[High density respiratory syndrome: II. The mechanics of forced respiration with artificial resistive load under normobaric pressure].

The dynamics of forced inhale (I series) and exhale (II series) parameters with additional external artificial resistive load was studied under normobaric conditions. The artificial resistance to breathing increased stepwise using removable diaphragms with sequential decrease of hole diameter from 25, 17, 13, 9, 7.5, 4.5 to 3 mm. While studying forced inhale the diaphragms were set up at Fleish pipe airflow input. In the case of forced inhale the diaphragms were set up at the pipe output. A phenomenon is revealed which consists in appearance of respiratory flow oscillations on the "flow-volume" curves during forced breathing with an increase of resistive load. Frequency maxima of the oscillations were located within the range of 6-15 Hz. The possible mechanisms for appearance of respiratory muscle tremor and respiratory flow oscillations are under discussion.