Limitations & Problems

While ECMO is one of the most technologically advanced devices in the medical field, there are still a multitude of issues associated to it, ranging from medical risks to ethical problems.

Medical Risks

Fig. 1: Thrombosis

1.Thromboembolism

Exposure of the blood to a foreign surface (ECMO circuit) can result in clot formation.

Clots in the circuit or the blood vessels can cause a blockage in the system, leading to stroke or organ failure.

Fig. 2: Brain haemorrhage

2. Haemorrhage

Anticoagulants are used to prevent clots from forming within the circuit; however, this presents a risk of excessive thinning of the blood, resulting in bleeding.

Bleeding is one of the most common complications in ECMO, and can be seen in 21-66% of patients.

3. Infection & Sepsis

ECMO involves a high risk of infections, complication arise in about 30-55% of ECMO runs. The chance of infection increases the longer the patient is on ECMO. There are also concerns of leaching of microplastics like diethylhexyl phthalate (DEHP from the ECMO circuit materials plasticised for flexibility. The long-term accumulation of these foreign toxins can result in sepsis.

Fig. 3: Formation of biofilm. The development of biofilm will lead to bloodstream infection.

4. Low/Uneven Levels of Blood Oxygen

Typical blood oxygenation levels range from 95-100%; target range for ECMO is 86-92%.

For V-V ECMO, the return cannula is situated in the right atrium. As a result, the oxygenated blood from return cannula mixes with deoxygenated blood in the right atrium and ventricle; the resulting blood has a lower saturation than normal (~88% saturation).[1]

In the case of V-A ECMO, the return cannula is inserted into the femoral artery, which supplies blood to the lower body. The rest of the body receives blood from the heart(oxygenated by lungs). The tissues prior to insertion will receive blood with lower oxygenation, resulting in differential hypoxia.[2]

Fig 4. Differential Hypoxia (aka Harlequin's syndrome). Upper body takes on a blueish shade, while the lower body appears normal.

Fig. 5

5. Dependency

As advanced as ECMO may be, it can only be used as a temporary support mechanism, to alleviate the burden from the heart and lungs. If the patient cannot recover sufficient heart/lung function, they cannot be weaned off the device.

Availability & Costs

Since operating ECMO requires advanced technology and skilled staff, its availability is limited to well-equipped medical centres.

ECMO also has high operational costs due energy consumptions and expensive equipment, as well as the human resources needed to constantly monitor and maintain the system.

For perspective, the average cost of an ECMO unit comes to about 73000 USD[2](~100000 SGD), and operational costs range from 20000-40000 USD per day. This makes ECMO unaffordable for a large fraction of the population.

Ethical Considerations

Finally, there are the ethical concerns regarding ECMO.

While ECMO does help extend a patient's life, it doesn't help with recovery. In the case of patients who are unlikely to recover, ECMO may only prolong their suffering.

ECMO is also considered to be quite invasive - many patients may be uncomfortable with or refuse treatment.

Fig. 6: Quote by Hippocrates

References

Fig. 1: Blood Clots: Symptoms & Risks | The Well by Northwell. (n.d.). Retrieved 14 November 2024, from https://thewell.northwell.edu/heart-health/blood-clots

Fig. 2: Brain Hemorrhage Treatment in Raipur: NHRCC. (n.d.). Neurospine Hospital & Revive Critical Care. Retrieved 14 November 2024, from https://www.nhrcc.in/brain-hemorrhage-treatment-in-raipur/

Fig. 3: Edwards, A. M. (2019). Silence is golden for Staphylococcus. Nature Microbiology, 4(7), 1073–1074. https://doi.org/10.1038/s41564-019-0493-7

Fig. 4: Amacher, S., Quitt, J., Hammel, E., Zenklusen, U., Darwisch, A., & Siegemund, M. (2021). Case Report: Left Ventricular Unloading Using a Mechanical CPR Device in a Prolonged Accidental Hypothermic Cardiac Arrest Treated by VA-ECMO – a Novel Approach. Frontiers in Cardiovascular Medicine, 8, 707663. https://doi.org/10.3389/fcvm.2021.707663

Fig. 5: Meta AI. (2024.) Generated Image of ECMO system

Fig. 6: I3 Quote of the Week | i3 Consult | Integrated Intelligence for Healthcare. (n.d.). Retrieved 14 November 2024, from https://www.i3consult.com/quote-of-the-week/

[1] Teijeiro-Paradis, R., Gannon, W. D., & Fan, E. (2022). Complications Associated With Venovenous Extracorporeal Membrane Oxygenation—What Can Go Wrong? Critical Care Medicine, 50(12), 1809. https://doi.org/10.1097/CCM.0000000000005673

[2] Conrad, S. A. (2017). Persistent hypoxemia on ECMO. Qatar Medical Journal, 2017(1), 18. https://doi.org/10.5339/qmj.2017.swacelso.18

[3] Mishra, V., Svennevig, J. L., Bugge, J. F., Andresen, S., Mathisen, A., Karlsen, H., Khushi, I., & Hagen, T. P. (2010). Cost of extracorporeal membrane oxygenation: Evidence from the Rikshospitalet University Hospital, Oslo, Norway. European Journal of Cardio-Thoracic Surgery, 37(2), 339–342. https://doi.org/10.1016/j.ejcts.2009.06.059

Other sources:

Abrams, D. C., Prager, K., Blinderman, C. D., Burkart, K. M., & Brodie, D. (2014). Ethical Dilemmas Encountered With the Use of Extracorporeal Membrane Oxygenation in Adults. Chest, 145(4), 876–882. https://doi.org/10.1378/chest.13-1138
Karagiannidis, C., Brodie, D., Strassmann, S., Stoelben, E., Philipp, A., Bein, T., Müller, T., & Windisch, W. (2016). Extracorporeal membrane oxygenation: Evolving epidemiology and mortality. Intensive Care Medicine, 42(5), 889–896. https://doi.org/10.1007/s00134-016-4273-z
Kim, D. H., Cho, W. H., Son, J., Lee, S. K., & Yeo, H. J. (2021). Catastrophic Mechanical Complications of Extracorporeal Membrane Oxygenation. ASAIO Journal, 67(9), 1000. https://doi.org/10.1097/MAT.0000000000001354
Quill, T. E., & Holloway, R. (2011). Time-Limited Trials Near the End of Life. JAMA, 306(13), 1483. https://doi.org/10.1001/jama.2011.1413
Tonna, J. E., Abrams, D., Brodie, D., Greenwood, J. C., Mateo-Sidron, J. A. R., Usman, A., & Fan, E. (2021). Management of Adult Patients Supported with Venovenous Extracorporeal Membrane Oxygenation (VV ECMO): Guideline from the Extracorporeal Life Support Organization (ELSO). ASAIO Journal (American Society for Artificial Internal Organs : 1992), 67(6), 601. https://doi.org/10.1097/MAT.0000000000001432
What Is ECMO? (n.d.). Cleveland Clinic. Retrieved 13 November 2024, from https://my.clevelandclinic.org/health/treatments/21722-extracorporeal-membrane-oxygenation-ecmo

Kokkatt Rohan Abraham

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