Quantifying Delivered Dose With Jet and Mesh Nebulizers During Spontaneous Breathing,Noninvasive Ventilation and Mechanical Ventilation Using an In Vitro Adult Lung Model With Exhaled Humidity

Abstract

Background:

Direct comparison of aerosol deposition with jet and mesh nebulizers during spontaneous breathing, noninvasive ventilation and mechanical ventilation using an adult lung model with exhaled humidity has not been reported.

Methods:

Drug delivery with jet (Mistymax10, CareFusion) and mesh (Solo, Aerogen) nebulizers was compared during spontaneous breathing, noninvasive ventilation and mechanical ventilation using adult lung models with exhaled humidity. To simulate a spontaneously breathing adult, a mannikin was attached to a sinusoidal pump via a collecting filter at the level of bronchi. An adult receiving noninvasive ventilation was simulated through a ventilator (V60 Phillips) attached via face mask to a mannikin with a collecting filter at the level of bronchi connected to a passive test lung. To simulate a mechanically ventilated adult, a ventilator (Servo-i, Maquet) was operated with a heated humidifier (Fisher & Paykel) and heated-wire circuit attached to an 8 mm ID ETT. The ETT cuff was inflated in a 15 mm ID/22 mm OD adapter, which was then inserted into the housing of an absolute filter (Respirgard II) fixing the tip of the ETT 1 cm from the filter media. To simulate exhaled humidity, a heated humidifier (Fisher & Paykel) was placed between the collecting filter and test lung (35 ± 2 C, 100% relative humidity). Breathing parameters were V_T: 450 mL, RR: 20 breaths/min, I: E ratio 1: 3. During mechanical ventilation, devices were placed in the inspiratory limb proximal to the airway; with noninvasive ventilation they were positioned between the face mask and the leak port; while mouthpiece was used during spontaneous breathing. Albuterol sulfate (2.5mg/3 mL) was delivered with jet and mesh nebulizers. Drug deposited on the collecting 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. Drug delivery during mechanical ventilation was greater than noninvasive ventilation and spontaneous breathing used with the mesh nebulizer (P=0.0001) but not with the jet nebulizer (P=0.384). Delivery efficiency of the mesh nebulizer was greater than the jet nebulizer during mechanical ventilation, noninvasive ventilation, and spontaneous breathing (P=0.0001).

Conclusions:

Delivered dose to the adult lung model with the mesh nebulizer differs during mechanical ventilation, noninvasive ventilation and spontaneous breathing, while it is similar with jet nebulizers.

	Mechanical Ventilation	Noninvasive Ventilation	Spontaneous Breathing	p value
Jet Nebulizer	6.80 ± 1.55	6.10 ± 0.34	6.12 ± 0.26	0.384
Mesh Nebulizer	23.16 ± 0.67	18.36 ± 1.06	17.20 ± 1.69	0.0001
p value	0.0001	0.0001	0.0001