Objective: To determine the frequency with which children ≥6 years with acute asthma can perform peak expiratory flow rate measurements (PEFR) in an emergency department (ED).
Design/Methods: Data were obtained from a prospective cohort study of children with acute asthma. All children (age 2-18 years old) treated in an urban pediatric ED for an acute exacerbation during randomly selected days over a 12-month period were prospectively evaluated. According to treatment protocols, PEFR was to be measured in all children age 6 years and older before therapy and after each treatment with inhaled bronchodilators. Registered respiratory therapists obtained PEFR and evaluated whether patients were able to perform the maneuver adequately.
Results: Four hundred and fifty-six children, 6 to 18 years old (median 10 years), were enrolled; 291 (64%) had PEFR measured at least once. Of those in whom PEFR was attempted at least once, only 190 (65%) were able to perform adequately. At the start of therapy, 54% (142/262) were able to perform PEFR. Of the 120 who were unable to perform initially, 76 had another attempt at the end of the ED treatment, and 55 (72%) were still unable to perform. A total of 149 patients had attempts at PEFR both at the start and end of treatment, of these, only 71 (48%) provided valid information on both attempts. Patients unable to perform PEFR were younger (mean ± SD = 8.7 ± 2.8 years) than those who were able to perform successfully (11.2 ± 3.2 years) and those with no attempts (10.0 ± 3.4 years). Children admitted to the hospital were more likely to be unable to perform PEFR (58/126 = 46%) than those discharged from the ED (43/330 = 13%, P < 0.0001).
Conclusion: Adequate PEFR measurements are difficult to obtain in children with acute asthma. Treatment and research protocols cannot rely exclusively on PEFR for evaluation of severity.
National guidelines for treatment of acute asthma call for measurement of peak expiratory flow rate (PEFR) as a more valid and reproducible measure of airway obstruction than clinical examination. 1 However, compliance with guidelines has been found to be low. 2,3 In one study, pediatric emergency physicians surveyed reported obtaining PEFR on only 60% of eligible patients. 2
One reason for infrequent use of PEFR in children may be uncertainty about their ability to perform the maneuver, which is effort-dependent and requires a significant degree of coordination. It has been reported that by 5 years, many children can reliably perform PEFR 4; there are some reports of successful use of PEFR in children as young as 3 years. 5 The ability of children to perform PEFR during emergency department (ED) treatment of acute asthma, however, has not been well studied. The purpose of this study was to determine the frequency with which children were able to perform PEFR in the context of ED treatment of an acute asthma exacerbation and to identify factors associated with proper performance.