Oronasal and tracheostomy delivery of soft mist and pressurized metered-dose inhalers with valved holding chamber

Abstract

BACKGROUND: Some pediatric tracheostomized patients who receive inhaled drugs undergo decannulation, and it is unknown whether the dose has to be adjusted. Pressurized metereddose 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 a .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 a .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.