BACKGROUND

This study was conducted to compare the efficiency of jet nebulizers, vibrating mesh nebulizers, and pressurized metered-dose inhalers (pMDI) during assisted and unassisted administration techniques using a simulated spontaneously breathing pediatric model with a tracheostomy tube (TT).

METHODS

An in vitro breathing model consisting of an uncuffed TT (4.5-mm inner diameter) was attached to a collecting filter (Respirgard) connected to a dual-chamber test lung and a ventilator (Hamilton Medical) to simulate breathing parameters of a 2-y-old child (breathing frequency, 25 breaths/min; tidal volume, 150 mL; inspiratory time, 0.8 s; peak inspiratory flow, 20 L/min). Albuterol sulfate was administered using a jet nebulizer (MicroMist, 2.5 mg/3 mL), vibrating mesh nebulizer (Aeroneb Solo, 2.5 mg/3 mL), and pMDI (ProAir HFA, 432 μg). Each device was tested 5 times with an unassisted technique (direct administration of aerosols with simulated spontaneous breathing) and with an assisted technique (using a manual resuscitation bag in conjunction with an aerosol device and synchronized with inspiration). Drug collected on the filter was analyzed by spectrophotometry.

RESULTS

With the unassisted technique, the pMDI had the highest inhaled mass percent (IM%, 47.15 ± 7.82%), followed by the vibrating mesh nebulizer (19.77 ± 2.99%) and the jet nebulizer (5.88 ± 0.77%, P = .002). IM was greater with the vibrating mesh nebulizer (0.49 ± .07 mg) than with the pMDI (0.20 ± 0.03 mg) and the jet nebulizer (0.15 ± 0.01 mg, P = .007). The trend of lower deposition with the assisted versus unassisted technique was not significant for the jet nebulizer (P = .46), vibrating mesh nebulizer (P = .19), and pMDI (P = .64).

CONCLUSIONS

In this in vitro pediatric breathing model with a TT, the pMDI delivered the highest IM%, whereas the vibrating mesh nebulizer delivered the highest IM. The jet nebulizer was the least efficient device. Delivery efficiency was similar with unassisted and assisted administration techniques.