In-vitro/in-vivo comparison of inhaled salbutamol dose delivered by jet nebulizer, vibrating mesh nebulizer and metered dose inhaler with spacer during non-invasive ventilation

Background: Patients receiving noninvasive ventilation (NIV) may benefit from medical aerosol, but most guidance on dosing with different aerosol devices is limited to in-vitro studies. The study was designed to in-vitro, ex-vivo, and in-vivo compare aerosol delivery during bilevel NIV with three types of aerosol generators: metered dose inhaler with AeroChamber-MV spacer (AC), Aerogen Pro vibrating mesh nebulizer (PRO), and Sidestream jet nebulizer (SIDE). Materials and Method: A bilevel ventilator with dry single limb circuit and fixed expiratory port was set in spontaneous mode with initial inspiratory and expiratory pressures of 20 and 5cmH(2)0, 1:3 inspiratory-expiratory ratio, and 15 breaths.min(-1). Aerosol generators were placed proximal to facial mask of NIV chronic obstructive pulmonary disease (COPD) patients. 1 mL salbutamol nebulizer solution (5 mg/mL) was nebulized using PRO and SIDE. 12MDI doses, containing 100g salbutamol each, were delivered using AC. In-vitro aerosol fate and aerodynamic droplet characteristics, in-vivo amount of salbutamol excreted 30mins and pooled up to 24h post inhalation in urine from 12 COPD patients (as indices of pulmonary deposition and systemic absorption, respectively) and amount of salbutamol deposited on ex-vivo filters (expected inhalable amount) was determined. Results: The in-vitro, in-vivo and ex-vivo testing showed that PRO had better aerosol delivery compared to SIDE (p < 0.01). However, with smaller nominal dose MDI with AC resulted in similar aerosol delivery to PRO suggesting better aerosol delivery stress on careful attention and proper delivery by health care provider. Conclusions: These similarities and differences between the three aerosol generators tested suggest that aerosol delivery methods should be carefully chosen or substituted in non-invasive ventilated patients.