Assessment of Respiratory Responses

The assessment of responses of the respiratory system to new drugs is dependent upon the particular pathology and condition being treated. The lung can be divided into vascular and parenchymal compartments. Pharmacological manipulation of the pulmonary vasculature is discussed elsewhere. Diseases of the parenchyma involve either the conducting airways, as in asthma or chronic obstructive pulmonary disease, or the alveoli, interstitium and gas-exchanging membranes, as in pulmonary fibrosis. Asthma is a condition characterised by airway hyperresponsiveness to a wide variety of specific and non-specific stimuli, and is defined in physiological terms by variable airway narrowing. In chronic asthma physiological assessment may become more complex, particularly if the diagnosis is not clear. Indices of gas transfer are rarely abnormal in asthma in remission. The assessment of responses to drug therapy depends upon the underlying condition. Changes in parameters of airflow obstruction and lung volumes are commonly used in the measurement of therapeutic responses in asthma.