Combined use of HFPPV with low-rate ventilation in traumatic respiratory insufficiency

Abstract

Two patients with chest injuries, flail chest and respiratory failure were mechanically ventilated by a system composed of 2 Bennett respirators and an independent source of gas. This system provides high-frequency positive pressure ventilation (HFPPV), low-frequency conventional mechanical ventilation (LFCMV) and high inspiratory flow of fresh gas (HIF), through the independent source. This system made use of the advantages of HFPPV and also solved the problem of possible CO2 retention. Using this system we could ventilate the patients while they were fully conscious and cooperative, thus eliminating the need for sedatives and muscle relaxants. Time of mechanical ventilation was shortened since the internal pneumatic fixation was very good and made it possible for the fractured ribs to unite rapidly. Restoration of spontaneous breathing was immediate after disconnection from the ventilator. We suggest this method as another mode of ventilation for patients with flail chest and respiratory failure.

Hemodynamic effects of high frequency ventilation superimposed on intermittent positive pressure ventilation in dogs

“…The problem was eliminated with the combined ventilation. Barzilay et al (15) used the combination of low frequency ventilation and high frequency ventilation at a rate of 140-160 in two patients and observed an increase in arterial oxygenation compared to IPPV alone. We did not find any changes in arterial oxygenation during the study, probably as a result of normal alveolar function with no true shunt or areas with low ventilation/perfusion ratio because of the high oxygen content in the inspired air.…”