Nebulization for Tracheostomised Patients on Mechanical Ventilation
For adult ICU patients with tracheostomy on mechanical ventilation, use a vibrating mesh nebulizer (VMN) placed in the inspiratory limb of the ventilator circuit with the cuff inflated and an expiratory filter in place to maintain a closed circuit and optimize drug delivery. 1
Device Selection: Vibrating Mesh Nebulizer is Superior
Vibrating mesh nebulizers are strongly preferred over jet nebulizers for mechanically ventilated tracheostomy patients because they:
- Allow medication reloading without breaking the ventilator circuit and can remain in-line for up to 28 days 1
- Have a closed medication chamber physically separated from patient secretions, preventing contamination and subsequent aerosolization of bioaerosols 1
- Do not require circuit disconnection, avoiding explosive depressurization that releases bioaerosols into the environment 1
- Produce significantly lower fugitive aerosol emissions compared to jet nebulizers across all interfaces 1
Jet nebulizers have critical design flaws for ventilated patients: their open reservoir below the ventilator circuit allows gravitational flow of circuit rainout and patient secretions into the medication cup with subsequent aerosolization 1. If a jet nebulizer must be used, it requires a valved T-adapter that allows removal without breaking the circuit 1.
Optimal Circuit Configuration
Place the nebulizer in the inspiratory limb of the ventilator circuit, proximal to the Y-piece (ideally within 30 cm) 1. This positioning maximizes aerosol delivery while maintaining circuit integrity 1, 2.
Maintain a closed-circuit system throughout treatment by:
- Keeping the tracheostomy cuff inflated at 20-30 cmH₂O during mechanical ventilation to prevent air leaks and maintain circuit integrity 1
- Installing an expiratory filter on the expiratory limb of the ventilator to capture exhaled aerosols 1
- Using proprietary high-efficiency particulate air (HEPA) filters designed for specific ventilators, as these remove aerosols more efficiently and for longer periods before increasing resistance compared to nonproprietary filters 1
Critical Infection Control Measures
Healthcare workers must wear N95 respirators (not surgical masks) when administering nebulized therapy to patients with suspected or confirmed respiratory infections, as N95 respirators reduce aerosol exposure more efficiently 1.
Avoid breaking the ventilator circuit during treatment because explosive depressurization releases bioaerosols into the environment 1. The VMN design specifically addresses this by allowing medication reloading without disconnection 1.
Humidification Management
Temporarily discontinue heated humidification for a few minutes before and throughout nebulization to optimize aerosol delivery 1. Humidity reduces aerosol deposition efficiency in the ventilator circuit 3.
After treatment, if the patient requires disconnection from the ventilator, immediately place a heat-moisture exchanger (HME) with viral filter on the tracheostomy tube to minimize aerosolization 1.
Common Pitfalls to Avoid
Never place masks over the tracheostomy tube for nebulization—they fail to prevent adequate aerosol escape into the environment 1. For spontaneously breathing tracheostomy patients not on the ventilator, use a T-piece with an expiratory filter instead 1.
Do not use vented masks in any setting if avoidable, as they allow aerosol escape 1.
Avoid placing filtered HMEs between the nebulizer and patient during treatment, as they block >99% of aerosol delivery 4. Non-filtered HMEs allow >60% of the control dose to pass through, but filtered HMEs reduce delivery to <0.5% 4.
Do not leave nebulizers permanently in-line when not in use—they should be cleaned and changed between treatments to prevent bacterial aerosol generation 1.
Alternative: MDI-Spacer System
For bronchodilator therapy specifically, consider using a metered-dose inhaler (MDI) with a spacer connected to the inspiratory limb of the ventilator circuit, with actuation synchronized to the onset of lung inflation 1, 5. This delivers 4-6% of the dose to adult lungs 1 and avoids the infection control concerns of nebulization 5.
Drug Dosing Considerations
Aerosol deposition during mechanical ventilation is reduced compared to spontaneous breathing (typically 1.2-3.0% for jet nebulizers in adults) 1. However, under optimal conditions with proper technique, up to 30% of the nebulizer charge can be inhaled 3. This variability underscores the importance of proper device selection and circuit configuration.
Dilute the drug solution to fill the nebulizer to capacity when using jet nebulizers, and use high nebulizer gas flow 1.