II. Preparations: Surgical Face Mask

  1. Description
    1. Disposable, loose fitting physical barrier between the wearer's mouth and nose and the patient
    2. Some masks are also available with a Face Shield to protect the mid-face and eyes
    3. Blocks large-particle droplets, splashes, sprays or splatter (and the infectious agents they harbor)
  2. Indications
    1. Personal Protective Equipment during patient care (standard protection from low level exposure to body fluids)
    2. Sterile procedures (e.g. surgery) to protect the patient from the operating staff's oral and nasal secretions
  3. Limitations
    1. Does not filter small, aerosolized particles (e.g. cough, sneeze transmitted highly infectious agents)
    2. No significant protection against most toxins due to the loose fit

III. Preparations: N95 Mask

  1. Description
    1. Single-use, disposable, tightly fitting Face Mask offers protection against airborne particles
    2. Blocks small aerosolized particles, in addition to large particles, splashes and spray
    3. N95 Masks filter >=95% of particles <5 µm diameter
  2. Indications
    1. Protection against contagious, small aerosolized infectious agents (e.g. pandemic Influenza)
  3. Precautions
    1. Adequate respirator mask protection assumes that it is donned correctly and it is worn throughout contact exposure
    2. Mask must fit snugly without gaps (FIT testing needed)
  4. Limitations
    1. Requires special FIT Testing
    2. Not oil resistant
    3. Not designed for children or those with significant facial hair (beard)
    4. May be contraindicated in those with chronic lung disease (e.g. COPD or Severe Asthma)
    5. Not designed for toxin exposures ("hot zone") vapors or gases
      1. See Personal Protective Equipment
  5. Adverse Effects
    1. Headache
      1. Occurs in up to 70% of healthcare workers who remain in N95 Mask >6 hours per day
      2. Ong (2020) Headache 60(5): 864-77 [PubMed]

IV. Preparations: Powered Air Purifying Respirator (PAPR)

  1. Description
    1. Reusable battery-powered PPE device with HEPA Filters that are 99.97% effective against 0.3 micron particles
    2. Powered blower forces air through filter canisters and into an enclosed helmet, hood or Face Mask worn by user
  2. Indications
    1. Protection against dangerous, contagious, small aerosolized infectious agents (e.g. Ebola)
    2. Alternative device to N95 Mask for those who cannot adequately be fit (e.g. beard)
  3. Limitations
    1. Complicates the process of Donning and Doffing Personal Protection Equipment
    2. PAPR is reusable and requires careful cleaning procedures
    3. Interferes with communication
    4. Unable to use Stethoscope (no ear access in hood or helmet)

V. Preparations: M40 Mask (Chemical Defense Mask)

  1. Description
    1. Full face respirator
    2. External filter canister
      1. HEPA filter
      2. ASZ charcoal impregnated
  2. Indications
    1. Protects face and respiratory tract
    2. Volatile agents and aerosols
    3. Removes biological and toxin agents
  3. Limitations
    1. Does not protect in close space with Oxygen <19.5%
    2. Substances not filtered
      1. Ammonia
      2. Carbon Monoxide
      3. Nitric oxide
      4. Carbon dioxide

VI. Preparations: Cloth Mask (home use, patients)

  1. Indications
    1. These masks are primarily to protect others from the mask wearer
      1. When masks are used by everyone, the risk of contagious dispersion and exposure is reduced
    2. Risk of exposure to potential serious respiratory pathogen (e.g. COVID-19)
      1. Indoor environments outside home
      2. Outdoors when social distancing cannot be maintained
  2. Fit
    1. Masks should cover nose, mouth and chin
    2. Masks should fit relatively snugly around face
    3. Masks should have at least 2 layers of fabric
  3. Disadvantages
    1. Unlikely to be sufficient for exposures with close contact (at least N-95 is recommended)
    2. Misuse is common
      1. Avoid pulling mask down below chin (contaminates inner surface of mask)
      2. Avoid vented masks or breaching surface to allow for straws (defeats purpose of mask)
  4. Care
    1. Store masks in clean paper bag
    2. Wash hands when putting on, adjusting or removing mask
    3. Launder Cloth Masks in fragrance-free detergent when mask is soiled or damp or otherwise contaminated
  5. Adverse Effects
    1. Anxiety or Claustrophobia
      1. Reassure patients that masks do not decrease their oxygenation (may demonstrate with Oxygen Saturation)
      2. Encourage Relaxation Techniques (e.g. breathing Exercises)
    2. Heat Build-up
      1. Consider 100% cotton masks
      2. Decreases after first 30 minutes in mask
    3. Fogging Glasses
      1. Fogging is reduced when mask leaks less air at its upper boundary
        1. Consider taping mask to Nasal Bridge and cheeks
        2. Consider masks with moldable material over Nasal Bridge (e.g. surgical masks)
      2. Anti-fog solution (soapy water)
        1. May be applied to glasses and reduce fogging
    4. Ear Irritation
      1. May secure mask ties together in back of head (e.g. plastic device, paperclip) to keep strings off ears
    5. Headaches
      1. Maintain hydration
      2. Secure mask to avoid ear irritation (see above)
  6. (2020) Presc Lett 27(9): 49

VII. Prevent

  1. Mask Irritation
    1. Consider barrier cream (e.g. Desitin) at areas of pressure and irritation (e.g. bridge of nose, ears)
    2. Consider mask string holder that pulls the mask strings off the ears
    3. Consider Wound Dressing (e.g. Duoderm) in areas of pressure
    4. Consider topical irritant or allergans in the mask (e.g. latex)
    5. (2020) Presc Lett 27(6):31-2

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