Pattern of Peak Expiratory Flow Rates in apparently Healthy School Children aged 10-15 Years in Oredo Local Government Area of Edo State

Abstract

Background: The peak expiratory flow rate (PEFR) is a useful screening tool in the diagnosis and subsequent monitoring of children with obstructive pulmonary diseases especially asthma. However, PEFR readings are subject to diurnal variations. Objective: To determine the pattern of PEFR and the influence of a number of determinants on the pattern in a cohort of apparently healthy school children. Subjects and Methods: A cross-sectional study was carried out to determine PEFR among 438 subjects, aged 10-15 years old, attending public junior secondary schools in Oredo Local government Area of Edo State, between March and November 2005. The biodata, weights and heights were recorded. The PEFR was then determined at 6am, 2pm and 10pm over a 14- day period, using a mini-Wright PEF meter. Results: The PEFR (mean ± SD) L/min for all subjects at 6am, 2pm and 10pm were 380.4 ± 48.1, 394.9 ± 48.2 and 392.4 ± 47.8, respectively. Further analysis showed that the PEFR at 6am, 2pm and 10pm were 392.7 ± 57.0, 406.8 ± 57.1 and 402.5 ± 56.7 in males compared with 369.8 ± 35.9, 383.7 ± 43.9 and 380.1 ± 35.7, respectively in the females. The gender difference in the mean PEFR values at 6am (t = 5.1, p<0.0001), 2pm (t = 4.823, p<0.0001) and at 10pm (t = 5.021, p<0.0001) were all statistically significant. The PEFR showed a direct relationship with the age, height and weight, whereas the socioeconomic class had no obvious effect on the PEFR. Regression equations for PEFR were derived for age, height and weight. Conclusion: The PEFR was higher in males than females at any time of the day. However, for both males and females, the PEFR was highest at 2pm and lowest at 6am. This is important in the adjustment of treatment and monitoring of asthmatic patients.

Keywords

• peak expiratory flow rate
• pattern
• children