Home / Blog / You might know what PPE is, but have you clarified the details?

You might know what PPE is, but have you clarified the details?

Update:20 Feb

Indications for the FFP2 mask

         The FFP2-type protective filtering masks must be reserved exclusively for HCWs when performing invasive medical procedures or maneuvers on the respiratory tract that may generate an aerosol: intubation/extubation/laryngeal mask, invasive ventilation with open-expiratory circuit, non-invasive ventilation, endotracheal aspiration, bronchial fibroscopy, aerosol therapy, aerosol-generating chest physiotherapy (bronchial decongestion, induced sputum, etc.), nasopharyngeal sampling, functional respiratory explorations, dental surgery procedures, autopsy or other procedures at risk of aerosol.

 

         Most real-world research comparing standard face masks with respirator masks has been in the context of influenza or other relatively benign respiratory conditions and based in hospitals. There are no published head-to-head trials of these interventions in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, COVID-19, and no trials in primary or community care settings. Current guidance is therefore based partly on indirect evidence – notably, from past influenza, SARS and MERS outbreaks – as well as expert opinion and custom and practice.

 

         Policy guidance from various bodies (e.g. Public Health England, WHO) emphasizes the need to assess the contagion risk of an encounter and use the recommended combination of equipment for that situation. A respirator mask and other highly effective PPE (eye protection, gloves, long-sleeved gown, used with good donning/doffing technique) are needed to protect against small airborne particles in aerosol-generating procedures (AGPs) such as intubation. For non-AGPs, there is no evidence that respirator masks add value over standard masks when both are used with recommended wider PPE measures.

 

         A recent meta-analysis of standard v respirator (N95 or FFP) masks by the Chinese Cochrane Centre included six RCTs with a total of 9171 participants with influenza-like illnesses (including pandemic strains, seasonal influenza A or B viruses and zoonotic viruses such as avian or swine influenza). There were no statistically significant differences in their efficacy in preventing laboratory-confirmed influenza, laboratory-confirmed respiratory viral infections, laboratory-confirmed respiratory infection and influenza-like illness, but respirators appeared to protect against bacterial colonization.

 

CONTEXT


         Concerns have been raised about the limited personal protective equipment (PPE) provided for UK primary and community care staff with some GP surgeries, pharmacies and care homes having very limited provision. We were asked to find out whether and in what circumstances standard masks are putting healthcare workers at risk of contagion compared to respirator masks. A separate review (ongoing) looks at other aspects of PPE.

BACKGROUND


         COVID-19 is spread by four means: contact (direct or via a fomite); droplet infection (droplets from the respiratory tract of an infected individual during coughing or sneezing are transmitted onto a mucosal surface or conjunctiva of a susceptible individual or environmental surfaces); airborne (transmission of infectious agents in small airborne particles, particularly during procedures such as intubation); and faeco-oral.1 2  Coughing and sneezing can generate aerosol particles as well as droplets.

         This review considers respiratory protective measures e.g. use of face masks as PPE, to reduce droplet and airborne spread.  It should be noted that in one recent laboratory study, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus that causes COVID-19) survived airborne as long as SARS COV-1 (the virus that causes SARS) when artificially aerosolised and persisted longer on some surfaces.3 This finding is relevant because it suggests that deposited particulates may become resuspended i.e. airborne, when disturbed.

 

 FFP2 Respirators

 

 FFP2 Respirators (Credit: Left: 3M, Right: Honeywell)

What Is a Respirator?

         A respirator is personal protective equipment that prevents the wearer from inhaling aerosols (dust, smoke, mist) as well as vapors or gases (disinfectants, anesthetic gases) that are health hazards. It also protects those who wear them from inhaling “droplets” of infectious agents. 

What Is It Made Of?

Those masks generally consist of four layers:

       1, an outer layer ;
       2, a non-woven filter layer, generally made of polypropylene microfibre to capture the virus ;
       3, an acrylic backing for mask support ;
       4, and an inner layer for facial comfort;
       5, Respirators can be insulating and filtering. Filtering respirators consist of a facepiece and a filtering device. Depending on the type of filter, the mask will either be effective only against particles, only against certain gases and vapors, or against particles, gases and vapors. Filtering respirators can sometimes also be equipped with an exhalation valve to improve user comfort. The valve prevents condensation inside the mask, misting on the glasses and helps the user breathe in and out easily. Respirators can be disposable or reusable. In the second case, it is possible to replace the filter when it is full.

What are the Standards?

1, Respirators are tested in the direction of inspiration (from outside to inside). The tests take into account the efficiency of the filter and leakage to the face. 
2, In Europe, they must meet the European standard EN 149: 2001which has three classes of disposable particulate respirators
3, FFP1refers to the least filtering of the three masks with an aerosol filtration of at least 80% and leakage to the inside of maximum 22%. This mask is mainly used as a dust mask (home renovations and various types of work).
4, FFP2masks have a minimum of 94% filtration percentage and maximum 8% leakage to the inside. They are mainly used in construction, agriculture, and by healthcare professionals against influenza viruses.
5, FFP3masks are the most filtering mask of the FFPs. With a minimum filtration percentage of 99% and maximum 2% leakage to the inside, they protect against very fine particles such as asbestos.
 

In the United States, respirators must meet NIOSH (National Institute for Occupational Safety and Health) standards. Within this standard, there are several classes of respirators depending on the degree of oil resistance:

     1, Class N: no oil resistance. A distinction is made between N95, N99 and N100. The number after the letter indicates the percentage of filtration of suspended particles.
     
     2, Class R: mask resistant to oil for up to eight hours. Here again, a distinction is made between R95, R99 and R100.
     3, Class P: a completely oil-resistant mask. There are also P95, P99 and P100.

 

 

Respirators must be fit tested before being worn in order to offer the best protection. (Credit: TSI)

Do Respirators Protect Against Covid-19?

         Respirators of class FFP2 or FFP3 (EU standards) and of class N95 (US standards) are the ones offering maximum filtration of particles and aerosols. Unavailable in pharmacy, they are the ones that best protect the wearer from airborne infectious agents i.e. against contamination by a virus such as coronavirus, SARS, H1N1, etc. They remain the n°1 protection in the event of an outbreak as we the one we are experiencing today.

Who Should Wear a Respirator?

         Caregivers have the obligation to wear a respirator when caring for a patient who is infected or suspected of being so. Everybody who wants to have the best protection because of his/her job or because he/she is in contact with people at risk and/or work in an environment at risk should wear a respirator. However, respirators must be fit tested before being worn in order to prevent any leakage and to offer the best protection.

How Much Does a Respirator Cost?

Depending on the vendors, respirators can cost around 30€ the unit.

 

Conditions for prolonged usage

         Both surgical and FFP masks are single-use devices, intended to be worn while caring for one patient and to be changed between patients. However, in the context of a supply shortage, prolonged use may be envisaged albeit with strict adherence to the following conditions: tolerance and accessibility for HCWs according to the duration of wearing; sealing and integrity during the wearing,especially in case of proven exposure to infective droplets; no re-use of mask since it has been manipulated or removed with increased risk of contamination for HCWs and their environment [9].

         It is important to note that, even when considering the stipulations above, the duration of wearing may not exceed 4 hs for surgical  masks and 8 hs for FFP masks, according to the supplier's recommendations.

 

Conclusion

         Simple barrier measures of hand hygiene and respiratory measures through the use of anti-projection or surgical masks are effective measures for preventing the transmission of SARS-CoV-2. Wearing FFP masks is strictly reserved for HCWs exposed to aerosol during invasive or specific procedures for patients suspected or confirmed as having COVID-19, although airborne transmission cannot completely be excluded. Hand hygiene is a key additional barrier measure to control the SARS-CoV-2.

         WHO continues to recommend droplet and contact precautions for those people caring for COVID-19 patients, and airborne precautions for circumstances and settings in which aerosol-generating procedures and support treatment are performed, according to risk assessment [10]. Applying this strategy aims to mitigate the effects of the epidemic wave and limit its health impact on the population by acting upon the transmissibility and clinical effect of SARS-CoV-2, the vulnerability of the population (the immunocompromised, the elderly, etc.), the morbidity (number of sick people in the population), the mortality (number of deaths in the population), and the disorganization of the health system due to saturation of the healthcare system.

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