BLS / ACLS key terms

The sequence of actions that give a person in cardiac arrest the best chance of survival: early recognition and activation, high-quality CPR, rapid defibrillation, advanced care, and recovery support after the event.

Irregular, slow, gasping breaths that may appear in the first minutes after cardiac arrest. They do not move enough air and are treated as cardiac arrest, so CPR should start immediately.

Deciding that a person is unresponsive and not breathing normally, then calling for help and starting compressions at once. A lay rescuer does not need to check a pulse first.

Chest compressions given at the correct rate and depth with full recoil, few interruptions, and appropriate ventilation, producing enough blood flow to keep the brain and heart viable.

The speed of chest compressions, recommended at 100 to 120 per minute for adults, children, and infants. Faster rates tend to reduce depth, and slower rates reduce blood flow.

How far the chest is pushed down: about 5 cm (2 inches) for adults and about one-third of chest depth for children and infants, allowing full recoil between compressions.

Letting the chest return fully to its resting position after each compression without leaning on it, so the heart can refill and forward blood flow is maintained.

The share of resuscitation time actually spent doing compressions. A target above 60 percent, and ideally 80 percent or more, means pauses for rhythm checks, shocks, and ventilations stay short.

The number of compressions given for each set of breaths. It is 30:2 for a single rescuer at any age and 15:2 for two-rescuer CPR in children and infants.

An infant compression method in which both thumbs press the lower sternum while the hands encircle the chest. With two rescuers it is preferred because it produces better depth and pressure.

Swapping the rescuer who is doing compressions about every two minutes, or sooner if tired, usually during a rhythm check, so compression quality does not fall off.

Giving breaths to a person who is not breathing adequately but still has a pulse, at roughly one breath every 6 seconds for an adult, watching for chest rise.

Squeezing a self-inflating bag attached to a face mask to deliver breaths. It works only with a good seal, an open airway, and just enough volume to make the chest rise.

A curved plastic device placed in the mouth to keep the tongue from blocking the throat of an unresponsive person who has no gag reflex and is breathing spontaneously.

A maneuver that opens the airway by tipping the head back and lifting the chin, which pulls the tongue away from the back of the throat before giving breaths.

A portable device that analyzes the heart rhythm and, when a shockable rhythm is detected, delivers a shock while voice prompts guide the rescuer through each step.

An unsynchronized electrical shock that depolarizes the heart muscle all at once, giving it a chance to restore an organized rhythm in ventricular fibrillation or pulseless ventricular tachycardia.

Positioning defibrillator electrodes on the bare chest, usually the right upper chest and the left lower side, so current passes through the heart; an anteroposterior position is an alternative.

A rhythm that a shock can treat, namely ventricular fibrillation and pulseless ventricular tachycardia. All other arrest rhythms are non-shockable and are managed with CPR and drugs.

Chaotic, disorganized electrical activity in the ventricles that produces no effective contraction and no pulse. It is the arrest rhythm most likely to be reversed by early defibrillation.

A fast, wide-complex rhythm arising in the ventricles that generates no detectable pulse. It is treated with CPR and defibrillation in the same way as ventricular fibrillation.

A flat-line rhythm showing no electrical activity in the heart. It is not shockable and is managed with CPR, epinephrine, and a search for reversible causes.

An organized rhythm visible on the monitor with no palpable pulse, usually driven by an underlying problem such as hypovolemia, hypoxia, or tension pneumothorax rather than a primary heart rhythm fault.

A vasoconstrictor given during cardiac arrest, typically 1 mg IV or IO every 3 to 5 minutes for adults, to raise blood pressure and improve blood flow to the heart and brain.

An antiarrhythmic given for shockable arrest rhythms that persist after defibrillation, usually as a bolus followed by a second dose in refractory ventricular fibrillation or pulseless ventricular tachycardia.

Placing a needle into the marrow cavity of a bone to give fluids and drugs when intravenous access cannot be obtained quickly. It behaves like a vein and is used in arrest and shock.

A team pattern in which the leader gives a clear order to a named person, who repeats it back and then confirms when the task is finished, reducing missed or duplicated actions.

A short structured review held after a resuscitation to examine what went well and what should change, improving later team performance and patient outcomes.

The reappearance of a palpable pulse and effective circulation after cardiac arrest. It marks the start of post-cardiac arrest care rather than the end of the resuscitation.

Deliberately holding body temperature between about 32 and 37.5 degrees Celsius for a period after cardiac arrest to protect the brain, then actively preventing fever.

The aim of giving enough oxygen without excess. After circulation returns, oxygen is titrated to an SpO2 of roughly 94 to 99 percent, and hyperoxia is avoided.

A heart attack caused by complete blockage of a coronary artery, identified by ST elevation on the ECG and treated with emergency reperfusion by primary PCI or fibrinolysis.

Emergency percutaneous coronary intervention, in which a balloon and stent open the blocked artery. It is the preferred reperfusion method for ST-elevation myocardial infarction when it can be delivered promptly.

A clot-dissolving drug given for ST-elevation myocardial infarction or ischemic stroke when timely mechanical reperfusion is not available, after screening for bleeding risks.

The last moment a stroke patient was seen acting normally. It defines the treatment window for fibrinolysis and thrombectomy and should be established as early as possible.

A quick check for Face drooping, Arm weakness, and Speech difficulty that prompts immediate action on Time. Positive findings trigger activation of the stroke system of care and urgent imaging.