Assessment of Aerosol Delivery to Adult and Paediatric Tracheostomised Patients during Weaning from Mechanical Ventilation
Mary Joyce1, Sorcha Ní Mhurchú1, Gavin Bennett1, Ian MacDonnacha1, Louise Sweeney1 & Ronan MacLoughlin1
1Aerogen, Galway Business Park, Dangan, Galway, H91 HE94, Ireland
During periods of weaning from mechanical ventilation there are intervals when patients are alternatively mechanically ventilated and spontaneously breathing via a tracheostomy. Aerosol therapy is routinely administered in spontaneously breathing tracheostomised patients.  The percentage of inhaled aerosolised drug can be affected by the mode of delivery. 
This study investigated the use of a vibrating mesh nebuliser for aerosol delivery to both adult and paediatric tracheostomised patients during mechanical ventilation and whilst spontaneously breathing. The nebuliser was placed on the dry side of a humidifier within a dual limb breathing circuit for mechanical ventilation. The nebuliser was attached to a paediatric T-piece at the tracheostomy tube using a breathing simulator for spontaneous breathing.
Results: At the completion of this testing, it was established that for both adult and paediatric tracheostomised patients, there were no statistically significant differences in the quantity of inhaled drug being delivered during mechanical ventilation in comparison to spontaneously breathing. For adults, drug delivered on ventilator gave a slightly higher inhaled dose of 33.93% ± 2.36%. For paediatrics, a higher inhaled dose of 30.31% ± 1.39% was observed for spontaneously breathing.
Conclusion: The effect of alternating between mechanical ventilation and spontaneous breathing during patient weaning showed no significant differences (P-values > 0.05) in drug delivery for both populations.