Microsoft word - surgical masks & respirators.doc

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Surgical Masks & Respirators A respiratory protection issue for the health care industry There recent outbreak of Swine Influenza A (H1N1) virus has generated major interest in respiratory protection for biohazards that may be spread through the air. General infection control procedures have been in use for decades, but
more attention has been paid to the respiratory protection aspect in recent
years. This first started with tuberculosis (TB) concerns, followed by
Hantavirus, anthrax, sudden acute respiratory syndrome (SARS), avian flu
(H5N1) and most recently, Swine Influenza A (H1N1) virus. These
biohazards may become airborne; perhaps as the agent itself such as
an anthrax spore, or as part of other airborne material such as dusts, mists
droplets and aerosols. In fact, rarely does the bioaerosol exist as a naked
organism. Wearing appropriate respiratory protection may reduce
inhalation of these bioaerosols.
There has been a good deal of confusion in the Health Care Industry in
regards to what is appropriate respiratory protection and product selection
for specific applications. The two types of product involved in this
confusion are the surgical mask and the respirator.
Differences between respirators and surgical masks
The biggest difference between a respirator (a respiratory protective device
that meets the requirements of AS/NZS1716) and a surgical, medical, or
patient care mask is the intended use. Respirators are designed to help
reduce the wearer's respiratory exposure to airborne contaminants such as
particles, gases or vapours. Particulate respirators are used to reduce
exposure to particles that are small enough to be inhaled - particles less
than 100 microns (μm) in size down to nanometre size. This includes
airborne particles that may contain biological material, e.g. mould, Bacillus
anthracis, Mycobacterium tuberculosis, the SARS virus, etc.
Surgical masks (even those that meet Australian Standard AS 4381 for
surgical masks) do not have adequate filtering and/or fitting attributes to
provide effective respiratory protection for the wearer to this range of
particle sizes. They are designed to help prevent contamination of the work
environment or sterile field from particles generated by the wearer (e.g.
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Surgical Masks and Respirators spit, mucous). Surgical masks may also be used to help reduce the risk of splashes or sprays of blood, body fluids, secretions and excretions from "Products that lack
reaching the wearer's mouth and nose. compliance to AS/NZS
Importance of Face Fit
Face Fit performance is a critical differentiator between the surgical mask
1716, including
and the respirator. In the "surgical mask" standard AS 4381, there are numerous references made to the importance of facial fit in respect to the untested or
use of ties, loops and headbands and statements made that the mask should unclassified surgical
achieve a "proper facial fit" so that risk of infection (for the patient) is minimised. There are, however, no test procedures in this Standard to masks and the so-
actually test the fitting performance of the surgical mask on any face. Neither is there a minimum requirement for filtration performance. Many called nuisance dust
surgical mask manufacturers put filtration data on the packaging, however the test conditions indicated are not standardised and these results can be masks, should NOT be
misleading. Many will not comply even with the simplest filter used in any workplace
performance requirements of AS/NZS1716 but in practice it doesn't really matter so much how good or poor the actual filter media is in a surgical where respiratory
mask, because significant amounts of air and contaminants will leak around the edges of the mask. protection is
Respirators are designed to seal to the face of the wearer. Therefore most of the inhaled air is drawn through the filter media and does not leak through gaps between the respirator and the wearer's face. The filtration efficiency and face fitting capability of a respirator is tested as part of Australian Standard AS/NZS1716 to demonstrate a minimum performance requirement using standardised, testing protocols. A fit testing panel is tested wearing the respirator to ensure that the product has a reasonable performance in effectively fitting a range of face sizes. If the various members of this panel (who have a range of face shapes and sizes specified in the Standard) cannot get an effective face seal, the mask will not pass the Standard. Products that lack compliance to AS/NZS 1716, including untested or unclassified surgical masks and the so-called nuisance dust masks, should NOT be used in any workplace where respiratory protection is required. 3M 2008. All rights reserved. Please recycle. Printed in Australia.

3M TechUpdate
Surgical Masks and Respirators Surgical masks are not necessarily designed to provide a good seal to the face. However when the concern over laser generated particles or plumes came about a number of years ago, some surgical mask manufacturers started putting filter media into their masks to appear to improve their performance, but without meeting any respirator Standard. Most surgical "…surgical masks that
masks are open on the sides and do not provide for a good facial seal. Therefore, the potential for air leakage around the edges exists. It is a appear similar to
common misconception in health care applications that having good filter media in a surgical mask will give effective respiratory protection respirators have not
equivalent to an AS/NZS1716 compliant respirator. Even those surgical been designed or
masks that appear similar to respirators have not been designed or tested to protect the wearer from inhalation of airborne hazards and will not provide tested to protect the
a level of respiratory protection that meets the Standard. wearer from inhalation
Fit Testing
of airborne hazards…"
While a respirator may pass the standard, there is still no guarantee that a
specific model will fit a specific face. To determine if they can achieve a
suitable fit for regular use in a workplace, wearers must be fit tested to
ensure they wear the appropriate model and size. AS/NZS 1715 "Selection,
use and maintenance of respiratory protective devices" has a requirement
for the selected respirator to be fit tested on the wearer prior to issue and
then at least annually, or whenever there is a change in facial
characteristics of the wearer. The "fit" issue and "fit testing" are often not
addressed at all in many Australian workplaces and the level of protection
is thereby diminished. Face fit is pivotal to providing effective protection.
Respiratory Protection Program
AS/NZS 1715 also mandates the use of a respiratory protection program to
supervise and control use of respirators in workplaces, with a number of
specific elements that need to be addressed. All of these elements are
required to achieve a satisfactory level of respiratory protection across a
workforce. However, note that no respirator will prevent the inhalation of
all particles; they cannot eliminate the risk of exposure, infection and
The wearer must also perform a "user seal check" each time the respirator
is worn prior to entering the contaminated environment to check the
respirator-to-face seal. Respirators must be donned and worn properly the
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Surgical Masks & Respirators entire time the wearer is in the contaminated area. Training and appropriate information are required to achieve the results expected with any respiratory protection product. "Federal Government
Historically, "surgical masks" have been used for many purposes in the health care setting, while "respirators" are now recommended for use in Infection Control and
certain applications where respiratory protection for the wearer is required. Pandemic Guidelines
Federal Government Infection Control and Pandemic Guidelines recommend the use of P2 rated respirators (i.e. compliant with recommend the use of
AS/NZS1716) for aerosol generating procedures like aerosolised medication treatments (e.g. albuterol), diagnostic sputum induction, P2 rated respirators
bronchoscopy, airway suctioning, endotracheal intubation, etc. (i.e. compliant with
The role and targeted uses of respiratory protection in the health care AS/NZS1716) for
sphere is still evolving. There is currently much discussion on the significance of various transfer paths for infectious diseases, especially in aerosol generating
regards to transmission by droplet transfer versus airborne aerosol transfer. The historical Universal Precautions view still applies, but it may need to be adjusted in the light of new information coming from research into aerosol behaviour, indicating there is an airborne pathway for bioaerosols which can put health care workers at risk. Clearly there are many unknown factors associated with the swine flu or another pandemic. Physical parameters like particle shape and size range, density, aerial transport mechanisms, thermal and electrostatic effects as well as organism specific issues like infectivity, survivability, concentration and virulence will all impact on the spread of the disease. While there is still debate and the full picture is not clear, there is, at the very least, a real case to take a precautionary approach leading to use of respirators for all applications where there is a real potential for significant airborne transfer of infectious aerosols. Although respirators are aimed at airborne precautions, it is clear that a respirator is just one of several preventative measures that can be used to help reduce exposure to airborne bioaerosols. Precautions for other transmission paths (e.g. contact, vectorborne, common vehicle) also need to be followed. 3M 2008. All rights reserved. Please recycle. Printed in Australia.

3M TechUpdate
Surgical Masks and Respirators Worker safety relies on the precautionary principle that reasonable action to reduce risk should not await scientific certainty. This was a major finding of the Canadian SARS experience – protection of the worker as well as the patient is paramount. Whenever there is concern for worker exposure to an airborne hazard - infectious or otherwise, appropriate respiratory protection should be worn. For more information please contact your 3M representative or
3M TechAssist Helpline or Email 1800 024 464 or 3M Australia Customer Service Occupational Health
and Environmental
Safety Division
3M Australia Pty Limited
ABN 90 000 100 096
950 Pacific Highway
Pymble NSW 2073
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Canada's controlled goods program

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Mclean and foa.pdf

THEMED ARTICLE ❙ Anxiety disorders For reprint orders, please contact Prolonged exposure therapy for post-traumatic stress disorder: a review of evidence and dissemination Expert Rev. Neurother. 11(8), 1151–1163 (2011) Carmen P McLean1 and Post-traumatic stress disorder (PTSD) is a highly prevalent, often chronic and disabling psychiatric