Dyspnea in acute asthma : relationship with other clinical and physiologic variables

This investigation comprised 58 patients (35 men, mean age 61 years) with acute asthma: mean FEV 1 35% of the predicted. The dyspnea score (Borgs seale), breathing rate, pulse rate, blood pressure, FEV 1 , and PEF were measured on arrival and 30, 60, and 150 minutes after bronehodilator treatment. The level of elinieal severity was evaluated using Hedstrands asthma severity scale. The variables that correlated most closely with dyspnea score at arrival were asthma severity score (r=.51 P<.001) and breathing rate (r=.38, P<.01). The measurement of airflow obstruction with the closest correlation to improvement in dyspnea was FEV 1 expressed as a percentage of the pretreatment value (r=-.30 * after 30 min, r=-.42 ** after 60 and r=-.34 * after 150 minutes, * P<.05, ** P<.01)