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Essentials Of PPEs Against
COVID 19
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Dr Karnav Patel,
Oral And Maxillofacial Surgeon
Hashi Care (Virtual Multi Speciality Hospital) |
Personal Protective Equipments (PPEs)
are protective gears designed to safeguard the health of
workers by minimizing the exposure to a biological agent.
PPEs have become
extremely essential during the current coronavirus
(COVID-19) pandemic. COVID-19 is mostly caused by contact
or droplet transmission attributed to relatively large
respiratory |
particles which are subject to gravitational
forces and travel only approximately one metre from the
patient. Airborne transmission may
occur if patient respiratory activity or medical
procedures generate respiratory aerosols. These aerosols
contain particles that may travel much longer distances
and remain airborne longer, but their infective potential
is uncertain. Contact, droplet and airborne transmission
are each relevant during airway maneuvers in infected
patients, particularly during tracheal intubation. Personal protective
equipment is an important component, but only one part, of a
system protecting staff and other patients from COVID-19
cross-infection. Appropriate use significantly reduces risk of
viral transmission. Recommendations from international
organizations are broadly consistent,
but equipment use is not.
Airborne transmission occurs when smaller respiratory
particles (generally <5 µm) circulate in the air for prolonged
periods. Viral particles are absorbed via the respiratory
mucosa and potentially across the conjunctivae. Particles
smaller than 10 µm are most likely to penetrate deeply into
the lung and cause infection. However, certain procedures ,
particularly those associated with airway management can
create aerosols containing virus that linger in the air and
therefore risk transmission over distances beyond two metres.
Aerosol generation occurs when air accelerates across a fluid
surface, but whether that aerosol has infective potential is
impacted by many factors, including where the fluid originates
(e.g. upper airway, vocal cords or lower respiratory tract)
and these may differ according to the
procedure.
Aerosol generating procedures can usefully be separated into
respiratory and surgical: only respiratory aerosol generating
procedures aerosolise respiratory or upper airway secretions.
These are likely to have a higher viral content and pose a
greater risk of transmission than surgical aerosol (excluding
upper airway and oral cavity) generating procedures which
aerosolise blood and tissue fluid.
COMPONENTS OF PPE AGAINST COVID19
The key components for protection against SARC-CoV-2 are
goggles, face-shield, mask, gloves, coverall/gowns (with or
without aprons), head cover and shoe cover.
FACE SHIELD AND GOGGLES
Contamination of mucous membranes of the eyes, nose and mouth
is likely in a scenario of droplets generated by cough, sneeze
of an infected person or during aerosol generating procedures
carried out in a clinical setting. In advertently touching the
eyes / nose / mouthwitha contaminated hand is another likely
scenario. Hence protection of the mucous membranes of the
eyes/nose/mouth by using face shields/ goggles or a
combination of both is an integral part of standard and
contact precautions. The flexible frame of goggles should
provide good seal with the skin of the face, covering the eyes
and the surrounding areas and even accommodating the
prescription glasses.
MASKS
Respiratory viruses that includes Coronaviruses target mainly
the upper and lower respiratory tracts. Hence protecting the
airway from the particulate matter generated by droplets /
aerosols prevents human infection. Contamination of mucous
membranes of the mouth and nose by infective droplets or
through a contaminated hand also allows the virus to enter the
host. Hence the droplet precautions/airborne precautions using
masks are crucial while dealing with a suspect or confirmed
case of COVID-19/performing aerosol generating procedures.
Masks are of different types. The type of mask to be used is
related to particular risk profile of the category of
personnel and his/her work.
There are two types of masks which are recommended for various
categories of personnel working in hospital or community
settings, depending upon the work environment:
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Triple layer medical mask :
A triple layer medical mask is a disposable mask,
fluid-resistant, provide protection to the wearer from
droplets of infectious material emitted during
coughing/sneezing/talking.
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N-95 Respirator/mask : An
N-95 respirator/mask is a respiratory protective device with
high filtration efficiency to airborne particles. To provide
the requisite air seal to the wearer, such masks are designed
to achieve a very close facial fit.
Such mask should have high fluid resistance,
good breathability (preferably with an expiratory valve),
clearly identifiable internal and external faces,
duckbill/cup-shaped structured design that does not collapse
against the mouth.
If correctly worn, the filtration capacity of
these masks exceeds those of triple layer medical masks. Since
these provide a much tighter air seal than triple layer
medical masks, they are designed to protect the wearer from
inhaling airborne particles..
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