Peak Expiratory Flow Rate (PEFR) Corrected for Forced Expiratory Pressure

ABSTRACT

Traditionally, PEFR is a measure of airway resistance and estimate of bronchoconstriction. It is used as adiagnostic as well as prognostic marker for respiratory diseases, especially asthma. But PEFR is effortdependent parameter which not only depends upon the airway resistance but also the Forced ExpiratoryPressure (FEP) generated by the respiratory muscles. This expiratory force generated needs to be consideredwhen interpreting the results of PEFR. Therefore, present study was undertaken to explore relationshipbetween PEFR and FEP and to find corrected PEFR.A total of 56 physically fit volunteers were examinedfor PEFR using Wright’s peak flow meter and FEP was estimated using a mercury manometer connectedto a mouth piece with airtight seal. The results of multiple linear regression model suggested that FEP hasstatistically significant influence on PEFR (beta coefficient = 1.18, adjusted R20.699). The formula forcorrected PEFR was derived and the coefficient of variance before and after PEFR correction was 35.53%and 30.13% respectively, suggesting that for better clinical utility PEFR should be corrected for FEP. Toextrapolate the present study results to other age groups and diseased population further studies areneeded.