II. Preparations: Surgical Face Mask
- Description
- Disposable, loose fitting physical barrier between the wearer's mouth and nose and the patient
- Some masks are also available with a Face Shield to protect the mid-face and eyes
- Blocks large-particle droplets, splashes, sprays or splatter (and the infectious agents they harbor)
- Indications
- Personal Protective Equipment during patient care (standard protection from low level exposure to body fluids)
- Sterile procedures (e.g. surgery) to protect the patient from the operating staff's oral and nasal secretions
- Limitations
- Does not filter small, aerosolized particles (e.g. cough, sneeze transmitted highly infectious agents)
- No significant protection against most toxins due to the loose fit
III. Preparations: N95 Mask
- Description
- Single-use, disposable, tightly fitting Face Mask offers protection against airborne particles
- Blocks small aerosolized particles, in addition to large particles, splashes and spray
- N95 Masks filter >=95% of particles <5 µm diameter
- Indications
- Protection against contagious, small aerosolized infectious agents (e.g. pandemic Influenza)
- Precautions
- Adequate respirator mask protection assumes that it is donned correctly and it is worn throughout contact exposure
- Mask must fit snugly without gaps (FIT testing needed)
- Limitations
- Requires special FIT Testing
- Not oil resistant
- Not designed for children or those with significant facial hair (beard)
- May be contraindicated in those with chronic lung disease (e.g. COPD or Severe Asthma)
- Not designed for toxin exposures ("hot zone") vapors or gases
- Adverse Effects
- Headache
- Occurs in up to 70% of healthcare workers who remain in N95 Mask >6 hours per day
- Ong (2020) Headache 60(5): 864-77 [PubMed]
- Headache
IV. Preparations: Powered Air Purifying Respirator (PAPR)
- Description
- Reusable battery-powered PPE device with HEPA Filters that are 99.97% effective against 0.3 micron particles
- Powered blower forces air through filter canisters and into an enclosed helmet, hood or Face Mask worn by user
- Indications
- Protection against dangerous, contagious, small aerosolized infectious agents (e.g. Ebola)
- Alternative device to N95 Mask for those who cannot adequately be fit (e.g. beard)
- Limitations
- Complicates the process of Donning and Doffing Personal Protection Equipment
- PAPR is reusable and requires careful cleaning procedures
- Interferes with communication
- Unable to use Stethoscope (no ear access in hood or helmet)
V. Preparations: M40 Mask (Chemical Defense Mask)
- Description
- Full face respirator
- External filter canister
- HEPA filter
- ASZ charcoal impregnated
- Indications
- Protects face and respiratory tract
- Volatile agents and aerosols
- Removes biological and toxin agents
- Limitations
- Does not protect in close space with Oxygen <19.5%
- Substances not filtered
- Ammonia
- Carbon Monoxide
- Nitric oxide
- Carbon dioxide
VI. Preparations: Cloth Mask (home use, patients)
- Indications
- These masks are primarily to protect others from the mask wearer
- When masks are used by everyone, the risk of contagious dispersion and exposure is reduced
- Risk of exposure to potential serious respiratory pathogen (e.g. COVID-19)
- Indoor environments outside home
- Outdoors when social distancing cannot be maintained
- These masks are primarily to protect others from the mask wearer
- Fit
- Masks should cover nose, mouth and chin
- Masks should fit relatively snugly around face
- Masks should have at least 2 layers of fabric
- Disadvantages
- Unlikely to be sufficient for exposures with close contact (at least N-95 is recommended)
- Misuse is common
- Avoid pulling mask down below chin (contaminates inner surface of mask)
- Avoid vented masks or breaching surface to allow for straws (defeats purpose of mask)
- Care
- Store masks in clean paper bag
- Wash hands when putting on, adjusting or removing mask
- Launder Cloth Masks in fragrance-free detergent when mask is soiled or damp or otherwise contaminated
- Adverse Effects
- Anxiety or Claustrophobia
- Reassure patients that masks do not decrease their oxygenation (may demonstrate with Oxygen Saturation)
- Encourage Relaxation Techniques (e.g. breathing Exercises)
- Heat Build-up
- Consider 100% cotton masks
- Decreases after first 30 minutes in mask
- Fogging Glasses
- Fogging is reduced when mask leaks less air at its upper boundary
- Consider taping mask to Nasal Bridge and cheeks
- Consider masks with moldable material over Nasal Bridge (e.g. surgical masks)
- Anti-fog solution (soapy water)
- May be applied to glasses and reduce fogging
- Fogging is reduced when mask leaks less air at its upper boundary
- Ear Irritation
- May secure mask ties together in back of head (e.g. plastic device, paperclip) to keep strings off ears
- Headaches
- Maintain hydration
- Secure mask to avoid ear irritation (see above)
- Anxiety or Claustrophobia
- (2020) Presc Lett 27(9): 49
VII. Prevent
- Mask Irritation
- Consider barrier cream (e.g. Desitin) at areas of pressure and irritation (e.g. bridge of nose, ears)
- Consider mask string holder that pulls the mask strings off the ears
- Consider Wound Dressing (e.g. Duoderm) in areas of pressure
- Consider topical irritant or allergans in the mask (e.g. latex)
- (2020) Presc Lett 27(6):31-2