What is the immediate management of sudden cardiac arrest occurring in a public setting?

Immediate Management of Sudden Cardiac Arrest in a Public Setting

Immediately begin high-quality chest compressions at a rate of 100-120 per minute with a depth of at least 5 cm (2 inches), activate emergency medical services, retrieve an AED, and deliver a shock as soon as the device arrives if a shockable rhythm is detected. 1

Initial Recognition and Response

Verify scene safety before approaching the victim to avoid becoming a second casualty. 2 Check for responsiveness by tapping the victim's shoulder and shouting "Are you all right?" 1 If the victim is unresponsive with no breathing or only gasping, assume cardiac arrest and immediately activate the emergency response system (call 911 or equivalent). 1

Critical First Steps for Lone Rescuer:

• Shout for help to attract nearby bystanders 1
• Activate emergency services via mobile device if available 1
• Send someone to retrieve an AED or get it yourself if nearby and easily accessible 1
• Do not waste time checking for breathing separately—the 2020 guidelines emphasize simultaneous assessment of breathing and pulse within 10 seconds 1, 2

When Multiple Rescuers Are Present:

• First rescuer begins chest compressions immediately 1
• Second rescuer activates emergency services and retrieves the AED 1

High-Quality CPR Technique

Begin chest compressions immediately without delay. 1, 3 The quality of compressions is the single most critical determinant of survival. 4

Compression Parameters:

• Rate: 100-120 compressions per minute (not just "at least 100" as older guidelines stated) 1, 3
• Depth: At least 5 cm (2 inches) in adults, up to 6 cm maximum 1, 3
• Allow complete chest recoil between compressions—incomplete recoil prevents cardiac refilling and is a critical error 1, 2
• Minimize interruptions—aim for less than 10 seconds for any pause 1
• Position: Center of the chest with arms perpendicular to the patient's chest 5

Compression-to-Ventilation Ratio:

• Untrained bystanders: Compression-only CPR (hands-only) is acceptable and encouraged over no CPR 1, 3
• Trained rescuers: 30 compressions to 2 breaths until an advanced airway is placed 1
• Avoid excessive ventilation, which increases intrathoracic pressure and decreases cardiac output 1, 6

Common Pitfall:

Healthcare providers often take too long checking for a pulse (>10 seconds), delaying compressions. 3 If uncertain about pulse presence after 10 seconds, start CPR immediately. 2

Early Defibrillation

Use the AED as soon as it arrives—do not delay CPR to retrieve it, but apply it immediately once available. 1, 2 Public access defibrillation programs significantly improve survival. 1

AED Sequence:

1. Turn on the AED and follow voice prompts 1
2. Attach pads to bare chest (continue compressions during pad placement if possible) 1
3. Clear the victim and analyze rhythm 1
4. If shockable rhythm detected (VF/pVT): Deliver one shock 1
5. Immediately resume CPR for 2 minutes starting with chest compressions 1, 7
6. Do not check pulse or rhythm immediately after shock—the majority of patients remain pulseless for over 2 minutes post-shock, and up to 25% have asystole lasting longer than 120 seconds 7

Critical Evidence:

Resume compressions immediately after shock delivery without checking rhythm or pulse. 1, 7 The 2020 AHA guidelines emphasize minimizing pre-shock and post-shock pauses, with compressions continuing during defibrillator charging when possible. 1

If Non-Shockable Rhythm:

• Resume CPR immediately for 2 minutes 1
• Recheck rhythm every 2 minutes 1
• Continue until advanced life support arrives or victim shows signs of life 1

Special Considerations for Public Settings

Athletic Events:

If cardiac arrest occurs during organized sports, the presumption should be that any unexpected collapse with unresponsiveness is cardiac arrest, even if the athlete continues breathing or has eyes open. 1 Resist demands to move the athlete unless the location presents immediate safety concerns. 1

Witnessed Collapse:

For witnessed sudden collapse in a public setting, immediately activate emergency services and begin CPR—do not perform 2 minutes of CPR before calling for help as was previously recommended for unwitnessed arrests. 1 The 2020 guidelines removed the recommendation for pre-specified CPR duration before defibrillation. 8

Avoiding Critical Errors

• Do not delay compressions to obtain history—immediate action is the priority 2
• Do not perform prolonged pulse checks—if no definite pulse within 10 seconds, start CPR 1, 2
• Do not lean on the chest between compressions—this prevents adequate cardiac refilling 2, 5
• Do not provide inadequate compression depth—compressions must be hard and fast to generate sufficient coronary and cerebral perfusion pressure 2, 4
• Do not stop compressions for rhythm checks except when prompted by AED 1

Continuing Until Help Arrives

Continue CPR cycles until:

• Advanced life support providers arrive and take over 1
• The victim starts to move or shows signs of life 1
• You are physically unable to continue 5
• The scene becomes unsafe 2

Change compressors every 2 minutes (or sooner if fatigued) to maintain compression quality, as fatigue significantly degrades performance. 1, 5