Cardiac Arrest and Cardiopulmonary Resuscitation

Cardiac arrest is recognised by unresponsiveness and abnormal or absent breathing. Immediate 999 contact, CPR and early use of an AED give the person the best available chance before professional help arrives.

Cardiac arrest happens when the heart suddenly stops pumping blood effectively. Blood flow to the brain and other organs falls immediately, so the person becomes unresponsive and stops breathing normally. Cardiac arrest is not the same as a heart attack. A heart attack is usually caused by blocked blood flow to heart muscle, and the person may remain awake and breathing. A heart attack can sometimes trigger cardiac arrest. Recognising cardiac arrest First check that it is safe to approach. Speak loudly to the person and gently check for a response. If there is no response, call 999 and put the phone on loudspeaker. The 999 call handler will help you assess breathing and guide the next steps. Look and listen for normal breathing for no more than about ten seconds. Occasional gasps, snorting or irregular breaths are called agonal breathing and are not normal breathing. If a person is unresponsive and not breathing normally, assume cardiac arrest and start CPR. A lay responder should not delay CPR by spending time trying to find a pulse. Calling for help and finding an AED Tell the call handler that the person is unresponsive and not breathing normally. Give the exact location and follow the instructions. If another person is present, ask them to call 999 and bring an AED while you start chest compressions. An AED is an automated external defibrillator. If you are alone, use a mobile phone on loudspeaker. The call handler may direct someone to the nearest registered public AED. Starting adult chest compressions Place the heel of one hand in the centre of the chest, on the lower half of the breastbone. Place your other hand on top and interlock your fingers. Keep your arms straight and position your shoulders above your hands. Press the chest down by at least 5 centimetres but not more than 6 centimetres. Give compressions at 100 to 120 each minute. This is close to two compressions each second. Allow the chest to rise fully after each compression. Keep interruptions as short as possible because blood flow falls whenever compressions stop. CPR can cause rib or chest injuries. In cardiac arrest, the risk of doing nothing is far greater than the risk of injury from correctly attempted CPR. Rescue breaths If you have been trained and are willing, alternate 30 chest compressions with 2 rescue breaths. Give only enough air to make the chest begin to rise. If you are not trained in rescue breaths, give continuous chest compressions without interruptions. The 999 call handler will guide you. Rescue breaths are particularly important in many arrests caused by breathing problems, including drowning and many cardiac arrests in children. The practical technique differs by age and circumstance. Using an AED An AED checks the heart rhythm and decides whether an electrical shock may help. It will not advise a shock unless its analysis identifies a rhythm that should be shocked. Switch the AED on and follow its spoken and visual instructions. Expose the chest and attach the pads exactly as shown on the device. Continue CPR while the AED is prepared when another rescuer is available. Stop touching the person when the AED tells everyone to stand clear for rhythm analysis or a shock. After a shock, or when no shock is advised, resume CPR immediately as directed. Not every cardiac arrest has a shockable rhythm, so CPR remains essential. Public AEDs are designed for use by members of the public. Lack of previous training should not stop someone from switching one on and following its prompts during a suspected cardiac arrest. When to stop CPR Continue CPR and AED use until professional help takes over, the person begins to show clear signs of life and breathes normally, you become physically unable to continue, or the emergency service tells you to stop. If the person begins breathing normally but remains unresponsive, follow the call handler's advice. They may need the recovery position and continued monitoring. Do not stop because a gasp appears or because the AED says no shock is advised. Gasping is not normal breathing, and a non shockable rhythm still requires CPR. Adults, children and babies The principles of safety, rapid recognition, 999 contact and early CPR apply at every age. However, hand position, compression depth and the importance of initial rescue breaths differ for babies and children. Current UK guidance includes five initial rescue breaths for babies and children before compressions. The 999 call handler can guide an untrained responder through the correct age specific steps. This lesson concentrates on adult CPR. Accredited practical training should include adult, child and baby resuscitation. After the event A cardiac arrest is distressing for witnesses and rescuers. Feeling shaken, tearful or uncertain afterwards is common, even when every reasonable action was taken. Emergency services, employers and first aid organisations may provide debriefing or support. Seeking help after a difficult resuscitation is appropriate. This page supports understanding but cannot replace hands on CPR and AED training. During a real collapse, call 999 immediately and follow the call handler and AED prompts.

An unresponsive person who is not breathing normally needs immediate 999 contact, CPR and an AED. Do not wait for diagnostic certainty.