Understanding the mismatch between in-vivo and in-silico rhinomanometry

TL;DR

This study investigates the discrepancy between in-vivo and in-silico rhinomanometry measurements, highlighting the critical impact of probe placement on measurement accuracy and suggesting potential systematic biases in clinical devices.

Contribution

It reveals that probe placement significantly affects rhinomanometry results, challenging assumptions about measurement invariance and emphasizing the need to consider device design in nasal resistance assessments.

Findings

Probe position critically influences measurement accuracy

Numerical simulation uncertainty is minor compared to probe placement effects

Systematic bias may exist in clinical rhinomanometers due to device design

Abstract

Numerical simulations and clinical measurements of nasal resistance are in quantitative disagreement. Bias introduced by the design of medical devices has not been considered until now as a possible explanation. The aim of present paper is to study the effect of the location of the probe on the rhinomanometer that is meant to measure the ambient pressure. Rhinomanometry is carried out on a 3D silicone model of a patient-specific anatomy; a clinical device and dedicated sensors are employed side-by-side for mutual validation. The same anatomy is also employed for numerical simulations, with approaches spanning a wide range of fidelity levels. We find that the intrinsic uncertainty of the numerical simulations is of minor importance. To the contrary, the position of the pressure tap intended to acquire the external pressure in the clinical device is crucial, and can cause a mismatch comparable to that generally observed between in-silico and in-vivo rhinomanometry data. A source of systematic bias may therefore exist in rhinomanometers, designed under the assumption that measurements of the nasal resistance are unaffected by the flow development within the instruments.