Types of Nebulizers
The three main types of nebulizers are jet nebulizers, vibrating mesh nebulizers, and ultrasonic nebulizers, each with distinct mechanisms, advantages, and limitations for delivering aerosolized medications to the respiratory tract. 1, 2
Jet Nebulizers (JNs)
- Operate using the Venturi principle, requiring a driving gas source (compressed air or oxygen) with flow rates of 6-10 L/min to convert liquid medication into aerosol 1, 2
- Have an open connection between the patient and solution chamber, potentially allowing gravitational flow of patient's secretions into the medication reservoir, causing contamination 1, 2
- Generate continuous airflow which contributes to higher aerosol dispersion to the environment compared to other nebulizer types 1, 2
- Typically cool the medication solution during nebulization, unlike ultrasonic nebulizers which may heat it 3
- Increase drug concentration in the reservoir during nebulization as water evaporates 3
- Leave a residual volume of medication in the chamber when nebulization has ceased, affecting drug delivery efficiency 1
Vibrating Mesh Nebulizers (VMNs)
- Use a vibrating mesh or plate with multiple apertures to generate aerosol without requiring a driving gas source 1, 2
- Feature physical separation between medication chamber and patient's secretions, reducing contamination risk 1, 2
- Produce lower fugitive aerosol concentrations compared to jet nebulizers, potentially reducing environmental contamination 1
- Generally more efficient in drug delivery than jet nebulizers 4, 5
- More compact, quieter, and faster than other nebulizer types, potentially improving patient compliance 4
- Typically more expensive than jet nebulizers 3, 5
Ultrasonic Nebulizers (USNs)
- Utilize the converse piezoelectric effect to convert alternating current to high-frequency acoustic energy for aerosol generation 3
- Have an open connection between patient and solution chamber similar to jet nebulizers 1, 2
- Unable to effectively nebulize suspensions and may denature some medications through heat generation 1, 2, 3
- Generally produce higher output rates than jet nebulizers but with larger average particle size 3
- Can substantially increase reservoir solution temperature during operation, unlike the cooling effect of jet nebulizers 3
- Drug concentration in the reservoir does not increase during nebulization, unlike with jet nebulizers 3
Technical Considerations for All Nebulizer Types
- Optimal particle size for reaching small airways is 1-5 μm (mass median aerodynamic diameter) 2, 4
- Fill volumes typically range from 2-4.5 ml depending on the nebulizer's residual volume 1, 2
- Nebulization time for bronchodilators should ideally be less than 10 minutes for optimal patient compliance 1, 2
- Interfaces include mouthpieces (generating less fugitive aerosol) and face masks (easier for acutely ill patients but producing more fugitive aerosol) 1, 2
- Nebulizers can be connected to ventilator circuits, high-flow nasal cannulas, or tracheostomy tubes for patients requiring respiratory support 1, 2
Special Considerations
- For patients with respiratory infections, mouthpieces with attached filters are preferred over face masks to reduce fugitive aerosol 1
- Aseptic techniques should be used during medication loading to prevent contamination 1
- Proper cleaning between uses is essential to prevent bacterial growth and cross-contamination 2
- Nebulizers should not be used with essential oils due to risk of exogenous lipoid pneumonia 6
- When using ipratropium bromide, a mouthpiece is preferable to reduce risk of eye contact which can cause temporary blurring of vision, pupil enlargement, or worsening of narrow-angle glaucoma 7