The Rise and Fall of Modern Medicine (15 page)
Read The Rise and Fall of Modern Medicine Online
Authors: James Le Fanu
Strictly speaking, this was not the first âblind' operation. Before the war a similar procedure had been attempted on the left side of the heart to relieve narrowing of the mitral valve. In 1923, Elliott Cutler in Boston had inserted a knife through the ventricle of a twelve-year-old girl to dilate her tight mitral valve.
7
Henry Souttar in England repeated the same procedure two years later.
8
Cutler's next few patients did badly and he became so discouraged that he gave up the operation. As for Souttar, he never performed another as his colleagues at the London Hospital were so shocked at his impudence in performing an operation on the heart (though the patient did well) that they never referred him another case. Bill Cleland, Britain's leading heart surgeon in the 1960s, believes it was âjust as well' Souttar was never given the chance to repeat his operation: âFor disaster would surely have ensued . . . there was no blood transfusion service, no antibiotics and appropriate anaesthesia for heart surgery had not been developed.'
9
By 1945, thanks to the necessities of war, these essentials for heart surgery were all available and the heart was no longer seen as a surgical âno-go area', since an American thoracic surgeon, Dwight Harken, based in England in the final year of the war, had shown it was quite possible to remove bullets and shrapnel from the heart without killing the patient.
10
Returning to the United States, Harken repeated Elliott Cutler's operation on the mitral valve on the left side of the heart, the same year that Russell Brock and Holmes Sellors performed the first pulmonary valvotomy.
11
The surgeons, however, soon realised that operating on the heart was âdifferent', for whereas there had been remarkably few complications following Blalock's operations, six of Harken's ten patients did not survive. He subsequently recalled:
This was so devastating that with the tenth patient and my sixth death, I left the operating theatre, insisting I would never do another heart operation. I went home and to bed. The late Dr Laurence Brewster Ellis, my wonderful cardiologist friend and collaborator, drove to our house and asked
my wife if it were true that I had said I would never do another heart operation. She confirmed this and he asked if he could see me. She urged him to wait until the next day. The next day, I again insisted I intended to do no more heart surgery, he said, âI think that would be very irresponsible of you.' I replied, âWhat in the world is irresponsible about that? I refuse to kill any more people.' He said, âYou have never killed anybody. I have never sent you a patient who wasn't dying.' I replied that, âI would not expect any responsible physician to send me another patient.' He replied, âI am President of the Heart Association and generally regarded as responsible. I would certainly send you patients and I would criticise you if you did not operate. You must have learnt something from those six disasters.' I went back to work and we lost only one of the next fifteen patients.
12
This pattern of initial disaster followed â if a surgeon kept his cool and carried on â by ultimate success is difficult to explain other than in terms of the âsteep learning curve': with repetition everything gets easier and heart surgery is no exception. The precedent of this pattern was to be important in the next phase of cardiac surgery, in encouraging surgeons to persist even though at times their operating theatres resembled killing fields.
By 1950, these âblind' operations had reached their intellectual limits and, taking Fallot's Tetralogy as the paradigm of the evolution of cardiac surgery, the next step was to combine dilating the narrow pulmonary valve with repairing the hole in the wall of the ventricle. This could only be achieved by âopening up' the heart so its interior could be closely scrutinised. The brain is irreparably damaged if deprived of oxygenated blood for five minutes, but the simplest open-heart operation takes fifteen minutes. Hence the whole future of cardiac surgery depended
on whether or not the ten minutes' difference (at least) could be bridged, and here there were essentially two possibilities. Cooling the body, or âhypothermia', prolongs the length of time the circulation can be interrupted, because cold reduces the brain's requirement for oxygen. The alternative is the pump. In the early 1950s both had their advocates, but the pump ultimately proved to be the better option.
The story of the pump starts in Massachusetts General Hospital in February 1931, when a 28-year-old junior research surgeon, John Gibbon, spent a night sitting by the bedside of a woman who had had a gall bladder operation fifteen days earlier. Both the operation and her convalescence had gone smoothly until she was struck by the most serious of complications of major surgery, a pulmonary embolus, or clot in the lungs. The clot, which originates in the veins of the leg, breaks off and is carried to the right side of the lung to lodge in the pulmonary artery, preventing blood passing into the lung. If the clot cannot be dissolved or removed surgically, the circulation of the blood is effectively interrupted, blood cannot get into the lungs to receive oxygen and the patient dies. John Gibbon subsequently recalled his reflections during his nocturnal vigil:
My job that night was to take the patient's blood pressure and pulse rate every fifteen minutes and plot it on a chart . . . during the seventeen hours I was by this patient's side, the thought constantly recurred that her hazardous condition could be improved if the blue blood in her veins could be withdrawn into an apparatus where it could pick up oxygen and discharge carbon dioxide and then pump this blood back into the patient's arteries. At 1 a.m. the patient's condition became worse . . . Dr Edward Churchill [Director of Surgery at Massachusetts General] immediately opened the chest and
opened the pulmonary artery with a long incision and removed massive blood clots. All this took place in the space of six minutes and thirty seconds, a fact carefully noted by me, the rather green surgical fellow standing at the head of the table beside the anaesthetist. Despite the rapidity of the operation, the patient died on the operating table and could not be revived.
13
Gibbon's âboss' Edward Churchill apparently âtook a dim view' of his young research registrar's idea of âan apparatus where the blood could pick up oxygen and discharge carbon dioxide'. This was scarcely surprising as, with the exception of a Russian, Professor S. S. Brukhonenko, who had performed some crude experiments with dogs (the development of the pump was to be an anti-vivisectionist's nightmare), no one else had tried to develop such a machine, for the obvious reason that the technical problems involved were so vast.
Some notion of how fantastical Gibbon's idea must have seemed to his contemporaries can be gleaned from reflecting on the structure of the lungs. The air sacs, if they were to be dissected out and laid side by side, would cover an area the size of a tennis court. This great space is necessary to accommodate the blood flowing through the lungs that must pass through minute capillaries in the lining of the air sacs, where it absorbs oxygen and gives up carbon dioxide. It was impossible at the time to conceive that a mechanical oxygenator could be built of sufficient size to ensure adequate amounts of oxygen reaching the blood. Further, the blood cells themselves, by being exposed to the mechanical stresses of the pump, were readily fragmented and destroyed.
But as absurd as Gibbon's idea might have seemed to his contemporaries, he would not be dissuaded and âover the next three
years I had this idea constantly in the back of my mind'. In 1934 Edward Churchill, despite his scepticism, finally agreed to give Gibbon a further year as a research fellow, and he was joined in the laboratory by Mary Hopkins, one of Dr Churchill's technicians, whom he had recently married. It was to be an unusually intimate scientific collaboration. They started by trying to work out the many factors that influenced the circulation of the blood:
My wife and I experimented on ourselves and on friends. For instance, to find out how constriction and dilatation of the vessels in the extremities could be caused by a slight shift in body temperature, my wife, and I know this sounds odd, would stick a highly sensitive thermometer into my rectum after which I would swallow a stomach tube. She then poured ice water down the tube and measured the effect of this on temperature.
14
Gibbon's first pump had three main components. He purchased an air pump to impel the blood around the circuit for a few dollars from a second-hand shop in East Boston. Then he used glass tubes (as plastic had not yet been invented) to transport the blood to and from the oxygenator with valves fashioned from a rubber cork to ensure it flowed in one direction. Finally, the oxygenator itself was a rapidly rotating drum whose centrifugal forces flattened the incoming blood to form a thin layer on the inner surface where, being exposed to the air, it took up oxygen.
Gibbon's early experiments were performed on cats, and when they were in short supply he âwould prowl around the local area at night with some tuna fish as a bait and a sack to catch any of the numerous stray alley cats which swarmed over
Boston in those days'. The easiest experimental means of testing whether the pump could take over the action of the heart and lungs was to place a clamp around the cat's pulmonary artery, thus interrupting the circulation and diverting the blood into the oxygenator. The experiments themselves were arduous and time-consuming:
We were at the laboratory bright and early. We had to bring a cat down from its upstairs quarters, anaesthetise it, perform a tracheostomy and connect the animal up to [a mechanical ventilator] . . . next the [heart] vessels were exposed and an open clamp placed over the pulmonary artery. These preparations usually took from four to five hours, so it was mid-afternoon before we were able to start the critical part of the experiment . . . the things that were apt to go wrong were infinite . . . We would terminate the period of [clamping] of the pulmonary artery, put the cat back on its own circulation, and see whether it would maintain its blood pressure at a near normal level. If it succeeded in doing this, the animal was nursed tenderly for an hour or two . . . then it was sacrificed, autopsied, the instruments and general mess cleaned up, and we could go home â a long day.
To the Gibbons' apparent astonishment, the first year's experiments were not entirely in vain:
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 pump 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 âHurray!' That year, then, marked
the first successful demonstration that life could be maintained by an artificial heart and lung outside the body, and that the animal's own heart and lungs could again maintain the circulation.
15
The pump may have worked but the cat invariably died a few hours later. It was not until 1939, after a further four years of experimentation, that they were able to report as âlong-term survivors' three out of a series of thirty-nine cats who had survived a year or more.
16
But then the war came. Though many areas of medical research benefited enormously from the years of conflict, the pump was not one of them, as the general opinion still prevailed that the heart was simply âbeyond the reach of surgery'. Immediately the war was over, Gibbon, now Professor of Surgery at the Jefferson Medical College in Philadelphia, started again. His most difficult problem was how to increase the capacity of the pump. It was one thing to keep a cat alive for a few hours and even have a handful of long-term survivors, but a small animal only had a small blood volume. It was quite another to design a machine that would cope with that of humans.
Progress was very slow but by 1948 Gibbon had started experimental heart surgery in dogs, making an incision in the wall of the two ventricles to simulate a âhole in the heart' and then sewing it up again. Certainly very few of the dogs survived, but aspirant heart surgeons such as John Kirklin realised by now that âclosed' cardiac surgery had already reached its limits and that progress would require a machine such as Gibbon had been developing:
My fellow residents and I filled pages of notebooks with drawings and plans of how we would repair Fallot's Tetralogy
once science gave us a method to get inside the heart . . . at a meeting of the American College of Surgeons in 1948, Dr John Gibbon presented an update on his experimental studies and I can clearly recall his saying that âwe are encouraged and believe some day the heart/lung machine will be a practical affair'.
17
It seemed as if John Gibbon's hour had finally arrived, but when it came to operating on humans the results were so uniformly disastrous it began to look as if open-heart surgery was, as the sceptics had claimed all along, a fantasy. Gibbon performed his first open-heart operation on a child in 1952 and a further three the following year. Only one survived. The first patient was a fifteen-month-old baby who was thought to have a defect in the wall separating the two atria, but during the operation an entirely different abnormality was found. Gibbon botched the operation and the child died. In May the following year, he performed his only successful open-heart operation, on an eighteen-year-old woman, Cecilia. Her circulation was sustained by the pump for just under half an hour while a hole between the two atria of her heart was closed by continuous silk suture. His next operation was on an eighteen-month-old girl, but âa cardiac arrest occurred after we had opened the chest'. Her heartbeat was restarted and she was attached to the pump; the abnormality was repaired, but âthe heart never recovered normal function'. In his final operation the diagnosis, as with the first, was incorrect: âThe heart flooded with blood . . . you could not get a clear field to work and the flow of bright red blood was so excessive.' They were unable to proceed and the child died. It is clear from Dr Gibbon's own account of these operations that he felt he was out of his depth, with neither the surgical skills nor the psychological stamina to continue. After
the panic and helplessness no doubt induced by this last operation, with blood spurting everywhere, he decided to call it a day. Not only did he never again attempt open-heart surgery but there was also the impression that he was deeply discouraged. Though still only fifty-three, his scientific career was over and the account of these operations was the last paper to be published from his research laboratory.
18
