Comparison of Isocapnic Hyperventilation and Histamine or Methacholine Inhalation for the Assessment of Airway Responsiveness

Several stimuli have been used to evaluate the degree of airway hyperresponsiveness in asthma. Each of these has possible advantages and disadvantages when compared to the other methods. The most widely used involves the inhalation of chemical bronchoconstrictors, most commonly histamine or methacholine. This paper contrasts these inhalation tests with airway challenges using isocapnic hyperventilation of dry air. Isocapnic hyperventilation …