In vitro aerodynamic characteristics of aerosol delivered from different inhalation methods in mechanical ventilation

Abstract

Aerodynamic characteristics of aerosol delivery during invasive mechanical ventilation (IMV) are mostly determined by inserting cascade impactor in the circuit. Impactor might have some effect on airflow within IMV. Hence, the aim of the present study was to develop and evaluate new in vitro aerodynamic characterization methodology without affecting airflow in IMV. Breathing simulator was set in standard adult IMV circuit with inspiratory and expiratory pressures of 20 and 5 cm HO, 1:3 inspiratory-expiratory ratio, 15 breaths min, and tidal volume of 500 ml. Two ml of salbutamol solution containing 10,000 μg was nebulized using three different vibrating mesh nebulizers (VMNs) and Sidestream jet nebulizer (JET). Sixteen-metered doses, containing 100 μg salbutamol each, were delivered using three different spacers. Each device was placed in inspiration limb of Y-piece of ventilator tubing. Aerodynamic characteristics of aerosol delivered were measured using cooled Andersen cascade impactor, with mixing inlet connected to it. VMNs used had significantly more total mass in the impactor (p < .001) and fine particle dose (p < .001) compared to JET. Spacers used had higher total mass in the impactor percent (p < .001) and fine particle fraction compared to nebulizers. The in vitro IMV methodology setting suggested here showed encouraging results in comparison of different aerosol delivery systems in intubated patient.

Effect of Nebulizer Designs on Aerosol Delivery During Non-Invasive Mechanical Ventilation: A Modeling Study of In Vitro Data

“…VMNs again showed much better efficiency in aerosol delivery compared to JN, resulting in higher inhaled dose (p\0.001) and lower residual dose (p\0.001) [13][14][15].…”

Effects of Fill Volume and Humidification on Aerosol Delivery During Single-Limb Noninvasive Ventilation

“…Salbutamol entrained on the filter was described as total inhaled dose (aerosol emitted) and assayed for salbutamol using previously validated highperformance liquid chromatography. 12,13,25,26,32,33 We used the 25 mm ϫ 4.6 mm Zorbax Eclipse Plus C18 and the ODS1 column (Agilant), through which the mobile phase consisted of a mixture of acetonitrile and water (0.1% phosphoric acid) (90:10, v/v) was pumped at 1 mL/min using the 1260 Infinity preparative pump (G1361A, Agilant) the 1260 Infinity Diode array detector VL (G131SD, Agilant) was set at 225 nm with an injection volume 100 L. Calibration solutions ranged from 4 to 100 g/mL (weight/volume). Limit of detection was 0.35 g/mL, and the lower limit of quantification was 2.55 g/mL.…”

“…[4][5][6][7] The type and position of the aerosol generator, ventilator settings during aerosol delivery, and other variables during NIV have been investigated. 4,5,[7][8][9][10][11][12][13][14][15][16][17][18] Many previously published studies recommended switching off the humidifier while delivering aerosol for improved aerosol delivery. 9,19,20 However, we have shown that there was no significant effect on delivered aerosol associated with this practice during auto-CPAP or duallimb ventilation.…”

Performance of Large Spacer Versus Nebulizer T-Piece in Single-Limb Noninvasive Ventilation

“…In addition, the patient interface (mask vs endotracheal tube) and placement of the aerosol generator differ with noninvasive ventilation (NIV) compared with conventional invasive ventilation. [10][11][12][13] In a previous in vitro study, we reported that the standard T-piece and large spacer were equally efficient for salbutamol delivery by a vibrating mesh nebulizer in a single-limb NIV under nonhumidified conditions. 14 In vitro methods that study the aerodynamic characteristics and fate of aerosol by using a lung simulator model are thought to offer some degree of guidance to clinical delivery and response.…”