Background: So-called intrapulmonary percussive ventilation (IPV), frequently coupled with a nebulizer, is increasingly used as a physiotherapy technique; however, its physiologic and clinical values have not been rigorously assessed.
Study objective: To compare in vitro and in vivo characteristics of the nebulizer of the IPV device (Percussionaire; Percussionaire Corporation; Sandpoint, ID) with those of standard jet nebulization (SST) [SideStream; Medic-Aid; West Sussex, UK].
Design: Aerodynamic particle size was studied by an cascade impactor. The deposition of (99m)Tc-diethylenetriaminepenta-acetic acid was measured in 10 healthy subjects by tomoscintigraphy during spontaneous breathing with both nebulizers.
Measurements and results: The mass median aerodynamic diameter (0.2 micro m vs 1.89 micro m for IPV and SST, respectively) and the fine-particle fraction (16.2% vs 67.5%, respectively) were significantly smaller with IPV. In vivo, respiratory frequency (RF) was lower with the IPV device (10.1 +/- 3.4 breaths/min vs 14.6 +/- 3.4 breaths/min, p = 0.002). Whole-body deposition was significantly higher with IPV (15.63% vs 9.31%), but it was due to a higher extrapulmonary deposition. Although intrapulmonary deposition (IPD) was not different with both devices (4.20% for SST vs 2.49% for IPV), it was much more variable with IPV, compared to SST. The penetration index into the lung was higher with IPV than SST when normalized for RF (0.045 +/- 0.018 breaths/min vs 0.026 +/- 0.013 breaths/min, p = 0.007).
Conclusion: The two techniques showed comparable lung deposition despite a large difference in particle size. However, IPV IPD was too variable and thus too unpredictable to recommend its use for drug delivery to the lung.