How Doctors Think (18 page)

Of course, individuals for whom faith is not a cornerstone can find the resilience to endure and sustain the presence of mind to search for information and parse the logic of their doctors. They often employ strategies that mirror those of religious people. Instead of "praying on" a problem, they shift their mind to quietly contemplate the complexities of an issue. While Rachel Stein looked to God as her best friend, a trusted ally, agnostics and atheists recruit family or colleagues into this role. All of us—people of faith or not—can emulate Rachel Stein when we enter our doctor's mind seeking gaps in his analysis, and pressing for answers that might fill those gaps.

Chapter 6

The Uncertainty of the Expert

M
OST PEOPLE BELIEVE
that a child is rarely born with a malformed heart; in fact, congenital cardiac abnormalities occur at the rate of 8 per 1,000 live births. More than 30,000 such infants are delivered each year in the United States. If the baby can survive beyond twelve months, he or she has an 80 percent chance of entering adulthood. Today, about one million adults in America are living with congenital heart disease. This gratifying statistic is the result of the work of pediatric cardiologists and cardiac surgeons who diagnose and repair malformations of the heart and great vessels, like the aorta. The greatest challenge to these physicians is the extraordinary diversity of abnormalities that they encounter. Even when uncertain, they are often forced to create solutions on the spot, in the ICU or the OR. What kind of doctor is attracted to a specialty that demands repeated innovation, a specialty where the treatment of many cases is an experiment of one?

Dr. James Lock is the chief of cardiology at Boston's Children's Hospital. In his early fifties, Lock is a tall, thin man with thick black hair and aviator glasses. He seems to be in constant motion. As I set up my tape recorder for an interview, he stretched out in his chair, put his feet, shod in cross-trainers, on top of his desk, and then began shifting position, turning his head, crossing and uncrossing his legs, moving his hands up and down the sides of the chair. Lock grew up in a small town in rural Ohio. Nobody in his family had ever gone to college. Because he is a renowned inventor of several cardiac devices, I assumed that he was a tinkerer in his youth. I was wrong. "My brother and father were the ones who fixed cars," Lock said. "I wasn't with them in the garage. I was in my room, reading." Lock explained that for lower-middle-class people, becoming a doctor was the way to get out.

But his escape via a profession was not always certain. He was suspended from school in the second grade and expelled in the sixth. "Both times the principal brought in a psychiatrist from the big city," meaning Akron. The psychiatrist seemed to recognize Lock's potential despite his subpar performance. "The psychiatrist rescued me by suggesting that I be advanced into eighth grade." I commented on the sweep of his head and moving limbs, and suggested that these days the psychiatrist may have diagnosed him with ADHD and prescribed Ritalin. "I surely would have been given something," Lock said and laughed. Lock was a National Merit Scholar, and at the age of fifteen he went to college at Case Western Reserve, then on to medical school at Stanford. "I went to the places where I got a scholarship. It was all about getting a full ride.

"When I was holed up in my room," Lock went on, "I read Arthur Conan Doyle over and over and over again. Sherlock Holmes was all about observation and deduction. So I spent a lot of time thinking about how people make observations and how they make deductions." Arthur Ignatius Conan Doyle was born in 1859 in Edinburgh, Scotland, into a struggling Irish-Catholic family. Wealthy relatives provided for his education at a Jesuit boarding school in England, which he loathed. Looking back on his school days, Doyle wrote, "Perhaps, it was good for me that the times were hard, for I was wild, full-blooded and a trifle reckless. But the situation called for energy and application so that one was bound to try to meet it." Although many members of the family were artists, Conan Doyle chose medicine, and returned from England to Edinburgh for his studies.

In March 1886, Conan Doyle began the novel that would make his fame. Published a year later in
Beetons Christmas Annual
under the title "A Study in Scarlet," it featured a detective named Sherlock Holmes and his colleague, Dr. Watson. Conan Doyle transposed his fascination with the way physicians observe and make deductions in their search for a clinical diagnosis to another type of sleuthing.

As World War I approached, Conan Doyle, then in his fifties, was frustrated that he could not enlist as a soldier. So he peppered the War Office with ideas and suggestions for inventions that he believed could save British lives. Concerned about a future blockade by enemy submarines, he offered as a solution a tunnel under the English Channel that would connect the southern coast of England with France. The naval experts dismissed this as a Jules Verne fantasy. He also imagined inflatable rubber belts and inflatable lifeboats to save drowning sailors, as well as body armor for the infantry. Again his suggestions were dismissed.

Like his hero Holmes, James Lock ponders the nature and interpretation of available evidence and tries to imagine a better future. "I keep an ongoing tap," he said, "on how I know what I know." Lock stopped talking. His head moved back and forth, like a radar antenna scanning the horizon. After several arcs, he seemed to locate his thoughts and spoke again. "Epistemology, the nature of knowing, is key in my field. What we know is based on only a modest level of understanding. If you carry that truth around with you, you are instantaneously ready to challenge what you think you know the minute you see anything that suggests it might not be right.

"Most of what we do in pediatric cardiology, we make up. In fact, a fraction of what is routinely done today in my specialty, I made up," Lock said with a grin. That is because children often have such unique problems with their hearts that there is little precedent. But, Lock continued, "you simply have to do something. The big problem is that most people assume that once it's made up, it's actually real. Especially the people who make it up themselves. Then they think it came straight from God."

"Couldn't the admission that a certain practice is made up paralyze a clinician?" I asked.

"Not everyone in medicine can be constantly making calculations about the value of the information. You'd go crazy. But if you are in a subspecialty field, as you train, you not only need to know what people know, but how they know it. You have to regularly question everything and everyone."

Ironically, James Lock learned the seminal lesson about the care of children with malformed hearts from the case of a child born with a normal one. Holly Clark was a four-year-old in Minnesota with dark brown eyes and long brown braids. One spring morning she told her mother that she didn't feel good. Mrs. Clark felt her forehead and then reached for a thermometer. Holly's temperature was 100.5° F. A virus was going through the nursery school class. Mrs. Clark gave Holly some liquid Tylenol for her fever and put her to bed. By the next day, she was breathing in short, forced gasps, and her skin had a dusky color. Mrs. Clark drove Holly to the ER at a local hospital affiliated with the University of Minnesota Medical School.

The ER doctor found that when Holly took in a deep breath, her blood pressure fell sharply. A chest x-ray showed that the normal contours of her heart were distorted. Instead of the usual boot shape, the heart had a globular appearance, like a water balloon suspended in the chest. Holly was never seriously ill before, only the occasional runny nose or upset stomach, and as far as Mrs. Clark knew, her daughter's heart and lungs always had been normal. The doctor performed an EKG that showed reduced electrical voltage. "It's a textbook diagnosis," he told Mrs. Clark, "cardiac tamponade." Cardiac tamponade means that fluid had accumulated around the heart and was compressing it. This can occur as a result of swelling of the tissue from a viral infection. The buildup of fluid grips the heart like a fist and prevents much blood from entering the organ or exiting to the body. Holly could go into shock if the fluid was not removed.

An attending pediatric cardiologist was called to the ER. He explained to Holly's mother how he would drain the fluid from around the heart. First he would use a large-bore needle to penetrate the pericardium, the fibrous sac that surrounds the heart; then he would employ a syringe to draw off the liquid. Once the fluid was drained from under the pericardium, the heart would pump unhindered and Holly's circulation would be restored.

"Where do you stick the needle?" Lock asked. We were sitting in his office, and he was telling me about this case from his training some thirty years earlier.

I quickly replied, "Subxiphoid," meaning that the needle was inserted below the xiphoid, the tail of cartilage that extends from the lower end of the breastbone. And, I continued, after inserting the needle below the xiphoid, you angle it up toward the right collarbone and advance until you penetrate the pericardium.

As the young James Lock stood next to the attending cardiologist, learning the procedure, that was exactly what the cardiologist said would be done. The senior doctor first palpated the child's breastbone and then ran his fingertips down to the pliant cartilage that forms the xiphoid. At the lower tip of the xiphoid, he cleaned the skin with an antiseptic and applied a local anesthetic. Then he took the syringe with a large-bore needle attached to an EKG lead. He punctured the skin and a halo of blood formed around the needle's shaft. He moved the needle up under the xiphoid, advancing slowly until he felt the tip meet the firm fibrous sac, the pericardium. The doctor waited a moment and then pushed deeper. The sac gave way.

"Why do you stick the needle under the xiphoid?" Lock asked.

I paused. "Because that was how my teachers taught me in my training."

"And why do you think your teachers taught you the way they did?" Lock asked. "Because that's how
they
were taught."

When the cardiologist pulled back on the plunger of the syringe, he met resistance; straw-colored fluid should have come rushing out, but instead the plunger would not budge. Sometimes, the cardiologist said to Lock, the fluid beneath the pericardium is so thick with protein and inflammatory debris that it is difficult to drain even through a large-bore needle.

The cardiologist cautiously moved the needle a few millimeters deeper, thinking he might reach a less thick collection of fluid. He pulled back on the syringe. Bright red blood gushed in. The cardiologist froze, the needle still in Holly's chest.

"She almost died," Lock recounted. "The needle went right into her heart muscle. It was a catastrophe. She needed emergency surgery." Although the cardiologist had advanced the needle only a short distance, it turned out that there was almost no fluid in that area beneath the pericardium. Nearly all of the fluid had accumulated off to the side.

Lock was shaken by the event. He questioned everyone he could about why the procedure was done this way, and he received the same answer that I had given him, that it was handed down by mentors. "I looked at the medical literature and dug back into the 1920s," Lock told me. "It turned out that one of the earliest reports on how to drain fluid came from a woman physician. Her first attempt was done by sticking the needle through the back, and was a success." At the time, Lock continued, the only way to know whether there was fluid was by percussing the heart, tapping one's fingers over the chest and listening to the dull sound from fluid that contrasted with the high notes from air that filled the lungs.

After the successful report of drainage via the back in the 1920s, the approach was widely adopted. But complications soon ensued. The coronary arteries run over the surface of the heart muscle, and sticking a needle through the back sometimes punctured those vessels. "So cardiologists looked for the part of the heart where you have the smallest chance of meeting a coronary artery," Lock explained, "and that turned out to be under the xiphoid."

Lock returned to the lesson of Holly Clark. "Now I teach my trainees not to go by rote under the xiphoid. We should always go where the fluid is. We follow Sutton's law." Sutton's law is named after the 1930s Brooklyn bank robber Willie Sutton, who robbed bank after bank and accumulated a fortune before he was captured. When Sutton was brought into court, the judge asked him why he robbed banks. "Because that's where the money is," he answered. (The tale is probably apocryphal: the reply attributed to Sutton likely was made up by a reporter at the trial to color his story. But the term "Sutton's law" has stuck.) Lock helped change the way the procedure is done. Now an ultrasound is always performed first, to visualize the fluid around the heart, and a small needle is inserted under ultrasound guidance.

The heart is a pump with four chambers, two on the right and two on the left. Each upper chamber is called an atrium, from the Latin denoting an "entry," and each lower chamber a ventricle, also from Latin, for "belly," since it is somewhat oval in shape. Blood depleted of oxygen returns from the body to the right atrium; it moves from this chamber into the right ventricle. The right ventricle pumps the blood out through the pulmonary valve into the pulmonary artery to the lungs. In the lungs, the blood is recharged with fresh oxygen, and waste products like carbon dioxide are released. The refreshed blood returns from the lungs via the pulmonary veins to the left atrium; the valve that separates the left atrium from the left ventricle reminded early anatomists of a bishop's miter, so they named it the mitral valve. Once the blood crosses the mitral valve, it enters the left ventricle. The left ventricle is much thicker than the right ventricle. Its thick muscle contracts and generates high pressure to pump the blood across the aortic valve into the aorta, the large artery that carries it to all parts of the body.