Effects of mechanical load on flow, volume and pressure delivered by high-frequency percussive ventilation

Early Short-Term Application of High-Frequency Percussive Ventilation Improves Gas Exchange in Hypoxemic Patients

“…The mechanical properties of HFPV have been recently described [16]. HFPV was found to be effective in patients with severe gas exchange impairment while CV was demonstrated to be failing [19].…”

“…To obtain the same previously measured P aw , the following adjustments were made on a volumetric diffusive respirator (VDR-4®; Percussionaire Corporation, Sandpoint, Idaho, USA): during inspiration a pulsatile flow with a percussive frequency of 500 cycles/min and a pulse inspiratory and expiratory ratio (i and e respectively) of 1 was used; during expiration a mean PEEP level similar to that used during CV was obtained by oscillatory PEEP. During the trial, the breathing frequency was adjusted by modifying the I:E ratio, and the oscillating PEEP was varied, if necessary, to maintain normocapnia and the same P aw [16]. During 12 h the patients were ventilated under these conditions and every 4 h blood samples were collected for gas analysis, and MAP and P aw were recorded.…”

Gas distribution in a two-compartment model ventilated in high-frequency percussive and pressure-controlled modes

“…We based our study on the two-compartment parallel model introduced by Otis et al [21], extending our previous studies [19,20]. In such a model the distribution of the overall flow in the separate branches depends on the impedances of each independent compartment.…”

“…Recently a one-compartment linear model of the respiratory system has been successfully used to demonstrate the effects of mechanical resistive and elastic loading on flow, tidal volume, and pressure curves generated by HFPV as well as on the resulting washout of gas from the lungs [19,20]. However, the consequences of HFPV on a mechanically heterogeneous lung have yet to be explored.…”

Intrapulmonary Percussive Ventilation Superimposed on Conventional Mechanical Ventilation: Comparison of Volume Controlled and Pressure Controlled Modes

“…It has been shown that pressure and volume delivered by IPV are influenced by changes in lung compliance and resistance. 19 In conclusion, as suggested by this bench study, when the trigger of the ICU ventilators is adjusted to avoid any autotriggered breath, the PC-CMV mode should be selected when using IPV in combination with conventional mechanical ventilation.…”