QUANTIFICATION OF DYSPNEA

Several methods have been proposed in the recent years to quantitate d yspnoea in healthy subjects or patients. Dyspnoea can be serially asse ssed on exercise, using either a visual analogue scale or a Borg scale , and is usually analyzed in relation to ventilation, which defines a dyspnoea threshold and a dyspnoea/ventilation slope. Inhaled bronchodi lators, oral morphine, continuous (or inspiratory) positive airway pre ssure or respiratory rehabilitation programmes are able to decrease th e dyspnoea/ventilation slope in patients with chronic obstructive pulm onary disease, while atenolol and pneumectomy have a deleterious effec t. Measurement of dyspnoea in everyday life is feasible using the oxyg en cost diagram or the baseline dyspnoea index; these indices are resp onsive to therapy, e.g. to oral theophylline in patients with chronic obstructive pulmonary disease. Dyspnoea measured at rest is a marker f or evaluating the perception of added loads (open scale) or acute bron choconstriction in normals or patients; in the latter it may also refl ect the perception of the degree in baseline ventilatory impairment or that of acute bronchodilation (bipolar visual analogue scale). Some r espiratory patients being poor perceivers, methods able to improve the perception of airway obstruction are desirable in these individuals.