In vitro measurement of respiratory mechanics during HFPV using a mechanical lung model

High-frequency percussive ventilation (HFPV) may be defined as flow-regulated time-cycled ventilation that creates controlled pressure and delivers a series of high-frequency subtidal volumes in combination with low-frequency breathing cycles. In recent years, the usefulness of HFPV has been clinically assessed as an alternative to conventional mechanical ventilation. In the clinical practice, HFPV is not an intuitive ventilatory modality and the absence of real-time delivered volume monitoring produces disaffection among the physicians. For this purpose, it would be useful to develop a monitor able to realize a complete online characterization of high-frequency percussive ventilators and to identify the best combination of their parameters according to the specific pathological situation. This paper describes an innovative acquisition and elaboration system based on the use of new generation pressure transducers presenting high sensitivity and fast response. Such a system is compact and inexpensive, and it allows the user to carry out a more correct online characterization of high-frequency percussive ventilators. This output allowed best real-time ventilatory setting, minimizing the potential baro-volutrauma hazard.