Does peak nasal inspiratory flow relate to peak expiratory flow?

AIMS: Measurement of Peak Nasal Inspiratory Flow (PNIF) seems to be a cheap and easily performed method to assess nasal patency. As demonstrated in a previous work, PNIF is influenced by SEX, AGE and HEIGHT. However there is a large degree of between-patient variability in PNIF levels. The purpose of this analysis is to determine whether the measurement of the pulmonary ventilatory capacity, by mean of Peak Expiratory Flow (PEF), enables more precise determination of PNIF. METHODS AND RESULTS: Repeated measurements of PNIF and PEF were performed in 112 volunteers. 100 of these fulfilled the study criteria (55 females and 45 males) and all of them were non-smokers, non-asthmatic, without nose and paranasal sinuses problems, with ages ranging from 15 to 71 years. Statistical analysis was undertaken to determine whether a relationship existed between PNIF and age, sex and height, but which also considered PEF. The data from both experiments were analysed together. In both groups there is a clear tendency for PNIF to increase with PEF. As clearly demonstrated in this work the value of PEF is informative in predicting PNIF and that the larger the value of PEF, the larger the value of PNIF. CONCLUSIONS: PNIF is a useful method to study nasal patency in both primary and secondary care to aid diagnosis of nasal disease, but low values of PNIF have to be confirmed by a study of the PEF as PNIF low values may be an expression of low ventilatory activity rather than an expression of nasal obstruction.