Albuterol Delivery via Facial and Tracheostomy Route in a Model of a Spontaneously Breathing Child

Abstract

BACKGROUND: Some pediatric patients receiving therapeutic aerosols undergo tracheostomy, and others who are tracheostomized continue requiring inhaled therapies upon decannulation. It is unknown whether a dose adjustment is required. Different devices are available for facial and tracheostomy delivery, and in some instances, the assisted technique is used. We hypothesized that the change from face mask to tracheostomy would result in a decrease in the lung dose. METHODS: A breathing simulator connected in series to a filter holder and an anatomically correct head model of a child was used. The drug captured in the filter was termed the lung dose. Breathing patterns with tidal volumes of 50, 155, and 300 mL were tested. Albuterol hydrofluoroalkane (pressurized metered-dose inhaler [pMDI]) with an AeroChamber Mini (face and 4.5-mm tracheostomy), AeroTrach (4.5-mm tracheostomy), and AeroChamber (face) and albuterol (2.5 mg/3 mL) with a continuous output nebulizer (face and 4.5-mm tracheostomy) were tested. Masks were used for facial delivery. Four units of each device were tested. Particle size of the pMDI was measured by cascade impaction. Albuterol concentration was determined via spectrophotometry (276 nm). RESULTS: Switching from facial to tracheostomy delivery increased lung dose with nebulizer (all breathing patterns). When a pMDI was used, lung dose was unchanged or increased for the 50-and 155-mL and decreased for the 300-mL breathing pattern. The use of the assisted technique increased lung dose only during nebulization with the 300-mL breathing pattern. The particle size of the pMDI decreased by 19 -23% when traveling through the tracheostomy tube, which retained < 4% and < 26% of the nominal dose of a nebulizer and pMDI, respectively. CONCLUSIONS: The effect of changing the delivery route from face to tracheostomy was variable and depended on the delivery device and the breathing pattern. There is no advantage of using the assisted technique to enhance aerosol delivery.

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

“…The model was operated in the vertical position as previously reported. 11,12 After selecting a breathing pattern, the accuracy of the tidal volume was verified using a mass flow meter (TSI, Shoreview, Minnesota). 11,12 The seal between the head/airway model and the mask was achieved with putty.…”

“…11,12 After selecting a breathing pattern, the accuracy of the tidal volume was verified using a mass flow meter (TSI, Shoreview, Minnesota). 11,12 The seal between the head/airway model and the mask was achieved with putty. 12 The pMDI was primed with 4 puffs at the beginning of every testing day and was shaken for 5 s before each actuation.…”

“…12 Briefly, a 3-dimensional printed oronasal head model of a 5-y-old child was connected in series to a low dead space filter holder and a breathing simulator (PARI Compass, Munich, Germany) (Fig. 1).…”

“…9 Due to the paucity of clinical studies, most of our insight on optimization of aerosol delivery with pMDIs and VHCs through tracheostomy derives from in vitro studies. [10][11][12] Those studies reported that the type of VHC, breathing patterns, and other factors affect drug delivery of pMDI through tracheostomies. Recently, Cooper et al 12 compared oronasal and tracheostomy delivery of albuterol using a pMDI with 2 different VHCs and a continuous output jet nebulizer.…”

“…They found that the type of VHC and breathing pattern affect the difference between the lung dose obtained via tracheostomy and oronasal routes. 12 Knowledge regarding the effect of different drug delivery devices (pMDI vs SMI) and VHCs (metallic vs antistatic polymer) is needed. We hypothesize that the use of SMI, larger tidal volumes, and changing the delivery route from tracheostomy to oronasal will result in a higher lung dose.…”