The nasal mucosa of 10 healthy volunteers was studied with the combination of rhinostereometry and laser Doppler flowmetry during a challenge with 0.14 ml histamine dihydrochloride in stepwise increasing concentrations of 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 mg/ml. Five and 10 min after each challenge the degree of congestion and the microcirculatory parameters perfusion, velocity of flow and concentration of moving blood cells were recorded. A complex reaction pattern was seen. It was possible to measure simultaneously the degree of congestion and the microcirculatory parameters. With this combination of methods, it seemed possible to identify the effects of histamine on the different components of the nasal mucosa. The combination of the two methods appears to make possible detailed studies of the relationship between changes in congestion and microcirculation during intranasal challenges in humans.
Fourteen healthy volunteers were examined using rhinostereometry (RSM) and micromanipulator-guided laser-Doppler flowmetry (LDF) on the inferior turbinate and nasal septum. There were significant differences of the flowmetry readings at different distances from the mucosal surface within 0–1.0 mm. Changes in LDF values due to a change in distance between probe and mucosa seem to be an important artefact that will influence the flowmetry, especially if the probe is fixed to the framework of the nose (i.e. the skull) and if the congestive status of the mucosa changes. This can be a problem especially during intranasal challenges with substances that influence congestion. These artefacts can be eliminated by using an RSM-guided micromanipulator that allows the probe to follow changes in congestion.
The mucosa of the inferior turbinate was studied using rhinostereometry and micromanipulator-guided laser Doppler flowmetry in 10 healthy volunteers. First, spontaneous fluctuations were studied measuring congestion and multiple microcirculatory parameters simultaneously every 2 minutes. The subjects were then challenged with oxymetazoline using the same measuring technique studying the effects of the challenge during 12 minutes. There were spontaneous variations in congestion of up to 2.1 mm and variations in perfusion from 38% to 175% of average. There was no correlation between congestion in itself, or change in congestion, to perfusion or any other microcirculatory parameter. After challenge with oxymetazoline there was a rapid decrease in perfusion at 3 minutes after which there were no significant changes. The congestion decreased gradually throughout the procedure. Because congestion reflects the filling of the venous sinusoids and the flowmetry the state of the superficial vessels, we conclude that there are spontaneous short-term fluctuations in the sympathetic tone with independent actions on the different vessels. After challenge with a sympathomimetic drug, there was a decrease in both swelling and flow, but not synchronized. The combination of rhinostereometry and micromanipulator-guided laser Doppler flowmetry is a useful tool to study the dynamics of intranasal challenge reactions.
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