[Results of functional analysis on an obstructive model of the lung using an Ergojet CVT high-frequency jet...

This paper expands a previous study on functional analysis of high frequency jet (HFJV) "Ergojet CVT" ventilation module inserted in Ergotronic 3 (Temel SA) respirator. The analysis was made on a pulmonary monoalveolar model with a compliance of 50 ml/cmH2 = and a resistance of 20 cmH2O/l/se simulating an obstructive pattern. Results were also compared with those obtained in a previous study on normal lung. HFJV was applied using a jet with or without additional gas input (VE) at respiratory rates of 90, 120, 150, 180, 210, 240, 270, and 300 per minute varying in each frequency the releasing pressure of the jet (PG 1, 2, and 3 kg/cm2) and the inspiratory time (Ti 30 to 50%) giving rise to a total of 96 different situations. In each of these conditions we measured the air way pressure (Paw) and the alveolar pressure (PA) and we calculated the tidal volume (VT) and the trapped volume (VAT). These measurements were correlated with those monitored by the respirator and those obtained in the normal lung. Results show that the VT is composed almost exclusively by the jet volume (VTjet), being only of consideration the VE with a Ti of about 33% and a PG of 2 to 3 kg/cm2. When the normal pattern was compared with the obstructive one, a small reduction in VT (average of 15%) and a marked increase in peak Paw (average of 75%) were observed. The use of a Ti of 50% has no clinical interest due to the large VAT that it produces.(ABSTRACT TRUNCATED AT 250 WORDS)