ABSTRACT
BACKGROUND: The Acapella device produces high-frequency oscillations and positive expiratory pressure to promote bronchial secretion clearance. Its performance during aerosol delivery has not been described. We evaluated the effect of nebulizer and Acapella configuration on pulmonary deposition of radio-tagged aerosol in healthy subjects. METHODS: Ten healthy male subjects (mean age 24.4 ± 2.2 y) participated in a crossover study that compared pulmonary delivery of 4 mL of technetium-99m-labeled diethylene triamine penta-acetic acid (25 mCi) and 0.9% saline solution via jet nebulizer. We tested 3 configurations: nebulizer attached to the distal end of the Acapella; nebulizer placed between the mouthpiece and the Acapella; and nebulizer alone (control). With scintigraphy we measured radio-aerosol deposition in 6 lung regions: upper, middle, lower, central, intermediate, and peripheral. RESULTS: Deposition was similar between the right and left lungs, with no significant differences between device configurations. Lung deposition was less with the nebulizer attached to the Acapella than with nebulizer between the mouthpiece and the Acapella (P = .001, for both lungs) or without the Acapella (P = .003 and P = .001 for the right and left lungs, respectively). There was no significant difference between the setup without Acapella and the setup with the nebulizer between the mouthpiece and the Acapella (P = .001, for both lungs). On the vertical axis, deposition was lower with the nebulizer attached to the distal end of the Acapella than with the nebulizer between the mouthpiece and the Acapella (upper region P < .001, middle region P = .001, lower region P = .003), and lower with the nebulizer attached to the distal end of the Acapella than with the setup without Acapella (upper and middle region both P = .001, lower region P = .002), with up to a 3-fold difference in the middle and lower regions. On the central-peripheral axis, deposition was lower with the nebulizer attached to the distal end of the Acapella than with the nebulizer between the mouthpiece and the Acapella (central region P < .001, peripheral region P < .001), and lower with the nebulizer attached to the distal end of the Acapella than with the setup without Acapella (central and peripheral regions both P = .002), with differences of 3-4-fold between the central and peripheral regions. CONCLUSIONS: Placing the nebulizer distal to the Acapella, as recommended by the manufacturer, decreased intrapulmonary deposition, compared to placing the nebulizer between the Acapella and the patient airway, or delivering aerosol without the Acapella in the circuit. (ClinicalTrials.gov NCT01102166).
