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

Abstract

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.

Table

	Mechanical Ventilation (MV)	Noninvasive Ventilation (NIV)	Spontaneous Breathing (SB)	p value
Jet Nebulizer (JN)	4.30 ± 0.61	2.97 ± 0.64	4.54 ± 0.88	0.075
Mesh Nebulizer (MN)	11.82 ± 0.65	7.25 ± 0.20	8.94 ± 0.34	0.001
p value	0.001	0.001	0.001