Sunday, November 27, 2005

Heart-lung Machines

This is an excellent question from G., in Germany:

I have a question if you would have the time to answer it I would
really appreciate it.If you take out your heart in a operation how are
you going to live ? Are they putting a fake heart inside your body?
When they are changing it how does your blood get oxygen?

To which I say:

Dear G.,

What an excellent question! We take hearts out when we transplant them, which means that we put another one back in to replace the heart that isn't working. That happens pretty fast, so people don't go without a heart for very long. But for the short time (usually about three hours) that their heart is disconnected from their veins and arteries, and isn't pumping blood around their bodies anymore, we have a machine called a heart-lung machine that does the work of the heart for them. It's really cool.

The machine connects to the biggest artery that comes out of the heart, which is called the aorta, and to the veins that come back to the heart, which are called the vena cavas. It takes the blood from the veins, puts oxygen into it, just like the lungs do, and then puts the blood with the oxygen in it back into the aorta, where it gets pumped back to the rest of the body. So it does the same job as the heart and the lungs while the patient's heart is being operated on.

You couldn't have the machine on when you're awake and walking around, though, because it is very big and would hard to move around with. Here's a picture of what it looks like in the operating room:

Can you imagine having to have that whole machine and the guy to run it following you around when you went out to the grocery store?! So for the moment, you still need to have a heart in your body most of the time. We are working on making artificial hearts for people whose hearts don't work and who can't get a transplanted heart from another person, but so far they don't work nearly as well as the real thing!

I hope that helps to answer your question! Let me know if you have more questions. It would be a pleasure to do my best to answer them.

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