An In Vitro Comparison of Jet and Mesh Nebulizers During Mechanical Ventilation,Noninvasive Ventilation,and Spontaneous Breathing in Pediatrics

Background:

The purpose of this study is to determine aerosol deposition with jet (JN), and mesh nebulizers (MN) during spontaneous breathing (SB), noninvasive ventilation (NIV) and mechanical ventilation (MV) using a pediatric lung model with exhaled humidity.

Methods:

Drug delivery with JN (Mistymax10, CareFusion), and MN (Solo, Aerogen) was compared during SB, NIV and MV using 3 lung models with exhaled humidity. To simulate a spontaneously breathing child, a mannikin was attached to a sinusoidal pump via a collecting filter at the level of bronchi. NIV was simulated through a ventilator (V60 Phillips) attached via face mask to a mannikin with a collecting filter at the level of bronchia connected to a passive test lung. To simulate a mechanically ventilated child, a ventilator (Servo-i Siemens) was operated with a heated humidifier (Fisher & Paykel) with a heated-wire circuit attached to a 5 mm ID ETT. The ETT cuff was inflated in a 15 mm adapter, which was then inserted into the housing of an absolute filter (Respirgard) fixing the tip of the ETT 1 cm from the filter media. A heated humidifier (Fisher & Paykel) was placed between the collecting filter and test lung to simulate exhaled humidity (35 ± 2 °C, 100% relative humidity). Breathing parameters were set at V_T: 250 mL, RR: 20 breaths/min, I: E ratio 1: 3. Nebulizers were placed at the in inspiratory limb proximal to the Y during MV; between the face mask and the leak port for NIV; and via mouthpiece during SB. Albuterol sulfate (2.5 mg/3 mL) was aerosolized with JN and MN. The drug deposited on an absolute filter was eluted and analyzed with spectrophotometry. Factorial ANOVA was used for data analysis (P<0.05).

Results:

The table below shows mean (± SD) percent dose delivered. Aerosol delivery with JN was not significantly different during MV, NIV and SB (P=0.075), while delivery efficiency of MN was greater in MV than NIV and SB (P=0.001). Delivery efficiency of MN was better than JN (P=0.001) during MV, NIV and SB.

Conclusions:

Delivery efficiency of JN is similar during MV, NIV and SB while aerosol deposition obtained from MN differs with different modes of ventilation.

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