Aerosol Delivery Efficiency of Two Nebulizers With and Without Handheld Oscillatory Pressure Therapy

Abstract

Background:

Nebulized hypertonic saline (HS 7%) is commonly prescribed for cystic fibrosis (CF) patients using nebulizers and handheld devices that generate oscillatory positive end-expiratory pressure (OPEP) . There is limited evidence for the delivery of nebulized HS 7% and whether OPEP use impacts efficiency. This study examined particle size and delivered lung dose in a spontaneously breathing model between different nebulizers with and without OPEP therapy. We hypothesized that particle size and delivered lung dose would be similar among testing scenarios.

Methods:

The Pari LC Plus and AeroEclipse II provide continuous aerosol output. AeroEclipse II can also be configured as a breath-actuated nebulizer (BAN). We modeled 5 testing conditions: Pari LC Plus (continuous); AeroEclipse II (continuous and BAN), and both nebulizers (continuous) integrated with an Aerobika OPEP device. Particle droplet size (µm, Dv ₅₀) was measured by a laser diffractometer. Nebulized HS 7% was applied to a 3D anatomic nasotracheal airway of a spontaneously breathing child lung model (frequency 15 breaths/min, V_T of 350 mL, and I:E of 1:2). The nebulizers, OPEP devices (when applicable) and a capture filter were pre-conditioned in a vacuum heater and weighed (µg). The nominal HS 7% dose was quantified based on the dry salt mass. The filter was placed between the airway and lung model. The HS 7% was nebulized via a mouthpiece, until sputtering, for 3 runs for each condition (no. = 15). Following testing, each component was dried 70°C for 24 hours and reweighed. The difference in pre-post filter and nebulizer weights represented delivered lung dose and residual nebulizer dose, respectively. Values were referenced to the nominal nebulizer dose (%). The mean lung doses were compared using ANOVA.

Results:

The Dv ₅₀ was 2.2 ± 0.2, 3.2 ± 0.1, 1.94 ± 0.1, and 2.6 ± 0.1 µm for Pari LC Plus, AeroEclipse II, Pari LC Plus/Aerobika and AeroEclipse II/Aerobika, respectively. The AeroEclipse BAN-mode had the greatest lung dose (%) than the other condition (P < .05, see Figure). AeroEclipse II compared to Pari LC plus had greater lung dose with the Aerobika (P < .05). The nebulizer residual was lower with AeroEclipse II than Pari LC plus for all conditions.

Conclusions:

We showed small, inhaled HS 7% particles (<5.4µm) are generated with each nebulizer. The AeroEclipse II performed with the highest efficiency and provided similar lung deposition of HS 7% with and without OPEP. Patients may benefit from greater drug delivery using the AeroEclipse II with BAN mode.