Asthma: the pulse is not the paradox.

Some interesting, unusual features of asthma are discussed: that patients may be better able to evaluate the severity of their asthma than physicians; that expiratory obstruction indirectly increases the work of inspiration; that 1 of the responses to airflow obstruction is hyperventilation; that localized areas of airflow obstruction may cause increased ventilation/perfusion ratios by decreasing perfusion more than ventilation; that increasing tidal volume may cause a reduction in alveolar ventilation; and, finally, that there is evidence that asthma has worsened in recent years, despite advances in the understanding and treatment of this disease.