Prevention of Work- related SARS Personal Protective Equipment

Hierarchy of methods of hazard control Engineering control Administrative control Personal protective equipment

Control of infection Administrative control Environmental control Personal protective equipment

Control of transmission of infectious disease Airborne Droplet Contact

Personal protective equipment Surgical mask Respirator Goggles Gown Gloves

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

Surgical mask Food and Drug Administration NIOSH

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

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

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

Respirators Purpose Function Respiratory protection program

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

Description and selection of respirators Respirator classification : Air purifying respirators Atmosphere supplying respirators

Respirator selection Hazard Oxygen deficientToxic Contaminant IDLH: No Particulate Filter respirator PAPR Airline respirator IDLH: Yes Pressure-demand S.C.B.A. Pressure –demand airline-respirator with escape provision

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.

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

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.

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 %.

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

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

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

Work condition Job characteristics Work environment Psychological stresses Equipment –related stresses

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

Certification of use of respirator Full use Restricted use

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.

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

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

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.

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.

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.

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