Resuscitation in the event of cardiac arrest

In the event of a cardiac arrest, first aiders must start chest compressions immediately to ensure the survival of the affected person until emergency services can get the stopped heart beating again. With chest compressions, first aiders restore the suspended pumping function of the heart by pushing the sternum deeply (5 to 6 cm) and quickly (100 to 120 times per minute) towards the spine with outstretched arms: this pumps the blood and thus oxygen into the body's circulation and to the brain, preventing brain cells from dying (information: https://herzstiftung.de/wiederbelebung). „Cardiac massage is crucial for the survival of the emergency patient and for preventing serious long-term damage to the brain and other organs until the arrival of the emergency services“, emphasises cardiologist Prof. Dr Thomas Voigtländer, Chairman of the Board of the German Heart Foundation. Every year, more than 65,000 people die of sudden cardiac death in Germany.

In the research project „BRAINSAVER“ (for „brain saviour“), Leipzig researchers led by cardiologist PD Dr Karsten Lenk, managing senior physician at the Clinic and Polyclinic for Cardiology (Director: Prof. Dr Ulrich Laufs) at the University of Leipzig. Ulrich Laufs) at Leipzig University Hospital and other scientists from the Innovation Centre for Computer Assisted Surgery (ICCAS) at Leipzig University and the Gesellschaft für Angewandte Medizinische Physik und Technik (GAMPT) in Merseburg are focusing their work on the quality of cardiac massage as a crucial component.

The research work is supported by funding from the Heart Foundation in the amount of 95,000 euros as part of the special research initiative "Cardiac death". Information on the eleven projects of the special research initiative „Cardiac Death“ (volume: one million euros) at https://herzstiftung.de/forschung-herztod

Dr. Lenk and colleagues have developed the prototype of an ultrasound-supported measuring device in a neck brace with the cooperation project „Brainsaver“, with the help of which it is possible to recognise whether the sufficient amount of blood is being pumped through the body circulation and thus also into the brain of the emergency patient during chest compressions.

Brainsaver, like „Wearable“, measures the blood flow through the carotid artery
Studies have already indicated that the blood flow through the carotid artery is a sign of how well the cardiac massage is performed. „The aim of chest compressions is to continue to supply the brain with the oxygen-rich blood still in the body until the heart starts to work again“, explains Lenk. Time is life in cardiac arrest: for every minute that passes without chest compressions, the chances of survival decrease by ten per cent.

In addition, of the at least 50,000 people requiring resuscitation in Germany every year, only around ten per cent of patients leave hospital with an acceptable neurological outcome without serious long-term damage, according to experts (1,2).

emphasises Dr Lenk.

The Brainsaver is easy to use

The Leipzig researchers have therefore developed the neck brace with an integrated Doppler sonography probe in such a way that it can be used by rescue teams without prior comprehensive sonography training. The cervical collar consists of an immobilisation collar that is used in intensive care and emergency medicine to protect the neck and nape area. Thanks to analysis software, the device automatically records blood flow velocities and displays them on a mobile monitor connected to the Brainsaver. A signal tone warns first aiders during chest compressions as soon as the ultrasound probe indicates an undersupply of blood to the circulatory system. „The probe uses the blood flow in the carotid artery, the arteria carotis communis, which supplies the brain with blood“, explains Dr Lenk. For the researchers, the significance of blood flow in the carotid artery is important in many respects:
– for determining the effectiveness of cardiac massage,
– for assessing the prognosis and
– it provides feedback for those performing cardiac massage.

The Brainsaver prototype, which Dr Lenk and his colleague Dr Georg Stachel, senior physician at the Clinic and Polyclinic for Cardiology and the Central Emergency Department at Leipzig University Hospital, developed in collaboration with ICCAS and GAMPT, contains an algorithm that determines the depth of the target vessel under the skin and specifies the measuring range of the ultrasound device.

Fast and effortless placement of the ultrasound probe and reliable automatic recording of the flow spectrum are among the most important technical requirements for clinical use of the neck brace,

explains Dr Lenk.

Of decisive importance for the development and realisation of the Brainsaver prototype was, according to Dr. Lenk, the interdisciplinary collaboration between the doctors at the Clinic and Polyclinic for Cardiology and the Central Emergency Department at Leipzig University Hospital, the engineers Reinhard Fuchs and Prof. Dr Thomas Neumuth from ICCAS and the physicist Dr Michael Schultz from GAMPT was crucial to the development and realisation of the Brainsaver prototype.

First method tests on test subjects were promising

First tests on test subjects from the research group are promising. However, the Brainsaver must be trialled in clinical settings in stages. In an initial test phase for technical feasibility, the „brain saver“ must prove itself at Leipzig University Hospital on 100 patients without circulatory arrest and then on patients in the intensive care and monitoring wards of the university hospital: on 96 patients in shock and on 80 patients undergoing resuscitation.

We are now testing the benefits of the device so that perhaps all rescue units in Leipzig will be equipped with it in the future.

Source: innovations report from 12 December 2023