What is the proper procedure for performing cardiopulmonary resuscitation (CPR) on an adult patient in cardiac arrest?

Adult Cardiopulmonary Resuscitation (CPR)

Immediately begin high-quality chest compressions at 100-120 compressions per minute with a depth of at least 2 inches (5 cm) but not exceeding 2.4 inches (6 cm) as soon as cardiac arrest is recognized, as this is the single most critical intervention for survival. 1, 2

Initial Recognition and Activation

• Check for responsiveness by shouting and tapping the victim while simultaneously assessing breathing and pulse within 10 seconds. 2, 3
• Look specifically for absent breathing or only gasping respirations—agonal gasps are common in cardiac arrest and must not be mistaken for normal breathing. 1, 2
• If you cannot definitively palpate a pulse within 10 seconds, immediately start CPR without further delay, as pulse checks are notoriously unreliable even among trained providers. 2, 3
• Activate the emergency response system immediately (call 911 or send someone to do so) and retrieve an automated external defibrillator (AED). 1, 3

Chest Compression Technique

• Position your hands on the lower half of the sternum and deliver compressions at a rate of 100-120 per minute with a depth of at least 2 inches (5 cm) but not exceeding 2.4 inches (6 cm). 1, 2
• Allow complete chest wall recoil between each compression by avoiding leaning on the chest, as incomplete recoil prevents adequate cardiac refilling and reduces perfusion pressure. 1, 3
• Minimize all interruptions in chest compressions, keeping pauses to less than 10 seconds, as any pause dramatically reduces coronary and cerebral perfusion pressure. 1, 4
• Change the compressor every 2 minutes (or sooner if fatigued) to maintain compression quality and prevent deterioration in technique. 2, 4, 3

Compression-to-Ventilation Ratio

• Deliver cycles of 30 chest compressions followed by 2 breaths until an advanced airway is placed. 1, 2
• Each breath should be delivered over approximately 1 second with enough volume to produce visible chest rise. 1
• Untrained lay rescuers should provide compression-only CPR without attempting rescue breaths, continuing until EMS arrives or an AED becomes available. 1, 3
• Trained rescuers should add rescue breaths in the 30:2 ratio, though compression-only CPR is a reasonable alternative for all rescuers if unable or unwilling to provide ventilations. 1

Common pitfall: Even trained professional rescuers typically take 7-10 seconds to deliver 2 breaths (not the recommended 4-5 seconds), which significantly reduces the number of compressions delivered per minute. 5, 6 However, taking up to 10 seconds for ventilations does not worsen survival outcomes as long as you maintain at least 70 compressions per minute overall. 6

Defibrillation Protocol

• Apply the AED as soon as it becomes available and follow its prompts for rhythm analysis. 2, 3
• For shockable rhythms (ventricular fibrillation or pulseless ventricular tachycardia), deliver one shock immediately and then resume chest compressions without performing a pulse or rhythm check. 2, 4, 7
• Continue CPR for a full 2-minute cycle (approximately 5 cycles of 30:2) before pausing briefly for the next rhythm check. 4, 7
• Use biphasic defibrillators at 120-200 Joules (or manufacturer recommendation) or monophasic defibrillators at 360 Joules. 2

Critical evidence: After defibrillation, the majority of patients remain pulseless for over 2 minutes, with 25% experiencing asystole lasting longer than 120 seconds before return of pulses. 7 This strongly supports immediately resuming compressions rather than checking for a pulse after shock delivery.

Rhythm and Pulse Checks

• Perform rhythm checks every 2 minutes at the end of each CPR cycle, keeping the pause as brief as possible (less than 10 seconds). 4
• Only check for a pulse if an organized rhythm appears on the monitor—if there is any doubt about pulse presence, immediately resume chest compressions. 4
• Do not interrupt compressions for frequent rhythm checks, as each interruption decreases perfusion pressure and reduces the likelihood of successful resuscitation. 4

Advanced Airway Management

• Once an endotracheal tube or supraglottic airway is placed, switch to continuous chest compressions without pauses and deliver 1 breath every 6 seconds (10 breaths per minute). 1, 2, 8
• Use waveform capnography to confirm proper tube placement and monitor CPR quality (target end-tidal CO2 >10 mmHg during CPR). 2
• If the patient is on a mechanical ventilator when cardiac arrest occurs, immediately disconnect the ventilator and switch to manual ventilation with a self-inflating bag. 8 Modern mechanical ventilators erroneously sense chest compressions as spontaneous breathing efforts and deliver excessive respiratory rates, which decreases venous return and cardiac output. 8

Medication Administration

• Establish intravenous or intraosseous access as soon as feasible without interrupting chest compressions. 2, 3
• Administer epinephrine 1 mg IV/IO every 3-5 minutes throughout the resuscitation for all cardiac arrest rhythms. 2, 3
• For refractory ventricular fibrillation or pulseless ventricular tachycardia, consider amiodarone or lidocaine after the second or third shock. 3

Recognition of Return of Spontaneous Circulation (ROSC)

• Recognize ROSC by palpable pulse with measurable blood pressure, abrupt sustained increase in end-tidal CO2 to ≥40 mmHg, or spontaneous arterial pressure waves on invasive monitoring. 2
• If waveform capnography shows a sudden sustained increase in end-tidal CO2, perform an immediate rhythm and pulse check even before the 2-minute interval. 4
• When ROSC is achieved, immediately transition to post-cardiac arrest care targeting mean arterial pressure ≥65 mmHg and oxygen saturation 92-98%. 3

Special Considerations for Opioid Overdose

• For patients with known or suspected opioid overdose who have a definite pulse but no normal breathing (respiratory arrest only), administer intranasal or intramuscular naloxone in addition to providing rescue breathing. 1, 3
• For patients in full cardiac arrest from suspected opioid overdose, prioritize chest compressions first, then consider naloxone administration after initiating CPR, as medications are ineffective without adequate perfusion. 1

Key principle: The 2022 International Consensus reinforces that laypersons should initiate CPR for presumed cardiac arrest without concerns of causing harm to patients not actually in cardiac arrest, as the risk of injury from unnecessary CPR is extremely low. 1