Tailoring of HFPV Treatment by Respiratory Parameters Measurement

High-frequency percussive ventilation (HFPV) is a non-conventional ventilatory modality which has proven highly effective in patients with severe gas exchange impairment. HFPV delivers a series of high-frequency sub-tidal volumes, by pulsatile flow, in combination with low-frequency breathing cycles. Currently, the mean airway pressure is the only parameter that allows an indirect comparison between conventional volume controlled ventilation and HFPV treatment set up. In the clinical practice, HFPV is not an intuitive ventilatory modality and the absence of valuable information during the treatment as delivered tidal volume, respiratory system resistance and compliance produces disaffection among the physicians. The aim of this study was to tailor HFPV treatment setup, avoiding under and overtreatment, using new bedside measurements of the main respiratory parameters. For this purpose pressure, flow and volume were measured in six patients undergoing HFPV. Respiratory system resistance and compliance were estimated using multiple linear regression method on Dorkin’s high frequency model, while endotracheal tube pressure drop was estimated using Blasius’s model. This study offers a new approach for HFPV treatment tailoring in accordance with protective ventilatory strategy and optimization of the alveolar ecruitment. The possibility to measure respiratory parameters has opened a new horizon in clinical monitoring during this particular ventilator strategy, improving the beneficial effect of HFPV and minimizing iatrogenic lung damage.