Heart
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The person who contributed most to the invention of the heart-lung machine was a similarly generous, if ambivalent, soul. Toward the end of his first year at Jefferson Medical College in Philadelphia, John Heysham Gibbon Jr. considered quitting medicine to become a writer, a passion he’d nurtured since his college years at Princeton. His father, a pragmatist, advised him to obtain his medical degree, telling him (in advice that sounds very familiar) that he would not “write worse for having it.” So Gibbon persevered and received his MD three years later, in 1927.
During his internship at Boston City Hospital, he began to toy with the idea of “extracorporeal circulation.” One night, his research mentor, Edward Churchill, had him monitor a dying young woman who had developed a massive lung clot after a routine gallbladder operation. Churchill knew that incising the blood-filled pulmonary arteries to evacuate the clot, an operation called a pulmonary embolectomy, would almost certainly result in fatal bleeding. But isolating the heart to prevent exsanguination was not an option; without oxygen delivery, the brain would get irreversibly damaged within minutes. The pulmonary embolectomy operation was invented in 1908 by Friedrich Trendelenburg, a German surgeon, but none of his patients survived. “Twelve times we have done it at the clinic,” he lamented in 1912, “my assistants oftener than myself, and not once with success.” Noting this horrible mortality, Trendelenburg’s contemporary, the Swedish surgeon Gunnar Nyström, said, “Our rule is not to operate until the patient, as far as is humanly possible to judge, no longer has any chance of returning to life.”*
An early heart-lung machine, circa 1954 (Courtesy of Walter P. Reuther Library, Archives of Labor and Urban Affairs, Wayne State University)
So Churchill, stuck in a surgical catch-22, vacillated. Perhaps the clot would dissolve on its own or crumble and migrate down smaller arterial byways. Perhaps other areas of the lung would increase ventilation to compensate. He instructed Gibbon to notify him when the patient’s condition became so tenuous, so near death, that a Hail Mary operation would be justified. Early the following morning, as the patient’s blood pressure dived and she became unresponsive, Gibbon called his chief. The woman was rushed to the operating room but died on the table.†
Though Gibbon was a stoic researcher more comfortable around pipettes than people, he wept over that young woman. But in her death, he had a eureka moment. “During that long night,” he said in 1970, “helplessly watching the patient struggle for life as her blood became darker and her veins more distended, the idea naturally occurred to me that if it were possible to remove continuously some of the blue blood from the patient’s swollen veins, put oxygen into that blood and allow carbon dioxide to escape from it, and then to inject continuously the now-red blood back into the patient’s arteries, we might have saved her life. We would have bypassed the obstructing embolus and performed part of the work of the patient’s heart and lungs outside the body.”
Gibbon and his research assistant (and wife), Mary Hopkinson, essentially devoted the rest of their professional lives to this goal. His mentors discouraged him, believing that his outsized ambition would be better spent on a less risky project. Churchill himself took a “dim” view of the proposed work. In the medical academy, then as now, huge outlays of time and money for big ideas were frowned upon. In a publish-or-perish world, you had to get your name in the top journals with regularity. Gibbon’s mentors advised him to pursue iterative problems, problems whose solutions might tweak the existing paradigm but would not try to supplant it.
However, Gibbon had a stick-to-itiveness that was unusual, even for a medical scientist, and so he applied himself and forged on. The result was a thirty-year academic career devoted to one big idea. But it changed medicine forever.
What Gibbon faced was an engineering problem: how to drain blood from the body, oxygenate it in a machine of metal and plastic without forming clots,* and then pump it back into the body without air bubbles to nourish the vital organs. To solve this problem, he needed animals. He and Mary performed their early experiments on stray cats they plucked with tuna fish bait and a gunnysack from the streets of Boston. They went to the lab early in the morning because the preparations for their experiments took several hours. They would anesthetize a cat, perform a tracheotomy, and connect the animal to an artificial respirator. By mid-afternoon, they were ready to start the main demonstration: sucking blood out of the animal, circulating it through a machine while the heart was stopped, and then pumping it back into the animal to keep it alive. After much trial and error, they settled on the following scheme: isolate the cat’s heart by tying off the major veins and arteries; withdraw blood from a vein in the head at a rate of about half a soda can per minute; pass it in a thin stream down a rotating metal cylinder in an atmosphere of almost pure oxygen, which allowed the blood to pick up oxygen and give up carbon dioxide through diffusion; and finally collect the blood at the bottom of the cylinder, warm it, and return it to an artery in the animal’s leg via an air pump, which Gibbon purchased for a few dollars at a secondhand shop near the hospital. Mary later said, “We would keep the clamp completely occluding the pulmonary artery for as long as we thought the cat could stand it, or nothing went wrong with the apparatus, but things that were apt to go wrong were infinite.”
Their machine was, as Gibbon described it, an assemblage of “metal, glass, electric motors, water baths, electrical switches, electromagnets, etc. … [that] looked for all the world like some ridiculous Rube Goldberg apparatus.” It went through numerous refinements through the 1930s, eventually growing to the size of a grand piano. But inelegant as it was, it worked. By the end of the decade, Gibbon could keep cats and dogs alive for several hours and, most important, was able to wean the animals off the machine to resume their own heart and lung function. In 1939, Gibbon published his findings in a paper titled “The Maintenance of Life During Experimental Occlusion of the Pulmonary Artery Followed by Survival.” He later wrote, “I will never forget the day when we were able to screw the clamp down all the way, completely occluding the pulmonary artery, with the extracorporeal blood circuit in operation and with no change in the animal’s blood pressure. My wife and I threw our arms around each other and danced around the laboratory laughing and shouting hooray.” He added, “Although it gives great satisfaction to me and others to know that the [heart] operations are being performed daily now all over the world, nothing in my life has duplicated the ecstasy and joy of that dance with Mary around the laboratory of the old Bulfinch building in the Massachusetts General Hospital.”
Humans are a lot bigger than cats, however; we have roughly eight times the blood volume of a feline. So Gibbon began to think of ways to adapt his machine for human use. His research was interrupted when he was called to serve as a trauma surgeon in the Pacific theater from 1941 to 1945. After the war, when Gibbon returned to his project, major problems still needed to be solved. Blood cells were getting chewed up in the pump. Particles of protein, fibrin, fat, and gas were injuring vital organs. And of course, a larger machine was required to handle the greater blood volume in humans—no longer a soda can but a milk gallon. To help him solve these problems, Gibbon turned to the IBM Corporation, whose chairman, Thomas Watson, was the father-in-law of one of his students. With the aid of IBM’s engineers, Gibbon refined his machine: adding filters to catch clots, increasing the size of the oxygenator, and incorporating special roller pumps. The postwar years were ripe for such research. Large-scale public-private projects were being launched in computing, nuclear technology, and space exploration. Gibbon’s team took advantage of this political environment to essentially compress three billion years of evolution into two decades of intense human endeavor. By the early 1950s, the mortality rate in his animal experiments had decreased from 80 percent to 12 percent, and Gibbon believed the time had come to try his machine on a human being.
Gibbon wasn’t the only scientist working on a heart-lung machine. Between 1950 and 1955, five medical
centers were engaged in the pursuit, each with a different design. At the University of Toronto, William Mustard developed a machine that used isolated rhesus monkey lungs to oxygenate the blood. At Wayne State University in Detroit, Forest Dodrill and engineers from General Motors built a heart pump that looked very much like the engine in a Cadillac. At the Mayo Clinic, John Kirklin and his colleagues constructed a heart-lung machine based on Gibbon’s design that used a vertical oxygenator and roller pumps (it was eventually called the Mayo-Gibbon oxygenator). At the University of Minnesota, Clarence Dennis, a colleague of Lillehei’s, developed his own machine based on drawings that Gibbon had shared with him on a visit to Gibbon’s lab. Dennis would be the first to try the heart-lung machine on a human, six-year-old Patty Anderson, who would die on the operating table. His next attempt also failed when assistants let the reservoir run dry, pumping air into the patient’s arteries, killing her instantly. From 1951 to 1953, eighteen patients were reported to have undergone open-heart surgery with heart-lung machine support. Seventeen died.
It is only fitting that Gibbon, who conceived of the heart-lung machine and worked on it longer than anyone else, was the first, and not Dennis, to use it successfully on a person. Gibbon’s first attempt, after decades of animal experiments, proved tragic when the fifteen-month-old baby bled to death as he frantically searched for an atrial septal defect she did not have. (She had been misdiagnosed.) On March 27, 1953, he tried again, this time on Cecelia Bavolek, an eighteen-year-old freshman at Wilkes College in Pennsylvania. She had been hospitalized with heart failure three times in the previous six months. The surgery to repair her ASD took more than five hours. Managed by six assistants and weighing more than a ton, Gibbon’s machine took over the patient’s circulation for approximately thirty minutes while he sewed the half-dollar-sized hole closed with cotton sutures. The operation had an unexpected complication: the machine clogged because it ran out of blood thinner and had to be operated manually. When Gibbon took Bavolek off the machine, he had low expectations. But her young heart restarted almost immediately. One hour after he closed up her chest, she was awake and could move her limbs on command. Her recovery was uneventful, and after thirteen days, she was discharged from the hospital. She went on to live for almost fifty years, dying in 2000 (the year before I started my cardiology training) at the age of sixty-five.
John Gibbon and Cecelia Bavolek beside a heart-lung machine, 1963 (Courtesy of Thomas Jefferson University, Archives and Special Collections)
Though Time proclaimed that Gibbon had “made the dream [of open-heart surgery] a reality,” he was painfully shy and avoided publicity. He posed for a picture with his machine only after Bavolek agreed to join him. In the end, he published the only account of his operation in a little-noticed journal, Minnesota Medicine.
After the Bavolek surgery, Gibbon attempted four more with his heart-lung machine, with poor results. Though his research career was marked by tremendous perseverance and courage, after those four children died under his knife, he lost heart. Unlike Walt Lillehei, who never lost sight of the greater goal, even in the face of surgical deaths, Gibbon could not stomach putting young children at risk, even if it meant giving up on his lifelong project. He decided that his machine was too immature to be used safely and called for a one-year moratorium on its use. He never operated on the heart again. Research on his machine was taken up by universities and private companies. In 1973, he died of a heart attack while playing tennis.
Today heart-lung machines are barely the size of a small refrigerator. Hospitals have full-time staff to operate them. Of course, there are still complications: blood cells get chewed up in the plastic and metal apparatus and patients suffer strokes. A small but significant number of patients have some degree of cognitive impairment afterward, such as memory and attention deficits and language problems, a condition known as “pump head,” which can persist years after surgery and in many cases is probably irreversible. The cause is unclear but may include tiny blood clots or bubbles, inadequate blood flow to the brain during surgery, the dislodgement of fatty material from the aorta, and brain inflammation.
But despite these problems, the heart-lung machine has been indispensable for advancing the field of heart surgery over the past half century, saving countless lives. Open-heart surgery was already the beacon of American medical prowess in the early 1950s, and Gibbon’s invention only quickened the field’s progress. The mortality rate for cardiac surgery dropped from 50 percent in 1955, to 20 percent in 1956, to 10 percent in 1957. By the late 1950s, even the most complex congenital lesions were being repaired. “A physician at the bedside of a child dying of an intracardiac malformation as recently as 1952 could only pray for a recovery!” Lillehei wrote. “Today with the heart-lung machine, correction is routine.” The heart became, as one writer put it, “an object of surgical assault.”
Perhaps my own family history would have had a different trajectory had Gibbon’s invention been ready for my grandfather, who surely had coronary artery disease and almost certainly died of a coronary thrombosis. Alas, the field would have to wait until 1960, when the first successful human coronary artery bypass operation was performed by Dr. Michael Rohman in the Bronx. In 1967, René Favaloro performed the world’s first coronary bypass surgery at the Cleveland Clinic using veins from the leg to bypass the coronary obstructions, the standard technique still in use. Today more than one million cardiac operations are performed annually worldwide—three thousand a day—with the heart-lung machine.
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One of those operations was that valve surgery in Fargo on Christmas Day. It had been going on for more than two hours when Dr. Shah finally cut out the infected valve with a pair of scissors. I’d been standing quietly next to him the whole time, my legs increasingly heavy and sore, wondering when the operation would end. Shah put green-and-yellow Gore-Tex threads, the same stuff in my winter jacket, through the cloth ring holding the prosthetic tissue valve. It was a mess, like the tangled ropes of a parachute, a topological nightmare, but when he slid the new valve down the circular array of stitches, the sutures straightened out and the valve went right into place.
When he was finished, he tipped the head of the table down so if there was any air in the heart, it would travel upward, away from the brain. The perfusionist turned a dial, and the flow of the heart-lung machine slowed. When Shah took the clamp off the aorta, blood started to flow down the coronaries, washing out the potassium solution that had made the heart fibrillate. The heart began to beat weakly, almost in synchrony with the labored breathing of the ventilator. Shah removed the remaining tubes from the chest. Then, with stainless-steel wires, his assistant closed up the breastbone.
We were done. I was so relieved, mostly for the patient but also, I must admit, because I wanted to go home. It was nearly five o’clock in the morning, and I could barely stand. But Shah looked worried. The patient’s blood pressure was 70/40, dangerously low. The heart hadn’t quite resumed adequate function. After conferring with the anesthesiologist, he inserted a helium-filled balloon pump into the aorta to support the blood pressure. With a pained expression, he sat down on a stool next to the still-unconscious patient and waited.
I waited, too, for a while, hoping something would happen so we could call it a night. By then Shah was ignoring me. I went to the locker room to change. Some time later, a nurse woke me up on the hard bench and told me she was going to take me home. We drove quickly along slushy roads coated with what looked like mashed potatoes and gravy. The sun was rising, and the trees along the road carried the weight of several inches of snow that had fallen during the night. She dropped me off at my parents’ house. I went in and immediately crashed.
Shah never called me to tell me what happened, but the next day I heard from my parents that the patient never made it out of the OR. His blood pressure continued to drop, despite the balloon pump and intravenous medications, and around seven that morning, nearly seven hours after we’d arrived at the
hospital, he died, another victim of endocarditis, Osler’s great killer. It was an important lesson for me at that early stage in my career. No matter the extraordinary progress that has been made in heart surgery over the past century, the heart remains a vulnerable organ. Despite our best efforts, cardiac patients still die.
*Edward Churchill himself said in 1934, “Although our enthusiasm is somewhat dampened by a series of ten failures, we shall continue to recommend the Tren-delenburg operation under favorable circumstances.”
†The first successful pulmonary embolectomy in America took place at the Peter Bent Brigham Hospital in Boston on January 14, 1958, well after the invention of the heart-lung machine.
*The clotting problem was solved with the use of heparin, a blood-thinning protein discovered by Jay McLean, a medical student at Johns Hopkins, in the brains of salamanders. (The substance was initially called cephalin.) In the 1920s, animal experiments confirmed that heparin was an effective anticoagulant.
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The contemplation of the period when arterial disease of the heart can be prevented or retarded produces an aura of greatness. Next to food, shelter, and the absence of war, there is probably nothing more important.
—Claude Beck, Journal of Thoracic Surgery (1958)