PROMOTING SAFE AND EFFECTIVE USE OF AEROSOL DEVICES IN COVID-19:RISKS AND SUGGESTIONS FOR VIRAL TRANSMISSION

Figures & data

Table 1. The advantages, limitations and risks for device contamination and viral transmission of aerosol devices

Devices	Advantages	Limitations	Risk for Device Contamination	Risk for Viral Transmission
pMDIs	Portable Compact Easy to use Multi-dose device Short treatment time	High oropharangeal deposition Requires hand-breath coordination Need to prime if not used recently Need to shake before use Not all medications are available	Low	Low
DPIs	Portable Compact Breath-actuated Short treatment time	Requires moderate to high inspiratory flow Some devices are single dose Susceptible to environmental humidity Not all medications are available	Low	Low
SMIs	Portable Multi-dose device Less dependence on inspiratory flow Slow velocity aerosol Long plume duration No propellant Dose indicator	Needs to be assembled initially Not breath actuated Need to prime if it is not used for several days Not all medications are available	Low	Low
Jet Nebulizer	No need for hand-breath coordination Easy to use Effective with tidal volume No need for hand-breath coordination High doses possible Dose modification possible	Less portable Requires pressurized gas source Long treatment time Device preparation needed Contamination possible Large residual volume	High	High
Mesh Nebulizer	Quiet Portable Compact No need for hand-breath coordination Easy to use Effective with tidal volume Low residual volume High dose reproducibility Dose modification possible Less drug loss during exhalation	Cost Requires device preparation Less portable	Low	Low

Figure 1. The use of filters with jet and mesh nebulizers attached to a mouthpiece

Table 2. Suggestions for safe and effective delivery of aerosolized medications with inhalers and nebulizers

Aerosol Devices	Suggestions for Effective Delivery of Aerosolized Medications	Suggestions for Safe Delivery of Aerosolized Medications
pMDIs	Use pMDIs with VHCs. Prime and shake the pMDI before therapy Exhale, actuate the pMDI at the onset of inspiration and breath-hold for 10 seconds	Train patients to exhale into the VHC to reduce exhaled bioaerosol dispersion to the environment. Use a VHC with a mouthpiece. Do not use the same pMDI in multiple patients
DPIs	Follow the manufacturer’s guidelines when using DPIs	Do not use DPIs in patients with cough or airway irritations as well as those who cannot generate a high inspiratory flow rate.
SMIs	Follow the manufacturer’s guidelines when using SMIs	Make sure the patient has some level of hand-breath coordination to use the device correctly.
Jet Nebulizers	Increase the fill volume to 4–5 ml Set the flow rate to 6–8 L/min unless the jet nebulizer is designed for a low flowrate Follow manufacturer’s recommendations to use compressor/nebulizer combination. Do not use different brands of nebulizers and compressors together to prevent deterioration in their performance.	Prefer mouthpiece instead of a facemask Attach a filter to the expiratory port of the nebulizer Remove the remaining drug solution from the nebulizer reservoir after each therapy. Rinse the nebulizer cup with distilled or sterile water Let it air dry on a clean absorbent paper towel. Replace disposable nebulizers every 24 hours
Mesh Nebulizers	Follow the manufacturer’s guidelines when using mesh nebulizers.	Prefer mouthpiece instead of a facemask Attach a filter to the expiratory port of the nebulizer Make sure that the filter does not block the exhalation valve on the mouthpiece. Using a 22 mm silicon adapter is an option to avoid such an issue. Keep the reservoir cap close after use. Clean the nebulizer based on the manufacturer’s guidelines.