Part VII – Dr. Richard DeWall and Bubbles – Standing on Tall Shoulders – The History of Cardiac Surgery by Thomas N Muziani PA-C, CP

“I say there is no darkness…but ignorance.” –William Shakespeare

Walt Lillehei’s research lab in the basement of University of Minnesota felt like Penn. Station with the superfluity of activity. Richard DeWall had become fully engrossed in attempting to create a completely functioning bubble oxygenator. The “no money available” response he would receive every time he talked with Dr. Lillehei became kind of their running joke. In reality, DeWall was having a great time admiring his Rube Goldberg* contraption that he called heart-lung machine with oxygenator and heat exchanger.

Along this path, DeWall realized each experiment provided valuable lessons about bubble management. He discovered that bubbles naturally rise to the top in any oxygenating system and can be kept safely away from the patient by drawing blood from the bottom of the reservoir. Armed with this knowledge and realizing he was treading straight into the “thou shall not use bubbles to oxygenate blood” dictum that Dr. Lillehei admonished him with, Dr. Richard DeWall was sending bubbles of oxygen through a helical reservoir of blood. The blood was becoming oxygenated, CO2 was blowing off through the top of the oxygenator and there was very little turbulence or foaming. These were major obstacles during the 1950’s.  The goal of creating a machine that would take over the function of the heart, lungs, anesthesia and temperature management was now developing into fruition.

On the issue of CO2 extraction, DeWall conveyed great pride in his solution, especially since he did not spend a dime on the answer. He realized that carbon dioxide is 20 times more soluble in blood than oxygen. Factoring this in, he reasoned that fewer large bubbles of oxygen would present a smaller total surface area for reaction than more numerous smaller bubbles. Therefore, he created larger bubbles by pumping oxygen through 18 large-bore No. 22 needles that he had pushed through a rubber stopper.

Dr. Richard DeWall’s glorious oxygenator was published in a medical journal in 1955 and said:  “Surgeons at the University of Minnesota began using a bubble oxygenator, which cost less than $15.00 and will serve as a temporary replacement for the human lungs during direct-vision intracardiac surgery”.

However, as serendipity always seems to prove, it was the simple construction due to an essentially zero budget that made DeWall’s oxygenator so appealing. Contrasted to Mayo Clinic’s model that required four technologists to operate the heart-lung machine and oxygenator, and was beyond the financial means of most hospitals to purchase.

The simplicity and low cost of Dr. DeWall’s heart-lung machine and oxygenator aroused a great deal of skepticism and suspicion. The frugality and pragmatic nature that exemplified Midwesterners, once again, cast doubt and derision in the medical community. I had the privilege to be a close friend of Richard Jensen who was Lillehei’s and DeWall’s perfusionist and also the first president of the American Society of Extracorporeal Technology (the society for perfusionists). Richard and I spent many hours testing the veracity of numerous wines while talking about his days at University of Minnesota. To the casual observer, the machine and oxygenator appeared to be a pile of junk. The original version was placed on a patient gurney for mobility, which did nothing to convey “quality” in its appearance. It looked like a pile of garbage ready for transport out to the trash. DeWall and Lillehei thought it was hilarious.

As DeWall told Dr. William S. Stoney during an interview that was one of a series conducted on the history of cardiac surgery by the Annette and Irwin Eskind  Biomedical Library at Vanderbilt Medical School: “My oxygenator was kind of a Rube Goldberg affair. It was really bizarre, looking like a bunch of tubes gathered in a heap and on a stand. Every bend and every curve, and every piece had a purpose in it,” DeWall added: “but, if you didn’t know what the purpose was, it looked strange and peculiar”.

Unfortunately, many hospitals and individuals attempted to replicate its functions and failed. When you live intimately with an inanimate object for some time, such as a heart-lung machine and oxygenator, it will either begin to “speak” to you or you will end up clueless. When I first started in 1968, I carried a stethoscope around my neck. Not to listen to hearts, although that came later in the case. It was to listen to my heart-lung machine. The rubber pulleys that operated the roller heads that connected them to the motors were also used in helicopters. They had a tendency to slip making that sound your fan belt would make in your car and you could hear that sound with the stethoscope long before that slippage would actually occur. I also carried a percussion hammer, the same type your doctor uses to check your reflexes. Only the purpose for my percussion hammer was to tap out bubbles that would stick in my filters and tubing. My running joke was: “Always use the appropriate instrument for its intended purpose”.

As a result of the perception that only Lillehei’s group could operate the machine and oxygenator, a major figure at the time urged surgeons not to use it. The criticism would have proven the death knell for the widespread use the DeWall-Lillehei Heart-Lung machine and oxygenator had not Dr. Denton Cooley come to its defense. Once Denton Cooley reported his great success using it in 125 cases, DeWall said: “That was the end of the discussion”.

Over the next few years, DeWall’s oxygenator quickly spread around the globe and its simplicity of use made it a favorite in countries that found exotic parts difficult to purchase. Dr. Richard DeWall and Dr. C. Walton Lillehei’s names became etched in the Pantheon of history in Cardiac surgery.

As another interesting side note: Observing from the notes and discussions of Dr. Wilfred Bigelow on pacemakers, Earl Bakken, another brilliant engineer, teamed up with C. Walton Lillehei to introduce the first transistorized, wearable permanent cardiac pacemaker for clinical use in 1957. Earl Bakken went on to co-found Medtronic. In addition, Lillehei and colleagues developed 4 prosthetic heart valves, including the Lillehei-Kaster and St. Jude Medical prostheses.

During the ensuing years, many of the world’s finest surgeons acquired their collective empirical knowledge at University of Minnesota and Mayo Clinic. Drs. C. Walton Lillehei and Richard DeWall blended the best of academic and industrial aspects of surgery to produce many fine surgeons. As Dr. Denton Cooley once stated: ” Dr. Lillehei was a true visionary surgeon who created a favorable environment uncluttered by the cobwebs of tradition”.

The widespread practice of surgery had been so profoundly affected by the meteoric developments in cardiac surgery that in July of 1959, “recognizing the great advances in cardiac surgery,” the title of the Journal of Thoracic Surgery was changed to Journal of Thoracic and Cardiovascular Surgery.

Almost overnight, you could watch surgeons who coveted the chance to operate in the “Heart Room” in order to utilize higher quality cautery equipment, improved and extra overhead surgical lights and monitoring equipment that was a shade above a blood pressure cuff and water monometer. They would even tell their patients with great pride: “We’re going to be in the high tech room tomorrow”.

 

 

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Perfusion Theory is an educational platform for the Oxygen Pressure Field Theory (OPFT). August Krogh’s theoretical concept of the oxygen pressure field is explained and then applied to clinical applications in perfusion practice.