treating asthma with bronchodilator acutely does not treat inflammation

The acute bronchoconstriction has improved, but the inflammatory process in the airway has not (choice B is correct). The origins of dyspnea in a patient with an acute asthma attack are multifactorial. Chest tightness is a very common descriptor used by patients with bronchoconstriction. The exact origins of the sensation are not fully known, but available evidence suggests that it is related to stimulation of airway receptors associated with active contraction of the airway muscles. Laboratory evidence suggests that it is not due to hyperinflation and is not relieved significantly by providing ventilatory support (see the article "Quality of Dyspnea in Bronchoconstriction Differs From External Resistive Loads" by Moy et al). In addition, these patients experience a sense of increased effort or work of breathing. These sensations are associated with increased mechanical loads on the respiratory system, such as increased airway resistance and the load associated with dynamic hyperinflation (decreased respiratory system compliance at high lung volume and reduced efficiency of inspiratory muscles that initiate contraction at shorter length). When bronchoconstriction is induced with methacholine, chest tightness is the predominant symptom at mild levels of bronchoconstriction, and the sense of work and effort become predominant at more severe levels of obstruction (Figure 1).

When a patient develops asthma attack over several days, airway resistance is due to a combination of bronchoconstriction and narrowing of the airways due to inflammation and mucosal edema. The administration of a bronchodilator may reduce the sense of tightness but does nothing for the airway inflammation and edema. Consequently, the intensity of dyspnea decreases out of proportion to the change in FEV1 (see the article "Language of Dyspnea in Assessment of Patients With Acute Asthma Treated With Nebulized Albuterol" by Moy et al). This all supports the idea that the acute bronchoconstriction has improved but the inflammatory process has not. Patients such as this should receive steroids as well before consideration for discharge to ensure that the inflammatory component of the acute asthma is being treated effectively.

The patient wanting to avoid hospital admission is an inference about patient motives with nothing in the history to support this assumption (choice A is incorrect).

The asthma-COPD overlap syndrome describes elements of chronic asthma leading to chronic obstruction and, in some cases, changes in lung compliance suggesting emphysema. The average patient with this disease is older than 60 years. This patient does not fit the elements of the syndrome (choice C is incorrect).

Repeated spirometry is unlikely to cause ventilatory muscle fatigue to explain these results (choice D is incorrect).