MAXIMAL EXPIRATORY FLOW RATES IN AUSTRALIAN ADULTS

Summary The Wright peak flow meter is a useful, simple, portable instrument for the recording of maximal expiratory flow rates (M.E.F.), which reflect the degree of obstruction to air flow. Normal values for M.E.F. under Australian conditions have been determined in 44 males and 76 females, aged 18 to 78 years, who had no history of chronic respiratory disease and who had never smoked. Regression equations have been prepared for the prediction of “normal values” in practice. In normal subjects, the recorded M.E.F. may vary from the predicted value by up to 20%. In 10% of the subjects, the reproducibility of the test was not good. Increasing age is associated with loss of M.E.F. in both sexes (for males 2·1 litres per minute, and for females 1·2 litres per minute, each year). In males, stature (as reflected by height) is important as a determinant of the absolute value for M.E.F. In women over the age of 60 years, three determinations are adequate to achieve a maximum value, but in younger women at least four determinations and in men at least five determinations should be made.