Rhinomanometer

Rhinomanometer is a medical device used to measure nasal airway resistance by analyzing the pressure–flow relationship in the nasal passages during breathing. The basic principle is to create a known pressure drop across the nasal airway and measure the resulting airflow, allowing resistance to be calculated as R = ΔP / V̇, where ΔP is the transnasal pressure difference and V̇ is the airflow. Measurements are typically reported as nasal airway resistance at a standard transnasal pressure, commonly around 100 pascals.

Most rhinomanometers perform active anterior rhinomanometry. In this setup, the patient breathes through the nose while a sealed nasal interface or mask isolates the nasal route. A flow sensor records airflow and a pressure transducer records the pressure difference across the nasal passages. This yields a pressure–flow curve and provides quantitative metrics for total and, when needed, unilateral nasal resistance. The technique can be repeated over several breaths to obtain reliable estimates.

Applications of rhinomanometry include evaluation of nasal obstruction due to conditions such as allergic or nonallergic rhinitis, deviated septum, and nasal polyps. It is used in preoperative assessment, postoperative follow-up, and to assess the pharmacological response to decongestants or other therapies. The data complement subjective symptom scores and imaging findings in both clinical practice and research.

Limitations include the need for patient cooperation and a proper seal, potential influence of the nasal cycle or environmental factors, and variability in reference values across populations. Standardization of protocols and interpretation can vary, which may affect cross-study comparisons.