What should be done if a patient experiences cardiac arrest outside a hospital setting?

Management of Out-of-Hospital Cardiac Arrest

Immediately call emergency services (911) and begin high-quality chest compressions without delay—this is the single most critical intervention to improve survival from out-of-hospital cardiac arrest. 1, 2

Immediate Recognition and Activation

• Check for responsiveness by tapping the victim and shouting "Are you all right?" If the person is unresponsive with no breathing or only gasping (agonal respirations), assume cardiac arrest has occurred 2
• Activate emergency response system immediately (call 911) as soon as cardiac arrest is recognized 1, 2
• Do not delay to check for a pulse—failure to recognize gasping as a sign of cardiac arrest is a common and dangerous pitfall 2

Critical Pitfall to Avoid

Many bystanders misinterpret agonal gasping as normal breathing, leading to delayed recognition of cardiac arrest. Dispatchers should be specifically trained to help callers identify absent or abnormal breathing patterns to correctly identify cardiac arrest. 1, 2

High-Quality CPR: The Foundation of Survival

For lay rescuers (bystanders):

• Begin chest compressions immediately at a rate of 100-120 compressions per minute 2
• Push hard and fast in the center of the chest with a depth of at least 2 inches (5 cm) 1, 2
• Allow complete chest recoil after each compression 2
• Minimize interruptions in chest compressions—every second counts 2
• Hands-Only CPR is recommended for untrained or unwilling bystanders witnessing adult sudden cardiac arrest 1
• If trained and willing, provide rescue breaths in a 30:2 ratio (30 compressions to 2 breaths), but chest compressions alone are acceptable and effective 2

The American Heart Association strongly recommends Hands-Only CPR for adult sudden cardiac arrest because it is simpler, increases bystander willingness to act, and is nearly as effective as conventional CPR for cardiac causes. 1

Exception for Rescue Breathing

CPR should include rescue breathing when treating patients with high likelihood of asphyxial causes (drowning, drug overdose, children) rather than primary cardiac causes. 1

Dispatcher-Assisted CPR

• Emergency dispatchers should offer and instruct bystanders in CPR during all suspected out-of-hospital cardiac arrests 1
• Dispatchers must be trained to systematically question callers to identify potential cardiac arrest through focused questions about consciousness and breathing quality 1
• Instructions should be provided in a confident, assertive manner with straightforward chest compression-only guidance to achieve early Hands-Only CPR 1
• Dispatcher-assisted CPR can potentially double the proportion of patients receiving bystander CPR and approaches the survival effectiveness of CPR by previously trained bystanders 1

Automated External Defibrillator (AED) Use

• If an AED is available, use it as soon as possible following the device prompts 2
• Resume chest compressions immediately after shock delivery without delay to check pulse 2
• Early defibrillation significantly improves survival, particularly for shockable rhythms (ventricular fibrillation/pulseless ventricular tachycardia) 2
• Only 3.7% of cardiac arrest patients receive bystander AED treatment before EMS arrival, representing a major opportunity for improvement 3

For Healthcare Providers

• Provide chest compressions and rescue breaths in a 30:2 ratio until advanced airway placement 2
• After advanced airway placement, provide continuous chest compressions with ventilations at 1 breath every 6 seconds (10 breaths/minute) 2
• Consider administration of medications per ACLS protocols, including Amiodarone or Lidocaine for shock-refractory ventricular fibrillation/pulseless ventricular tachycardia 2

Evidence Supporting Bystander CPR

Bystander CPR more than doubles survival rates but is performed in only 33-37% of witnessed arrests. 1, 4, 3

• Patients who receive bystander CPR have significantly higher overall survival (11.2%) compared to those who do not (7.0%) 3
• Among the optimal scenario—witnessed arrest with shockable rhythm—survival to discharge reaches 30.1% 3
• For nonelderly patients and those with noncardiac causes of arrest, immediate CPR-first action (before calling 911) may provide additional benefit when the bystander has sufficient CPR skills and can call shortly after 5

Post-Resuscitation Care

• Continue CPR until EMS providers arrive and take over or until the patient shows signs of life 2
• When return of spontaneous circulation is achieved, transport to a facility capable of comprehensive post-cardiac arrest care, including targeted temperature management and coronary intervention 1
• A regionalized approach to post-cardiac arrest care is reasonable when comprehensive care is not available at local facilities 1

Key Distinctions from Heart Attack Management

Cardiac arrest requires immediate CPR and defibrillation, while heart attack requires medical therapy focused on restoring coronary blood flow. 2

• Cardiac arrest is the cessation of cardiac mechanical activity with absence of circulation 3
• Heart attack (myocardial infarction) involves coronary artery occlusion but the heart continues to beat 2
• High-quality CPR with minimal interruptions is the priority for cardiac arrest; rapid transport to a facility capable of coronary intervention is essential for heart attack 2