What is the recommended basic life support (BLS) algorithm for an unresponsive person who is not breathing normally?

Basic Life Support Algorithm for Unresponsive, Non-Breathing Patients

For any unresponsive person who is not breathing normally or only gasping, immediately begin chest compressions at 100-120 compressions per minute with a depth of at least 5 cm (2 inches), while simultaneously activating emergency services—this compression-first approach is the cornerstone of modern BLS and takes priority over all other interventions. 1, 2

Step-by-Step BLS Sequence

1. Scene Safety and Initial Recognition (0-10 seconds)

• Verify scene safety first before approaching to avoid becoming a second victim 2, 3
• Check responsiveness by tapping the victim's shoulder and shouting 1, 3
• Shout for nearby help immediately upon finding an unresponsive victim 1, 3

2. Simultaneous Assessment (Within 10 Seconds Total)

• Check for breathing AND pulse at the same time—do not perform these sequentially 1, 2
• Look for no breathing or only gasping (agonal gasps occur in 40-60% of cardiac arrests and must be treated as absent breathing) 1, 3
• Limit pulse check to maximum 10 seconds—if uncertain about pulse presence after 10 seconds, start CPR immediately 1, 2

Critical pitfall: Healthcare providers correctly detect pulses only 78% of the time and average 20 seconds on pulse checks, which dangerously delays compressions. 2 When in doubt, start compressions—injury from compressions in a non-arrest patient is rare. 3

3. Activate Emergency Response System

• Call 9-1-1 immediately (or direct someone else to call while you begin CPR) 1
• Keep the phone on speaker at the victim's side if possible 1
• Retrieve the AED/defibrillator as soon as possible, but do not delay CPR to get it 1, 2

4. Begin High-Quality CPR Immediately

Chest Compressions (Start Here—Not Airway)

The 2010 Guidelines changed the sequence from A-B-C to C-A-B (compressions first) to minimize time to first compression. 1

• Rate: 100-120 compressions per minute 1, 2
• Depth: At least 5 cm (2 inches) in adults 2
• Hand position: Center of chest on firm surface 2
• Allow complete chest recoil between compressions—do not lean on the chest 2
• Minimize interruptions: Keep pauses under 10 seconds 1, 2

Why compressions first matters: Initiating CPR within 1.9 minutes of collapse doubles to triples survival compared to initiation at 5.7 minutes, with the greatest benefit occurring within 4-6 minutes. 2

Compression-to-Ventilation Ratios

• Single rescuer (lay or healthcare provider): 30 compressions : 2 breaths 1, 2
• Two healthcare providers (adults): 30 compressions : 2 breaths 1
• Two healthcare providers (pediatrics): 15 compressions : 2 breaths 2, 4

Ventilation Technique

• Open airway with head-tilt/chin-lift maneuver 3
• Provide 2 breaths after every 30 compressions (each breath over 1 second, enough to produce visible chest rise) 2
• Use bag-mask ventilation with 100% oxygen when available 2, 3

Critical pitfall: Do not provide excessive ventilation—this decreases venous return and cardiac output. 3

5. Apply AED/Defibrillator as Soon as Available

• Apply pads without interrupting compressions if possible 1
• Turn AED on and follow prompts 1
• After 2 minutes of CPR, pause briefly to analyze rhythm 2, 3

If Shockable Rhythm (VF/Pulseless VT):

• Deliver one shock immediately 2, 3
• Resume CPR immediately for 2 minutes before rechecking rhythm 2, 3

If Non-Shockable Rhythm:

• Resume CPR immediately for 2 minutes before rechecking rhythm 2, 3

6. Continue Until Advanced Help Arrives

• Maintain cycles of 2 minutes of CPR followed by rhythm check 2, 3
• Rotate compressors every 2 minutes to prevent fatigue and maintain quality 2, 4
• Continue until the patient shows signs of life or advanced providers assume care 3

Special Circumstances

If Definite Pulse Present But No Normal Breathing (Respiratory Arrest)

• Provide rescue breathing only: 1 breath every 5-6 seconds (10-12 breaths/minute) in adults 3
• Recheck pulse every 2 minutes—if pulse becomes absent, immediately start full CPR 3

Pediatric Modifications

• Start CPR if heart rate <60/min with signs of poor perfusion (mottled skin, weak pulses, altered mental status) 2, 4
• Use 2-finger technique for infant chest compressions, compressing at least one-third of chest depth 4
• Provide rescue breaths at 1 breath every 2-3 seconds (20-30 breaths/minute) if pulse present 4

Suspected Opioid Overdose

• Administer naloxone (2 mg intranasal or 0.4 mg intramuscular) as soon as available while continuing CPR 1, 2
• Standard resuscitation takes priority—do not delay CPR for naloxone 1

Team-Based Approach (Multiple Rescuers)

When multiple rescuers are present, perform actions simultaneously rather than sequentially: 1, 3

• First rescuer: Begins chest compressions immediately
• Second rescuer: Activates emergency response and retrieves AED
• Third rescuer: Manages airway and provides ventilations
• Fourth rescuer: Prepares medications and establishes IV/IO access 3

Critical Pitfalls to Avoid

• Do not mistake agonal gasping for normal breathing—gasping indicates cardiac arrest and requires immediate CPR 1, 3
• Do not extend pulse checks beyond 10 seconds—if uncertain, start compressions 2, 3
• Do not delay compressions to obtain history or establish IV access—compressions are the absolute priority 2, 3
• Do not provide inadequate compression depth or rate—compressions must be hard (5 cm) and fast (100-120/min) 2
• Do not lean on chest between compressions—complete recoil is essential for cardiac refilling 2
• Do not assume brief seizures are primary seizure disorder—seizures can be the first manifestation of cardiac arrest 1, 3

Dispatcher Role

Emergency dispatchers should determine if patient is unresponsive with abnormal breathing and assume cardiac arrest if present, then provide telephone CPR instructions to bystanders. 1 Dispatchers must be educated to recognize agonal gasps across various clinical presentations. 1