When the question-and-answer period is over, your doctor will examine you. First he listens to your chest with his stethoscope to hear how air passes in and out of your lungs. With healthy lungs, he hears a soft, low rushing sound. With obstructed airways, the sound the air makes depends on the nature of the obstruction.

Airway obstructionpresent in chronic bronchitisproduces wheezing, the sound of turbulence caused as air is forced around mucus and through narrowed airways. Although for a long time wheezing was thought to happen only during expiration, recent evidence indicates that it occurs during inspiration too. Wheezes differ in tone and loudness depending on when they are listened to (during inspiration or expiration, during a temporary worsening or not), and exactly where in the lungs. A rale (pronounced rahl) is another abnormal sound heard in COPD patients. This is the noise air makes as it bubbles through accumulated mucus. In patients with advanced emphysema, the large number of grossly hyperinflated air sacs filled with trapped air make all breath sounds faint and distant. But the most severe cases of COPD often produce no breath sounds at all. The obstruction is so great that air cannot be pushed through the airways with enough force to produce the amount of turbulence needed to make a detectable sound.

We know what the different sounds mean. The problem is agreeing on what to call them. Laennec was, understandably, the first to describe abnormal breath sounds. But his clarity has been lost. In his initial treatise, Laennec called all abnormal lung sounds rales from the French word for rattle, and qualified each rale with the proper adjective (e.g., gurgling rales were due to air passing through fluids). But the popular association of rattle with "death rattle" led Laennec to abandon it for rhonchi (from the Greek work for "snore"). Things got scrambled when Laennec's work was translated into English. Rales and rhonchi were suddenly used to describe different types of sounds.

Three broad categories of breathing sounds, each with subtypes, soon developed in the United States: (1) rales (crepitations and crackles), describing delicate sounds from the smaller airways; (2) rhonchi, the coarser gurgling sounds of air passing through mucus in the larger airways; and (3) wheezes, the continuous musical sounds associated with air passing through narrowed, obstructed airways. Recently, both the American Thoracic Society and the American College of Chest Physicians suggested a different categorization system: crackles for discontinuous sounds, and wheezes for high-pitched musical sounds.

What else will you doctor look for when he examines you? He will observe the way you breathe, the muscles you use, the shape of your chest, and your sitting posture to get a sense of how severely your breathing is obstructed.

The patient with more severe obstruction gives the appearance of intense inspiratory activity, forcefully inspiring and then expiring slowly against pursed lips. Because his seriously hyperinflated lungs have pushed out his ribcage and flattened the diaphragm sitting beneath them, he is barrel-chested and his neck muscles bulge. (Because the patient's flattened diaphragmalong with shortened inspiratory intercostal musclesdon't provide adequate inspiratory power, he now regularly uses his accessory inspiratory muscles, located in his neck, which has overdeveloped them.)

The patient sits forward in a chair with his arms or hands braced against his knees or the table in front of him, a position that naturally makes these muscles more effective.

The physical examination can also indicate the general adequacy of gas exchange. In chronic bronchitis, the patient with bluish lips and fingernail beds (a condition called cyanosis) does not have enough oxygen in his blood. If there is also excess carbon dioxide retention, the veins become visibly engorged.

Heart function in the earlier stages of COPD is normal. But in more advanced cases, especially where chronic bronchitis predominates, cardiac complications are frequent. The observable physical signs are: extensive cyanosis; swollen ankles (called peripheral edema); engorged jugular vein (the large blood vessel in the neck); enlarged liver.

So you have abnormal breath sounds and you use your inspiratory muscles excessively. Perhaps you also cough up a lot of mucus, or your lips are tinged with blue, or you have become barrel-chested. All of this clearly confirms that your problem involves obstructed airways. The physical examination's purposesubstantiating the existence of airway obstruction suggested by your historyhas been fulfilled.

At this point, an array of objective tests will help your doctor decide which of the three obstructive respiratory diseaseschronic bronchitis, emphysema, or asthmais your problem and how severe it is, and provide some idea of your prognosis. (Deciding which of the different possibilities is the actual problem is the "differential diagnosis.")