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 (1/min) was 1.4256 x height (m) + 33.0215 x gender (where 0 = female, 1 = male) + 1.4117 x age (years) -136.6778. The lower limit of normal was calculated by subtracting from the peak nasal inspiratory flow reference value (84 1/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.