As a junior emergency department (ED) physician, I clearly remember my first code -first cardiopulmonary resuscitation (CPR) attended- and the mixed feelings of sorrow and helplessness for not being able to bring that soul back to life despite our best efforts. After a couple of more codes, listening to the sounds of the hearts slowly fading away, my mind started to question: How effective is the current standard Advanced Cardiac Life support (ACLS) protocol we follow?
I remember admitting to one of my attendings how desperate I felt about the ACLS during every code, expecting very abysmal neurological and overall outcomes, even if the patient was lucky enough to achieve the return of spontaneous circulation (ROSC). It almost felt that what we did was completely futile. A couple of weeks later, during my cardiology rotation, I had a field trip in the cardiac intensive care unit (ICU) with one of the cardiologists who introduced me to different advanced mechanical support devices, including extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump (IABP) and others. While he explained the basic concepts behind how they functioned, it almost immediately occurred to me: “Well! That’s what we need in cardiac arrest patients!”
While certainly, it was not a very novel idea, it did urge me to search into the available evidence and where we stood in terms of bringing this idea into more practical terms. This is how I was introduced, as a postgraduate year one (PGY-1) ED resident, to the concept of ECMO-CPR.
What is ECMO?
Extracorporeal membrane oxygenation (ECMO) is the use of a blood pump and an oxygenator to support either pulmonary or both pulmonary and cardiac function. An ECMO circuit is usually made of a centrifugal pump and a membrane oxygenator for oxygen delivery, CO2 removal, and temperature management.
What are the types of ECMO?
There are two main types of ECMO circuits:
Veno-venous (V-V) ECMO
Veno-venous (V-V) ECMO provides lung support only so it requires a functional heart. Venous cannulae are usually placed in the right or left common femoral vein (for drainage) and right internal jugular vein (for infusion). The tip of the femoral cannula should be maintained near the junction of the inferior vena cava and right atrium, while the tip of the internal jugular cannula should be maintained near the junction of the superior vena cava and right atrium.
Veno-arterial (V-A) ECMO
Veno-arterial (V-A) ECMO provides both cardiac and pulmonary support. The drainage (access) cannula is placed into the inferior vena cava via the femoral vein, and the “return” cannula is inserted into the femoral artery to the level of the common iliac artery.
We will focus on V-A ECMO given its relation with E-CPR.
How does V-A ECMO work?
Venous blood (blue) drained via a cannula positioned at the inferior vena cava to the right atrial junction passes through the extracorporeal membrane where oxygenation and CO2 removal occurs. The oxygenated blood (red) is returned via a “return” cannula positioned in the common iliac artery or descending aorta. After ECMO support is established, the distal perfusion catheter is inserted into the superficial femoral artery distal to the insertion point of the femoral return cannula, and it supplies oxygenated blood to the distal limb to prevent distal limb ischemia (Figure 1).
What are the indications for VA-ECMO?
- Cardiac arrest
- Low Cardiac Index (<2L/min/m2) and hypotension despite inotropic support and an IABP.
- Failure to wean from cardiopulmonary bypass
- Cardiogenic shock or severe cardiac failure, caused by:
- Acute coronary syndrome
- Ventricular tachycardia storm or refractory arrhythmias.
- Drug overdose/toxicity
- Massive pulmonary embolism
- Cardiac trauma
- Acute anaphylaxis
What are the contraindications for VA-ECMO?
The list below includes both absolute and relative contraindications:
- Patients with non-recoverable cardiac dysfunction who are not candidates for left ventricular assist device (LVAD) or transplantation
- Chronic organ dysfunction
- Prolonged CPR without adequate tissue perfusion
- Disseminated malignancy
- Known severe brain injury
- Unwitnessed cardiac arrest
- Contraindications to therapeutic-dose anticoagulation
- Severe aortic regurgitation
- Aortic dissection
- Existent multiorgan failure
- Mechanical ventilation >7–10 days
- Advanced age
We will continue with the use of ECMO during CPR in the part 2. Stay tuned!
References and Further Reading
- Berdowski, J., Berg, R. A., Tijssen, J. G., & Koster, R. W. (2010). Global incidences of out-of-hospital cardiac arrest and survival rates: systematic review of 67 prospective studies. Resuscitation, 81(11), 1479-1487.
- Bougouin, W., Dumas, F., Lamhaut, L., Marijon, E., Carli, P., Combes, A., … & Jouven, X. (2020). Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest: a registry study. European Heart Journal, 41(21), 1961-1971.
- Dennis, M., Lal, S., Forrest, P., Nichol, A., Lamhaut, L., Totaro, R. J., Burns, B., & Sandroni, C. (2020). In-Depth Extracorporeal Cardiopulmonary Resuscitation in Adult Out-of-Hospital Cardiac Arrest. Journal of the American Heart Association, 9(10), e016521.
- Gräsner, J. T., Lefering, R., Koster, R. W., Masterson, S., Böttiger, B. W., Herlitz, J., … & Zeng, T. (2016). EuReCa ONE-27 Nations, ONE Europe, ONE Registry: A prospective one month analysis of out-of-hospital cardiac arrest outcomes in 27 countries in Europe. Resuscitation, 105, 188–195.
- Grunau, B., Reynolds, J., Scheuermeyer, F., Stenstom, R., Stub, D., Pennington, S., … & Christenson, J. (2016). Relationship between time-to-ROSC and survival in out-of-hospital cardiac arrest ECPR candidates: when is the best time to consider transport to hospital?. Prehospital Emergency Care, 20(5), 615-622.
- Hutin, A., Abu-Habsa, M., Burns, B., Bernard, S., Bellezzo, J., Shinar, Z., … & Lamhaut, L. (2018). Early ECPR for out-of-hospital cardiac arrest: best practice in 2018. Resuscitation, 130, 44-48.
- Hutin, A., Loosli, F., Lamhaut, L., Mantz, B., & Corrocher, R. (2017). How Physicians Perform Prehospital ECMO on the Streets of Paris. Accessed Feb 26, 2021, from https://www.jems.com/patient-care/how-physicians-perform-prehospital-ecmo-on-the-streets-of-paris/
- Inoue, A., Hifumi, T., Sakamoto, T., & Kuroda, Y. (2020). Extracorporeal Cardiopulmonary Resuscitation for Out‐of‐Hospital Cardiac Arrest in Adult Patients. Journal of the American Heart Association, 9(7), e015291.
- Kim, S. J., Jung, J. S., Park, J. H., Park, J. S., Hong, Y. S., & Lee, S. W. (2014). An optimal transition time to extracorporeal cardiopulmonary resuscitation for predicting good neurological outcome in patients with out-of-hospital cardiac arrest: a propensity-matched study. Critical Care, 18(5), 1-15.
- MacLaren, G., Masoumi, A. & Brodie, D. (2020). ECPR for out-of-hospital cardiac arrest: more evidence is needed. Critical Care24, 7
- Nickson, C. (2020). Extracorporeal Membrane Oxygenation. Accessed Feb 26, 2021, from https://litfl.com/ecmo-extra-corporeal-membrane-oxygenation/
- Singer, B., Reynolds, J. C., Lockey, D. J., & O’Brien, B. (2018). Pre-hospital extra-corporeal cardiopulmonary resuscitation. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 26(1), 1-8.
- Tan, B. K. K. (2017). Extracorporeal membrane oxygenation in cardiac arrest. Singapore Medical Journal, 58(7), 446.