(0525) Portable Rhinomanometry

Introduction: Four-phase rhinomanometry is a clinical test providing quantifiable metrics physicians can leverage to analyze the respiratory function of the nasal cavity with respect to conditions such as nasal valve collapse and procedures such as rhinoplasty. This study demonstrates a novel and portable rhinomanometry device to analyze pressure and flow through the nasal cavity; such a device can aid in making rhinomanometry more accessible in the clinical setting.

Methods: The testing apparatus consisted of a 3L calibration syringe to simulate airflow, a differential pressure sensor (Sensioron SDP816-500 Pa), a Schiller Spirometer Spiro Flow Tube (REF 2.100077) connecting the differential pressure sensor and the output of the calibration syringe, and an Arduino UNO microcontroller to acquire the serial pressure measurements. Flow was calculated from differential pressure using Bernoulli’s principle, and flow calibration was performed across three inhale and exhale trials as simulated with the 3L calibration syringe. The calibration constants for each trial were calculated using Romberg’s method for integration by integrating the square root of the differential pressure vs. time curve in accordance with Bernoulli’s principle. Following calibration, nasal breathing was simulated with the calibration syringe, and the time series pressure and flow were visualized in real time using MATLAB.

Results: The calibration constant for the rhinomanometer was determined to be 258.3 mL/[s*Pa^(0.5)] with a standard deviation of 8.3 mL/[s*Pa^(0.5)]. Flow validation over a 3L simulated exhale yielded an error of 0.45%.

Conclusions: The study herein demonstrates the feasibility and utility of a portable rhinomanometer, which can facilitate increasing its accessibility as a clinical assessment in otolaryngologic practice.