: BMI > 40 (for VA-ECMO)

  • C: cardiogenic shock (eg. AMI)

  • C: coding for how long?

  • D: drips currently on

  • Drug overdose with profound cardiac depression

  • Downtime: greater 30-45 minutes has unlikely neurological recovery

  • E: ETT (# of days intubated)

  • E: etiology must be a reversible cause

  • F: Failure to wean post cardiac surgery

  • G: Graft Failure (Heart/Lung) post transplant

  • H: head injury/bleed

  • I: Intrabdominal/pelvic pressure elevated (makes femoral cannulation difficult - see article)

  • M: Myocarditis

  • M: Massive hemoptysis/pulmonary hemorrhage/trauma

  • P: Peripartum cardiac complications

  • P: Pulmonary Embolism

  • S: Sepsis with profound cardiac compromise

  • T: trauma: head injury, long bone fracture that bleed...)

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Risk Factors

  • leg ischemia (femoral artery cannulation): 20%

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Heparin 100 units/kg

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  • 3 assistants ideally

    • cannulator​

    • helper

    • pressure holder

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Equipment

  • US machine to determine artery and vein if coding

  • turkey baster and basin

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Cannulas (go from BIG to small)

  • venous cannula (access cannula) (drainage cannula) (long cannula)

    • drains the blood from the venous system into the ECMO circuit​

    • Edwards: 18-20-22-24-28 (smaller cannula in emergency situation)

    • Femoral:  Distal tip rests in the IVC, generally at the level of T10 – T11

    • you do not want to advance the cannula past the hepatic vein (level of diaphragm), as this can cause hepatic congestion​/obstruction (view via ECHOcardiography)

    • measure the distance: lay the catheter against the groin to the umbilicus and then to the xiphoid, note this length

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  • arterial cannula (return cannula) (short cannula)

    • returns blood back to the patient from the ECMO circuit​

    • Edwards: 16-18-20​-22​ (smaller cannula in emergency situation)

    • Femoral: distal tip rests in the iliac artery

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  • distal perfusion cannula (antegrade cannula)

    • delivers blood antegrade down the leg distal to the ECMO return cannula to maintain perfusion to the leg​

    • 5-6-7-8-9 Fr

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Cannulation

  • use the dilator of the cannula by itself first and then together with the cannula for easier placement​

  • when removing the dilator/wire, place your thumb over the cannula exit to prevent exsanguination

  • you can flush the line back with the turkey baster after the first line is in

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Femoral-Femoral

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Differential hypoxia (harlequin)

  • can place a side port off the return cannula to the internal jugalar vein with the tip in the SVC

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Physiology

  • Poiseuille's law

    • maximize drainage cannula diamter​

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Management

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Complications

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Code Blue

 

Steps:

  • turn up ECMO flows to FULL

  • defibrillation: YES

  • antiarrhythmic: YES

  • chest compression: NO

  • code drug boluses: NO (continue on current medications)

 

These patients are receiving blood flow and pulmonary gas exchange. Patients on VA-ECMO benefit from some cardiac ejection as it prevents LV distention. If a patient on VA ECMO develops VF, defibrillation is beneficial. It is easier to defibrillate a decompressed heart than a full one. Thus treatment is to first ensure that the ECMO flows are maximized and then defibrillate. 

 

Inotropic drips can be managed as normally to maintain adequate MAPs

 

In general there is no role for ACLS/CPR. External compressions will not add blood flow support if the ECMO flow is adequate and risks dislodging the cannula(s). ACLS boluses of pressors can also be detrimenetal if the increase in afterload decreases ECMO flow.

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References:

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Pitfalls in percutaneous ECMO cannulation L. Rupprecht1 , D. Lunz2 , A. Philipp1 , M. Lubnow3 , C. Schmid1

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http://www.alfredicu.org.au/assets/Documents/ICU-Guidelines/ECMO/ECMOGuideline.pdf

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http://www.papworth-anaesthesia.org/new/docs/ECMO.pdf

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http://www.criticalcarecanada.com/presentations/2012/an_ecmo_primer.pdf

 

Management

  • continue to check cardiac enzymes at least daily; if they continue to be elevated something else needs to be done because of the ongoing ischemia (eg. revascularization)

  • hypothermic cooling for cardiac arrest

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