What are the steps for basic life support (BLS) in cardiac arrest management?

Basic Life Support Steps for Cardiac Arrest Management

Begin chest compressions immediately upon recognizing cardiac arrest (unresponsive victim with no breathing or only gasping), following the CAB sequence (Compressions-Airway-Breathing) rather than the older ABC approach to minimize delay to first compression. 1, 2

Recognition of Cardiac Arrest

• Ensure scene safety first before approaching any victim 1
• Check for responsiveness by tapping the victim's shoulder and shouting "Are you all right?" 1
• Simultaneously assess for absent or abnormal breathing (no breathing or only gasping) - this takes no more than 10 seconds 1
• Healthcare providers should check pulse simultaneously with breathing assessment, limiting pulse check to maximum 10 seconds to avoid delaying compressions 1, 2
• Lay rescuers should NOT check for pulse - if victim is unresponsive with no normal breathing, assume cardiac arrest 1, 2

Critical pitfall: Agonal gasps are often mistaken for normal breathing by bystanders and dispatchers, leading to failure to recognize cardiac arrest and initiate CPR. Dispatchers must be educated to identify agonal gasps as a sign of cardiac arrest. 1

Immediate Activation of Emergency Response

• Shout for nearby help immediately upon recognizing unresponsiveness 1
• Activate emergency response system (call 911) - ideally this occurs simultaneously with CPR initiation in the era of mobile devices 1
• Lone rescuer sequence: Check responsiveness → activate emergency system via mobile device (speaker mode) → retrieve AED if nearby → begin CPR 1
• Multiple rescuer sequence: First rescuer begins compressions, second rescuer activates emergency system and retrieves AED 1
• Follow dispatcher instructions - dispatcher-guided CPR substantially increases bystander CPR performance and improves survival 1

High-Quality Chest Compressions (The Priority)

Compression technique and quality parameters: 1, 2

• Rate: 100-120 compressions per minute (updated from "at least 100" to prevent excessive rates) 2
• Depth: At least 2 inches (5 cm) for adults 1, 2
• Hand position: Lower half of sternum, heel of palm 1, 3
• Body mechanics: Arms extended, elbows locked, shoulders directly over victim's chest 3, 4
• Allow complete chest recoil after each compression - incomplete recoil impairs venous return 1
• Minimize interruptions - any pause reduces coronary perfusion pressure and decreases likelihood of return of spontaneous circulation 5
• Avoid excessive ventilation during CPR 1, 2

Switch compressors every 2 minutes to prevent fatigue and maintain compression quality 5

Airway and Breathing

For trained rescuers providing conventional CPR: 1

• Compression-to-ventilation ratio: 30:2 (30 compressions followed by 2 breaths) 1, 3
• Each breath delivered over 1 second with visible chest rise 1
• Tidal volume: 400-600 mL per breath 3, 4
• After advanced airway placement: Continuous compressions with 1 breath every 6 seconds (10 breaths/minute) 1

For untrained or unwilling rescuers: 1, 2

• Hands-only CPR (compression-only) is recommended and easier to perform 2
• Dispatcher should guide hands-only CPR for untrained bystanders 1, 2

The 2015 AHA Guidelines emphasize that conventional CPR (compressions plus ventilation) may provide better outcomes than compression-only CPR in some observational studies, so trained rescuers should provide both when able. 1

Early Defibrillation

Retrieve and apply AED as soon as available: 1, 2

• Lone rescuer: After activating emergency system, retrieve nearby AED before starting CPR if immediately accessible 1
• Multiple rescuers: Second rescuer retrieves AED while first begins compressions 1
• Turn on AED and follow prompts 1
• Minimize interruptions: Resume chest compressions immediately after shock delivery 1
• Check rhythm every 2 minutes as prompted by AED 1

Defibrillation sequence: 1

• Turn AED on
• Follow AED prompts
• If shockable rhythm: Deliver 1 shock → immediately resume CPR for 2 minutes
• If non-shockable rhythm: Immediately resume CPR for 2 minutes
• Continue until advanced life support arrives or victim shows signs of life

When to Stop CPR

Continue CPR until: 3, 4

• The victim wakes up (shows signs of life, normal breathing, movement)
• Advanced life support providers take over
• You are physically unable to continue
• AED prompts you to stop for rhythm analysis or shock delivery

Special Consideration: Opioid Overdose

For suspected opioid overdose with respiratory arrest (pulse present, no normal breathing): 1

• Provide standard BLS care first (rescue breathing at 1 breath every 5-6 seconds) 1
• Administer intranasal or intramuscular naloxone if available and provider is trained 1
• For cardiac arrest with suspected opioid involvement: Initiate CPR first, then consider naloxone after compressions started (medication ineffective without chest compressions for drug delivery) 1

Team-Based Approach for Healthcare Providers

When multiple trained rescuers are available, perform actions simultaneously: 1, 2

• One rescuer performs chest compressions
• Second rescuer manages airway and provides ventilations
• Third rescuer retrieves and operates AED/defibrillator
• Fourth rescuer activates emergency response and prepares equipment
• This choreographed approach minimizes delays and optimizes resuscitation efficiency 2