Cardiopulmonary Resuscitation (CPR)

Cardiopulmonary resuscitation (CPR) is an emergency life-saving technique that manually keeps blood and oxygen moving through the body when the heart has stopped beating or is beating too weakly to sustain life. It is performed immediately at the scene of a cardiac arrest (when the heart suddenly stops pumping) and continued until the heart can be restarted or advanced medical help takes over.

CPR works by combining chest compressions — firm, rhythmic pressing on the breastbone — with rescue breaths or assisted ventilation (breathing support). The compressions physically squeeze the heart between the breastbone and the spine, pushing blood to the brain and other vital organs. This buys critical minutes during which the underlying cause of the cardiac arrest can be treated, most often with a defibrillator (a device that delivers an electric shock to restore a normal heart rhythm).

CPR is used in any situation where a person's heart or breathing has stopped, or is so compromised that the brain is at immediate risk of irreversible damage. It is always an emergency response, not a planned or elective procedure. The goal is to preserve brain and organ function until definitive treatment can be given.

• Cardiac arrest — the heart stops beating suddenly, regardless of the underlying cause.
• Ventricular fibrillation (VF) — a chaotic, disorganised heart rhythm that produces no effective pumping.
• Ventricular tachycardia (VT) without a pulse — the heart beats very fast but too weakly to circulate blood.
• Pulseless electrical activity (PEA) — the heart shows electrical signals but no actual pumping movement.
• Respiratory arrest — breathing has stopped even if the heart is still beating, such as after drowning, choking, a drug overdose, or a severe asthma attack.
• Sudden collapse with no signs of life — unresponsiveness, no normal breathing, and no detectable pulse.

CPR is not appropriate in every situation. Doctors and emergency teams consider several factors before deciding whether to begin or continue resuscitation.

• When a valid do-not-resuscitate (DNR) order is in place, documented by the patient or their legal representative.
• When cardiac arrest has occurred much earlier and clear signs of irreversible death are already present.
• When a patient's underlying illness is so advanced that CPR would cause harm without any realistic chance of meaningful recovery, as determined by the medical team.
• In cases of traumatic injury where the injuries are not survivable.

CPR is performed only when someone's life is in immediate danger, so its potential complications must always be weighed against the certainty of death without it. The physical force needed to keep blood moving does carry recognised risks.

• Rib fractures — the most common physical consequence; the force required for effective compressions frequently cracks one or more ribs, especially in older adults.
• Sternum fracture — the breastbone itself can crack under repeated compression.
• Bruising or internal bleeding around the chest wall and surrounding tissues.
• Lung contusion (bruising of the lung tissue) or, rarely, a pneumothorax (a collapsed lung caused by air leaking into the chest cavity).
• Damage to the liver or other abdominal organs if compressions are placed too low on the chest.
• Aspiration (inhaling stomach contents into the lungs) during rescue breathing, which can lead to lung infection.
• Brain damage from oxygen deprivation if CPR is delayed or is not fully effective — this reflects the underlying cardiac arrest rather than the CPR itself.
• Skin abrasions or burns if a defibrillator is used alongside CPR.

Because CPR is an unplanned emergency response, there is no time for the patient to prepare beforehand. However, understanding the process — and having important medical information ready — can be valuable for family members and caregivers who may be present when an emergency occurs.

For patients with known serious heart or lung conditions, doctors may discuss advance care planning, which can include decisions about resuscitation preferences. Relevant information that helps an emergency team includes: a list of current medications (including blood thinners or antiarrhythmic drugs — medicines that control heart rhythm), known allergies, recent medical history, and any existing do-not-resuscitate orders. This information should be kept accessible, for example in a wallet card or medical alert bracelet.

There are no fasting requirements, no medication pauses, and no pre-procedure tests because the procedure is driven entirely by a life-threatening emergency. When a cardiac arrest occurs, the emergency response follows a structured sequence:

• Step 1 — Recognise the emergency: the person is unresponsive, not breathing normally, and has no detectable pulse.
• Step 2 — Call for help: emergency services are contacted immediately, and a defibrillator (AED — automated external defibrillator) is retrieved if one is nearby.
• Step 3 — Begin chest compressions: the rescuer places both hands on the centre of the chest and presses down firmly and rhythmically, allowing the chest to fully rise between each compression.
• Step 4 — Open the airway and give rescue breaths (if trained to do so): the head is tilted back gently, the chin is lifted, and two slow breaths are given into the mouth, watching for chest rise.
• Step 5 — Continue cycles: compressions and breaths are repeated in continuous cycles until the person shows signs of life, the defibrillator is ready to use, or trained emergency personnel arrive and take over.
• Step 6 — Use the defibrillator when available: the AED analyses the heart rhythm and delivers a controlled electric shock if needed, then CPR is immediately resumed.
• Step 7 — Advanced care: when paramedics or hospital emergency teams arrive, they take over with advanced equipment including airway tubes, intravenous (IV) medications, and cardiac monitoring.

If CPR successfully restores a heartbeat — a state doctors call return of spontaneous circulation (ROSC) — the patient enters an intensive phase of monitoring and care. Recovery varies greatly depending on how long the heart was stopped, what caused the arrest, and the patient's overall health before the event. The goals of aftercare are to protect the brain, identify and treat the underlying cause, and support the body as it recovers.

• Immediate monitoring in an intensive care unit (ICU): the patient is connected to continuous heart monitoring (EKG), blood pressure monitoring, and blood oxygen sensors.
• Breathing support: many patients require a ventilator (a machine that breathes for them) for a period of time until they can breathe independently.
• Targeted temperature management: in some hospitals, the patient's body temperature may be carefully controlled for a period to help reduce brain injury — your doctor will explain if this applies.
• Investigation of the cause: tests such as coronary angiography (imaging of the heart's blood vessels), echocardiography (ultrasound of the heart), CT scans, and blood tests are usually performed to find out why the arrest happened.
• Treatment of the underlying condition: this may include procedures to open blocked coronary arteries (the blood vessels that feed the heart), implantation of a pacemaker or ICD (implantable cardioverter-defibrillator, a device placed under the skin to monitor and shock the heart if needed), or changes to medication.
• Physical rehabilitation: once stable, patients usually work with physiotherapists to rebuild strength, as the body and muscles can weaken significantly after a serious cardiac event and a period of bed rest.
• Neurological assessment: doctors monitor brain function closely, as the brain is the organ most sensitive to oxygen loss.
• Chest wall care: rib or sternum fractures sustained during CPR are generally managed with pain relief; they heal on their own in most cases but can cause discomfort for several weeks.
• Psychological support: surviving a cardiac arrest can be frightening and emotionally overwhelming. Many patients and their families benefit from counselling or support groups.
• Follow-up appointments: regular check-ups with a cardiologist (heart specialist) are usually scheduled after discharge to monitor heart function and adjust treatment as needed.
• Lifestyle guidance: doctors typically advise on heart-healthy habits — such as diet, physical activity levels, and stopping smoking — as part of long-term recovery, tailored to each patient's situation.