North African reference equation for peak nasal inspiratory flow

Aim: To assess, in healthy North African subjects, the applicability and reliability of a previously published reference equation and normal values for peak nasal inspiratory flow, and to calculate a peak nasal inspiratory flow reference equation in this population. Subjects and methods: Anthropometric data were recorded in 212 volunteers (100 females and 112 males) aged 13–27 years. Peak nasal inspiratory flow was measured several times. Univariate and multiple linear regression analyses were used to determine the reference equation. Results: The previously published reference equation and normal values did not reliably predict peak nasal inspiratory flow in the study population. In our subjects, the reference equation ( r 2  = 30 per cent) for peak nasal inspiratory flow (l/min) was 1.4256 × height (m) + 33.0215 × gender (where 0 = female, 1 = male) + 1.4117 × age (years) − 136.6778. The lower limit of normal was calculated by subtracting from the peak nasal inspiratory flow reference value (84 l/min). Conclusion: This is the first published study to calculate a reference equation for peak nasal inspiratory flow in North African subjects. This equation enables objective evaluation of nasal airway patency in patients of North African origin.