SINGAPORE - A study of healthcare workers in Singapore and India has found that a majority of those who have to wear personal protective equipment (PPE) experience symptoms of thermal strain, including excessive sweating, exhaustion, and dizziness.
The Covid-19 pandemic has resulted in more front-line workers having to wear PPE for a prolonged period of time.
In a paper published in the peer-reviewed International Journal of Environmental Research and Public Health on Tuesday (Nov 3), the researchers said that this exacerbates their risk of thermal strain.
The study's senior and corresponding author, Associate Professor Jason Lee from the National University of Singapore's Yong Loo Lin School of Medicine, explained on Thursday that thermal strain refers to the amount of heat a person experiences internally.
This is influenced not just by climatic conditions, but other factors such as a person's fitness, and what they are wearing or doing.
Prof Lee, who is from the school's Human Potential Translational Research Programme, told The Straits Times that in a worst-case scenario, thermal strain can result in heat stroke and death.
"Before that, your performance will be compromised... it's not just you (who will be affected), but those who you care for," he said, adding that if a healthcare worker is experiencing thermal strain, patient care could also be affected.
Prof Lee added that even in a milder form, thermal strain can affect morale as it makes people feel uncomfortable.
"One or two days (of thermal strain) a week may probably be tolerable, but when it comes to this pandemic, when you go into months and potentially years, it can be quite damaging," he said.
One of the study's other authors, Dr Jimmy Lee, a consultant at Ng Teng Fong General Hospital's (NTFGH) Emergency Medicine department, said that front-line healthcare workers in his hospital keep their PPE on for about seven to eight hours at a time.
Standard PPE includes goggles, a surgical cap, an N95 mask, surgical gloves and a gown. But most of these components are moisture impermeable, which means they also trap sweat.
Prof Lee said: "Many people assume that once you sweat, it's okay. But if sweat doesn't evaporate, it does nothing - you're not losing heat... in PPE, sweat cannot evaporate."
Dr Lee, who wears PPE in the course of his daily work, said he has seen some medical officers get "soaked" in sweat after just two hours.
So together with a team of other researchers, he and Prof Lee conducted a study of 55 healthcare workers at NTFGH and another 110 from India, who were asked to answer a questionnaire on their knowledge about thermal strain, attitudes towards PPE use and behavioural changes while wearing PPE.
Some 90 per cent of the healthcare workers in Singapore reported sweating excessively in their PPE, while 76 per cent said they felt exhausted.
Twenty-nine per cent experienced dizziness as a result of their PPE, 22 per cent got headaches, and 13 per cent said they had difficulty breathing.
Respondents were also given ice slurry - a beverage made by mixing ice with a sports drinks - and asked to rate their thermal comfort before and after drinking it. Those who drank the ice slurry reported that they felt more comfortable afterwards.
The researchers made three recommendations in the light of their findings. First, that ice slurry machines should be provided to healthcare workers to help them lower their body temperature.
Second, there is a need to optimise the work-rest cycle of healthcare workers.
The researchers said that although more research would be needed to prescribe a specific balance, it would be an area worth looking into as this too would help manage the effects of thermal strain.
Finally, Prof Lee said that aerobic fitness is the most effective way to mitigate the effects of thermal strain, so more emphasis needs to be placed on raising it among healthcare workers.
He said: "We want to make life better for healthcare workers... It shouldn't be (that) during the next pandemic or related event, we go about quantifying another round of healthcare worker thermal stress. That should be part of the preparation package. (If) we know something's coming and PPE will have to be on, then ice slurries and cooling facilities should be part of the logistics."
Dr Lee added: "In this period, occupational health is very important. We wanted to raise awareness about the importance of (thermal strain). Because we have limited resources and manpower... preserving this resource is important."