In vitro evaluation of positive expiratory pressure devices attached to nebulizers

Abstract

ACKGROUND: Patients with cystic fibrosis perform airway clearance techniques and receive nebulized medications on a regular basis. Some positive expiratory pressure (PEP) devices allow concomitant administration of aerosol. I hypothesized that this practice alters the aerosol characteristics and patient dose. I compared the aerosol characteristics and patient dose of nebulized albuterol from 2 types of nebulizer, alone and when connected to different PEP and vibratory PEP devices. METHODS: Three units of a continuous-output nebulizer (Up-Draft II Opti-Neb) and 3 units of a breath-enhanced nebulizer (LC Plus) were tested alone and connected to PEP devices (Acapella Choice, Acapella Duet, and EzPAP for Up-Draft II Opti-Neb, and Pari PEP at 2 different settings, and Pari PEP S system with the LC Plus). Aerosol characteristics were evaluated with a cooled cascade impaction technique. The nebulizers were loaded with 2.5 mg/3 mL albuterol solution and operated for 4 min at 6 L/min (wall air). Patient dose was evaluated with simulated breathing patterns for a child, small adult, and large adult. Albuterol was assayed via spectrophotometry. RESULTS: Connecting the LC Plus to the PEP devices did not change the aerosol characteristics or patient dose. Connecting the Up-Draft II Opti-Neb to the PEP devices significantly reduced the mass median aerodynamic diameter, from 4.13 μm to 3.72 μm with EzPAP (P =.02), 1.24 μm with Acapella Choice (P