Some clinical problems in patients with airways obstruction.

T he physiologic approach to the clinical problem of airway obstruction is too often limited to laboratory measurements made on one or a few occasions, on an individual patient or upon a group of patients. The observations are then summarized by the unwary physician by labels, which have the implication of well recognized lung pathology, but for which in the individual in whom they are applied there is in fact little or no evidence. Thus, on the basis of apparent irreversible airway obstruction, the term chronic bronchitis may be applied when there is no history of cough or sputum and no longitudinal records of airway resistance measurements; on the basis of large lung volumes, emphysema is applied when the radiograph is incompatible; and on the basis of wheeziness and airflow obstruction, the term asthma is applied when, on the measurements available, there is no evidence of reversibility. In attempts to avoid these well-known piffalls, the intellectually elite have sometimes used the term, chronic obstructive airway disease. This term has the virtue of avoiding one set of disadvantages, but promptly presents equally great ones, in that it fails to make important practical distinctions so necessary for good management. As it bears no relation to any recognized pathology, it thus, by including all, means virtually nothing. If the clinician is to predict pathology, and thus apply treatment rationally, we have to do better; but to be practical, we have to be simple. There still remains a considerable gulf between the physiologist, with his increasingly sophisticated laboratory tests, and the clinician, caring for large numbers of patients suffering from these exceedingly common conditions. The clinicians often fail to make the most of what the physiologist has to offer, but the physiologists have all too often failed to reach out and recognize the subtleties of the clinical problems. Even to a group of international experts, it is appropriate to illustrate some of the real clinical