The Treatment of Blue Baby Syndrome

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The Treatment of Blue Baby Syndrome

Overview

In 1944 a small, frail child was wheeled into the operating room at Johns Hopkins Hospital in Baltimore. As the doctors prepared for surgery, the team in the operating room looked at the cyanotic (blue) 15-month-old girl, who hovered close to death. The operation she was about to undergo would be the first attempt to treat her congenital heart condition, which was called the tetralogy of Fallot or blue baby syndrome. The team consisted of surgeon Alfred Blalock (1899-1964), pediatric cardiologist Helen B. Taussig (1898-1986), and surgical technician Vivien T. Thomas (1910-1985).

The groundbreaking surgery took place on November 29, 1944. The operation joined an artery leading from the heart to an artery leading to the lungs, giving the sick child a vital oxygen supply and taking the necessary first step toward a complete surgical cure. The success of this procedure, known as the Blalock-Taussig shunt, made medical history.

Background

Even in the early 1900s the heart itself was thought to be inoperable, although medical procedures had improved to allow surgery on the arteries surrounding it. Alexis Carrel (1873-1948) had shown that a piece of aorta wall could be replaced with a fragment of another artery or vein. Carrel's observation of a lacemaker had helped him develop an effective way to sew vessels together, a process called anastomosis; in 1920 he transplanted an entire vessel by sewing the ends together. Robert Gross (1905-1988) of Boston performed the first successful surgery on one of the large vessels. All of these could be carried out while the heart was beating.

Congenital (present at birth) heart problems originate early in fetal development, probably within the first two months. The defect has little effect while the baby is in the womb because circulation and respiration are accomplished thorough the umbilical cord attached to the mother's placenta. However, at birth, when the child must use its own respiratory and circulatory systems, the deformities become life threatening. Before surgical intervention was possible, children who were born with heart abnormalities usually died or suffered severe disabilities.

The tetralogy of Fallot (ToF) or blue baby syndrome is a congenital condition. It was named for Etienne-Louis-Arthur Fallot, who first described the defect and its four components in 1888. The condition is outwardly characterized by a bluish discoloration of the skin called cyanosis, and accompanied by difficult breathing, and digital clubbing (short, blunt fingers).

Dr. Fallot identified the set of four (tetralogy) anatomical defects that comprised the syndrome after studying autopsies and postmortems performed on blue babies:

The pulmonary valve, between the heart and pulmonary artery, which enables the blood to pick up oxygen, was narrowed. This is called infundibular pulmonary stenosis.
The right ventricles were swollen or enlarged (from trying to pump blood through the narrow valve).
The heart had a large ventricular septal defect (VSD), literally a hole in the wall between the two ventricles of the heart; this allowed oxygenated and deoxygenated blood to mix.
The aorta (the main artery that sends blood to the rest of the body), normally on the left, had shifted to the right, sending blood from both sides into systemic circulation.

To understand why ToF is so lethal, you must first understand how a normal heart works: The heart muscle has an atrium and a ventricle on each side. The atria are the receiving chambers, the ventricles are pumps. The atria and ventricles are each divided into two chambers by a partition or wall called a septum. The wall between the two chambers of the atria is called the interatrial septum; the wall between the ventricles is called the interventricular septum.

The right atrium receives blood that has circulated through the body. Because this blood is deoxygenated (without oxygen) and also contains waste and carbon dioxide, it appears dark. (This is why veins appear bluish when viewed through the skin.) The blood then goes into the right ventricle where it is pumped to the lungs through the pulmonary artery. Here it picks up oxygen and gives off carbon dioxide. It travels through the pulmonary vein to the left atrium. This is called pulmonary circulation. The blood then flows from the left atrium to the left ventricle where, now rich with oxygen and bright red, it goes through the aorta, into the arteries, and out to the cells of the body. This is called systemic circulation.

Babies born with ToF are cyanotic, an indication their blood is not sufficiently oxygenated. Before surgical intervention became possible, one-fourth of children born with ToF died before their first birthday. Within 10 years 70% had died; only 5% survived past the age of 40. When the careers of three physicians came together in 1944, the procedure they performed would save many lives. The unique preparation of Blalock, Taussig, and Thomas allowed them to each contribute their talents.

Impact

After Blalock graduated from Johns Hopkins Medical School in 1922, he went to Vanderbilt University Hospital in Nashville as a resident in surgery. His research led him into pioneering work on how to overcome shock when much blood is lost. While working on shock, he created different conditions in dogs. In 1938 he did an experiment in which he joined the left subclavian artery to the left pulmonary artery to produce pulmonary hypertension. (The subclavian artery, at the back of the neck, supplies blood to the arm. The joining of the arteries is referred to as anastomosis.) The experiment failed and Blalock put aside his idea.

In 1941 he returned to Johns Hopkins as surgeon in chief and director of the department of surgery at the medical school. While there, he continued to work on a shunt technique that could be used to bypass an obstruction (coarctation) in the pulmonary artery. While at Vanderbilt in 1930, Blalock had hired Vivien Thomas, a young African-American who had been forced to leave college by a lack of funds. Thomas got a job in Blalock's surgery laboratory and soon became his right-hand surgical assistant. He learned to perform surgery, make chemical determinations, and keep precise records. When Blalock went to Baltimore, he took Thomas with him and the two continued their collaboration in research for 30 more years.

In 1930, Helen B. Taussig was appointed to head the pediatric cardiac unit at John Hopkins, the Harriet Lane House. She had been denied entry into Harvard Medical School because of her gender, but had been accepted at Johns Hopkins. Her studies of congenital heart conditions led her to discover the single-biggest problem with ToF: the lack of blood flow to the lungs.

One day in 1943, Taussig overheard a conversation between Blalock and a colleague about the difficulty of cross-clamping the aorta to repair a coarctation. The colleague wondered aloud if it would be possible to anastomose the carotid artery to the aorta below the obstruction. Taussig, inspired, then joined the conversation, asking, if that were possible, why couldn't you also put the subclavian artery into the pulmonary artery, and repair the biggest physical defect in blue babies?

Bells went off in Blalock's mind. He remembered the experiment he had done at Vanderbilt. He and Thomas went right to work to retry the experiment. Taussig believed that the pulmonary artery could be repaired and attached to a new vessel. She persuaded Blalock to work on the problem. During the 18 months, Blalock and Thomas worked on technical procedures using 200 experimental dogs.

Eileen Saxon was a desperately ill child in 1944, and it was obvious she would die if nothing were done. For Thomas the surgery came sooner than he wished because he felt the procedure was not yet perfected. But they had a dying child who could not wait. They wheeled her into surgery on November 19th. With Taussig as consultant and Thomas giving advice on technicalities and suturing, Blalock did the surgery. He took a branch of the aorta that normally went to the arms and connected it to the lungs. The child who had been so much at risk survived and gradually regained the normal color. After two weeks it was obvious the procedure was a success. Second and third operations were performed, and the success of each was apparent. Taussig described the third patient as "an utterly miserable six-year-old who could no longer walk." What a thrill it was for her to see the little boy with deep purple lips return to a happy, normal child.

In 1945 Blalock and Taussig published reports of their three successful operations in the Journal of the American Medical Association. The news caused a worldwide stir in the scientific community. Doctors from all over the world came to Johns Hopkins to learn their techniques. The operation became known as the Blalock-Taussig Shunt. While further operations were still necessary to repair the remaining ToF defects (the hole in the ventricular wall and narrowed pulmonary valve) patients were well on the road to a normal childhood.

The shunt is now widely performed and has saved thousands of children. The isolation and division of the subclavian artery, a time-consuming and difficult procedure, is rarely performed today. A polytetrafluoroethylene (PTFE) tube is most often used to create the shunt. The tube is sutured to the subclavian artery on one side, and the pulmonary artery on the other. The same effect is achieved but neither artery is interrupted; the risk of damaging nerves and disrupting blood supply to the arm is also lessened.

The feat of Blalock, Taussig, and Thomas is heralded as one of the great achievements of twentieth-century medicine. The three were recognized throughout the world and had numerous honors bestowed upon them.

EVELYN B. KELLY