A validation study of nasal spectroscopy: Rhinolux.

This study is the first to validate the Rhinolux against acoustic rhinometry in detecting nasal mucosal swelling when changing body position from sitting to supine. The Rhinolux (Rhios GmbH, Germany) is a new device using a light-absorption technique called nasal spectroscopy and to measure changes in nasal blood volume as a sign of nasal mucosal swelling in real time. The relationship between the changes in nasal blood volume measured with the Rhinolux and changes in nasal mucosal swelling has however, not previously been validated objectively. To evaluate this relationship we compared the Rhinolux to acoustic rhinometry following the change in body position from sitting to supine. The study population consisted of 20 healthy subjects (7 women, 13 men, mean age 34.7 +/- 9.3 years). The Rhinolux was applied sitting in the upright position followed by 5 min in the supine position. Acoustic rhinometry was measured sitting in the upright position and after 5 min in the supine position. In seven subjects the measurements were repeated on three different days to assess the repeatability. The mean change from baseline in minimal cross sectional area DeltaMCA measured with acoustic rhinometry was -0.12(+/-0.19) cm2 (right + left side), P = 0.013 but DeltaE (change in light extinction from baseline) measured with the Rhinolux was unchanged 0.02(+/-0.18) optical densities (OD), P = 0.56. There was no correlation between DeltaE and DeltaMCA r = 0.028, P = 0.9. The mean DeltaE result from repeated measurements on different days was 0.05(+/-0.08) OD, P = 0.09 and the DeltaMCA was -0.1(+/-0.11) cm2, P = 0.02. This study showed that the changes in nasal blood volume measured with the Rhinolux did not reflect changes in nasal mucosal swelling measured with acoustic rhinometry when changing body position from sitting to supine. The results indicate that the utility of the Rhinolux in assessing nasal mucosal reactions has to be evaluated further.