Intrapulmonary effects of setting parameters in portable intrapulmonary percussive ventilation devices.

Background: Despite potential benefits of intrapulmonary percussive ventilation (IPV) in various respiratory diseases, the impact of setting parameters on the mechanical effects produced by IPV in the lungs is unknown. We hypothesized that changing the parameters on IPV would modulate these effects. This in vitro study aimed at comparing the changes in intrapulmonary effects resulting from changes in parameters in 3 portable IPV devices (IMP2, Impulsator, and Pegaso).

Methods: Parameters were set in 72 combinations of frequency (90-250 cycles/min), inspiratory to expiratory (I/E) time ratio (from 1/2 to 3/1), and pressure (10-60 cm H(2)O). Four resulting effects were recorded on a test lung via a pneumotachometer: the expiratory to inspiratory flow ratio (E/I flow ratio), the PEEP, the ventilation, and the percussion. Percussion was assessed by the end-slope of the pressure curve. Analysis of variance was used for data analysis.

Results: E/I flow ratio increased with increasing I/E time ratio (P < .001). The Pegaso produced the lowest E/I flow ratio. PEEP raised 6 cm H(2)O in both IMP2 and Impulsator, and 17 cm H(2)O in the Pegaso with increasing frequency (P < .01), pressure, and I/E time ratio (P < .001). In all devices, ventilation increased with increasing pressure and decreasing frequency (P < .001). Percussion increased with increasing frequency and decreasing I/E time ratio (P < .001), and with increasing pressure when I/E time ratio was 1/1 or less. The Pegaso provided the poorest percussion.

Conclusions: This study suggests that changing the parameters considerably modulates the mechanical effects produced by portable IPV devices in the lungs. Increasing frequency increased PEEP and percussion, but decreased ventilation. Increasing I/E time increased PEEP and E/I flow ratio, and decreased percussion. Finally, increasing pressure increased PEEP and ventilation. The Pegaso produced the highest PEEP, least percussion, and smallest change in E/I flow ratio.