The Atomic Heart

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RTH
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Joined: Wed May 28, 2008 12:35 pm

The Atomic Heart

Postby RTH » Thu Oct 09, 2014 11:05 pm

In 1966 in South Africa, Dr. Christian Barnard did the world’s first heart/lung transplant from a car accident victim to a man who’s heart was failing. The recipient lived for 3-4 days and even walked around the hospital room. Little was known about tissue rejection then, so the man’s body could not tolerate the heart and he died. Immediately in the USA, DeBakey in Texas did a similar transplant and the medical race was on to solve rejection problems and allow more successful transplants.

And then the lawyers here got into it. “How did you know that by giving the victim an asprin that he wouldn’t recover? You docs are killing poor car crash victims by taking out their hearts…” and so the work stopped.

Donald Douglas had always thought about peaceful uses of atomic energy and had a 75 person lab in Richland, WA. near the Hanford area where nuclear development of the atomic bombs had begun. He thought about the legal matters of the transplants and decided that if a mechanical heart could be built, it would eliminate the lawyer problems. Douglas called the lab and told the Director he wanted a team assembled to make an atomic powered heart under funding from the National Heart Institute and Douglas Aircraft Co. A five-man team was formed and I joined it about 6 mos. later to provide materials engineering help.

This was a really challenging design about the size of a softball. The basis was an atomic pellet that produced 1200F heat, surrounded by a salt bath of lithium hydroxide, chosen because of it’s high specific heat and radiation protection. But when hot, this salt can eat thru almost anything and had to be contained in a tantalum shell. Next to that was a Sterling piston pump that operated between the 1200F and blood temp of 99F to produce a pulse of gas that was routed to a bladder pump with newly discovered Teflon ball valves on each end. The gas pulse compressed the bladder and pumped blood around the body. Sounded good on paper but making it happen was a different story, especially within the size constraints.

We got the blood pump built and put it into a 6 mos old calf which has the same blood flow requirement as an adult human. Calf was fine for 6 weeks until it dropped dead. Autopsy showed that it’s spleen and liver were filled with dead blood cells. Turns out that the Teflon ball valves were closing on each pump and making line contact with the seat. Each closure was killing blood cells faster than the organs could clean them out. One of the guys suggested using a softer material and we tried pigskin as the valve seat. It worked better and I believe to this day, pigskin is still used in heart valves.

I was assigned to come up with a speed control for the heart. The pellet was radioactive and if too large, would poison the person. So the person had to slow-down the heart at night for sleeping, which allowed the excess energy to be absorbed by the heat of fusion of the salt. In the daytime, the heart had to run faster so the person could function and that heat was pulled from the salt and it partially solidified. A simple valve controlled the gas to the blood pump and I had to come up with a way of moving that valve from outside the body. My solution was to devise a magnetic coupler- a magnet on the valve and piece of wood outside with another magnet on it, like TV remote. We took the valve and “remote” to a meat shop and found a slab of meat hanging in the cold room with same thickness as a human. Placed the parts on either side and turned the remote; the valve opened and closed. I claimed it a success!

The project was halted after 2 yrs because we could not get the efficiency high enough to be viable. We calculated our’s was 11% and needed 35% to be effective. But the small team did some pretty amazing engineering work and I was proud to be part of that.
You just never know what challenges may come your way if you are open to try ideas.
Bob H

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