Steinbeis experts work with project partners to design a patient cooling solution that can be used anywhere
In Europe, more than 375,000 people suffer a cardiac arrest away from a hospital every year. Over 82% of all cardiac arrests in western industrial nations are caused by heart problems. Also, because of demographic developments, more and more people are having to be revived using cardiopulmonary resuscitation. The prognosis for patients who have to be reanimated outside hospitals is bleak: Less than 10% of people who are successfully resuscitated will survive the incident without any (or with only minimal) neurological problems. Subsequent neurological damage is a result of cell damage caused by a lack of oxygen. To help avoid cell damage after a cardiac arrest, Sika, dretex Textiles, PRIME-tec, and RÖSSEL Instrumentation joined forces with the Steinbeis Innovation Center Automation in lightweight construction processes (ALP) and the professorial chair for technical thermodynamics at Chemnitz University of Technology to work on the development of a mobile patient cooling solution for use in emergencies following an acute cardiac arrest.
Every tissue in the body has different tolerance levels to situations involving oxygen deprivation. The most sensitive organ in the body is the brain, which depends almost exclusively on the oxidative breakdown of glucose to maintain required energy levels. As a result, a person will already become unconscious if the oxygen supply to the brain is interrupted for a matter of seconds. After three to six minutes at the most, they will suffer irreversible cell damage and sometimes severe brain damage. So-called ischemic tolerance, i.e. tolerance to a loss of blood supply to brain tissue, plays a decisive role in the neurological condition of resuscitated patients. It generally lasts between three and five minutes.
When the body cools down to between 32°C and 34°C, this is called mild hypothermia. Controlled hypothermia has proven to be a particularly effective method used in bypass surgery and neurosurgical procedures. Clinical studies have shown that deliberately inducing mild hypothermia has a significant positive impact on patients in neurological terms following reanimation [1, 2]. Not only is there a significant improvement in neurological outcomes, there is also a reduction in mortality levels. Until now, there has not been a suitable method for carefully managing patient temperatures outside the hospital, at least not in line with recommendations under ERC guideline 2015 . Because it’s so important to resuscitate patients successfully, if possible avoiding lasting damage, experts in research and development are working intensively on a suitable system. As part of a ZIM project called HypoTrans, four partner companies – Sika, PRIME-tec, dretex, and RÖSSEL – have been participating in an R&D project with the professorial chair for technical thermodynamics at Chemnitz University of Technology and the Steinbeis Innovation Center Automation in lightweight construction processes (ALP). Their joint aim is to develop an overall that will provide comprehensive emergency care to resuscitated patients. The project is being funded by the German federal government. The project partners took early patient cooling in an emergency as their starting point. Their aim was to develop a cooling system to plug the gap between the moment a patient is reanimated by a first aider and the moment an emergency vehicle arrives so that the patient can be handed over for treatment in intensive care. The system should make it easier to adhere to the ECR recommendations under guideline 2015 regarding targeted temperature management.
The project alliance was successful and as a result of its research and development efforts, a new HypoTrans Overall  has been created. The solution has also been patented by Chemnitz University of Technology. The suit is made from strong materials and offers integrated temperature management for carefully cooling down patients. It was specially designed to match the needs of first aiders and was first unveiled to the general public at Hannover Messe 2018 at a stand shared with the Federal Ministry for Economic Affairs and Energy.
The overall works by storing heat in phase change material (PCM). A self-regulating passive process takes place allowing the PCM to absorb heat from the body and make it dissipate. This results in the thermal energy being stored by the PCM rising continuously, even if the temperature of the PCM remains almost constant during phase changes. This allows heat to be transferred out of the patient’s body and as a result, the core body temperature drops as required. The process that takes place within the overall allows the defined temperature level to settle at around 34°C. The actual resulting temperature mainly depends on the melting temperature and actual mass of the PCM. To raise thermal conductivity, the experts working on the project modified the PCM and developed a PCM substance using graphite powder [5, 6, 7]. They packed this PCM substance into so-called macrocapsules so that it could be integrated into the overall. These capsules are produced in a vacuum using welding and they can be combined to create adaptable cooling elements of different sizes. With the HypoTrans overall, they are distributed throughout the suit and their job is to regulate temperature. Once in place, the macrocapsules can regenerate by being cooled down to a level below the melting temperature of the PCM mixture. They are then ready to be used again. Storage is an important aspect with the overall, which has to be kept below the melting temperature of the PCM material system.
The project team comprises experts in research, development, and business, and as a result of the HypoTrans Overall initiative they have successfully developed a robust, self-regulating, and self-supporting patient cooling system that can be used anywhere. The suit makes it possible to induce mild hypothermia in resuscitated patients even during first aid procedures away from a hospital. The experts believe the overall will be particularly useful in situations where trained first aiders are on hand with access to equipment such as automated external defibrillators (AEDs).
- Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. Hypothermia after Cardiac Arrest Study Group. N Engl J Med. 2002 Feb 21; 346(8): 549-56.
- Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. Bernard SA, Gray TW, Buist MD, Jones BM, Silvester W, Gutteridge G, Smith K. N Engl J Med. 2002 Feb 21; 346(8):557-63.
- Reanimation 2015 – Concise Guidelines. 1. 2015 Edition, ISBN: 978- 3-9814591-4-2
- Urbaneck, T.; Kresse, D.; Gebhardt, G.; Wilde, G.: DE102014118510A1 Textile coverings for inducing mild hypothermia.
- Böhme, H.; Urbaneck, T.; Oeser, S.; Platzer, B.: The HypoTrans Overall, Part 1: Principles of a Cooling Process for Treating Comatose Patients. ki – Refrigeration, Ventilation, and Air Conditioning Technology, Hüthig 54th yr. (2018) Issue 01-02 p. 42-47. – ISSN 1865-5432
- Böhme, H.; Urbaneck, T.; Platzer, B.: The HypoTrans Overall, Part 2: Investigations into Thermal Transfer and Macrocapsules. ki – Refrigeration, Ventilation, and Air Conditioning Technology, Hüthig 54th yr. (2018) Issue 03 p. 42-50. – ISSN 1865-5432
- Böhme, H.; Urbaneck, T.; Platzer, B.; Oeser, S.; Spieler, M.; Tirschmann, R.; Scheibner, C.: The HypoTrans Overall, Part 3: Practical Testing of Investigations into Thermal Temperature Management of the Human Body. ki – Refrigeration, Ventilation, and Air Conditioning Technology, Hüthig 54th yr. (2018) Issue 4 p. 49-55. – ISSN 1865-5432