A warming-up sleeping bag: every degree matters

Dr Paweł Jastrzębski
In medical rescue, it is not only time that matters, but also temperature. Nothing can be done about time, but UWM employees have found a way to keep the body temperature of accident victims at the right temperature – a heated sleeping bag.

The overcooling and hypothermia of road traffic or ski accident victims, drunken people sleeping outside or people in cold water for a long time is a serious problem.

“If the human body temperature drops below 33 degrees Celsius, the blood will not clot. It is then difficult to stop the bleeding. A cooled person can be warmed up at a rate of 1 degree per hour to avoid additional complications. Wind and rain is the worst weather for the injured. In such conditions, the body temperature quickly lowers. Traffic accident victims very often lie on wet grass, concrete or asphalt. Before the ambulance arrives, they are already cold and it often takes a long time before they get to hospital. In extreme cases, hypothermia leads to death,” says Dr Paweł Jastrzębski, the Head of the Chair of Emergency Rescue at the UWM School of Public Health.

Rescue ambulances are equipped with blankets made of NRC (gold and silver) foil, which are used to cover the victim. Such a foil protects against loss of heat, but does not warm up. The latest patent granted by the Polish Patent Office to the UWM concerns a sleeping bag for people and animals to maintain optimal temperature during medical and rescue operations.

“For a long time now, I have been discussing with my colleague, Professor Zbigniew Adamiak from the Faculty of Veterinary Medicine, what can be done about this, how to protect the body against hypothermia. The idea that it should be a warming sleeping bag came to our minds after long deliberation,” recalls Dr Jastrzębski.

The sleeping bag, which was designed by the Kortowo scientists, together with Kamil Krzyżanowski from the Medical University of Gdańsk, should be made of soft polymer material. Its interior contains a heating mat, which can be the same type as in heated car seats. It is powered by 12 V from a portable battery and in the ambulance from its mains. The sleeping bag has a temperature sensor with a thermostat and heating mat controller. This permits to set and maintain the required temperature. The insulation layer in the sleeping bag is air. It can be pumped with a self-expanding bag or with the mouth. The bottom of the sleeping bag is covered with corrugated rubber so that it can be laid on the ground, snow, mud and does not freeze or slip off the slope. In addition, it is equipped with straps that can be attached to the long spine board. The heating element is covered with a soft, flexible plastic that ensures safe use. It eliminates the risk of direct contact of the body with the mat.

“Our sleeping bag is light and reusable – because it can be decontaminated – and it is cheap to manufacture. It can have a heat-reflective coating on the outside or a camouflage outer coating, in which case it can be used on a battlefield. It is equally suitable for protecting animals.

The UWM received the decision to grant a patent to the sleeping bag in June this year, but for some time now, the UWM Innovation and Technology Transfer Centre has been looking for a manufacturer for the bag.

The thermal sleeping bag is not the only invention for which Dr Jastrzębski and Professor Adamiak have been granted patents. In 2018, they patented the stasis, a special band for staunching bleeding in the case of amputated limbs and massive haemorrhages (also reusable) and before that, shears for cutting clothes and bandages.

Lech Kryszałowicz

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