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

High-frequency percussive ventilation (HFPV) has proved its unique efficacy in the treatment of acute respiratory distress, when conventional mechanical ventilation (CMV) has demonstrated a limited response. We analysed flow (V(dot)), volume (V) and airway pressure (Paw) during ventilation of a single-compartment mechanical lung simulator, in which resistance (R) and elastance (E) values were modified, while maintaining the selected ventilatory settings of the HFPV device. These signals reveal the physical effect of the imposed loads on the output of the ventilatory device, secondary to constant (millisecond by millisecond) alterations in pulmonary dynamics. V(dot), V and Paw values depended fundamentally on the value of R, but their shapes were modified by R and E. Although peak Paw increased 70.3% in relation to control value, mean Paw augmented solely 36.5% under the same circumstances (maximum of 9.4 cm H2O). Finally, a mechanism for washing gas out of the lung was suggested.

High frequency percussive ventilation (HFPV). Principles and technique.

In recent years, the usefulness of high frequency ventilation (HFV) has been clinically reassessed as an alternative to conventional mechanical ventilation (CMV). HFV has often been combined with or in some cases even completely replaced CMV in the attempt to reduce iatrogenic injury. High frequency percussive ventilation (HFPV) is a specific mode of HFV that has been successfully applied in the treatment of acute respiratory failure after smoke inhalation; it has also been more widely used in pediatric than in adult patients. This article gives an introduction to and a description of the basic principles of HFPV, a mode of ventilation which we found particularly versatile and reliable in our preliminary clinical experience with the maneuver.

Comparison of high-frequency lung ventilation with conventional mechanical lung ventilation. Prospective trial in patients who have undergone cardiac operations.

High-frequency lung ventilation was compared with conventional mechanical lung ventilation following elective cardiac operation. The results indicate that this high-frequency ventilator works as well as conventional mechanical ventilators and that it accomplishes the desired gas exchange at lower peak airway pressures. We conclude that routine use of high-frequency ventilation in the postoperative period is possible and that it may be indicated if lower peak airway pressures are desired.