Selection and rational usage of personal protective equipment’s components to face COVID-19

Introduction

Coronaviruses are a large family of viruses, some causing illness in people and others that circulate among animals, including camels, cats and bats. Rarely, animal coronaviruses can evolve and infect people and then spread between people such as has been seen with MERS and SARS.

The outbreak of Novel coronavirus disease (now named COVID-19) was initially noticed in mid-December, 2019, has spread to more than 185 countries/territories worldwide.

The causative agent for COVID-19 earlier termed provisionally as novel Coronavirus has been officially named as SARS-CoV-2. WHO is providing technical information on appropriate available essential medical devices which are indispensable for treatment centers, community-based units and other preventive activities, in affected and neighboring countries.

There is clear evidence of human-to-human transmission mainly through respiratory droplets that get generated when people cough, sneeze or exhale.

It is also transmitted by touching, by direct touch and through contaminated surfaces or objects and then touching their mouth, nose, or possibly their eyes.

The people most at risk of COVID-19 infection are those who are in close contact with a suspect/confirmed COVID-19 patient or who care for such patients. This article discusses the rationale usage of personal protective equipment (PPE).

Personal protective equipment (PPE)

Personal Protective Equipment (PPE) is most important in preventing transmission of the Ebola virus not only in treatment centers but also in various activities, e.g. cleaning, waste management and safe burials, and community care related to the outbreak.

Personal Protective Equipment (PPEs) are protective gear designed to safeguard the health of workers by minimizing the exposure to a biological agent. Personal protective equipment, commonly referred to as “PPE”, is equipment worn to minimize exposure to hazards that cause serious workplace injuries and illnesses.

These injuries and illnesses may result from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards. Personal protective equipment may include items such as gloves, safety glasses and shoes, earplugs or muffs, hard hats, respirators, or coveralls, vests and full bodysuits.

Types of PPE

1. Gloves: Protects your hands from microbes and minimizes the possible spreading of microbes.
2. Masks: Cover your mouth and nasal area. Some masks have a see-through plastic piece, which also covers your eyes (shield). A special respiratory mask (respirator) forms a tight seal around your nose and mouth. It can be useful to minimize the inhalation of smaller microbes, such as tuberculosis bacteria. 
3. Eye protection: This includes face shields as well as goggles. They can protect the mucous membranes of your eyes from bodily fluids. If the fluids make contact with the eyes, microbes within the fluid can enter the body through the mucous membranes.
4. Clothing: Includes gowns, aprons, head covering, and shoe covers.

Selection of appropriate PPE

It is important to consider the following factors which are influencing the selection of PPE:

1. Type of anticipated exposure: Such as from touch or surfaces, splashes or sprays, or large volumes of bodily fluids, which may seep through the clothing. PPE selection (and combinations of PPE), is determined by the category of isolation of the patient being treated.
2. Durability and appropriateness of the PPE for the task. This will affect, for example, whether a gown or apron is selected. If a gown is required, the type of gown is also important. Does it need to be fluid resistant, fluid proof, both or neither.
3. Fitting. PPE must fit the individual user (form a proper seal). For example; if a glove is too large / too small than the person’s hand, it will compromise the level of protection while also affecting the dexterity of the health care provider.

Components of PPE

Components of PPE are goggles, face-shield, mask, gloves, coverall/gowns (with or without aprons), headcover and shoe cover. 

1. 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.

Inadvertently touching the eyes/nose/mouth with a contaminated hand is another likely scenario. Hence protection of the mucous membranes of the eyes/nose/mouth by using face shields/goggles is an integral part of standard and contact precautions.

The flexible frame of goggles should provide a good seal with the skin of the face, covering the eyes and the surrounding areas and even accommodating for prescription glasses.

2. Masks

Respiratory viruses that include 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 the 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:

1. Triple-layer medical mask
2. N-95 Respirator masks
3. Triple-layer medical mask

A triple layer medical mask is a disposable mask, fluid-resistant, protects the wearer from droplets of infectious material emitted during coughing/sneezing/talking.

1. 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 a 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.

3. Gloves

When a person touches an object/surface contaminated by COVID-19 infected person and then touches his own eyes, nose, or mouth, he may get exposed to the virus.

Although this is not thought to be a predominant mode of transmission, care should be exercised while handling objects/surfaces potentially contaminated by suspect/confirmed cases of COVID-19.

Nitrile gloves are preferred over latex gloves because they resist chemicals, including certain disinfectants such as chlorine. There is a high rate of allergies to latex and contact allergic dermatitis among health workers.

However, if nitrile gloves are not available, latex gloves can be used. Non- powdered gloves are preferred to powdered gloves.

4. Coverall/Gowns

Coverall/gowns are designed to protect the torso of healthcare providers from exposure to the virus. Although coveralls typically provide 360-degree protection because they are designed to cover the whole body, including back and lower legs and sometimes head and feet as well, the design of medical/isolation gowns do not provide continuous whole-body protection (e.g., possible openings in the back, coverage to the mid-calf only).

By using appropriate protective clothing, it is possible to create a barrier to eliminate or reduce contact and droplet exposure, both known to transmit COVID-19, thus protecting healthcare workers working nearby (within 1 meter) of suspect/confirmed COVID-19 cases or their secretions.

Coveralls and gowns are deemed equally acceptable as there is a lack of comparative evidence to show whether one is more effective than the other in reducing transmission to health workers.

Gowns are considerably easier to put on and for removal. An apron can also be worn over the gown for the entire time the health worker is in the treatment area. Coveralls/gowns have stringent standards that extend from preventing exposure to biologically contaminated solid particles to protecting from chemical hazards.

5. Shoe covers

Shoe covers should be made up of impermeable fabric to be used overshoes to facilitate personal protection and decontamination.

6. Headcovers

Coveralls usually cover the head. Those using gowns should use a headcover that covers the head and neck while providing clinical care for patients. Hair and hair extensions should fit inside the headcover.

Rational use of PPE

The PPEs are to be used based on the risk profile of the health care worker. The PPE used in different areas in a hospital and their rational usages are given below.

1.   Entry points

2. Hospital areas

3. In-patient services

4. Ambulance services

5. Ancillary services

Conclusions 

Personal protective equipment is not consistently employed as per medical directives. Reasons given for nonuse included non-availability, the judgment of non-necessity, or technical difficulties.

There are important public health implications of non-compliance. In epidemics of highly infectious diseases, such as Ebola Virus Disease (EVD) or SARS, healthcare workers are at much greater risk of infection than the general population, due to their contact with patients’ contaminated body fluids. Contact precautions by means of personal protective equipment (PPE) can reduce the risk.

It is clear now which type of PPE protects best, and the rational usage of PPE reduces the risk of pandemic diseases.

References:

1. https://www.who.int/medical_devices/meddev_ppe/en/
2. https://www.health.state.mn.us/facilities/patientsafety/infectioncontrol/ppe/comp/index.html 
3. https://www.osha.gov/SLTC/personalprotectiveequipment/
4.  https://www.hse.gov.uk/toolbox/ppe.htm
5. https://www.physio-pedia.com/Personal_Protective_Equipment_(PPE)