Variant formula for predicting peak expiratory flow rate in pregnant women in Kura Local Government Area, Kano State, Nigeria

Abstract

Observed Peak expiratory flow rate (PEFR), Predicted and Variant PEFR values in 123 females at their reproductive ages, living in Kura local government area of Kano State, Nigeria and its environs were obtained. The prediction and variant formulae used were; PEFR= 0.36AGE – 0.47WT + 391.67 and K = mean CC x mean TL /mean PEFR respectively. A constant value was derived in the second formula, which was used to calculate a variant PEFR value using the individual Chest Circumference (CC) and Thoracic Length (TL) values obtained during the study period. Analysis of variance was used to compare the three different PEFR values; Observed PEFR = 375.20 ± 3.12 L/min, Predicted PEFR = 375.05± 0.29 L/min and Variant PEFR = 375.62 ± 3.09 L/min with P> 0.05. Further more, graphs were plotted to show the variation of the three values of PEFR with age in the subjects. Data for plotting the graphs were generated using the prediction and variant formulae generated from this study. The graph illustrates close association of variant formula with the observed values of PEFR obtained from the study. Variant formula may be useful in clinical setting to assess people with respiratory disorders especially asthma.

Key words: Variant formula, Peak expiratory flow rate, Pregnancy, Kura local government area