[Effects of the Airway Obstruction on the Skin Microcirculation in Patients with Bronchial Asthma].

Background: Pulmonary hemodynamic disorders depend on the inflammatory phases and severity of the obstructive syndrome. However, the effect of asthma bronchial obstruction on the state of peripheral hemodynamics remains insufficiently known.

Aims: To study the effects of airway obstruction on skin blood flow parameters and its regulatory systems in patients with persistent atopic bronchial asthma in the remission state.

Materials and methods: A comparative study of the skin peripheral blood flow in patients with bronchial asthma with severe airway obstruction (1st group) and without obstruction (2nd group) was conducted. 20 patients with confirmed diagnosis of atopic asthma of 50–74 years old participated in the study. All patients received basic therapy in a constant dosing of high doses of inhaled glucocorticosteroids/long-acting beta-2-agonists. The control group included 20 healthy volunteers without evidence of bronchial obstruction. The study lasted for 3 months. The forced expiratory volume in 1 s (FEV1) was used to evaluate the bronchial obstruction by spirometry technique. Skin blood perfusion changes were recorded by laser Doppler flowmetry at rest and in response to short-term local ischemia. Registered peripheral blood flow signals were examined using the amplitude temporal filtering in five frequency intervals to identify the functional features of the peripheral blood flow regulation systems.

Results: Consistent two-fold decrease of the oscillation amplitudes was found in the neurogenic interval at rest (p=0.031), as well as in the myogenic (p=0.043; p=0.031) and endothelial intervals (p=0.037; p≤0.001) both at rest and during the postocclusive reactive hyperemia respectively in the 1st group of patients with bronchial obstruction (FEV1 <80%) compared with the control group. No significant changes were revealed for skin blood flow parameters in the 2nd patient group (without obstruction, FEV1 >80%) in comparison to control subjects.

Conclusions: The presence of bronchial obstruction has a significant impact on the changes of the amplitudes of skin blood flow oscillations in patients with bronchial asthma in the myogenic, neurogenic and endothelial intervals.