On getting ill or injured the organ of the body can take rest. During resting it evades injuries and simultaneously heals. Once organ is healed, the organ restart it functions and contributes to the body as it was doing before disease.
This is true for all organs of the body except Heart & Lung. If they stop to take rest the person will not survive. We only had heart & lung machine which could bypass heart & lung only for few hours. This we used to use for bypass surgeries only.
But if it is matter for few days or weeks, we were helpless. Both ECMO and VAD are the new devices which helps the organs to recover after an injury
With the advent of ECMO more than 54 thousand such dying patients have been saved all over the world. In case of severe of Road accidents, Heart Failures, Impaired Heart Functions, Patients waiting for heart transplant, poisoning like rat poisoning, severe pneumonia, patient with swine flu or H1N1 infections or respiratory failure due to any cause and much more complicated case ECMO takes over the function of the heart.
The another part is membrane like structure with exchanges gases like Oxygen into blood and takes out carbon dioxide out of Blood. It is virtually a lung. Both parts of the machine take over the function of Heart & Lung. This machine can support a patient for 4-6 weeks. As this is sufficient time for organs to heal and resume their normal functions.
Ventricular Assist Device (VAD) works as an artificial heart, taking over the function of left Ventricle that pumps blood to the body. It is indicated in end stage Heart Failure, Due to any disease of heart, where normal function of Heart becomes so weak that it cannot support the vital organs of the body like Kidney, Liver, Brain and Lung.
In end stage Heart Failure only two things can help, Heart transplant and VAD. Since donors are not easily available for the heart transplant, VAD becomes a valuable option in such conditions. VAD is a mechanical pump, which takes over the pumping function to the Heart and can be used either as an bridge to transplant or as a permanent destination therapy for such patients.