Performance of different add-on devices in dual limb non-invasive mechanically ventilated circuit

Aerosol delivery is thought to be improved by giving one or two pMDI puffs before the prescribed nebulizer dose during non-invasive ventilation (NIV). The aim of the present study was to in-vitro evaluate the efficiency of aerosol delivery using newly developed spacers versus standard T-piece in dual limb NIV circuit. Three add-on devices were evaluated: Combihaler, Minimhal, and standard T-piece which were connected to a vibrating mesh nebulizer (VMN), jet nebulizer (JN), or pMDI within NIV circuit. Three experimental setts were evaluated. Firstly, two pMDI puffs were actuated before nebulization of 1 ml of salbutamol respirable solution by VMN using Combihaler, and Minimhal; the second was the actuation of 10 pMDI puffs only without nebulization.; and the third was the nebulization of 1 ml respirable solution by either VMN or JN without the preliminary pMDI puffs. The amount of aerosol deposited on the inhalation filter was quantified by high-performance liquid chromatography. The Combihaler + VMN delivered the highest TID. Aerosol delivery by Combihaler + pMD and Minimhal + pMDI was significantly higher than that of T-piece + pMDI (p = 0.009 and 0.025, respectively). No significant difference was found between the TID of Minimhal + JN and T-piece + JN. No significant effect was found upon using 2 puffs before the nebulized dose with both Minimhal and Combihaler. Combihaler delivered higher aerosol from VMN and pMDI compared to Minimhal, and standard T-piece. Minimhal delivered higher aerosol from pMDI compared to standard T-piece. Introducing two puffs of pMDI before nebulization with both Minimhal and Combihaler insignificantly affected aerosol delivery.