Oronasal and Tracheostomy Delivery of Soft Mist and Pressurized Metered-Dose Inhalers With Valved Holding Chamber.

BACKGROUND: Some pediatric tracheostomized patients who receive inhaled drugs undergo decannulation, and it is unknown whether the dose has to be adjusted. Pressurized metered-dose inhalers (pMDIs) and soft mist inhalers (SMIs) used with valved holding chambers (VHCs) made of non-electrostatic material are available. We hypothesized that using an SMI and changing the delivery route from tracheostomy to oronasal would increase lung dose.

METHODS: Four units of a metallic VHC were studied with albuterol hydrofluoroalkane (pMDI) and albuterol/ipratropium bromide with an SMI using an anatomically correct in vitro model of a 5-y-old spontaneously breathing tracheostomized child. The drug was captured in a filter and was termed lung dose. We tested breathing patterns with tidal volumes of 50, 155, and 300 mL. A mask and a special adapter were used as interfaces for oronasal and tracheostomy delivery, respectively. Spectrophotometry (276 nm) was used to determine albuterol concentration.

RESULTS: The use of SMI resulted in a higher lung dose than the pMDI for all tested conditions except delivery through tracheostomy with tidal volume of 155 mL (P = .69). Switching from oronasal to tracheostomy delivery increased the lung dose for all tested conditions except for the pMDI with the 300-mL tidal volume (P = .83). The use of SMI resulted in higher deposition in the tracheostomy tube than the pMDI.

CONCLUSIONS: In general, an SMI delivers a higher lung dose than a pMDI when using a metallic spacer during oronasal and tracheostomy route with the latter providing a higher lung dose.