Prevention of Work-related SARS

1
Prevention of Work-related SARS

• Personal Protective Equipment

2
Hierarchy of methods of hazard control

• Engineering control
• Administrative control
• Personal protective equipment

3
Control of infection

• Administrative control
• Environmental control
• Personal protective equipment

4
Control of transmission of infectious disease

• Airborne
• Droplet
• Contact

5
Personal protective equipment

• Surgical mask
• Respirator
• Goggles
• Gown
• Gloves

6
Surgical mask

• Three layers
• Standards and guidelines set in US by
• American National Standards Institute
• The Association of Perioperative Registered
  Nurses
• American Study Society of Testing and Materials
• CDC

7
Surgical mask

• Food and Drug Administration
• NIOSH

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ASTM

• Categorize the surgical mask into general use,
  sub-micron filtering, fluid resistant
• Bacterial filtration efficiency
• Differential pressure
• Sub-micron particulate filtration
• Resistance to penetration by synthetic blood
• Flammability

9
Different types of surgical mask

• Can be used with face shield or eyewear
• Flat fold tie on
• Duck bill
• Cone shaped
• Flat-fold with shield
• High fluid resistant

10
Things to observe in using a surgical mask

• Worn properly
• Comfortably cover the mouth and nose
• Fit- no tenting around the side of the mouth
• Use the pliable strip to promote a close fit
• Change frequently when wet
• Handle only the string and promptly dispose into
  a waste receptacle
• On or off

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Respirators

• Purpose
• Function
• Respiratory protection program

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Description and selection of respirators

• NIOSH
• Facepiece Classification tight fitting
  facepiece, loose fitting facepiece
• Tight fitting facepiece is further classified
  into quarter masks, half masks and full
  facepiece
• Loose fitting facepieces include hoods, helmets,
  blouses or full suits which cover the head
  completely

13
Description and selection of respirators

• Respirator classification
• Air purifying respirators
• Atmosphere supplying respirators

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Respirator selection
15
N95 respirator

• 42 CFR 84
• Use the most penetrating 0.3 AM aerodynamic mass
  median diameter.
• 9 classes of filters- three levels of filter
  efficiency and each with three categories of
  resistance to filter efficiency degradation.
• three levels of filter efficiency- 95, 99 and
  99.97
• three categories of resistance to filter
  efficiency degradation- N, R, P.

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N95 respirator

• N not resistant to oil
• R resistant to oil
• P oil proof
• The N series are tested by a mildly degrading
  aerosol of NaCl. The P- and R- series will be
  tested against a highly degrading aerosol of
  dicotylphthalate. The specific maximum loading
  dose was 200mg. The N- and R- series is uaually
  certified with a single work shift limitation

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N95 respirator

• Certification of filters was based on statistical
  evaluation of results from 30 filter tested.
  Pass/ Fail test based on result from 20 filters
  tested.

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Fit test

• Seal check
• Qualitative testing
• Quantitative testing
• Combined direct penetration through the filter
  and leakage around the face seal
• TSI 8020 Portacourt plus TM measures the fit
  factors
• Without surrogate fit testing, average exposure
  was reduced to 33 of the ambient level, which is
  much less protection expected of this class of
  respirator, less than or equal to 10 .

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Fit test

• When fit tested first, greater protection than
  normally expected (the average exposure was
  reduced to 4 of the ambient level)
• Without fit testing, person unknowingly may have
  poor face seals, resulting in excessive leakage
  and exposure.
• An requirement by OSHA

20
Effects of respirator use

• Respiratory effects
• Increased airways resistance
• Increased dead space volume
• Cough
• Cardiovascular effects
• Discomfort
• Extraweight and Ergonomic concern
• Psychological and social effects
• Skin problems
• Senses

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Pregnancy

• No good data on respirator use in pregnancy
• Most common cause for denying medical clearance
• Consider the risk of the work environment to the
  mother and the developing child, the capacity of
  the mother to tolerate the PPE, as well as
  ergonomic consideration

22
Work condition

• Job characteristics
• Work environment
• Psychological stresses
• Equipment related stresses

23
Worker evaluation

• Work description
• Medical history and physical examination
• Special testing
• Re-evaluation

24
Certification of use of respirator

• Full use
• Restricted use

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Advice

• For infection control of patients with suspected
  SARS, CDC advises airborne precaution( including
  use of a N-95 filtering disposable respirator),
  wearing of eye protection and contact precaution
  was included in inpatient setting and outpatient
  setting. A qualitative fit test should be conduct
  for N95 respirator. If N95 respirator is not
  available, then surgical mask should be worn.
  The patient should wear a surgical mask.

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Advice

• For precaution for Aerosol generating procedures,
  CDC advises PPE should cover all exposed skin-
  single isolation gown, a disposable full-body
  isolation suit, a disposable surgical hood with
  an attached face shield in combination with a
  disposable respirator.
• Disposable gloves
• Eye protection
• A face field
• Disposable particulate respirators minimum level
  of respiratory protection

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Advice

• A fit test
• A higher level of respiratory protection should
  be used if fit test fails
• Various types of PAPRs
• Full facepiece elastometric negative respirators
  with N, R or P100 filter

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Advice

• WHO advises strict adherence with the barrier
  nursing of patients with SARS using precautions
  for airborne, droplet and contact transmission.
  N95 respirator should be worn all the time when
  attending patients with suspected and confirmed
  SARS. The patient should wear a surgical mask.
  All visitors, staff, students and volunteers
  should also wear N95 in entering the room of a
  patient with suspected or confirmed disease.
  Surgical masks are a less effective alternative
  to N95.

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Advice

• Hospital Authority advises
• Essential infection control advice
• All staff must receive infection control
  precaution.
• All persons inside hospital setting must wear a
  mask. For N95, ensure right size and check the
  leakage.
• All person must practice hand hygiene.

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Advice

• Personal Practice
• All hospital settings
• All persons must wear a mask
• All must practice hand hygiene
• All inpatient settings
• Standard precaution
• Droplet precautions surgical mask for all
  patient contact. Protective eyewear for close
  patient contact.

31
Conclusion

• Last resort
• Level of evidence expert panel
• Empirical measures based on the modes of
  transmission when the full picture of the disease
  is not known
• Brief introduction of surgical mask and
  respirator
• Brief summary of how personal protective
  equipment was recommended in various
  organizations