The DeWall – Lillehei Oxygenator

Lillehei’s apparatus was nothing like the complicated monstrosity Alec had seen Gibbon employ at Thomas Jefferson Hospital in Philadelphia; Lillehei’s machine was, indeed, simple. Save for the T-6S pump which was available from a small company in New York, Lillehei’s bubbler had no moving parts. It could be easily sterilized, or given the cost of the materials, treated as disposable.

Like all historical fiction, The Stars That Govern Us blends history and imagination. This article offers a brief history behind the heart-lung machine Alec and Pete copy in the story, “The DeWall-Lillehei Oxygenator.”

My idea for this novel was to have two young surgeons at a public hospital build their own heart-lung machine. At first, this seemed like a fanciful impossibility, given just how high-tech these machines were.

Initially, I should note the quest to build the machine to take the heart’s place during surgery began prior to World War II and is well-documented; in addition to the articles and reports written by the surgeons themselves both at the time and retrospectively (many of the early heart pioneers have only died in the last decade or two), several authors have written excellent non-fiction books detailing the heart-lung machine’s invention. These books and articles, most notably G. Wayne Miller’s, The King of Hearts: The True Story of the Maverick Who Pioneered Heart Surgery, proved instrumental in researching my novel and I highly recommend the “Sources” list that appears in the back of my book for anyone who wishes to dig further into this fascinating period.

In May 1953, Dr. John Gibbon performed the first successful open-heart surgery using extracorporeal perfusion. Built and financed by IBM, Gibbon’s machine was a film oxygenator design. (New tab: View a picture of Gibbon’s machine at the Smithsonian.)

“They’re working on a film oxygenator,” Pete said. “A film oxygenator exposes oxygen to a film that flows o’er a series of steel rollers. That design is prone to clogging and is far more complex.”

Film oxygenators were indeed complex and difficult to operate. Inefficient, requiring large priming volumes of blood to run, and prone to causing excessive hemolysis and bubbles, the machine also had to be broken down after each use and sterilized before being reassembled again. And, not only that, but these machines cost thousands of dollars to produce. Gibbon could not reproduce his success, however, and researchers continued the quest for a better alternative. The design Alec and Pete end up copying, the DeWall-Lillehei Oxygenator, was one of those alternatives.

“This is a simple bubbler. Safe and effective. And it’s something we could build.”

Richard DeWall (1926-2016; he was just a year younger than Alec) joined C. Walton Lillehei’s team in the 1950s as a newly minted MD and a lowly animal attendant. Tasked with occasionally managing pumps or other equipment used in cross-circulation operations while the anesthesiologists took breaks, DeWall became fascinated with the problems associated with oxygenating blood. In 1955, DeWall came up with a new design — a bubble oxygenator. (New Tab: Dr. DeWall and his oxygenator.

“You’ve never judged a science project that can take the place of the human heart and three billion years of evolution.” Alec spoke smoothly, his smile firmly intact. “We wanted to have something up and running. The machine needn’t win a beauty contest.”

In the novel, Alec’s boss, Henry Miller, derides the design as looking less sophisticated than a kid’s science project. While that is typical blustering hyperbole from Henry, the machine Alec and Pete build was, indeed, simple. Costing just $15 (excluding the pump), DeWall’s design may not have looked like much (especially compared to Gibbon’s computer-like machine) but it was easy to use and ingenious in its design.

A picture of the Lillehei-DeWall Oxygenator from the original 1955 article that inspired Alec and Pete.

Powering the machine was the Sigmamotor T-6S pump. (The Buffalo, New York Sigmamotor Company is still in business making medical equipment and has a copy of the brochure for its heart-lung machine pump that appeared in a medical journal. View the brochure in a new tab.)

Admittedly, the T-6S wasn’t much to look at, but Alec had done the research—this pump, with its twelve internal metal fingers for gently separating streams of liquid, just like the human heart could, was worth every bit he paid for it out of his department’s tiny research budget. He traced the smooth curves with his index finger, almost reverently.

The pumps Lillehei and his team started out using were originally designed for the dairy industry and were even used in making mayonnaise!

And how did the machine work? Alec explains the first steps.

“Blue blood from the patient is fed into this mixing tube. The machine creates large, visible bubbles using eighteen intravenous needles attached to an oxygen tank. Gas exchange occurs just as it does in our lungs, with carbon dioxide being released while the oxygen from the bubbles is absorbed. Blood with bubbles is, of course, lighter than blood without bubbles, so the lighter blood rises to the top and is separated.”

Of course, bubbled blood can lead to air embolisms. An air embolism is a gas bubble that becomes trapped in a blood vessel and blocks it; these blockages, depending on where they occur in the body, can be fatal. (As anyone who is a diver can readily attest to.) To help prevent an air embolism, a Dow agent, known as Anti-Foaming A, was used, as Pete explains.

“The newly oxygenated red blood flows past an anti-foaming agent,” Pete continued, taking the baton. “The dairy industry uses this agent to prevent frothing in skim milk. Gabe acquired us the same agent used in the States.”

And to ensure the machine did not leave behind microscopic bubbles, Lillehei did animal tests — which Alec and Pete end up again copying by operating on four lambs.

Alec concludes how the machine works:

“The blood then travels down this long plastic hose,” Alec said. “As the blood descends, any remaining bubbles rise and burst. The blood which drips into this reservoir is bubble-free. The pump massages the bubble-free arterialized blood through this tubing back to the patient.”

And what type of hose did Lillehei and his team use? None other than beer hose!

Not only was the DeWall-Lillehei Oxygenator safe and easy to build, but it was also effective. By 1957, Lillehi had performed 350 operations using this heart-lung machine. The era of open-heart surgery using heart-lung machines had begun in earnest. (New tab: View a picture of open-heart surgery using the DeWall-Lillehei Oxygenator.)