HIGH-DENSITY BREATHING SYNDROME .2. MECHANICS OF FORCED BREATHING WITH ARTIFICIAL RESISTIVE LOAD IN NORMOBARIA

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 pipera airflow input. In 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 te <<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.