Performance of newly developed add-on devices on aerosol delivery in noninvasive ventilated subjects.

Abstract

Background: Several techniques had been developed to generate aerosolized medications during noninvasive ventilation (NIV) using variable inhalation methods. This study hypothesized that large spacers were more efficient significantly than small spacers and adapters during NIV. Objective: The main objective of this study was to compare the performance of newly developed spacers with standard T-piece in NIV chronic obstructive pulmonary disease (COPD) subjects. Methods: Sixty COPD subjects requiring NIV were included in this study. A dual-limb circuit was used, and the mode of ventilator was set in spontaneous volume-controlled mode. Dual-limb ventilation circuit, consists of inspiratory-limb and expiratory-limb, is pressure and volume controlled in response to subject expiration providing relatively high resistance to expiratory flow. Two experimental sets were evaluated: the first was introducing two preliminary pressurized metered-dose inhalers (pMDI) puffs before the nebulization of 1 ml of a respirable solution of salbutamol by vibrating mesh nebulizer (VMN) using Minimhal and Combihaler. The second was to only nebulize 1 ml of salbutamol respirable solution by VMN using Combihaler, Minimhal, and standard T-piece. Two urine samples were collected after aerosol delivery: urine sample after 30 min. (USAL0.5) as an indicator of lung deposition and all urine pooled 24 h (USAL24) post-inhalation as an indicator of systemic absorption. The amount of salbutamol extracted from urine samples was assayed by high-performance liquid chromatography. Results: Minimhal + pMDI + VMN delivered a higher percentage of salbutamol 30 min post-inhalation than Minimhal + VMN (p < 0.001). Also, Combihaler + pMDI + VMN delivered a higher percentage of salbutamol 30 min post-inhalation than Combihaler + VMN (p < 0.001). Combihaler + VMN delivered a higher percentage of salbutamol 30 min and 24 h post-inhalation than both Minimhal + VMN and T-piece + VMN (p < 0.001). Standard T-piece delivered the lowest aerosol amount delivered to the lung compared to both spacers (p < 0.05). Conclusions: Introducing two pMDI puffs significantly improved aerosol delivery by both spacers. Combihaler significantly improves aerosol delivery more than Minimhal.