[Laser Doppler flow signal frequency analysis in physiological and drug modified nasal flow motion]

The term "flow motion" stands for the phenomenon of spontaneous and autonomous rhythmic variations of the contractile state of the smooth muscles of small dermal vessels. There also have been a few observations of variations in the microcirculation of the mucosa, but they have not been evaluated in detail to date. The aims of this study were to develop a method for investigation flow motion, especially in the nasal mucosa; to compare nasal flow motion to that of other skin and mucosal areas; to evaluate the influence of normal saline solution, as well as a sympathomimetic agent and histamine on flow motion. The microcirculation of the nasal mucosa of 40 healthy volunteers was measured under standardized conditions. In a first series of investigations, the microcirculations of the forehead, lobule of the ear, nose and oral mucosa were compared. In the second series, the microcirculation of the nasal mucosa was measured with laser-Doppler flowmetry before and after provocation with 0.9% saline solution, 0.25 mg oxymetazoline hydrochloride as sympathicomimetic preparation and 0.085 mg histamine in 0.5 ml of 0.9% saline solution. Evaluation of the data included signal analysis of the microcirculatory variations using fast-Fourier transformation and its changes before and after the pharmacological stimulations. Distribution of the power spectra showed that the nasal mucosa was significantly different from that of the skin of the forehead and the ear. Oxymetazoline hydrochloride led to a clear increase and histamine to a significant reduction in the frequencies of the flow motion. The results of this study demonstrated that nasal flow motion could be detected and evaluated with laser-Doppler flowmetry and a special analysis of the data recorded. Specific patterns of the flow motion frequencies could be detected in the nasal mucosa that were distinctive from those of the skin. The pattern of the flow motion frequencies reacted very sensitively to the pharmacological provocations used.