Physicians

understanding of ECMO

Physicians understanding of ECMO

Dear Doctor,

Till date, the most common mode of death in death certificates is cardiorespiratory failure. Even, if rest of the system and the body is intact, cardio/respiratory arrest is synonymous with cessation of life. Over the years, it was quite frustrating, to watch helplessly, our patients succumbing untimely, to cardiac and / or respiratory in sufficiency, after all machines and medicines fail to assist the heart and / or the lung to minimum efficiency.

Time and again, we have always been dreaming to overcome this major handicap to sustain life in presence of acute / chronic end stage cardiorespiratory failure. Other specialities like nephrologists have been successful in overcoming this limitation, using dialysis to maintain meaningful life for years together, after complete renal failure. Except brain, lungs and heart, other organs gives a breathing time between onset of end stage and collateral damages to the body. The crucial time to prevent secondary damage to rest of the body due to primary cardiac / respiratory dysfunction is very short. Hence, the management issues are demanding and difficult, but rewarding.

There has been remarkable progress in mechanical mode of critical care management Though, most of the medical centres in west, abroad, have struggled day and night on this philosophy from 1985 onwards. It is a concept to provide a early makeshift arrangement of perfusion and ventilation to each and every cell of the body in the setting of sudden and / or severe cardiac / respiratory crisis. Different types of devices have been invented to give immediate –to- short –to- intermediate –to- long –to- destination therapy by mechanical circulatory and respiratory support in lieu / assist to heart and lung transplant.

The first step in this modality of mechanical replacement therapy of critical care management is ECMO (Extracorporeal membrane oxygenation) which comes under the auspices of ECLS (Extracorporeal life support system). It is bringing the power of heart lung machine from the cardiac OT to ICCU. This becomes the escape goat in times of haemodynamic and /or ventilatory collapse.

We should already have been using this advantage long back, but due to our own inertia and other socioeconomic reasons, there is a long delay on our end to adopt and practise this state of the art of intense critical management.

What is ECMO

ECMO is a set of machines used for temporary replacement treatment (not assist) of heart and/or lung function by mechanical means via extracorporeal route. It comprises of set of tubings to divert the venous blood from the body to a artificial heart(blood pump). This heart pump provides the necessary force (blood pressure) for the blood to circulate without and within the body. After this, the blood is diverted inside the tubings to a artificial lung (respiratory filter) for oxygenation and removal of carbon dioxide. Then the blood is returned back to the body with pressure and oxygen to perfuse and ventilate the cells of the body.

What is the need to initiate ECMO (principles of treatment)

Till now, all modalities of critical management were assist therapy whether it may be IABP or ventilator or inotropes. They were to support the existing organ and improve its performance. But if the organs are damaged beyond a particular limit, they require absolute rest for recovery. Also, if rest to the organ is not given at proper time, it will lead to cumulative and collateral damages. Thus at this stage, further step up in assist mechanism will create more harm than good.

At this particular stage of advanced organ damage or malfunction, the mainstay of recovery is rest. Since, respiration and circulation can not take rest throughout life, ECMO appears as the only makeshift arrangement in this juncture. It is always wise to take a timely decision to switch over to temporary replacement treatment after assist therapy has failed and before secondary multiorgan failure has set in.

Other applications of ECMO

We feel, there is a great future of ECMO due to its wide applications, like first line short term replacement therapy in all refractory acute heart or lung failure, e-CPR, organ preservation in brain dead donors and switch over therapies.

Its advantages and challenges

It is a simple percutaneous procedure which can be initiated in short time. It can be done at bed side in any ICU without the need of any specialised machines. It is portable system and allows patients to be shifted across great distances by any transport and can be combined with other support systems. It has great flexibility and various combinations can be designed to support only heart / only lungs or both heart and lungs.

There is lot of physiology involved about hematology and haemorheology, physics of cannulae and pump, chemistry of respiratory membrane and hemofiltration, biology of the living, dying and dead cells, pathology of the disease process and overall medicine for management of the entire body. Thus, entire science is at work and the operator has to master of all and not jack of one. The challenge is worth taking and success is gratifying to the extent of playing GOD

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