Cardiopulmonary resuscitation
Emergency procedure to preserve brain function during cardiac arrest.
Cardiopulmonary resuscitation, or CPR, is a technique used in emergencies when someone’s heart or breathing has stopped. It combines chest compressions with, in some cases, artificial ventilation to keep blood and oxygen moving through the body, protecting the brain and other organs until normal heartbeat and breathing can return. CPR is meant for people who are unresponsive and not breathing, or who are breathing abnormally—for instance, with occasional gasps known as agonal respirations.
For adults, chest compressions should be between 5 and 6 centimeters deep, delivered at a rate of 100 to 120 per minute. The rescuer may also give artificial ventilation by blowing air into the person’s mouth or nose, or by using a mechanical device. Current guidelines stress that high-quality compressions are more important than ventilation; untrained bystanders are advised to perform compression-only CPR. However, for children, the 2015 American Heart Association guidelines note that compression-only CPR may lead to worse outcomes, because cardiac arrest in children usually stems from respiratory problems rather than heart issues. In adults, the recommended ratio of chest compressions to breaths is 30 to 2.
CPR alone rarely restarts the heart. Its main goal is to restore a partial flow of oxygenated blood to the brain and heart, delaying tissue damage and buying time for a successful resuscitation without permanent brain injury. To restore a normal heart rhythm, defibrillation—an electric shock—is often necessary. Defibrillation works only for certain rhythms, such as ventricular fibrillation or pulseless ventricular tachycardia; it is not effective for asystole or pulseless electrical activity, which require treating the underlying cause. Early defibrillation, when appropriate, is strongly recommended. CPR may sometimes help produce a shockable rhythm. Generally, CPR continues until the person regains spontaneous circulation or is declared dead.
CPR is indicated for anyone who is unresponsive and not breathing, or who has only occasional agonal gasps—these signs strongly suggest cardiac arrest. If a person has a pulse but is not breathing (respiratory arrest), artificial ventilation may be more appropriate. Because checking a pulse accurately is difficult, guidelines advise lay rescuers not to attempt it, though healthcare professionals may do so. In cases of cardiac
- field
- Emergency medicine
- known_for
- Chest compressions and artificial ventilation to maintain circulation and oxygenation during cardiac arrest
- compression_depth_adults
- 5 cm to 6 cm (2.0 in to 2.4 in)
- compression_rate
- 100 to 120 per minute
- compression_to_breathing_ratio_adults
- 30 to 2
Lore & Background
CPR involves chest compressions for adults between 5 cm and 6 cm deep at a rate of at least 100 to 120 per minute. The rescuer may also provide artificial ventilation by mouth-to-mouth resuscitation or using a device that pushes air into the lungs. Current recommendations emphasize early and high-quality chest compressions over artificial ventilation; a simplified method involving only chest compressions is recommended for untrained rescuers. With children, however, guidelines indicate that doing only compressions may result in worse outcomes because such problems in children normally arise from respiratory issues rather than from cardiac ones.
Reader's Guide
CPR alone is unlikely to restart the heart; its main purpose is to restore partial flow of oxygenated blood to the brain and heart. Administration of an electric shock, termed defibrillation, is usually needed to restore a viable heart rhythm, but defibrillation is effective only for certain rhythms such as ventricular fibrillation or pulseless ventricular tachycardia. CPR may succeed in inducing a heart rhythm that may be shockable. The brain may sustain damage after blood flow has been stopped for about four minutes and irreversible damage after about seven minutes. Low body temperatures, as seen in near-drownings, prolong the time the brain survives. The recommended order of actions includes calling for emergency medical services, obtaining an automated external defibrillator if available, and then performing CPR. For drowning victims or children who were already unconscious, two minutes of CPR should be performed before calling for help. The most important aspects of CPR are few interruptions of chest compressions, sufficient speed and depth, completely relaxing pressure between compressions, and not ventilating too much.
Did You Know?
- CPR is recommended for those who are unresponsive with no breathing or abnormal breathing, such as agonal respirations.
- The brain may sustain irreversible damage after about seven minutes without blood flow.
- Defibrillation is effective only for ventricular fibrillation or pulseless ventricular tachycardia, not for asystole or pulseless electrical activity.
- For children, doing only chest compressions may result in worse outcomes because their cardiac arrest often originates from respiratory issues.
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