Acoustic rhinometry: a study of transient and continuous noise techniques with nasal models.

The objective of this study is to compare the properties of two of the most frequently used acoustic rhinometers: the EcoVision (Hood Laboratories, USA) using the transient technique, and the Rhin2100 (RhinoMetrics, Denmark) using the continuous wide-band technique. In the wide-band rhinometer (Rhin2100), the transient analog signals of traditional rhinometers (EcoVision), are replaced by a digitally produced continuous wide-band noise signal. Tubular models and a plastic model produced by stereolithography (SLA), representing the true replicate of the nasal anatomy, were used to compare the accuracy of the two rhinometers.

Does nasal nitric oxide come from the sinuses?

Objective: The purpose of this study was to assess nitric oxide (NO) output by the nose and sinuses.

Method: In one volunteer, the osteomeatal complex and sphenoethmoidal recess were occluded to isolate the nose from the sinuses. The antrum and frontal sinus were each punctured by two catheters and irrigated with air at constant flow.

Aerodynamic influences on nasal nitric oxide output measurements.

Nitric oxide (NO) concentration in aspirated nasal air is flow-dependent. Nasal NO outputs calculated from steady-state plateaux at flows < 1 l/min are substantially smaller than those at flows > 2 l/min. This study aimed to determine the differences in NO output as calculated from the NO concentration plateaux in aspirated nasal air, resulting from different aspiration flows.

Aspiration flow optimized for nasal nitric oxide measurement.

The aim of the present study was to evaluate some of the factors which may influence the reliability of nasal NO measurements, and to optimize methods suitable for children and adults. Nasal nitric oxide (NO) output was determined by chemiluminescent analysis of aspirated samples in 16 adults and 6 children. With the velopharyngeal aperture closed, stable NO levels were obtained at flows ranging form 0.

Nasal nitric oxide is independent of nasal cavity volume.

This study was performed to evaluate the relationship between nasal nitric oxide (NO) and changes in nasal cavity volume resulting from the topical application of xylometazoline and saline and between upright and supine posture. Nasal NO was measured using a fixed high flow technique that avoids contamination with lower airways NO. In nine healthy subjects nasal NO concentration was measured by a rapid response chemiluminescent analyzer.