Rhinomanometry using computational fluid dynamics

• Grant number: 12/20823-9
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2013
• End date: March 31, 2016
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Richard Louis Voegels
• Grantee: Richard Louis Voegels
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Eloisa Maria Mello Santiago Gebrim ; Fabio de Rezende Pinna ; Guilherme Jose de Moraes Garcia

Abstract

The perception of sufficient airflow through the nasal cavity is a complex issue. Many factors, such as the inspiratory airflow rate, anatomic features and, the stimulation of thermoreceptors and mechanoreceptors on nasal wall, may affect the sensation of unobstructed breathing. In the clinical practice, it is usually difficult to quantify the role each factor plays in the patient's complaint, as well as the choice of the best treatment to re-establish satisfactory nasal breathing.Rhinomanometry and acoustic rhinometry are the most common methods used to the objective evaluation of nasal obstruction. However, a recent study that reviewed the literature on rhinomanometry and acoustic rhinometry was unable to establish a correlation between the patient's perception of an obstructed nose and the results of these two methods. A possible explanation for this lack of correlation is that the patient's complaint of an obstructed nose may be more correlated to local airflow patterns than to the total nasal resistance or cross section area measured by rhinomanometry and acoustic rhinometry respectively. Computational fluid dynamics (CFD) is a new technology which has been applied, in recent years, to investigate the biophysics of nasal airflow. Using computational fluid dynamics it is possible to evaluate the features of nasal airflow in anatomically-correct, three-dimensional models of the nasal passages built from medical images, such as computed tomography scan (CT) and magnetic resonance images (MRI).Objectives: The primary objective of this study is to compare the nasal resistance measured by rhinomanometry with nasal resistance computed with computational fluid dynamics. The secondary objective is to describe the location and magnitude of the shear stress, water evaporation rate, heat flux, and airflow resistance through the nasal cavity and its correlation with the perception of sufficient airflow through the nasal cavity. Study design: transversal Materials and Methods: Thirty volunteers (n=30) with previous indication for computed tomography (CT) scan of the face will be submitted to an active anterior rhinomanometry and to a nasal complaint questionnaire. The nasal anatomy of each patient, obtained from the CT scan, will be used to create a computer model for CFD simulations. Nasal resistance derived from rhinomanometry will be compared to CFD-derived nasal resistance. The location and magnitude of the shear stress, water evaporation rate, heat flux, and the airflow resistance through the nasal cavity will be described and compared to subjective symptoms evaluated by NO-VAS and N.O.S.E. score. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

CHEROBIN, GIANCARLO B.; VOEGELS, RICHARD L.; GEBRIM, ELOISE M. M. S.; GARCIA, GUILHERME J. M.. Sensitivity of nasal airflow variables computed via computational fluid dynamics to the computed tomography segmentation threshold. PLoS One, v. 13, n. 11, NOV 16 2018. (12/20823-9)

CHEROBIN, GIANCARLO B.; VOEGELS, RICHARD L.; PINNA, FABIO R.; GEBRIM, ELOISA M. M. S.; BAILEY, RYAN S.; GARCIA, GUILHERME J. M.. Rhinomanometry Versus Computational Fluid Dynamics: Correlated, but Different Techniques. AMERICAN JOURNAL OF RHINOLOGY & ALLERGY, v. 35, n. 2, AUG 2020. (12/20823-9)