Abstract
Background: Intrapulmonary percussive ventilation (IPV) is frequently used for airway clearance, together with delivery of aerosols containing medications. Drug delivery via IPV alone increases with decreasing percussion frequency and correlates with tidal volume (VT) while drug delivery via IPV during conventional mechanical ventilation (IPV/CMV) is not well characterized. We hypothesized that drug delivery via IPV/CMV would take place differently from that via IPV alone due to control of ventilation by CMV. Methods: An adult ventilator circuit was used for IPV/CMV. A normal or diseased lung model was configured to airway resistance (Raw) 5 cm H2O/L/s and lung compliance (CL) 100 mL/cm H2O or Raw 20 cm H2O/L/s and CL 50 mL/cm H2O, respectively. The ventilator settings were: pressure control continuous mandatory ventilation mode, 10 breaths/min, PEEP 5 cm H2O, FIO2 0.21, inspiratory time 1 s, no bias flow, and inspiratory pressure 10 or 15 cm H2O for the normal or diseased lung model, respectively, to reach VT 500 mL with IPV off. Albuterol nebulized from Phasitron 5 was captured in a filter placed before the lung model and quantitated by spectrophotometry. Results: The maximal efficiency of albuterol delivery via IPV/CMV was not different from that via IPV alone (3.7 ± 0.2% vs 4.2 ± 0.3%, mean ± SD of loading dose, P= .12). Albuterol delivery efficiency with IPV/CMV was lower for the diseased lung model than for the normal model (1.6 ± 0.3% vs 3.2 ± 0.5%, mean ± SD, P < .001), which increased with decreasing percussion frequency. In contrast, VT was lower for the normal lung model than for the diseased model (401 ± 14 mL vs 470 ± 11 mL, mean ± SD, P < .001). Conclusions: Albuterol delivery via IPV/CMV was modulated by percussion frequency but not increased with increasing VT. The delivery efficiency was not sufficiently high for clinical use, in part due to nebulizer retention and extrapulmonary deposition.
Footnotes
- Correspondence: *Yusuke Mimura, MD, PhD, Department of Clinical Research, National Hospital Organization Yamaguchi Ube Medical Center, 685 Higashikiwa, Ube, 755–0241 JAPAN, E-mail: mimura.yusuke.qy{at}mail.hosp.go.jp, Tel: +81-836-582300, Fax: +81-836-585219
- Received May 29, 2023.
- Accepted March 18, 2024.
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