Textile pads to act as first aid in case of cardiac arrest

For what can be done when for example a traveller collapses on a bus, train or aeroplane? Every year, 375,000 people suffer a cardiac arrest in Europe alone. The heart suddenly starts beating uncontrollably, the pulse becomes irregular. Within a few seconds the patient becomes unconscious and breathing and heartbeat stop.

For those affected, every second counts from this point on, because the patient's chances of survival decrease by ten percent with every second that passes until reanimation. Defibrillators have now become mandatory in public buildings and public transport. They use electric shock to restart the heartbeat.

For most cardiac arrest patients, however, even successful reanimation is merely a partial success – only a few patients survive this life-saving measure without consequential neurological damage. This is due to parts of the brain possibly sustaining lasting damage caused by the lack of blood flow and oxygen supply during the period until the ambulance arrives. This often results in the affected becoming invalid.

To avoid this type of brain damage in future, scientists from the faculty of Hygiene, Environment & Medicine at the Hohenstein Institute have developed a new therapy method for first aiders. In the framework of a research project supported by the state of Baden-Württemberg for the competition 'Biotechnology and medical technology', the scientists lead by Prof. Dr. Dirk Höfer developed the prototype of a textile cooling vest. The new type of medical product promises improved acute treatment for cardiac arrest by very quickly cooling down the patient's body.

It has been known for a long time that cooling can protect the brain against the dreaded oxygen deficit during a lack of blood flow. Targeted lowering of the temperature inside the body to 32 °C to 34 °C has been proven to protect the brain against irreparable neurological damage.

This simple but extremely effective therapy principle was used by the Hohenstein scientists. They started by developing water-proof and absolutely airtight textile hollow fabric – so-called cooling pads. These were equipped with appropriate connection options and integrated into a vest. The cooling pads are connected to a metal container under vacuum pressure containing a special mineral (zeolite).

When an interposed valve is opened, the water in the pads is instantly cooled down to nearly freezing (see info box), very effectively draining body heat from the patient's body at the same time.

The cooling system based on zeolite/water adsorption technology has a simple design and allows drastic lowering of the core body temperature after occurrence of a cardiac arrest at any time and in any place – without electric power! In future the self-sufficient cooling pads are intended to complement mobile defibrillators (with automated ECG analysis) for use by first aiders without medical knowledge e.g. in public buildings and public transport. For patients with cardiac arrest this means a much better chance of sustaining only minor consequential damage.