[Estimation of bronchial tree zones involved in formation of human forced expiratory wheezes through vortex shedding mechanism, depending on the dynamic compression of central airways].

Forced expiratory wheezes (FEWs) are examined for the diagnosis of pulmonary disease. However there is no clarity in the mechanisms and possible localization of their formation. Purpose--Clarification of the formation of FEWs in bronchial levels in different types of dynamic compression. Peak frequency mid-frequency (400-600 Hz) of FEWs of maximum power and peak frequency of high frequency FEWs (600 Hz) of maximum power and speed of the flow at the mouth were measured in the sample of 85 healthy male volunteers (16-23 years). Strouhal coefficients were calculated for variuow levels of bronchial tree according to Weibel's morphometry. It is shown that for FEWs, formed by the vortex shedding with Strouhal coefficients of 0.2-0.3, the trend is shifting their formation zone to the proximal region with increase of dynamic compression of the airways. The most reliable estimates of dynamic compression result in formation of mid-frequency FEWs in the area of exit of intrathoracic portion of trachea into its outer part and in bifurcation of trachea, while the most probable formation zone of early high FEWs are bifurcations of trachea and main bronchi.