Which is measured by the assessing the quantity of moisture vapor through a fabric during a specified time period and is reported as grams per square meter (g/m 2 ) under defined temperature and humidity. 3 Higher values indicate better moisture vapor removal and therefore better breathability.
Air permeability is a measure of the ability of a fabric to permit passage of air through the fabric's interstices. This is dependent on various factors like fiber porosity, fabric thickness and density, etc. Hygroscopic fibers like cotton can rapidly absorb moisture with changes in the ambient humidity, hence increasing the resistance to air or water permeation due to swelling and closeness of the pores in the fabric.
The breathability is dependent on the type of fabric used. Coveralls are generally manufactured using fabrics, most commonly non-woven polypropylene fibers. In common language, these fabrics are often known as Spunbond, Meltblown, Spunlace, etc., and are usually available in various compositions like spunbond meltblown spunbond (SMS), spunbond, meltblown, spunbond, meltblown (SMMS), etc.
Laminated fabrics are less breathable than coveralls made with SMS type polypropylene. Laminated fabrics are made from a substrate layer of either polypropylene, or a layer of bicomponent fibers with a polyester core and a polyethylene sheath.
The breathability of laminated fabrics can vary according to changes in the size of the micropores of the polyethylene film. The larger the micropores, the more breathable will be the fabric, although this may also mean less protective than a laminate with small micropores. Lamination material with appropriate size of micropores for good moisture vapor transmission rate (MVTR) is manufactured by very few good companies and the material is not easily available and incurs huge costs. More layers also means more heavy fabric (GSM—grams per square meter) and it adds to physical and chemical resistance at the cost of comfort to the HCW. Coveralls, which are laminated only at the stitch lines, are more breathable and also add to the protection by making the coverall seamless.
The current government specifications for PPEs are silent in terms of AP and water vapor transmission rate (WVTR)/MVTR. In the absence of clarity on specifications for PPEs related to these points, some of the available kits, despite having appropriate certifications from regulatory agencies regarding the fabric material, have extremely poor AP, WVTR/MVTR, and breathability.
As a general rule, all PPEs produce a significant impediment to heat loss because of their impermeability which reduces evaporation. Hence, HCWs often experience increases in skin and core temperatures which are further amplified in hot and/or humid conditions, an important factor in Indian conditions.4–6 A recent study comprising 4,308 HCWs across 161 COVID-19 hospitals in China found that nearly 30–40% reported heavy sweating, irritation, skin injuries and rashes, redness, and itching. The three most common forms of injury were device-related pressure injuries, moisture-associated skin damage, and skin tears over various parts of the body.7
This is a great cause of concern because excessive sweating can not only reduce the professional ability of the HCW to render effective care but can also be detrimental to the personal health of the HCW.
It is therefore very important for current guidelines to include technical specifications pertaining to AP and WVTR/MVTR (respectively, 100–150 L/m2/minute for AP and 400–500 g/m2/day for WVTR/MVTR), compliant with ASTMF96 standards or its equivalents. Despite complying with many of the mentioned technical specifications and claims of the manufacturers that their PPE kits are ergonomically designed, it is very important to validate these claims by “field testing” or “end-user trials” in which HCWs don the PPE and assess it for comfort and different work-performance indices. The UK PPE regulations (Personal Protective Equipment at Work Regulations 1992) also mention that, the institutions should choose a PPE that gives maximum protection and is associated with minimum discomfort.8
We propose an acronym COMFORT (COmfort and Material Fit is an Obviously Required Test) which should include the following: (a) Body heat impact and sweating assessment for 2 hours in an air-conditioned environment without any physical activity and assessment for sweating, dizziness, and feeling of fainting. (b) Flexibility testing of PPE kits with assessment of ability to perform patient care and nursing activities like Ryle's tube feed, hanging intravenous fluid on bed rails, sit comfortably on chairs with knee flexion to test for tightness of fit, and tearing of fabric, (c) and any additional points which the HCW wish to give feedback about including ease of donning/doffing, need for extra ties/laces/velcro to avoid slippage of shoe covers, etc.
A “comfort fit PPE assessment study” was performed among intensive care unit (ICU) personnel who were previously in good health and volunteered to take part in a pilot study. A total of 18 PPE kit samples were evaluated, and the donning period was limited to the time when the volunteers experience serious discomfort in a centrally air-conditioned ICU with ambient temperature 22–24°C and humidity 40–55%. Excessive sweating was experienced within 1–2 hours in 12/18 (67%) samples tested.
Hence, despite having appropriate certifications for fabric safety, two-third of PPEs tested had severe issues related to breathability and comfort of use due to excessive sweating. Since such PPE kits are unacceptable for use by the HCWs, and likely to be returned to the manufacturers, it is very pertinent that the Government of India issues modified certification criteria for breathability so that such type of poor quality PPE kits are not manufactured at all.
Messages: We propose that the proposed COMFORT fit testing should be a part of the mandatory testing process for PPE assessment so that industry and healthcare institutions invest wisely in PPE kits that are not only certified for fabric safety but also for AP and MVTR.
The acceptability of PPEs by HCWs can be vastly improved when the end-users are proactively invited to participate in the selection and comfort testing of PPEs. Hospital administrators should perform trials wherein the HCWs don the PPEs and offer opinions especially about desired comfort parameters, prior to the placement of purchase orders. Participation and feedback of HCWs in selection and testing of PPEs in such a way shall not only take into account a hitherto often ignored “human-comfort factor” but will also motivate them to use PPEs without any sense of undue worry.