|Year : 2017 | Volume
| Issue : 2 | Page : 86-87
Clinical questions: Responses to clinical queries from readers: Extracorporeal membrane oxygenation (ECMO)
Professor, Medical ICU, Division of Critical Care, Christian Medical College, Vellore, Tamil Nadu, India
|Date of Web Publication||18-May-2017|
Professor, Medical ICU, Division of Critical Care, Christian Medical College, Vellore, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Chacko B. Clinical questions: Responses to clinical queries from readers: Extracorporeal membrane oxygenation (ECMO). Curr Med Issues 2017;15:86-7
|How to cite this URL:|
Chacko B. Clinical questions: Responses to clinical queries from readers: Extracorporeal membrane oxygenation (ECMO). Curr Med Issues [serial online] 2017 [cited 2018 Apr 21];15:86-7. Available from: http://www.cmijournal.org/text.asp?2017/15/2/86/206544
What is extracorporeal membrane oxygenation (ECMO)? Is it a useful procedure? Are there any cases of survival after reaching this advanced stage of bad health? Before ECMO is started, is there possibility of brain death in the patient?
ECMO is a technique whereby the function of the lungs and/or heart is supported outside the body by an external pump and oxygenator. This is considered as a rescue treatment when patients are refractory to conventional therapy for either respiratory or cardiac failure.
How does it work?
Deoxygenated venous blood from the patient is passed through the oxygenator where carbon dioxide is removed and oxygen is added into the blood. This oxygenated blood is then returned back to the patient.
Depending on the return route of the oxygenated blood, ECMO can be classified into two main types [Figure 1].
- Venovenous ECMO (VV ECMO)
- Access of deoxygenated blood - femoral or jugular vein
- Return of oxygenated blood - into the femoral or jugular vein
- Indications: VV ECMO is recommended in refractory reversible hypoxemic respiratory failure (where conventional therapy - lung protective ventilation, proning, and paralysis have failed to improve gas exchange)
VV ECMO has been used in the following situations:
- Severe acute respiratory distress syndrome (ARDS) due to infectious etiology - H1N1, scrub typhus
- CO2 retention on mechanical ventilation despite high ventilatory support
- Severe air leak syndromes - bronchopleural fistulae - with hypoxemic respiratory failure where ventilation could aggravate the air leak
- Bridge to lung transplant.
- Venoarterial ECMO (VA ECMO)
- Access of deoxygenated blood - femoral or jugular vein
- Return of oxygenated blood - into the femoral artery or axillary artery
- Indications: VA ECMO is considered in refractory reversible cardiogenic shock (where conventional therapy - pharmacotherapy such as inotropes ± intraaortic balloon pump have failed to improve cardiac output and organ perfusion)
Situations where VA ECMO has been used are:
- Postmyocardial infarction with refractory cardiogenic shock
- Fulminant myocarditis
- Peripartum cardiomyopathy
- Extracorporeal cardiopulmonary resuscitation (CPR) refers to ECMO during CPR. This is usually considered after 10 min of adequate but unsuccessful advanced life support.
How does venoarterial extracorporeal membrane oxygenation help?
VA ECMO rests the heart by generating adequate flows of over 4 l/min – thereby allowing the heart to recover.
- Mechanical ventilation with persistently high-ventilatory requirements for 7 days or more.
VV ECMO and VA ECMO:,
- Central nervous system (CNS) hemorrhage that is recent or expanding
- Nonrecoverable comorbidities such as major CNS damage or terminal malignancy
- Age: no specific age contraindication but consider increasing risk with increasing age
- Nonrecoverable respiratory or cardiac condition (not candidates for lung/heart transplant).
- Uncontrollable bleeding
- Patients who cannot be anticoagulated (anticoagulation is needed for the maintenance of the ECMO circuit) and
- Very poor prognosis from the primary condition.
Does extracorporeal membrane oxygenation work? The evidence
With reports of improved outcome of patients on ECMO, there has been a paradigm shift in the way intensivists look at ECMO - from “should we do ECMO?” to “where, when, and how should we do ECMO?” This change in mindset should however, be in line with the evidence available for the efficacy of ECMO.
Evidence in favor of VV ECMO:
- CESAR trial  – While ECMO showed an impressive mortality benefit over conventional ventilation (63% vs. 47%), there were more patients with severe disability in the ECMO arm
- 2. ANZIC group found a notable mortality of only 21% with the use of ECMO in severe ARDS.
Evidence in favor of VA ECMO:
There is evidence to suggest that ECMO in severe myocarditis is associated with a 61% chance of discharge from the hospital.
When should we consider this mode of therapy?
Timing is extremely crucial. If ECMO is considered too early, it is an expensive and unnecessary exercise. On the other hand, if it is considered too late, it may be futile.
The general indications have been written above. As a general rule, once a patient develops multiorgan failure, one must give an even more guarded prognosis when offering ECMO to patients.
In response to your query, “before ECMO is started, is there possibility of brain death in the patient?” severe nonrecoverable neurological injury is considered an absolute contraindication for ECMO. The diagnosis of brain death should be made by standard definitions and criteria - if criteria are fulfilled, support with ECMO is not encouraged.
Prognostication of patients on extracorporeal membrane oxygenation
There are scoring systems that could help predict the likely prognosis of patients on ECMO:
- ECMO SAVE score for patients with refractory cardiogenic shock on VA ECMO
- The RESP score has been designed to assist prediction of survival for adult patients undergoing VV ECMO for respiratory failure.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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