Hospital working wearing PPE

Effects of long-term PPE use softened by talc and natural butters

Image credit: H Shaw | Unsplash

Talc and petroleum jelly among the best lubricants for people wearing PPE, study finds.

Talcum powder, a coconut oil-cocoa butter beeswax mixture, and petroleum jelly have been shown to provide the best skin protection for long-term PPE use, say scientists.

For frontline healthcare workers during the Covid-19 pandemic, wearing personal protective equipment (PPE) such as face visors, googles and respiratory protective equipment is an essential part of working life. More workers are wearing facial PPE now than ever before, often for extended periods of time, to protect them against the SARS-CoV-2 virus.

However, extended PPE use, particularly on the delicate skin of the face, can cause friction and shear injuries such as skin tears, blistering, ulcers and hives.

The effects of friction and shear can be reduced by lubricants, which workers are advised to apply every half an hour. Half-hourly applications can be impractical during shift work and removing the PPE in order to apply it could expose workers to the virus. Many typical moisturisers also don't last long, as they are designed to be absorbed into the skin quickly for a desirable 'non-greasy feel'.

Researchers from Imperial College London have investigated which products create the longest-lasting protective layer between PPE and skin. They hope their findings will help healthcare workers and other long-term PPE users, such as those working in hospitality environments, to prevent and avoid unnecessary skin injury and deformity.

The researchers found that the best lubricants are those that don't absorb into the skin, creating a long-lasting layer of protection between the skin and the PPE being worn. Non-absorptive creams, such as coconut oil-cocoa butter beeswax mixtures, and powders, such as talcum powder, are the most likely to provide PPE wearers with long-lasting skin protection.

Dr Marc Masen, lead author of the study, from Imperial's Department of Mechanical Engineering, said: "We think of moisturisers as good for our skin, but commercial skin creams are often designed to absorb into the skin without leaving any residue. While this is fine for everyday moisturising, our study shows that a greasy residue is precisely what's needed to protect skin from PPE friction."

To identify the best-performing lubricants, the researchers custom-built a tribometer – an instrument that assesses friction between two surfaces – and used it to test the friction between skin and polydimethylsiloxane (PDMS), a common component of PPE.

They used the tribometer to test commercially available products to measure how they changed the friction between PDMS and the inner forearm skin of a healthy 44-year-old male participant. They tested friction first upon application and then one, two and four hours after application.

The scientists found that while most products initially reduced friction by 20 per cent, some silicone-based and water and glycerin-based lubricants increased friction levels over time by up to 29 per cent compared to dry skin.

However, two products reduced friction as time went on. Talcum powder reduced friction by 49 per cent on application and by 59 per cent at four hours, while a commercially available product comprising coconut oil, cocoa butter and beeswax reduced friction by 31 per cent on application and by 53 per cent after four hours. A mixture of petrolatum and lanolin reduced friction by 30 per cent throughout testing.

When testing commercial moisturisers, they found that friction on application was low, but increased drastically within ten minutes of application. The researchers say this is because the active ingredients, known as humectants, attract water like magnets from the lower layers of skin to the upper ones, leaving it soft, unlubricated and breakable.

Co-author Dr Zhengchu Tan, also of the Department of Mechanical Engineering, said: "The products that don't absorb easily into the skin are the ones that provide a protective layer. In fact, for PPE wearers, it's best to actively avoid creams and moisturisers which advertise a 'non-greasy feel'."

Dr Masen said: "Friction can be incredibly damaging for the skin, particularly when applied for an extended period. We hope our study will save healthcare workers and other frontline PPE wearers from suffering with the painful and damaging effects of skin friction."

The researchers say that while their study signposts PPE wearers to the best skin-saving products, they are looking to perform further studies using facial skin and more participants. Due to Covid-19 restrictions during lockdown, they were only able to test the products on one study participant and only used his inner forearm as a surrogate for facial skin.

The research was funded by the Imperial College Covid-19 response fund. The authors declared that they paid for the products tested and have no competing interests.

At the height of the first pandemic wave in the early months of 2020, the demand for PPE surged to previously unseen levels, both from hospital staff and from consumers, causing deleterious shortages across the UK.

The response was wide and varied, with volunteers in Scotland making thousands of face shields for NHS staff; drones being deployed to fly PPE to remote locations, and online auction site eBay saying it would build an e-portal for NHS staff to order protective equipment necessary to safely tackle the Covid-19 pandemic.

Meanwhile, the UK government for its part spent £252m on 50 million face masks intended for the NHS, which were ultimately deemed ‘not fit for purpose’ and had to be set aside.

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