ECMO Background

  • ECMO Stands for Extracorporeal Membrane Oxygenation Circuit.
    • Extracorporeal means that it is outside the body
    • Membrane is a type of artificial lung
    • Oxygenation is the process of sending oxygenated blood back to the body.
  • ECMO is a life support machine that has a cardiopulmonary bypass circuit connected to the body in the way that it acts as a lung by sending back oxygenated blood to the body with a pump. [2, 7]
  • It can only be used as temporary support to support patients with pulmonary or cardiac failure or both. [1, 3]
  • The use of ECMO often times lead to blood coagulation. [4]
  • Blood coagulation is the formation of blood clots that avoids bleeding when there is a injury. Once the bleeding stops, the coagulation would normally dissolve.  [5]
  • However, patients connected to ECMO tend to have excessive blood coagulation in the veins due to exposure to synthetic surfaces that increase thrombin formation that prevents blood clots from dissolving. [6]
    • Blood & Oxygenator Membrane Interaction [7, 8]
    • Blood clots formation
      • Biomaterials prevent blood from moving across membrane pores
      • Protein fouling & platelets reduction
    • Deadly consequences

 

Figure 2. Standard ECMO circuit [8]
  • Basic ECMO Components [8]
    • Pump
      • Replaces or provides support to the heart
    • Oxygenator
      • Replaces or provides support to the lungs
    • Heat Exchanger
    • Access ports
      • Infusion
      • Sampling

 

Sources

[1]: Tramm, R., et al., Extracorporeal membrane oxygenation for critically ill adults. Cochrane Database Syst Rev, 2015. 1: p. CD010381.

[2]: Sarkar, M. and V. Prabhu, Basics of cardiopulmonary bypass. Indian J Anaesth, 2017. 61(9): p. 760-767.

[3]: Napp, L.C., C. Kuhn, and J. Bauersachs, ECMO in cardiac arrest and cardiogenic shock. Herz, 2017. 42(1): p. 27-44.

[4]: Straub, A., [Blood Coagulation Disorders During ECMO and LVAD Therapy]. Anasthesiol Intensivmed Notfallmed Schmerzther, 2019. 54(6): p. 402-412.

[5]: Hematology, A.S.o. Blood Clots. Available from: https://www.hematology.org/education/patients/blood-clots.

[6]: Doyle, A.J. and B.J. Hunt, Current Understanding of How Extracorporeal Membrane Oxygenators Activate Haemostasis and Other Blood Components. Front Med (Lausanne), 2018. 5: p. 352.

[7]: Romano, T.G., et al., Extracorporeal respiratory support in adult patients. J Bras Pneumol, 2017. 43(1): p. 60-70.

[8]: Lequier, L., Horton, S. B., McMullan, D. M., & Bartlett, R. H. (2013). Extracorporeal membrane oxygenation circuitry. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies, 14(5 Suppl 1), S7–S12. https://doi.org/10.1097/PCC.0b013e318292dd10