A cooling vest can effectively reduce heat stress for healthcare workers if they have to wear protective suits, such as during covid times. Biomedical scientist Yannick de Korte comes to this advice.
If it is a pleasant 23 degrees in a hospital ward, the temperature inside a protective suit can rise to tropical values. Sometimes even up to 36 degrees, especially if clothing is worn underneath. De Korte points this out in his recent PhD research, for which he looked at the physiological reactions and experienced heat stress of both top athletes and covid care workers who have to perform under heat stress.
In fact, De Korte only wanted to focus his PhD research on Olympic and Paralympic athletes who were preparing for the 2020 Summer Games in Tokyo, where they would have to perform in tropical temperatures and high humidity. In climate chambers he tested how athletes reacted to those conditions and how this had an effect on their sports performance. Through a literature study, he mapped out which cooling methods to cool down before, during or after a performance best helped them to reduce the consequences of heat stress. Wearing a cooling vest proved to be the most effective cooling method during exercise.
Covid pandemic
But during De Korte’s research, the Covid pandemic came, the Games were canceled and De Korte saw how another group of people struggled with obstructed heat dissipation: healthcare workers who had to wrap themselves in personal protective equipment (PPE) when working with covid patients. Apart from this and future pandemics, climate change will mean that healthcare workers will more often have to work in stressful, hot conditions, De Korte predicts.
He therefore questioned nearly eight hundred healthcare workers – mainly nurses, but also doctors, among others – who worked in a covid ward of a Dutch hospital for at least a week during covid time, wearing isolation gowns, face masks and eye protection. A whopping 93 percent of participants experienced at least one symptom of heat stress during those conditions. Thirst (mentioned by 79%), feeling hot (78%), excessive sweating (68%), fatigue (60%), headache (60%) and shortness of breath (55%) were the most frequently reported symptoms. Especially female employees and employees under the age of 40 experienced heat stress.
Alarming
In itself, the majority of those covid care employees from his research had access to various ways to reduce heat stress in the workplace, De Korte further noted. For example, they can enjoy cold drinks or ice shavings and retreat to air-conditioned rooms during breaks. But those resources are not enough to eliminate the symptoms of heat stress that cause PPE. De Korte calls this ‘alarming’, given the risks to health and safety. It also affects productivity: participants more often indicated that they would stop working earlier, or perform their tasks more slowly and less accurately if they wore PPE. In addition, it can reduce the willingness to don PPE and thus increase the risk of infection.
Cooling vests for athletes, which are used in sports such as hockey, cycling and Formula 1, mainly provide ‘short, hard and aggressive cooling’, according to De Korte, with material that freezes at 7 or 15 degrees. They are mainly worn during, for example, switches. For covid personnel, De Korte opted for vests that are suitable for wearing during shifts of several hours, and activities that also involve sitting still in between for administrative tasks, for example. These became vests with material in them that freezes below 21 degrees, and releases cold to the body for up to three hours and absorbs heat from the body. Vests made of material that can be easily disinfected were also chosen.
His research, conducted in two departments with covid nurses from Radboudumc, showed that such a cooling vest, worn under PPE, significantly reduces heat stress in a large proportion of nurses. Without a vest, about 80 percent of the nurses reported thermal discomfort and more than 90 percent experienced heat or heat sensations. With vest, that dropped to 18 and 36 percent respectively.
Other professions
De Korte chose nurses and not doctors for his research, based on the idea that the first group performs more physically demanding and therefore more intensive work. But De Korte assumes that the results can also be translated to other healthcare professions, such as doctors or, for example, healthcare workers in mobile medical teams, at GGD test facilities and nursing homes.
At Radboudumc, the vests are now made available to nurses who work with PPE when they come into contact with covid patients or patients with viral hemorrhagic fever. The investment is around 180 euros per vest – costs for cleaning or the refrigerator where they can be reactivated have not yet been included. De Korte: ‘Certainly in a medical setting, where healthcare personnel already have to think about so much, you have to arrange things in such a way that they can grab such vests without much effort and energy. Otherwise they won’t use them.’
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