Thread by @mahendr46642796

.#Thread N95 masks (respirators) and their rational use is a hot topic of discussion. A lot of queries are being raised regarding their usage & durability and why general public is being asked to restrict themselves to cotton/cloth mask. So, let us tackle them one by one.

The best PPE ever imagined was probably the armour donned by Darth Vader (Anakin Skywalker)made after he was rescued from a fight with his Jedi master that left him with 3rd degree burns & 3 amputated limbs, functioning both as life-support system and prosthetic encasement

Real respirators built by humans are of two types:
1. Air purifying respirators: They use filters/cartridges/canisters to remove the particulate matter from the air that we breathe.
2. Air supplied respirators: They have a separate source of compressed uncontaminated air (pic)

Fit Test: All tight fitted respirators have to undergo fit test when they are used for the 1st time. Ill fitted respirators would result in contaminated air getting sucked in.Things that can interfere in a fit test: facial hair, earrings, head scarves, wigs, and facial piercings.

Elastometric respirators: Can be half fitted or full fitted. they are provided with replaceable filters or canisters. These respirators can be cleaned, decontaminated and reused. These are widely used by for industrial, mining, and military purposes, but not in health care.

The powered air-purifying respirators (PAPR) can be loose fitted or tight fitted and have a battery powered blower that pulls air through attached filters and then pushes the filtered air via a tube into the face-piece which covers all of the user's face.

“Air Supplied” respirators include Self-Contained Breathing Apparatus (SCBA) which protect users against oxygen deficiency, dust, gases and vapors at plants, aboard vessels, at fire and in tunnels. They have reservoir cylinders with compressed air or oxygen based on situation.

Filtering face-piece half-mask respirators : These are what we commonly refer to as N95 masks, there are a lot of members in this group.The are named so as the entire face-piece is a filter. These protect against particles (e.g., dust) but not against chemicals/gas/vapour.

These masks are given prefix 'N", "R", "P" based on whether they are able to resist oil particles when used in places where oil droplets are present like in refineries, pesticide/insecticide industries Numerical suffix denotes their efficacy of filtering particles in percentage

Principle: These masks are made of polymer nano fibers which are electrically charged by a process called “ electrospinning”.The charged fibres then attract and trap oppositely charged aerosol particles as they pass through. Video link- Electrospinning

In USA, NIOSH (National Institute for Occupational Safety and Health) certifies respirators as N95/P95/R95 etc.Other countries have different certifying agencies and their equivalents (pic1).Approval number/TC no of an N95 mask can be used to tell if the mask is genuine(pic2)

This link provides list of all manufacturers and their models of whose filter face-piece respirators have been tested and found fit for use by NIOSH. If your respirator model does not feature in this library, its not N95/R95/P95 as claimed by the company.
cdc.gov/niosh/npptl/to…

Life of N95 masks: N95 mask should ideally be discarded after each encounter or procedure warranting use of a respirator. But as these masks are in short supply CDC has recommended guidelines for "Extended use" "Reuse"&" Mask rotation"to prolong their life and rationalize usage.

Mask Rotation: 4-7 masks(AIIMS says 5 with 1 as reserve) are rotated by drying for long enough at end of each day. Polypropylene in N95 masks is hydrophobic & has zero moisture. When the respirator is dry, in 3-4 days, the virus will no more be viable.

CDC has recommended certain precautions for health workers during the usage of N95 masks which can reduce coming in contact with the infectious agent while the mask is being reused or in extended use.

Other two masks are the triple layered masks and home made cloth mask.Triple layered masks are adviced to be used in health care workers in low risk settings( eg, health desk, quarantine facility,ambulance drivers during transport) or by healthy individuals in quarantine.

Cloth masks are being adviced to slow the spread of virus:
1. Should fit snugly against side of the face
2. Secured with ties or ear loops
3. Include multiple layers of fabric
4. Allow breathing without restriction
5. able to be washed & dried without damage/change to shape

A detailed overview of settings where N95 masks should be used along with other PPE by healthcare workers has been given in tabular form in this advisory issue by @MoHFW_INDIA .
mohfw.gov.in/pdf/Guidelines…

Source:
envirosafetyproducts.com/resources/dust…
osha.gov/video/respirat…
ncbi.nlm.nih.gov/books/NBK29422…
ohsonline.com/articles/2006/…

Thank you. Stay safe. Remember CDC does not recommend decontamination of N95 masks by heat, chemicals or by UV treatment. N95 masks are costly and in short supply. Present guideline strongly favour them to be used only by first responders.
#N95 #PPEkits #PPE #Covid19India

On 28 March 2020, US FDA approved a list (see pic) of Non NIOSH approved respirators for use in healthcare settings keeping in view short supply of N95 NIOSH approved masks.I believe these masks will be appropriate to use in our healthcare setting as well.
fda.gov/medical-device…

A nice story about the origin of N95 masks. Do read..
fastcompany.com/90479846/the-u…

In a series of interventions taken in view of extreme shortage of supply of PPE, the US FDA on 2nd march issued an Emergency Use Authentification(EUA) and allowed the use of NIOSH approved filtered facepiece respirators(FFRs) which had exceeded their manufacturer shelf life.

US FDA under this EUA deemed these FFRs as medical devices and brought them under the jurisdiction of FDCA( Food, Drug, and Cosmetic Act), and brought these masks under the category of "emergency use" which were earlier intended for general use.

Several non NIOSH approved N95 equivalent respirators manufactured by China and other countries were approved by FDA through an EUA issued on 24 th March , 28 March and 3rd April.
fda.gov/media/136403/d…
fda.gov/media/136663/d…
fda.gov/media/136731/d…

28 Mar:FDA approved "Battelle Critical Care Decontamination System"for decontamination of N95 masks without cellulose (eg.N95-1860).The system decontaminates masks by hydrogen peroxide vaporization & claims decontamination of N95 masks upto 20 times without degrading performance.

9th April: FDA issued another EUA and approved "“STERIS Sterilization Systems” for decontaminations of N95 masks.These too are based on Hydrogen peroxide vaporisation and can decontaminate a respirator upto 10 times.
beckershospitalreview.com/supply-chain/f…

11 April: FDA issued EUA and approved " STERRAD 100S, NX, and 100NX Sterilization Systems" for sterilisation of
N95 masks, based on the same principle as STERIS and Battelle. This system claims to decontaminate N95 masks upto 2 times.
businesswire.com/news/home/2020…

#correction EUA stands for Emergency Use Authorization

@drharshvardhan @MoHFW_INDIA @PMOIndia Sir if you look at the thread above there are a no of interventions that US FDA has taken to make N95 masks reusable, these Hydrogen Peroxide Vaporisers can be indigenously built by us to sanitize mask fr health workers. Please luk into this

@anandmahindra @MahindraRise @ICMRDELHI can we please look into innovative measures where equipment sanitizing machines can be tweaked to sanitize N95 masks thru hydrogen peroxide vaporisation. N95s are in short supply and US FDA has already approved such measures. Pls see thread

April14: US FDA issued EUA and allowed Stryker Sterizone VP4 decontamination system based on hydrogen peroxide vaporisation to decontaminate N95 masks. It can decontaminate an N95 mask upto 2 times. Hope @MoHFW_INDIA and @ICMRDELHI read this.
fda.gov/media/136976/d…

The ISI standard equivalent to N95 or FFP2 is IS1473:2002, India companies which sell their masks as N95 made in India must mention this on their mask. As NIOSH approved N95 masks are in short supply we can use these respirators( who isn't confident of an ISI mark???)

20April 2020: US FDA issued an EUA and approved the use of STERILUCENT sterilization system, based on hydrogen Peroxide Vaporisation to sterilize N95 masks upto 10 times for single user reuse. 5 such systems are now in use, approved by US FDA.
@MoHFW_INDIA @drharshvardhan

@IndianStandards can a manufacturer sell N95 masks on amazon with product description mentioning that it has been tested "as per" IS9473:2002 std and certified "as per" IS9473:2002 standards? Can you please clarify??
amazon.in/dp/B087TSXLJB/…