Basic Life Support for an Unresponsive Person
Immediately begin high-quality chest compressions at a rate of 100-120 per minute with a depth of at least 5 cm (2 inches) after confirming the person is unresponsive with no normal breathing and no definite pulse within 10 seconds. 1
Initial Assessment and Scene Safety
Ensure scene safety first before approaching the victim to protect yourself from environmental hazards such as electrical sources, traffic, or structural dangers. 1, 2
Check responsiveness by tapping the victim's shoulders and shouting "Are you all right?" 1, 2 This should take only seconds—avoid violent shaking that could cause cervical spine injury. 2
Simultaneous Breathing and Pulse Check (Healthcare Providers Only)
Healthcare providers should simultaneously assess breathing and check for a carotid pulse, taking no more than 10 seconds total. 1, 3, 2 Look for chest rise, listen for breath sounds, and feel for air movement while palpating the carotid artery at a single site. 1, 2
Critical distinction: Gasping is NOT normal breathing. Occasional gasps are agonal respirations that occur in 40-60% of cardiac arrest victims and indicate actual or impending cardiac arrest. 1, 3 Treat any victim with only gasping as if they are not breathing. 1, 3
If no definite pulse is felt within 10 seconds OR you are uncertain, immediately start chest compressions. 1, 3, 2 Do not waste time checking multiple pulse sites or bilateral pulses—this delays life-saving compressions. 2
Activation of Emergency Response System
Lone rescuer sequence: After confirming cardiac arrest, immediately activate the emergency response system (call 911), retrieve an AED if nearby and accessible, then return to begin CPR. 1
Two or more rescuers: One rescuer begins chest compressions immediately while the second activates emergency services and retrieves the AED. 1
High-Quality Chest Compressions
Position the victim supine on a firm surface. 1, 4 Place the heel of one hand on the center of the chest (lower half of the sternum), place your other hand on top, and interlock fingers. 1, 4
Compression technique:
- Push hard and fast with arms fully extended, elbows locked, and shoulders directly over the victim's chest 5, 4
- Compress at least 5 cm (2 inches) deep for adults 1, 5
- Rate of 100-120 compressions per minute 1, 3
- Allow complete chest recoil after each compression 1, 5
- Minimize interruptions—aim for at least 60 actually delivered compressions per minute 4
Rescue Breathing
Compression-to-ventilation ratio of 30:2 for both lay rescuers and lone healthcare providers. 1, 5 After every 30 compressions, give 2 quick breaths (each lasting about 1 second with 400-600 mL tidal volume). 5
Open the airway using head tilt-chin lift: place one hand on the forehead tilting the head back while lifting the chin with fingertips under the bony part of the jaw. 1, 2
If the rescuer is unwilling or unable to perform mouth-to-mouth ventilation, provide continuous chest compressions without pausing for breaths. 1, 6 Compression-only CPR is acceptable for lay rescuers and dispatcher-instructed CPR. 6, 5
AED Use
Turn on the AED as soon as it arrives and follow the voice prompts. 1
If a shockable rhythm is detected: Deliver one shock, then immediately resume chest compressions for 2 minutes before the AED analyzes the rhythm again. 1
If non-shockable rhythm: Resume CPR immediately for 2 minutes, then allow rhythm recheck. 1
Minimize interruptions in chest compressions when applying AED pads or during rhythm analysis—every interruption reduces coronary perfusion pressure. 1
Special Scenario: Pulse Present But No Normal Breathing
If a definite pulse is present (≥60 bpm) but breathing is absent or inadequate: Provide rescue breathing at 1 breath every 6 seconds (10 breaths per minute). 1, 3 Recheck the pulse every 2 minutes, spending no more than 10 seconds on each check. 1
When to Stop CPR
Continue CPR until:
- Advanced life support providers arrive and take over 1, 5
- The victim starts to move or breathe normally 1, 5
- You are physically unable to continue 5
- A valid Do Not Attempt Resuscitation order is presented 4
Critical Pitfalls to Avoid
Do not delay chest compressions by spending excessive time on pulse checks—if uncertain after 10 seconds, start compressions immediately. 1, 2 The risk of harm from unnecessary compressions on a person with a pulse is minimal compared to the harm of delayed CPR in true cardiac arrest. 1
Do not provide excessive ventilation or interrupt compressions for prolonged periods to give breaths—this reduces coronary perfusion and worsens outcomes. 1
Rotate compressors every 2 minutes when multiple rescuers are available to prevent fatigue and maintain compression quality. 4