The accuracy and reproducibility of rhinospirometry in detecting flow asymmetry in a nasal cavity model.

The objective of this study is to investigate the appropriateness of the NV1 rhinospirometer in the assessment of asymmetrical nasal airflow using a nasal cavity model. The Study is a laboratory-based basic-science study using an artificial model of nasal airflow. It is conducted in Medical Physics Department, Singleton Hospital, Swansea, Wales. A nasal cavity model was created with a series of parallel flow symmetry/asymmetries that were each assessed using standard flow volume measurements. The results were converted into Nasal Partition Ratios (NPRs) for each trial scenario and were examined against a mathematically calculated NPR derived using Pouseille's law. Experimental scenario results were assessed for correlation, accuracy and precision against the mathematically derived result. In this study 300 individual test scenarios were completed using 2 different flow volumes and 15 different symmetry/asymmetry combinations. Correlation of the attained results against the mathematically derived figure gave a very strong correlation, using Spearman's Rho = 0.975. Accuracy was excellent within one Standard deviation of the expected results. It was concluded that the NV1 rhinospirometer is an accurate and precise objective marker of airflow symmetry in the nasal cavity model giving strong correlation, accuracy, precision and reproducibility. The rhinospirometer, as a precision tool, has displayed potential to become an effective objective marker of nasal airflow in the assessment of nasal obstruction; however, clinical trials are required to examine whether the accurate results of this laboratory study are transferable to clinical practice.