Purpose of review: This article updates the state of the art in functional ventilation tests of the nasal airway. Multidisciplinary international cooperation has led within the last years to the development of four-phase rhinomanometry (4PR) by eradicating the errors of the ‘classic’ rhinomanometry.
Recent findings: Physical experiments, mathematical models and comprehensive statistical analyses implicate that the nasal breath consists of four phases of different diagnostic importance. Presuming the motility of the nasal entrance, it is necessary to depict the elastic behavior within the rhinomanometric curve, as well as to use new parameters for the clinical evaluation of the nasal obstruction. The parameters logarithmic vertex resistance and logarithmic effective resistance are related to the sensing of the patient. Their clinical importance was proved in studies of more than 12 000 patients.
Summary: The human eye is not able to estimate the degree of impairment in nasal breathing. Therefore, a functional diagnosis is mandatory to avoid unnecessary surgery and to control the results. 4PR is a substantial improvement over the currently used methods. It should be implemented in the standards of the international standardization committee for the objective assessment of the upper airway (ISOANA). Practical hints for correct measurements are given.