Scientists have found that petroleum jelly and talcum powder are most likely to provide long-lasting skin protection to those wearing personal protective equipment (PPE), an advance that may help healthcare workers prevent injury from prolonged use of masks and visors amidst the COVID-19 pandemic.
According to study, published in the journal PLOS ONE, the best lubricants to use are those that don't absorb into the skin, creating a long-lasting layer of protection between skin and PPE.
The scientists, including those from Imperial College London in the UK, noted that wearing PPE like face visors, goggles, and respiratory protective equipment have become an essential part of working life for frontline healthcare workers during the COVID-19 pandemic,
They said 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, the researchers said extended PPE use, particularly on the delicate skin of the face, can cause friction and shear injuries like skin tears, blistering, ulcers, and hives.
In order to reduce the effects of friction and shear, workers are advised to apply lubricants every half hour, which they said can be impractical during shift work and may expose workers to the virus. The scientists added that many typical moisturisers do not last long as they are designed to be absorbed into the skin for a 'non-greasy feel'.
"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," said study lead author Marc Masen from Imperial College London. "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," Masen said.
In the research, the scientists custom-built a tribometer -- an instrument that assesses friction between two surfaces -- and used it to test the friction between the skin and polydimethylsiloxane (PDMS), which is a common component of PPE. They tested 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, testing friction upon application.
The researchers repeated the testing process one, two, and four hours after application. The study 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, the scientists said two products reduced friction as time went on. According to the study, talcum powder reduced friction by 49 per cent on application and 59 per cent at four hours, and a commercially available product comprising coconut oil, cocoa butter, and beeswax reduced friction by 31 per cent on application and 53 per cent at four hours.
The scientists said a mixture of petrolatum and lanolin reduced friction by 30 per cent throughout testing. They found that when applying commercial moisturisers, the friction on application was low, but increased drastically within ten minutes of application.
The researchers explained that 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. "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'," said study co-author Zhengchu Tan.
"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," Masen said. The researchers believe the findings may help PPE wearers seek the best skin-saving products.