OBJECTIVES - To examine the time-dependent changes of spirometry (percent-predicted forced expiratory volume in 1 second [%FEV(1)]) and the Pediatric Respiratory Assessment Measure (PRAM) during the treatment of acute asthma exacerbations.
STUDY DESIGN - We conducted a prospective study of participants aged 5-17 years with acute asthma exacerbations managed in a Pediatric Emergency Department. %FEV(1) and the PRAM were recorded pretreatment and at 2 and 4 hours. We examined responses at 2 and 4 hours following treatment and assessed whether the changes of %FEV(1) and of the PRAM differed during the first and the second 2-hour treatment periods.
RESULTS - Among 503 participants, median [interquartile range, IQR] age was 8.8 [6.9, 11.4], 61% were male, and 63% were African-American. There was significant mean change of %FEV(1) during the first (+15.4%; 95% CI 13.7 to 17.1; p < .0001), but not during the second (+1.5%; 95% CI -0.8 to 3.8; p = .21), 2-hour period and of the PRAM during the first (-2.1 points; 95% CI -2.3 to -1.9; p < .0001) and the second (-1.0 point; 95% CI -1.3 to -0.7; p < .0001) 2-hour periods.
CONCLUSIONS - Most improvement of lung function and clinical severity occur in the first 2 hours of treatment. Among pediatric patients with acute asthma exacerbations, the PRAM detects significant and clinically meaningful change of severity during the second 2-hour treatment, whereas spirometry does not. This suggests that spirometry and clinical severity scores do not have similar trajectories and that clinical severity scores may be more sensitive to clinical change of acute asthma severity than spirometry.