Nebulized Albuterol Delivery in a Model of Spontaneously Breathing Children With Tracheostomy

Abstract

BACKGROUND: Nebulized therapy is commonly used in spontaneously breathing tracheostomized patients, despite a lack of recommended devices and techniques. I compared albuterol dose delivered to a model of spontaneously breathing children with tracheostomy, using different nebulizers, tracheostomy tube sizes, inhalation techniques, and breathing patterns. METHODS: A tracheostomy model was connected in series to a breathing simulator, with a filter interposed. I simulated the breathing patterns of a 16-month-old child and 12-year-old child, and tested tracheostomy tubes with internal diameters of 3.5 mm and 5.5 mm. Albuterol nebulizer solution (2.5 mg/3 mL) was used. A breath-enhanced nebulizer (Pari LC Plus), a breath-actuated nebulizer (AeroEclipse), and a nebulizer that continuously delivers aerosol (Up-Draft II Opti-Neb) were operated for 5 min at 6 L/min with wall air. The Up-Draft II was tested with T-piece and mask interfaces, with an extension tube, and with and without assisted breathing (every breath and every other breath). The amount of albuterol delivered was analyzed via spectrophotometry. Particle size distribution was measured with a cascade impactor. RESULTS: The Pari LC Plus was more efficient than the Up-Draft II or AeroEclipse. Assisted breathing with the Up-Draft II with extension increased albuterol delivery with every other breath (second best device/configuration), being superior to every breath technique. Adding an extension tube increased delivered albuterol. T-piece was more efficient than mask. Breathing patterns with larger tidal volume increased albuterol delivery. Tracheostomy size had less impact on drug delivery. Mass median aerodynamic diameter decreased by 48 -74% when passing through the tracheostomy tubes, and 0.8% of the nominal dose was deposited in the tracheostomy tube. CONCLUSIONS: Albuterol delivery in a model of spontaneously breathing children with tracheostomy is influenced by type of device and configuration, use of assisted breathing, breathing pattern, and tracheostomy tube size. Mass median aerodynamic diameter significantly decreases during passage through a tracheostomy tube.

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

“…10 Previous studies done in pediatric models of spontaneously breathing children reported that a pressurized metered-dose inhaler (pMDI) with a spacer/valved holding chamber (VHC) and a continuous output jet nebulizer used with the assisted technique delivered the highest amount of albuterol. 6,7 The same studies reported that use of the assisted technique was beneficial when used with jet nebulization but detrimental when pMDIs/VHCs were used. Other studies have shown a benefit of using the assisted technique or have been neutral.…”

“…The amount left in the nebulizer cup was calculated by subtracting the dry weight from the weight after the 5 mL were added and then multiplying this value by the albuterol concentration. 7 This method was used as a quality control measure, and since there were no differences, results were not reported. This was done to ensure that each nebulizer cup was operating correctly and that each run received approximately the same amount of drug.…”

“…3B). 6,7 All of the VHCs were made out of antistatic materials. The AeroChamber Plus is a 149-mL holding chamber with a built-in one-way valve.…”

“…5,9 The particle size of nebulized aerosols is significantly reduced when traveling through pediatric size tracheostomy tubes, but data on aerosols generated by a pMDI/VHC are lacking. 7 A better understanding of aerosol delivery through tracheostomies is clinically relevant and long-needed. We hypothesize that changing the delivery route from the face to the tracheostomy, using a smaller tidal volume, using a tracheostomy tube with smaller ID, the presence of tracheostomy during drug delivery through the face, and the use of the assisted technique with a pMDI/VHC will result in a lower lung dose.…”

“…[4][5][6][7][8][9] Multiple factors have been reported to affect drug delivery through tracheostomies, such as: type of aerosol generator, type of interface, inner diameter (ID) of the tracheostomy tube, use of bias flow, use of different breathing patterns, and use of the assisted technique. [4][5][6][7][8][9] The latter involves the use of a resuscitation bag to provide support breaths while the aerosol is being delivered. A survey about practices on aerosol delivery to spontaneously breathing tracheostomized children showed that many centers used devices/delivery techniques that have been shown to decrease aerosol delivery efficiency through tracheostomies.…”