One of the “boldest and most successful feats of man’s mind…not a deus ex machina but a machina a Deo.”
Although it may be hard for most people alive today to fathom, there was a time when congenital heart disease ranked among the top ten leading causes of death in the western world. It is thanks to medical pioneers, patients, and parents that this is no longer the case.
Approximately one in every 40,000 live births results in a child born with congenital heart disease–that’s about 1% of every child born. About one in four of these children will be born with a critical heart defect. Today, about ninety-seven percent of children born with a critical heart defect survive to adulthood.
As is the case with cancer, there are many different types of congenital heart defects. Defects can involve the heart’s valves, inner structures (such as the atrial or ventricular walls), muscles, or blood vessels. The most common type of heart defect is a ventricular septal defect (VSD). About fifteen percent of CHDs are thought to be associated with genetic conditions; for example, there is a link between CHD and Down’s Syndrome. Consumption of alcohol during pregnancy or certain illnesses (such as rubella) can also cause a child to be born with CHD, although in many cases, the cause is unknown.
For most of human history, surgeons did not dare to operate on the heart. However, by the 1920s and 1930s advances in anesthesia, blood transfusions, antibiotics and antiseptics, and overall knowledge had opened the opportunity for surgeons to attempt to repair, or at least palliate, simple congenital defects. World War II pushed the field forward even further.
But the heart’s role as the pump at the center of the circulatory system remained the salient obstacle to repairing defects. Oxygen is the molecule which fuels life; without a steady stream of oxygen, the body’s organs shut down and death occurs. This is why when the heart stops, we stop soon thereafter.
Surgeons thus needed something to take the heart’s place during surgery. While Alec and Pete are my creations, the machine they decide to build in The Stars That Govern Us, the DeWall-Lillehei Oxygenator, is based solidly on fact.
In May 1953, Philadelphia surgeon Dr. John Gibbon performed the world’s first successful open-heart surgery using extracorporeal perfusion, correcting an atrial septal defect. (New tab: View a picture of Gibbon’s machine at the Smithsonian.) Gibbon’s machine, which was built and financed by IBM, was of a film oxygenator design. It was complicated and difficult to run, however, and when Gibbon could not reproduce his success, he abandoned his quest to perform open-heart surgery.
While Gibbon ultimately gave up, others took up the mantle. In the early 1950s, at the University of Minnesota, a young doctor named Richard DeWall joined C. Walt Lillehei’s world-class cardiothoracic team as a lowly animal attendant. Tasked with occasionally managing pumps or other equipment used in Lillehei’s cross-circulation operations while the anesthesiologists took breaks, DeWall became fascinated with the various problems associated with oxygenating blood. Through tinkering and experimentation, DeWall devised a bubble oxygenator.
(New Tab: Dr. DeWall and his oxygenator.)
DeWall’s machine wasn’t much to look at; in the novel, Alec’s boss, chief of surgery Henry Miller, derides the design as looking like a child’s science project. Indeed, the DeWall-Lillehei Oxygenator, as it came to be known, was simple.
A picture of the Lillehei-DeWall Oxygenator from the original 1955 article that inspired Alec and Pete.
The machine’s components, save for the pump (view the brochure for the Sigmamotor pump in a new tab), cost only $15. Alec explains how the machine worked:
“Blue blood from the patient is fed into amixing 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.”
The main fear with this design was that “bubbled blood” would 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. To help prevent air embolisms, a Dow agent, known as Anti-Foaming A, was used.
Alec concludes how the machine works:
“The blood then travels down this long plastic hose. 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? Well legend has it they used beer hose!
By 1957, Lillehi had performed 350 operations using this heart-lung machine; pioneering surgeons around the world, like Alec and Pete, soon followed.
(New tab: View a picture of open-heart surgery using the DeWall-Lillehei Oxygenator.)