USEFULNESS OF LONG TERM PEF MONIITORING IN ASTHMATIC CHILDREN

To investigate the relationship between exacerbation of asthma and PEF variability, 32 institutionally hospitalized asthmatic children were enrolled in the study. Methods: PEF variability, asthma attack score, medication score were evaluated every one week for four weeks before 40 episodes of acute exacerbation, being required frequent inhalations of β-agonist, intravenous aminophylline, and/or systemic steroid during long-term hospitalization. Those parameters during most stable period were also evaluated to compare with 2 weeks before acute exacerbation. Subjects were divided into unstable group and stable group with or without asthma attack during 1 week before episode of acute exacerbation respectively. Results: 1. Averaged % PEF decreased and daily variability of PEF increased significantly in 1st week than in 2nd-4th week before acute exacerbation. 2. Averaged % PEF decreased and daily variability of PEF increased significantly in 2 weeks before acute exacerbation than in most stable periods. 3. Averaged daily variability of PEF was proportional to asthma attack score during 1 week before acute exacerbation. 4. Although no significant changes in % PEF and daily variability for 4 weeks before acute exacerbation were observed in stable group, averaged % PEF decreased and daily variability of PEF increased significantly in 2 weeks before acute exacerbation than in stable periods. Conclusions: These results suggest that information obtained by long term PEF monitoring is useful for predicting asthma exacerbation, and that measuring PEF and its daily variability even in stable period are also important to know individual PEF change.