Removal of Resuscitation Artefacts from Ventricular Fibrillation ECG Signals Using Kalman

Removing cardiopulmonary resuscitation (CPR) related artefacts from human ventricular fibrillation (VF) ECG signals would provide the possibility to continuously detect rhythm changes and estimate the probability of defibrillation success. This would avoid ”hands-off ” analysis times which diminish the cardiac perfusion and thus deteriorate the chance for a successful defibrillation attempt. Our approach consists in representing the CPR-corrupted signal by a seasonal state-space model. This allows for a stochastically changing shape of the periodic signal and also copes with time-dependent periods. The residuals of the Kalman estimation can be identified with the CPRfiltered ECG signal. Preliminary results using only a small pool of human VF and animal asystole CPR data show that the seasonal model is not as effective as models using reference signals, but it might be useful in combination with them. 1

Kommentar zu den Leitlinien 2010 zur kardiopulmonalen Reanimation des European Resuscitation Council

Administer chest compressions (minimum 100/min, minimum 5 cm depth) at a ratio of 30:2 with ventilation (tidal volume 500-600 ml, inspiration time 1 s, F(I)O(2) if possible 1.0). Avoid any interruptions in chest compressions. After every single defibrillation attempt (initially biphasic 120-200 J, monophasic 360 J, subsequently with the respective highest energy), chest compressions are initiated again immediately for 2 min independent of the ECG rhythm. Tracheal intubation is the optimal method for securing the airway during resuscitation but should be performed only by experienced airway management providers. Laryngoscopy is performed during ongoing chest compressions; interruption of chest compressions for a maximum of 10 s to pass the tube through the vocal cords. Supraglottic airway devices are alternatives to tracheal intubation. Drug administration routes for adults and children: first choice IV, second choice intraosseous (IO). Vasopressors: 1 mg epinephrine every 3-5 min IV. After the third unsuccessful defibrillation amiodarone (300 mg IV), repetition (150 mg) possible. Sodium bicarbonate (50 ml 8.4%) only for excessive hyperkaliemia, metabolic acidosis, or intoxication with tricyclic antidepressants. Consider aminophylline (5 mg/kgBW). Thrombolysis during spontaneous circulation only for myocardial infarction or massive pulmonary embolism; during on-going cardiopulmonary resuscitation (CPR) only when indications of massive pulmonary embolism. Active compression-decompression (ACD-CPR) and inspiratory threshold valve (ITV-CPR) are not superior to good standard CPR. Most effective improvement of outcome by prevention of full cardiorespiratory arrest. Basic life support: initially five rescue breaths, followed by chest compressions (100-120/min depth about one third of chest diameter), compression-ventilation ratio 15:2. Foreign body airway obstruction with insufficient cough: alternate back blows and chest compressions (infants), or abdominal compressions (children > 1 year). Treatment of potentially reversible causes: (4 Hs and 4 Ts) hypoxia and hypovolaemia, hypokalaemia and hyperkalaemia, hypothermia, and tension pneumothorax, tamponade, toxic/therapeutic disturbances, thrombosis (coronary/pulmonary). Advanced life support: adrenaline (epinephrine) 10 A mu g/kgBW IV or IO every 3-5 min. Defibrillation (4 J/kgBW; monophasic or biphasic) followed by 2 min CPR, then ECG and pulse check. Initially inflate the lungs with bag-valve mask ventilation (p(AW) 20-40 cmH(2)O). If heart rate remains < 60/min, start chest compressions (120 chest compressions/min) and ventilation with a ratio 3:1. Maintain normothermia in preterm babies by covering them with foodgrade plastic wrap or similar. Early protocol-based intensive care stabilization; initiate mild hypothermia early regardless of initial cardiac rhythm [32-34A degrees C for 12-24 h (adults) or 24 h (children); slow rewarming (< 0.5A degrees C/h)]. Consider percutaneous coronary intervention (PCI) in patients with presumed cardiac ischemia. Prediction of CPR outcome is not possible at the scene, determine neurological outcome < 72 h after cardiac arrest with somatosensory evoked potentials, biochemical tests and neurological examination. Even if only a weak suspicion of an acute coronary syndrome is present, record a prehospital 12-lead ECG. In parallel to pain therapy, administer aspirin (160-325 mg PO or IV) and clopidogrel (75-600 mg depending on strategy); in ST-elevation myocardial infarction (STEMI) and planned PCI also prasugrel (60 mg PO). Antithrombins, such as heparin (60 IU/kgBW, max. 4000 IU), enoxaparin, bivalirudin or fondaparinux depending on the diagnosis (STEMI or non-STEMI-ACS) and the planned therapeutic strategy. In STEMI define reperfusion strategy depending on duration of symptoms until PCI, age and location of infarction. In severe hemorrhagic shock, definitive control of bleeding is the most important goal. For successful CPR of trauma patients a minimal intravascular volume status and management of hypoxia are essential. Aggressive fluid resuscitation, hyperventilation and excessive ventilation pressure may impair outcome in patients with severe hemorrhagic shock. Any CPR training is better than nothing; simplification of contents and processes is the main aim

Basismaßnahmen zur Wiederbelebung Erwachsener und Verwendung automatisierter externer Defibrillatoren

Die Basismaßnahmen zur Wiederbelebung („basic life support“, BLS) beziehen sich auf das Freihalten der Atemwege sowie das Aufrechterhalten von Atmung und Kreislauf ohne Verwendung von Hilfsmitteln, abgesehen von einfachen Mitteln zum Eigenschutz [1]. Diese Sektion enthält die Leitlinien zu den Basismaßnahmen zur Wiederbelebung Erwachsener und zur Verwendung eines automatisierten externen Defibrillators (AED). Sie beinhaltet auch das Erkennen des plötzlichen Herztodes, die stabile Seitenlage und das Handeln bei Ersticken (Verlegung der Atemwege durch Fremdkörper). Leitlinien für den Einsatz von manuellen Defibrillatoren und zur Einleitung von Wiederbelebungsmaßnahmen im Krankenhaus finden sich in den Sektionen 3 und 4 [2, 3]