Quantitative evaluation of aerosol generation during manual facemask ventilation

Area of Science:

• Anesthesiology
• Respiratory Medicine
• Infectious Disease Control

Background:

• Manual facemask ventilation is considered an aerosol-generating procedure based on limited evidence from past outbreaks.
• There is a lack of direct scientific evidence to support the classification of facemask ventilation as high-risk for aerosol generation.

Purpose of the Study:

• To quantitatively assess bioaerosol generation during manual facemask ventilation in anesthetized patients.
• To compare aerosol levels from facemask ventilation with those from tidal breathing and coughing.

Main Methods:

• Aerosol monitoring was conducted during routine manual facemask ventilation and ventilation with an intentional leak in operating theaters.
• Measurements were compared against aerosol concentrations generated by tidal breathing and voluntary cough maneuvers in patients.

Main Results:

• Facemask ventilation, even with an intentional leak, produced significantly lower aerosol concentrations than tidal breathing.
• Aerosol levels during facemask ventilation were substantially lower than those generated by a cough.
• Specifically, facemask ventilation without a leak was 64-fold lower than tidal breathing, and with a leak, it was 17-fold lower.

Conclusions:

• Manual facemask ventilation does not generate high levels of bioaerosol.
• Based on this evidence, facemask ventilation should not be classified as an aerosol-generating procedure.