[Functional analysis of the high frequency jet respirator on a normal lung model. Ergojet CVT]

In this paper the results of the functional analysis of the Ergojet CVT, which is the high-frequency jet ventilation (HFJV) module of the Ergotronic 3 ventilator (Temel S.A.) are described. For a better understanding a detailed description of the module has been included. The functional analysis was performed on a standard lung model of normal compliance and resistance (C: 50 ml/cmH2O and R: 8 cmH2O.1-1.seg-1). High frequency jet ventilation was applied using the jet with and without additional gas entrainment, at frequencies of 90, 120, 150, 180, 210, 240, 270 and 300 rpm; for each frequency changes were made on the driving pressure (Pdriv: 1-2-3 kg.cm-2) and the inspiratory time (Ti: 33-50%). The combination of these parameters produced 96 different ventilatory circumstances. In each of them, airway and alveolar pressures (Paw and PA) were measured. Tidal and alveolar gas-trapped volumes (VT and Vtrap) were calculated from the previous PA measurements. These values were compared with those displayed by the ventilator. Following the results of the functional analysis of the Ergojet CVT, the VT delivered by the jet is the primary determinant of the VT, being little de increment due to the entrainment of gas. In the normal lung model, an adequate VT is obtained until frequencies of 240 rpm, using a Pdriv of 3 kg.cm-2. Vtrap, as in conventional ventilation, depend on VT and Te. The Pdriv and Ti, can be adequatelly combined in order to obtain a minimal Vtrap. Peak Paw depends on VT and Paw min on Vtrap.(ABSTRACT TRUNCATED AT 250 WORDS)