Sunday, June 1, 2008

An Artificial Heart for Michael Wyngre

Since 2004, Michael Wyngre and his finance have been asking for donations for his ailing heart. Mr. Wyngre has cardiomyopathy, a condition in which his heart muscles are continuously weakening. Without a heart transplant, he will soon die, and he's very worried about not being able to pay the doctor enough to actually perform the surgery. (While in the United States a hospital is required to save the life of anyone who enters it, even if they are unable to pay, this doesn't guarantee that he'll be on the organ donation waiting list. If he goes into the emergency room with a dying heart and there's no replacement, there's not much the hospital can do.)

Thinking about his case gave me an idea for an artificial heart, based on a few assumptions:

1. The heart primarily functions as a pump, and does not chemically alter the blood as it pushes it. (Other than the sheerly metabolic activities that all cells do, the heart does not work for free.)

2. The body counts on certain conditions that the heart puts into the circulatory system, namely the repeated increase and decrease in pressure.

3. A rotational pump, unlike a conventional one, would not damage the red blood cells as it pushes them. Conventional pumps would tear the cells.

4. There is an invention as of 2003 that can oxidize glucose to produce electricity, under a mechanism similar to that actually used by bodily cells.

5. The point of failure of most currently existing artificial hearts, such as the Jarvik-7 (a brilliant piece of engineering, incidentally,) is the failure of the valves. This heart should rely on pressure to keep blood flowing in the correct direction.

Okay, so I imagine a plastic structure that the major arteries and veins connect to. At the pulmonary vein's connection, a device siphons off some of the blood to oxidize for electricity. The blood is pushed into a rotational pump, that pumps the blood into the aorta. The rotational pump is repeatedly switched from high speed in one direction, to off, to simulate the start-stop enough of a biological heart. A microchip with a quartz timer should control the action. All of this on the left side.

On the right side, we have mostly deoxygenated blood that needs to be pushed into the lungs. It should receive power from the left side, and again, have a microchip controlled rotational pump to speed the blood to 120 mm Hg pressure, and then slow it to 80 mm Hg. Just like the left side, but this connects to the pulmonary artery, thus making the left side functional.

The device should be inserted while the patient's heart is stopped and cardiopulmonary action is artificially controlled for the patient by a Cardiopulmonary bypass machine (CPB). It would replace the heart entirely in function.

Before being implanted in any person, a number of tests should be performed. The FDA assuredly has a program for approval of medical prosthetics, but there are two others tests that I would want to try before even attempting the FDA's tests.

The first test would involve a maze of plastic tubing, 40 - 100 feet long, with a pressure meter at some point. The maze would be filled with a glucose solution to resemble blood. The pressure meter should fluctuate between 120 mg Hg and 80 mm Hg, the measurements of healthy blood pressure, all without leak or abrupt rise or drop in pressure.

The second test would be to replace the heart of a pig bought from a slaughterhouse. If the pig can live for at least 1 year with only the artificial heart, then it's ready for FDA testing. If it doesn't, the pig was destined to be a ham sandwich anyway.

This heart could take some of the pressure off the need for hearts, as there are far more people in need of heart replacement than donated hearts.

EDIT: Since posting this story, I can find no new information about Mr. Wyngre. I'm going to assume that he passed away, but my point here still stands for other people with congestive heart failure or other need of heart transplant.

No comments:

Related Posts Plugin for WordPress, Blogger...