point of maximal impulse

Finding the PMI is not difficult, but it can be subtle, and a light touch works best. Try it. You are feeling your right ventricle beating against your chest wall.

If the PMI is shifted a bit too far, however, it suggests that the heart has dilated. If the patient has just had an accident, it might suggest a collapsed lung.

Physicians rarely check for it these days. Most of the time it does not add much information to the physical examination. In an age when efficiency rules, and patients are herded through examination rooms, the moment or two to check it is not worth the rare times you might find something. The roentgenogram or the ultrasound or the stab wound to the chest make subtle physical findings obsolete.

The child was 11 years old--he was a healthy looking kid, and he was wheezing. The emergency room was hopping. This particular child had never wheezed before, and he had no family history of asthma, allergies, or eczema, which tend to run together in families. He got the usual treatment for wheezing in those days--a breathing treatment with metaproterenol, a bronchodilator, which helps open up the muscles around our small airways, and theophylline, a drug which we did not understand, but which seemed to help.

Because the child had never wheezed before, a chest film was ordered. He was getting a little better, but not well enough to go home. The radiology suite was between the ER and the adolescent floor. He stopped by on the way to the floor, had his picture taken, and late that evening, settled down in his room.

A few hours later, he coded. As the medical folks ran the code, breathing for the child, compressing his heart for him, injecting him with drugs in a vain attempt to restart his heart, someone fetched the film. The shadow of the child's heart was, in doctorspeak, "the size of Kansas."

The child did not have asthma; the child died of a dilated heart, likely from cardiomyopathy. He had improved a bit from the "asthma" medications because of their side effects. Bronchodilators, as anyone who has been treated for asthma knows, makes your heart beat harder. Theophylline acts as a diuretic. The treatment for heart failure is inotropes and diuretics. A physician's mantra: all that wheezes is not asthma.

In the ER, if anyone had taken the trouble to check for the PMI, the child would have been diagnosed sooner. Would he have surived? Not sure. When you are responsible for other lives, and you occasionally "miss one" that could have been saved, it wears on the soul. Most doctors do not start medical school looking worn out. Medical schools do not teach Aloofness 101. If they did, we would pass with honors.

The point of maximal impulse often rests just below the left breast. Since few doctors even check for it anymore on routine physical examinations, you better have a good reason. Lingering over any part of the body can raise suspicions in a culture that fears touch.

The PMI is also called the apical pulse--you are feeling the apex of the heart. Pulses. You can find the radial pulse on your wrist. You can find the femoral pulse in the crease between your leg and your trunk. The popliteal pulse hides in the back of your leg behind the knee, the dorsalis pedis pulse on top of your foot. The brachial pulse throbs in the crease inside your elbow. The carotid pulse reminds us that our brains need a constant flow of blood.

A normal pulse rises up then slides down, rhythmically under your fingertips. With just the right pressure, you can feel the wave as it undulates under your fingers. The throbbing of life. About 80 or so times a minute, give or take.

Recently I "treated" a child with a stab wound to the heart. I felt her pulses quicken as their strength diminished. Despite my inability to do the things this child needed done to survive, she lived. The bleeding stopped because of a cascade of normal physiologic events that formed a clot. The miracle was that these normal events were able to form a clot in that particular place. In this case knowing the pulses were abnormal did not add much to the child's diagnosis.

The key to being an adequate physician is knowing what normal is, and knowing what normal is depends on experience. If a doctor does not regularly check the PMI, she may miss the sometimes subtle boundary between normal and not. We usually get away with our incompetence because humans are resilient.

Since most people (including physicians) fail to see how much happens beyond our power, we are able to maintain our myth of control, an important myth in a culture that fails to see cycles, fails to acknowledge mortality (or rather, encourages us to believe we are immune to mortality). We are mountebanks, charlatans.

The first child died--meetings were held, accountability was distributed, mea culpas exchanged at the Morbidity and Mortality conference (a rather macabre and cathartic formality where physicians meet to exchange criticisms after things go badly for the patients). The second child lived, so praise is doled out without a formal review. In both cases, the outcome had less to do with the initial management than we like to believe.

Still, when a pulse disappears in a child, there has to be a reason. Our methods of searching for the reason shows how primitive our medicine remains.