The effects of saline-induced edema in the human nasal mucosa on laser Doppler flowmetry

The nasal mucosa on the anteromedial surface of the inferior turbinate was studied with laser Doppler flowmetry in ten patients who were under general anaesthesia. A specially designed adapter was used, which held an injection needle with a diameter of 0.4 mm in a fixed position to the tip of the probe. The tip of the needle was inserted to a depth of 0.7 mm below the surface of the mucosa, while the tip of the probe was held at a distance of 0.3 mm from the mucosa. The laser Doppler parameters of perfusion, concentration of moving blood cells (CMBC) and velocity were recorded before and after the injection of 0.8 ml saline, thus inducing an experimental edema. After the injection no change in perfusion was detected but CMBC decreased and velocity increased. The findings agreed with the view that an increase in mucosal edema would reduce CMBC. When studying unanaesthesised subjects we normally use both rhinostereometry and laser Doppler flowmetry. It is then possible to measure the degree of mucosal congestion and micro circulation simultaneously, thus permitting study of the effects of a change in interstitial fluid content on mucosal congestion.