The limitations of peak nasal flow measurement.

The Youlten Peak Nasal Flow Meter is a convenient device for obtaining objective measurments of nasal patency and gives static values which correlate well--though inversely--with resistance measured by rhinomanometry. In this study peak nasal flow and nasal resistance are compared before and after intranasal challenge using histamine. The comparatively small change in nasal resistance induced by low-dose histamine is not reliably detected by the peak flow meter. Large changes in nasal resistance with a higher dose of histamine are reflected by significant but small changes in peak nasal inspiratory flow. It is concluded that changes in nasal patency as measured by the Youlten meter are an insensitive measure of nasal patency compared with rhinomanometrically measured resistance changes. Continued use of the latter is recommended for physiological research.