Assessment of Peak Expiratory Flow Rate in School Children and Its Correlation with BMI, BSA, and Family History of Obstructive Diseases

Abstract

INTRODUCTION

Pulmonary function tests of various types are utilized clinically and epidemiologically to measure functional status of lungs and to assess their diseases. Peak expiratory flow rate is defined as the maximum airflow achieved during a forceful expiration after taking maximal inspiration. It is measured in Litres/min. It has received general acceptance as an useful index of ventilatory capacity. Asthma is the most common chronic inflammatory disease in children and is a major global health problem which exerts a substantial burden on the family, health care services and on the society as a whole. With increasing incidence of respiratory diseases in children, it is also essential to have a normal range of PEFR in children of different ages and its relation to body size, as measured by Body Mass Index (BMI) and Body Surface Area (BSA).

MATERIALS & METHODS

This was a prospective cross sectional study was carried out in various primary and secondary  schools is the city of Cuttack  to assess the pulmonary function in children and its relation to B.S.A, B.M.I & family history of obstructive diseases over a period of one year and eight months. Studies of lung function assessment have been performed for diagnosis, treatment & follow up of respiratory morbidity. Measurement of PEFR is of value for the identification of chronic obstructive lung disease and for assessment and follow up of patients with asthma. Different normal values of PEFR have been obtained in populations of different locality.

Results

In the present study, PEFR was measured in 950 primary and secondary school children. The children were between the age group of 6 to 14 years. Among them 507 were boys and 443were girls. The PEFR is significantly (p<0.05) higher in boys than girls in all ages, except at 12years of age , where the values are comparable in both sexes. The rate of increase in PEFR is comparatively higher in boys than girls. The difference is statistically significant as p value is < 0.05 in all height intervals except in interval of 110-119 cm (p>0.05). The PEFR value to be highest in normal B.M.I. range (18.0-24.99) both in boys and girls. Boys have significantly (p<0.05) higher PEFR than girls. As there are only two subjects in B.M.I. range by 30.0-34.99, the results are inconclusive.

Conclusion

Diagnosis and Management of bronchial asthma requires periodic assessment of pulmonary function especially ventilatory functions. The peak expiratory flow rate (PEFR) measurement is a very simple, reliable, reproducible ventilatory function test. PEFR can be performed by using mini –Wright’s  peak flow meter (a cheap, portable instrument). Reference values to be used in a locality should be evaluated. Personal best PEFR reading is as reliable as other pulmonary function tests.