Cardiac arrest and cardiopulmonary resuscitation

Cardiac arrest is the sudden cessation of cardiac function and blood circulation, manifesting as apnea, pulselessness, and loss of consciousness. In adults, cardiac arrest is most commonly caused by cardiac conditions (e.g., coronary artery disease), but it can also have noncardiac etiologies (e.g., hypothermia), whereas in children, etiologies are more varied and more frequently related to profound hypoxia (e.g., due to airway obstruction). Cardiopulmonary resuscitation (CPR) is a lifesaving procedure that artificially maintains circulation and ventilation until cardiac function is hopefully restored. Immediate initiation of high-quality chest compressions is the most important factor for survival after cardiac arrest.

There are two clinical algorithms to provide CPR: basic life support (BLS) for lay rescuers and medical professionals alike and advanced cardiac life support (ACLS) solely for medical professionals. BLS involves checking responsiveness, calling for help, performing chest compressions and rescue breaths, and, if available, using an automated external defibrillator (AED). ACLS includes additional measures (e.g., resuscitation medications, airway management) and identifying and treating reversible causes of cardiac arrest (e.g., Hs and Ts). Modifications to BLS and ACLS are required for children, neonates, and pregnant individuals.

After the return of spontaneous circulation (ROSC), comprehensive postresuscitation care is essential for good neurological and functional outcomes. This involves neuroprotective measures, hemodynamic support, critical care admission, monitoring for organ dysfunction, and treatment of underlying causes and complications.

Recommendations in this article are consistent with the 2025 American Heart Association (AHA) and International Liaison Committee on Resuscitation (ILCOR) guidelines and consensus statements. Practice may vary according to regional authorities and resources. Consult local protocols whenever possible. ^[1][2][3][4]

Chain of survival ^[1][5][6]

The initial approach to cardiac arrest is influenced by the rescuers (e.g., number of rescuers, training received), patient factors (e.g., age, pregnancy), and location (i.e., in-hospital vs. out-of-hospital).

• Identify cardiac arrest and initiate an emergency response.
• Begin BLS (i.e., immediate CPR, especially chest compressions).
• Defibrillate shockable rhythms.
• Transition care to ACLS providers.
• Initiate postresuscitation care.
• Provide comprehensive support throughout recovery.

Algorithms

Approach

• For sudden cardiac arrest, use the CAB approach to begin chest compressions as soon as possible. ^[1]
  1. Chest compressions
  2. Airway
  3. Breathing
• Consider prioritizing airway and breathing (i.e., ABC approach) for cardiac arrest secondary to drowning. ; ; ; ^[1][7]
• Minimize interruptions to CPR. ^[6]
• If the diagnosis of cardiac arrest is uncertain, initiating CPR is preferable to withholding CPR. ^[8]

Both chest compressions and ventilation are recommended for all causes of cardiac arrest. ^[1]

Chest compressions ^[1][8]

Chest compression technique differs in children, infants, and neonates; see “Basic life support in infants and children” and “Neonatal resuscitation.”

• Key targets for high-quality chest compressions
  • Compression rate: 100–120 per minute
  • Compression depth for adults: 5–6 cm (2–2.4 inches)
  • Allow full chest recoil between compressions.
• Provider positioning and technique (adults)
  • Align the patient's torso with the provider's knees as much as possible.
  • Center the hands (heel of one hand on top of the other, fingers interlaced) over the lower half or lower third of the sternum.
  • Consider placing the dominant hand directly over the patient's sternum.
  • Keep the arms straight (do not bend the elbows); the shoulders should be directly above the hands.
  • Use full body weight to deliver rapid, firm compressions.
  • Aim for equal compression time and chest recoil time with each chest compression.
• Patient positioning: supine on a firm surface
• Minimizing interruptions
  • Restart CPR between rhythm analysis and shock delivery (while the defibrillator is charging).
  • Resume CPR immediately after shock delivery.
  • Aim for a chest compression fraction (i.e., the proportion of time spent providing hands-on compressions) of at least 60%.

High-quality chest compressions are associated with better survival rates. ^[1]

Mechanical CPR devices ^[1][9]

• Provide automated chest compressions through various means.
• Not routinely indicated; consider if manual high-quality chest compressions cannot be consistently provided and the device can be deployed and removed without significant interruptions in CPR, e.g.: ^[10][11]
  • Prolonged CPR needs (e.g., hypothermic cardiac arrest)
  • Logistical challenges (e.g., during patient transportation)
  • Manual compressions carry a high risk to providers (e.g., pandemic settings).
  • Limited emergency response systems
  • Cardiac arrest occurring in the cardiac catheterization laboratory ^[3]

Rescue breathing ^[1][8]

Select a ventilation modality based on patient factors, available equipment, and provider expertise. ^[1][12]

• General principles for all techniques
  • Perform airway opening maneuvers first (e.g., head-tilt/chin-lift maneuver)
  • Use basic airway adjuncts as needed (e.g., OPA or NPA).
  • For patients in cardiac arrest without an advanced airway:
    • Administer each breath over ∼ 1 second.
    • Target a compression-ventilation ratio of 30:2 (i.e., administer 2 breaths after every 30 chest compressions).
  • For patients in respiratory arrest: Administer 1 breath every 6 seconds (10 breaths per minute).
  • Provide enough tidal volume to achieve visible chest rise.
• Mouth-to-mouth
  • Pinch the patient's nose closed.
  • Form a tight seal over the patient's mouth.
  • Breathe into the patient's mouth.
  • Move away from the patient's mouth between breaths to allow air to escape, ensuring the patient's airway remains open.
• Mouth-to-mask
  • Use a mask to form a seal over the patient's nose and mouth.
  • Breathe into the mask opening.
• Bag-mask ventilation
  • Ventilate with 100% O₂. ^[2]
  • If two rescuers are present, consider assigning the bimanual mask seal to one rescuer and bag inflation to the other.
  • See "BMV" for detailed technique.
• Advanced airway: see "Advanced airway and ventilation in ALS."

Chest compressions with rescue breathing is preferred for all trained CPR providers. However, compression-only CPR can be performed as an alternative by untrained providers or those unwilling to perform mouth-to-mouth rescue breathing.

Avoid hyperventilation and hypoventilation in patients with cardiac arrest, as they can both cause harm. ^[1]

Monitoring CPR quality ^[2]

Consider using the following diagnostic parameters in addition to clinical quality parameters (e.g., rate, depth, and recoil) to monitor and optimize the quality of CPR in real time.

• Capnometry (EtCO₂)
  • < 10 mm Hg: associated with a poor prognosis
  • > 10–20 mm Hg: increased likelihood of ROSC
• Continuous arterial blood pressure monitoring

Withholding CPR ^[13]

Only consider allowing natural death in limited situations, e.g.:

• An advance directive or valid DNR (ideally POLST) prohibiting CPR is in place.
• Situations that may pose a significant risk to the rescuer
• Signs of irreversible death

Initiate CPR if there is any uncertainty regarding the validity of a DNR or the irreversibility of death.

The BLS algorithm allows appropriately trained individuals to recognize cardiac arrest, provide high-quality chest compressions, deliver ventilations, and utilize an AED.

BLS algorithm ^{[1][3][14][15]}

The optimal sequence of some of the BLS steps varies between single-rescuer BLS and two-rescuer BLS; see "Single rescuer vs. two rescuers" for details.

• Assess scene safety
  • Check for fire and other hazards.
  • Don PPE for infectious or toxic exposures. ^[1]
  • Once scene safety is confirmed, proceed with BLS where the patient is found.
• Assess patient responsiveness : Proceed with BLS if there is no response and breathing is absent or abnormal (e.g., gasping respiration).
• Call for help: Shout for assistance and/or activate the emergency response.
• Retrieve an AED or defibrillator: e.g., from the nearest crash cart
• Assess for signs of life: Check pulse and respiration simultaneously.
  • Perform airway opening maneuvers in BLS as needed.
  • Look, listen, and feel for air movement.
  • Check for a central pulse for no longer than 10 seconds.
  • No palpable pulse, apnea, and/or agonal respirations: Begin CPR immediately.
  • Normal respirations: Place the patient in the recovery position before continuing with medical assessment.
  • Present pulse but abnormal respirations: Manage respiratory failure with rescue breathing, and if indicated, administer naloxone for opioid overdose.
• Perform high-quality CPR.
  • Position the patient supine on a hard surface when possible, if this does not delay CPR (activate CPR mode on the bed if present). ^[14]
  • If performing chest compression interrupted by rescue breaths, maintain appropriate CPR ratio: 30:2 for adults, i.e., 30 chest compressions followed by 2 rescue breaths per cycle.
  • Alternatively, consider providing 1 rescue breath every 6 seconds (i.e., 10 breaths per minute) asynchronously without pausing chest compressions, even in patients without an advanced airway.
  • Regularly switch roles if performing two-rescuer CPR.
  • Minimize interruptions to CPR.
• Defibrillate as needed.
  • Use an AED or defibrillator as soon as it is available.
  • Maintain CPR until the machine is ready for rhythm analysis.
  • Perform 5 cycles (2 minutes) of CPR between each rhythm analysis and/or shock.
• Consider naloxone for opioid overdose in situations with all of the following:
  • Opioid overdose is the suspected cause of cardiac arrest.
  • Naloxone is readily available.
  • Administration does not interfere with high-quality CPR.
• Endpoints ^[1]
  • ROSC achieved
  • ACLS-trained providers take over CPR

Minimizing the interruption and delays to the initiation of high-quality CPR and early defibrillation of shockable rhythms are the most important factors for survival and reducing long-term complications after cardiac arrest.

Avoid routinely applying cricoid pressure during airway management of patients in cardiac arrest because it does not prevent aspiration and may hinder securing the airway. ^[1]

Airway opening maneuvers in BLS

Perform the following airway opening maneuvers as needed during the initial assessment for signs of life (e.g., pulse check and breathing) of an unresponsive patient.

• Visible foreign body (FB): Remove FB; avoid blind finger sweep for FB aspiration.
• No sign of trauma: Perform head-tilt/chin-lift maneuver; consider OPA or NPA as an airway adjunct if the gag reflex is absent.
• Suspected trauma
  • C-spine injury: First perform the jaw-thrust maneuver; if the airway remains obstructed, consider head-tilt/chin-lift maneuver.
  • Basal skull fracture or coagulopathy: If using an airway adjunct, choose an OPA over an NPA.

Single rescuer vs. two rescuers

Automated external defibrillator (AED) ^[1]

• Description: a portable electronic defibrillator that independently identifies shockable rhythms and delivers a shock; designed to be used by lay rescuers in out-of-hospital settings
• Applying pads
  • Dry the skin where the pads will be applied, if necessary.
  • If the patient is wearing a bra, consider adjusting rather than removing it.
  • Anterior-lateral placement: Place one pad on the right chest (above the nipple) and the other on the left side of the thorax (below the nipple).
  • Anterior-posterior placement: Place one pad anteriorly on the chest and the other posteriorly on the back.
• Rhythm analysis
  • Pause CPR during rhythm analysis.
  • Perform pulse check for up to 10 seconds during rhythm analysis.
  • Repeat analysis every 2 minutes (5 cycles of CPR).
• Delivering shocks
  • The AED will indicate if a shock is advised and may begin to charge.
  • Resume CPR while the AED is charging.
  • When advised by the AED, clear the surroundings , then deliver the shock.
• Resume CPR immediately after shock delivery: Perform for 2 minutes (5 cycles) prior to the next rhythm analysis.

If a witnessed cardiac arrest occurs in patients who are already connected to cardiac monitoring and defibrillator pads, administer a shock as soon as a shockable rhythm is identified. ^[1]

Special situations ^[1][3]

• Obesity ^[1]
  • Use the same CPR and defibrillation techniques as for patients without obesity.
  • Weigh the risks and benefits of moving a patient to a firm surface for CPR if transportation time will delay the initiation of CPR.
  • Adjust manual force as needed to achieve the target chest compression depth.
• Drowning: See "Treatment of drowning" for details. ^[7]
  • Prioritize airway opening maneuvers and rescue breathing.
  • Use ABC approach (as long as resuscitation is not delayed, e.g., by waiting for equipment) or CAB approach.
  • Provide supplemental oxygen if available.
  • Perform CPR prior to calling for help or obtaining an AED.
  • AEDs can be used for shockable rhythms even though these are rare.
• Foreign body aspiration (FBA): See “Unresponsive patient with suspected FBA” for details. ^[18]
  • Begin chest compressions immediately and activate emergency response.
  • Defer pulse check in unresponsive infants or children with severe FBA.
  • Check airway for dislodged foreign body (FB) during 2-minute pulse check and remove if present.
  • Avoid blind finger sweep if FB is not visible.
  • If CPR is unsuccessful, consider emergency airway procedures for FBA.
• Hypothermia: See “Hypothermic cardiac arrest” for details.
  • Requires specialized vital signs assessment
  • CPR is generally continued until fully rewarmed (e.g., using ECLS).
• Nonthrombotic embolism: Specialized management is indicated.
  • See "Venous gas embolism."
  • See "Arterial gas embolism."
  • See "Amniotic fluid embolism."
• Electrocution: Standard BLS and ACLS are indicated (see "Electrical injury" for further management).
• Poor perfusion in patients with a left ventricular assist device (LVAD): If the LVAD is durable, begin chest compressions while systematically assessing for LVAD complications.

The precordial thump is not recommended for cardiac arrest, as there is no benefit to perfoming this maneuver. ^[3]

The ACLS algorithm adds the following to the BLS algorithm: rhythm recognition in cardiac arrest, resuscitation medications, treatment of reversible causes of cardiac arrest, and advanced airway management. Maximizing high-quality CPR and early defibrillation remain the most important factors for survival and good neurological outcomes. ^[2]

ACLS algorithm ^[2][15][17]

Sequence

1. Start CPR and attach defibrillator.
2. Analyze rhythm as soon as possible.
   1. Management of shockable rhythms (Vfib or pulseless VT): Defibrillate immediately; administer epinephrine and amiodarone in subsequent CPR cycles.
   2. Management of nonshockable rhythms (asystole or PEA): Administer epinephrine immediately; repeat in subsequent CPR cycles.
3. Resume CPR immediately for 2 minutes after rhythm analysis.
4. Repeat rhythm analysis and check for ROSC every 2 minutes and manage accordingly.

For patients already on a cardiac monitor with a defibrillator attached or nearby who develop cardiac arrest with a shockable rhythm, consider defibrillation before CPR. ^[1]

Priorities

• Priority 1: CPR
  • Perform high-quality CPR for at least 2 minutes before the first rhythm check.
  • Avoid interrupting CPR unless it is for rhythm and pulse checks and/or shock delivery.
  • Consider an advanced airway only if necessary and feasible without major interruption of CPR.
• Priority 2: rhythm and pulse check
  • Attach monitors and/or defibrillator pads.
  • Pause CPR for no longer than 10 seconds for rhythm recognition in cardiac arrest.
  • Shockable rhythms (Vfib or pulseless VT): Proceed to defibrillation; draw up epinephrine PLUS either amiodarone OR lidocaine.
  • Nonshockable rhythms (PEA or asystole): Do not defibrillate; draw up epinephrine.
  • Repeat rhythm and pulse check every 2 minutes, resuming CPR in between each check.
• Priority 3: defibrillation of shockable rhythms
  • Deliver a shock; (e.g., 200 J biphasic) as soon as Vfib or pulseless VT is recognized, see "Defibrillation" for details.
  • Resume CPR immediately after shock and continue for 2 minutes until next rhythm and pulse check.
  • If a second attempt at defibrillation is unsuccessful, administer resuscitation medications.
• Priority 4: resuscitation medications
  • Obtain vascular access for ACLS.
  • See "Resuscitation medications" for dosages and details.
• Priority 5: Hs and Ts
  • Address these in parallel with CPR, defibrillation, and resuscitation medications.
  • See “Reversible causes of cardiac arrest” for targeted therapies.
• Endpoints
  • ROSC identified during rhythm and pulse check: Begin postresuscitation care.
  • Termination of resuscitation decision is made: Follow procedure for declaration of death.

Evaluate and treat reversible causes of cardiac arrest (e.g., Hs and Ts) without stopping CPR, defibrillation, or administration of resuscitation medications.

Continue CPR and defibrillation attempts as long as the patient has a shockable rhythm.

Rhythm recognition in cardiac arrest

In prolonged cardiac arrest, rhythms frequently degenerate into asystole; check with emergency providers if another rhythm was detected prior to admission.

Avoid pausing CPR for longer than 10 seconds for rhythm and pulse checks.

Defibrillation ^[2]

Defibrillate as soon as possible once a shockable rhythm is recognized to maximize survival.

Procedure

1. Set the defibrillator to unsynchronized mode.
2. Place the paddles or pads firmly on the patient's thorax.
3. Set energy dosage and press the charge button.
   • Biphasic defibrillator (preferred) ^[15][19]
     • First shock: Use the energy recommended by the device manufacturer (e.g., 120–200 J). ^[2]
     • Subsequent shocks: Choose the same or higher energy (e.g., 200–360 J) based on device manufacturer instructions. ^[2]
   • Monophasic defibrillator : 360 J for all shocks
4. Resume CPR while the defibrillator is charging.
5. When fully charged, “clear” the patient, i.e., ensure no other personnel and equipment are in contact with the patient or pads.
6. Administer one shock per cycle. ^[2]
   • Paddles: Simultaneously hold down both shock buttons located under each thumb.
   • Pads: Press the shock button on the defibrillator.
7. Resume CPR immediately after defibrillation for a full 2-minute cycle. ^[17]

Ensure the defibrillator is set to unsynchronized mode when treating cardiac arrest with a shockable rhythm.

Pitfalls and troubleshooting

• Minimize interruptions: Provide interval CPR if there is a delay between rhythm recognition and shock delivery.
• Safe oxygen use: Turn oxygen off or divert the flow away from the patient.
• CIED present (e.g., pacemaker): Place pads in AP configuration or > 10 cm from the pulse generator ^[20]
• Persisting shockable rhythm: Vfib or pulseless VT that persists after ≥ 3 standard shocks ^[2]
  • Ensure the following components of the standard technique are implemented correctly:
    • Direct, firm contact between the pads or paddles and the skin
      • Conducting gel may be required for paddles.
      • Consider shaving the patient's chest if there is a lot of hair.
    • The pads are positioned such that they encompass the heart anatomically
    • Concomitant high-quality CPR is performed
  • Consider alternate defibrillation techniques if the standard technique is ineffective: The benefit of these are unclear.
    • Vector change defibrillation, e.g., using anterior-posterior pad placement ^[21]
    • Double sequential defibrillation ^[2]

Resuscitation medications ^[2][15][22]

Obtain vascular access and administer medications without interrupting CPR to ensure their circulation to the heart and brain.

• Vascular access for ACLS
  • Peripheral IV access (preferred)
  • IO access if IV access is unsuccessful
  • CVL insertion if both IV and IO access are impossible
• Shockable rhythms
  • Epinephrine 1 mg IV/IO
    • First dose: after second unsuccessful defibrillation attempt
    • Repeat every 3–5 minutes.
  • Amiodarone; 300 mg IV/IO (OR lidocaine; 1–1.5 mg/kg IV/IO)
    • First dose: after third unsuccessful defibrillation attempt
    • An additional dose of 150 mg of amiodarone or 0.5–0.75 mg/kg of lidocaine can be given after 3–5 minutes.
• Nonshockable rhythms: Administer epinephrine 1 mg IV/IO.
  • First dose: as soon as possible
  • Repeat every 3–5 minutes.
• Any rhythm: After the first dose of epinephrine, a limited number of additional medications may be considered (e.g., methylprednisolone 40 mg IV). ^[2][3][22]

Advanced airway management and ventilation in ALS ^[2]

• The decision to place an advanced airway or continue BMV should be based on:
  • Minimizing interruption of CPR and/or defibrillation
  • Likelihood of successful placement (e.g., out-of-hospital vs. in-hospital, clinician expertise)
• If CPR must be interrupted for airway placement, delay placement until the initial round of CPR and defibrillation has failed or ROSC is achieved.
• Minimize CPR interruptions to < 10 seconds for advanced airway placement. ^[23]
• Place either a supraglottic airway or an ET tube, depending on the likelihood of successful placement.
• Confirm airway placement using continuous waveform capnography.
• Once an advanced airway has been placed, deliver 1 breath every 6 seconds while performing continuous chest compressions.

Airway management in patients with infectious diseases ^[3]

E.g., for patients with high-consequence respiratory pathogens such as COVID-19 or other pandemic viruses

• Don PPE with airborne precautions (e.g., N95 mask, face shield, gloves, gown, goggles).
• Consider assigning a team member to monitor adherence to airborne precautions.
• Minimize the number of personnel in the room.
• Consider using a mechanical CPR device.
• Consider advanced airway placement instead of BMV in adults and children to reduce pathogen transmission during rescue breathing.
• If intubating:
  • Use video laryngoscopy when available.
  • Use ventilators with appropriate HEPA filters.
  • Avoid using improvised barriers such as intubating boxes.

Advanced airway placement is an aerosol-generating procedure.

Crisis resource management ^[3][17]

Effective teamwork is essential to the success of resuscitative efforts. The following roles, responsibilities, and communication strategies are recommended during ACLS:

• Assign a designated team leader prior to starting resuscitation.
  • All communication about patient status and treatments delivered should go through the team leader.
  • Final decisions about which treatments to pursue and when to stop resuscitation should be made by the team leader after discussion with other team members.
  • The team leader should set the maximum number of people present during resuscitation to optimize team effectiveness.
• Other suggested roles include:
  • At least two CPR performers: one for chest compressions and one for airway and ventilation
    • Providers of chest compressions should be swapped every 2 minutes to prevent fatigue.
    • Coordinate changeovers to minimize interruptions to CPR.
  • Provider(s) in charge of IV/IO access and medications
  • Provider(s) in charge of rhythm and pulse checks and defibrillation
  • Provider(s) in charge of specific procedures (e.g., intubation, pericardiocentesis, point-of-care ultrasound)
  • Provider in charge of team adherence to PPE.
  • Timekeeper and/or note taker
• Prior to each pause, ensure team members are aware of their roles to minimize interruptions to CPR.

Ensure resuscitation team members protect patient dignity through appropriate communication and responses in changes to patient status (e.g., expressions of distress and/or pain); bodily integrity should be maintained as much as possible. ^[13]

Apply the following for patients with Vfib or pulseless VT identified at any time during cardiac arrest. Simultaneously evaluate for and treat reversible causes of cardiac arrest, e.g., Hs and Ts.

1^st defibrillation attempt

• Continuous high-quality CPR started.
• Defibrillator turned on and set to unsynchronized mode.
• Pads or paddles placed appropriately
• Device charged
• • 200 J for biphasic defibrillators
  • OR 360 J for monophasic defibrillators.
• Shock administered after clearing patient
• CPR resumed until the next rhythm and pulse check (2 minutes or 5 cycles of CPR).

2^nd attempt

• Shock administered after clearing patient
• CPR resumed until the next rhythm and pulse check (2 minutes or 5 cycles of CPR).
• First dose of epinephrine given

3^rd attempt

• Shock administered after clearing patient
• CPR resumed until the next rhythm and pulse check (2 minutes or 5 cycles of CPR).
• First dose given of:
• • Amiodarone
  • OR lidocaine

4^th attempt

• Shock administered after clearing patient
• CPR resumed until the next rhythm and pulse check (2 minutes or 5 cycles of CPR).
• Repeat dose of epinephrine given

5^th attempt

• Shock administered after clearing patient
• CPR resumed until the next rhythm and pulse check (2 minutes or 5 cycles of CPR).
• Second dose (half of the first dose) given of:
• • Amiodarone
  • OR lidocaine

Endpoints

• If persistent VF or pulseless VT:
• • Continue CPR and defibrillation attempts.
  • Continue repeating epinephrine at regular intervals.
• If PEA or asystole: Immediately resume CPR and follow acute management checklist for nonshockable rhythms.
• If ROSC: Begin postresuscitation care.

Precharge the defibrillator prior to the next rhythm and pulse check to minimize interruption of CPR.

The following applies to patients with PEA or asystole identified at any time during cardiac arrest. Simultaneously evaluate for and treat reversible causes of cardiac arrest, e.g., Hs and Ts.

First identification of nonshockable rhythm

• CPR started and continued until next rhythm and pulse check (2 minutes or 5 cycles of CPR).
• First dose of epinephrine given as soon as possible

Subsequent identification of nonshockable rhythm

• CPR resumed until next rhythm and pulse check (2 minutes or 5 cycles of CPR).
• Repeat dose of epinephrine given at 3–5 minute intervals.

Endpoints

• If persistent PEA or asystole:
• • Continue CPR and repeat doses of epinephrine. ^[15][24][25]
  • Consider termination of resuscitation on an individual basis.
• If VF or pulseless VT: Defibrillate, resume CPR, and follow acute management checklist for shockable rhythms.
• If ROSC: Begin postresuscitation care.

Only consider pausing CPR if a lifesaving procedure requiring access to the chest must be performed, e.g., pericardiocentesis.

Overview of causes ^{[15][16][19][26]}

• The Hs and Ts can be used to help remember the most common reversible causes of cardiac arrest. ^[19]
• Other causes include hypoglycemia, hypocalcemia, hypomagnesemia, anaphylaxis, and asthma.
• Trauma: not managed with standard ACLS algorithms; see "Traumatic cardiac arrest" and "Resuscitative thoracotomy" for details.

Bedside diagnostic studies

• Rapid glucose and electrolytes (K⁺, Ca²⁺, Mg²⁺)
• ABG/VBG ± CO-oximetry ^[2]
• Core body temperature

POCUS in cardiac arrest

Consider the following on a case-by-case basis as adjunctive studies. ^[2]

• eFAST examination: to assess for hemoperitoneum, pericardial effusion, and lung sliding
• Focused cardiac ultrasound (FoCUS) ^[27][28]
  • Goal: to assess cardiac activity in patients with nonshockable rhythms (e.g., asystole, PEA, and pseudo-PEA) and help predict prognosis ^{[2][29][30][31]}
  • Findings
    • Cardiac activity (i.e., PEA or pseudo-PEA): suggests treatable causes (e.g., pulmonary embolism, hypovolemia, or pneumothorax) ^[2]
    • No cardiac activity (i.e., asystole): associated with low likelihood of ROSC

Avoid interruptions in high-quality CPR or delaying defibrillation to perform POCUS examinations. ^[2][27]

Use the subcostal view for FoCUS to minimize interference with chest compressions. ^[32]

Hs

Ts

Other reversible causes of cardiac arrest ^{[3][15][16][19][26]}

Several other reversible causes of cardiac arrest exist and may be screened for and treated during cardiac arrest.

Avoid routine dextrose administration for cardiac arrest (e.g., in potentially normoglycemic or hyperglycemic patients) as it can worsen survival and neurological outcomes. ^[43]

Return of spontaneous circulation (ROSC) ^[2][19]

• Indications of ROSC
  • Clear signs of life, e.g., breathing, coughing, or movement
  • Return of palpable pulse and blood pressure or presence of arterial waveform with intraarterial monitoring
  • An abrupt and sustained increase in expiratory CO₂ measured with capnography
• Management
  • Begin postresuscitation care.
  • Consult specialists for neuroprognostication.
  • Identify and treat complications of CPR and/or cardiac arrest.

Continue rescue breaths for patients who have ROSC but are still in respiratory arrest. ^[1]

Termination of resuscitation (TOR) ^[13][46]

Indications for TOR (in-hospital cardiac arrests)

• No clear guidance exists on when to terminate CPR in hospitals. Decisions and protocols should take into account the following factors:
  • The patient's wishes: Terminate resuscitation efforts if a valid DNR or an advance directive prohibiting resuscitation is discovered.
  • Experience of the provider and resuscitation team
  • Factors associated with poor outcomes ^[24]
    • Patient factors: advanced age, poor functional status, terminal illness, organ failure
    • Resuscitation factors: delay to onset of CPR, delay to defibrillation
  • Child and caregiver considerations
  • Pregnancy and neonatal considerations (See "Neonatal resuscitation.")
  • Patient and caregivers' cultural and religious beliefs
• Ongoing CPR can constitute a potentially inappropriate therapy depending on the circumstances.
• Discuss goals of care and any limitation of life-sustaining treatment with surrogate decision-makers and specialists (e.g., medical ethics, neurology, cardiology) when possible.

Important considerations

Evidence does not support using any single clinical decision rule to guide in-hospital TOR. See also “Tips and Links” below for AHA guidelines on the ethics of withholding CPR and terminating resuscitative efforts.

• End-tidal CO₂: The AHA suggests that an EtCO₂ < 10 mm Hg after 20 minutes of resuscitation in intubated patients may be considered alongside other factors in the decision to terminate resuscitation; it should not be used alone to determine TOR. ^[15][47][2]
• Shockable rhythms: Resuscitation should typically continue as long as the patient remains in a shockable rhythm. ^[15][24]
• Nonshockable rhythms: There is no recommended duration of asystole at which resuscitation should cease. ^[25]
• Prolonged resuscitation is typically appropriate in the following circumstances: ^[15][24]
  • Hypothermia: Continue until adequately rewarmed (e.g., core temperature > 35°C/95°F).
  • Toxicity (e.g., local anesthetic toxicity): Prolonged resuscitation may allow toxins to be metabolized and excreted.
  • Pulmonary embolism: Consult a specialist to determine how long to continue resuscitation after administering thrombolytics. ^[3]

Do not use EtCO₂ level cutoffs to guide TOR or predict outcomes in unintubated patients or in adults and children with hypothermic cardiac arrest. ^[2]

TOR for out-of-hospital cardiac arrest (OHCA) ^[2]

The 2025 AHA ACLS guidelines provide some guidance for TOR in OHCA for ALS-trained providers.

• If any of the following conditions are met, continue resuscitation and transport the patient to the hospital:
  • Witnessed cardiac arrest
  • Bystander CPR provided
  • Shock delivered prior to transport
  • ROSC achieved prior to transport
• If no conditions are met, consider terminating resuscitation.

The post-ROSC phase of cardiac arrest focuses on optimizing hemodynamic support, identifying and treating the underlying cause of arrest, and minimizing secondary brain injury through neuroprotective measures.

Initial postresuscitation stabilization ^[4][15]

• Airway: Secure the airway in comatose patients with early placement of an endotracheal tube.
• Target respiratory parameters: Titrate FiO₂, and initiate waveform capnography to target normoxemia and normocapnia. ^[4]
  • Respiratory rate: Start at 10 breaths/minute.
  • Titrate oxygen therapy to reach SpO₂ of 90–98% and PaCO₂ of 35–45 mm Hg.
  • Consider ABG sampling to measure PaO₂ and PaCO₂ in mechanically ventilated patients.
• Target mean arterial pressure: > 65 mm Hg ^[4]
  • Administer IV fluids as needed and consider vasopressors and/or inotropes. ^[4]
  • Mechanical circulatory support for cardiogenic shock
    • Not routinely recommended
    • Consider for patients with refractory cardiogenic shock, under specialist guidance in centers with trained personnel.
• Obtain 12-lead ECG: to evaluate for acute ST-segment elevation

Administer 100% oxygen until reliable SpO₂ or PaO₂ measurements are available, then titrate oxygen to target normoxia. ^[4]

Avoid hypoxemia after ROSC. Pulse oximetry can underestimate hypoxemia in patients with dark skin. ^[4]

Additional management and urgent interventions ^[4][15][22]

• Address the cause of arrest:
  • Consider POCUS or bedside echocardiography.
  • See “Reversible causes of cardiac arrest.”
• Identify patients who need coronary angiography: See "PCI after ROSC."
• Diagnose and manage seizures.
  • Perform an EEG on all patients with ROSC who cannot follow commands, and any patients with myoclonus.
  • Consider intermittent or continuous EEG monitoring for patients with ROSC who persistently cannot follow commands.
  • Consider antiepileptic drugs to manage acute seizures, including nonconvulsive status epilepticus diagnosed with EEG. ^[22]
  • Seizure prophylaxis is not routinely recommended.
  • Avoid treating myoclonus without diagnosing seizure activity on EEG.
• Temperature control in unresponsive patients ^[4][22]
  • Maintain a body temperature of 32–37.5°C (89.6–99.5°F) for at least 36 hours.
  • Avoid fever.
• Initiate other neuroprotective measures (e.g., targeting normoglycemia): See “Secondary brain injury and neuroprotective measures.”
• Consider whole-body CT: to assess for underlying causes and complications of cardiac arrest
• Admit to ICU: for further management and neuroprognostication

Percutaneous coronary intervention after ROSC^[4]

Percutaneous coronary intervention (PCI) is recommended for patients after ROSC in the following situations:

• Urgent PCI
  • All patients with ST elevation on ECG, irrespective of their level of consciousness
  • Consider for all patients without ST elevations and any of the following:
    • Cardiogenic shock
    • Recurrent ventricular dysrhythmia
    • Significant ongoing cardiac ischemia
• PCI before hospital discharge
  • Shockable rhythm at the onset of cardiac arrest
  • LV dysfunction of unclear etiology
  • Severe cardiac ischemia

Neuroprognostication ^[4][15]

• Neuroprognostication after cardiac arrest is complex and should be conducted by specialists.
• The extent of irreversible loss of brain function can be estimated clinically (e.g., neurological examination, apnea testing) and using ancillary brain death tests (e.g., EEG).
• Brain death assessment is typically carried out 72 hours after cardiac arrest or cessation of TTM.
• See also “Ethical issues concerning brain death.”

Organ and tissue donation ^{[4][13][22][48][49]}

• Consider organ and tissue donation for all patients with ROSC in whom brain death is declared.
• Consider controlled donation after circulatory death (DCD) before withdrawing life-sustaining treatment (LST).
• Separate end-of-life care decisions from organ donation considerations to prioritize the patient's benefit.
• See "Extracorporeal CPR" for details on the use of ECLS in organ and tissue donation.
• See “Organ and tissue donation” for more related clinical, systemic, legal, and ethical issues.

Survivorship after cardiac arrest ^[4][13]

Patients, caregivers, and health care providers may all benefit from follow-up measures after medical stabilization and before hospital discharge to prevent emotional distress, lasting impairments, and provider burnout.

• Patients and caregivers
  • Evaluate and refer for treatment of emotional distress.
  • Arrange rehabilitation assessment and treatment for potential cognitive and physiological impairment (e.g., occupational therapy, physical therapy, cardiac rehabilitation).
  • Ensure appropriate discharge planning and guidance is provided (e.g., appropriate follow-up, return to daily activities).
• Health care providers
  • Consider team debriefings and/or referral for emotional support.
  • Consider measures to mitigate burnout (e.g., positive thinking exercises, professional coaching).

• Airway: Secure the airway with early placement of an endotracheal tube.
• Breathing: target SpO₂ 90–98% and PaCO₂ 35–45 mm Hg
  • Start ventilation with 10 breaths/minute.
  • Titrate FiO₂.
  • Initiate waveform capnography.
• Circulation: target mean arterial pressure > 65 mm Hg
  • Administer IV fluids.
  • Consider vasopressors and/or inotropes.
  • Consider extracorporeal CPR for patients with refractory shock.
• Obtain 12-lead ECG: to identify any ST-segment elevations requiring PCI after ROSC
• Arrange PCI: see "PCI after ROSC" for indications.
• Admit to ICU: for additional management and urgent interventions
  • Maintain a temperature of 32–37.5°C.
  • Identify and treat the underlying cause: See “Hs and Ts.”
  • Identify and treat any complications (e.g., seizures, fever, cardiac arrhythmias).
• Monitor postresuscitation targets: See “Neuroprotective measures.”

Complications of CPR

• Rib fractures
• Hemothorax
• Hemopericardium
• Hemoperitoneum
• Solid organ injuries, e.g., liver
• Skin burns
• Complications of intubation

Complications of cardiac arrest

• Ischemic cardiomyopathy
• Acute kidney injury
• Shock liver
• Multiorgan dysfunction syndrome
• Neurological dysfunction

Anoxic-ischemic encephalopathy ^{[50][51][52][53]}

• Definition: global brain injury caused by complete cessation of blood flow during cardiac arrest
• Epidemiology: most common cause of death in patients surviving cardiac arrest ^[50]
• Pathophysiology: cardiac arrest → cessation of blood flow to the brain → anoxia → irreversible neuronal damage and death
• Clinical features
  • Neurological deficits (determined by the severity of injury and the affected structures)
    • Comatose state
    • Absent or abnormal motor response (e.g., extensor posturing)
    • Absent spontaneous eye movements
    • Absent brainstem reflexes (e.g., pupillary light reflex, oculocephalic reflex)
  • Convulsions (e.g., status epilepticus)
• Diagnostics
  • Clinical features consistent with cardiac arrest
  • It is imperative to exclude other causes of coma (e.g., toxic and metabolic encephalopathies, shock).
  • Laboratory studies (e.g., CBC, serum electrolytes, toxicology screens)
  • Imaging
    • CT brain
      • Usually normal within the first 2 days
      • Findings of anoxic injury: cerebral edema, inversion of gray-white matter density
    • MRI brain: allows for early detection of brain injury
  • EEG
    • Characteristic pattern: slowing of the EEG followed by delta activity and, eventually, EEG flattening
    • Some EEG patterns are markers of a poor prognosis (see below).
• Differential diagnosis: hypoxic-ischemic encephalopathy
• Management
  • Postresuscitation care (see above)
  • Avoid hyperthermia. ^[54][55]
  • Prevention of hyperglycemia
• Complications
  • Brain death
  • Coma
  • Persistent vegetative state
  • Minimally conscious state
  • Seizures
• Prognosis
  • The majority of cases have a poor prognosis, indicators of which include:
    • Increased duration of anoxia
    • Clinical markers
      • Absent brainstem reflexes (e.g., pupillary light reflex, corneal reflex)
      • Persistent dilated pupils
      • Absent or abnormal motor response
      • Myoclonic status epilepticus
    • Other specific markers
      • Laboratory studies: elevated serum level of neuron-specific enolase
      • EEG: nonreactive or presence of burst-suppression pattern (suggestive of myoclonic status epilepticus)

We list the most important complications. The selection is not exhaustive.

Cardiac arrest in pregnancy ^[3]

• Maternal cardiac arrest is rare.
• The majority of BLS and ACLS algorithms remain the same, including drug and defibrillation dosages.

Modifications to BLS and ACLS ^[16][56]

• Activate a dedicated team where available (e.g., maternal code blue team). ^[3]
• Place IV or IO lines above the level of the diaphragm.
• Anticipate a difficult airway and prioritize early airway management.
• Detach intrapartum fetal monitoring electrodes, if present.
• Left uterine displacement
  • Indication: cardiac arrest in a pregnant individual with fundal height at or above the umbilicus
  • Technique: Displace the uterus manually to the left to relieve aortocaval compression. ^[16]
    • One-handed manual displacement: Standing on the patient's right, push the uterus up and away.
    • Two-handed manual displacement: Standing on the patient's left, pull the uterus up and toward the rescuer.
• Consider the following causes in addition to the common causes of cardiac arrest (see “Hs and Ts”): ^[16]
  • Amniotic fluid embolism
    • Activate massive transfusion protocol.
    • Administer tranexamic acid.
  • Uterine atony
  • Placenta abruption or placenta previa (see “Antepartum hemorrhage” for details on management)
  • Eclampsia: Administer magnesium
  • Iatrogenic hypermagnesemia
    • Stop magnesium infusion.
    • Administer calcium chloride OR calcium gluconate.
• If available, consider ECLS for refractory cardiac arrest.

Prepare for perimortem cesarean delivery in pregnant individuals with cardiac arrest who have a fundal height at or above the umbilicus. ^[3]

Perimortem cesarean delivery (PMCD) ^[56]

• General overview
  • PMCD reduces aortocaval compression and increases the likelihood of ROSC.
  • Early PMCD also maximizes the chance of survival for a viable fetus by reducing anoxia.
• Indications
  • ROSC has not occurred within 4 minutes of cardiac arrest.
  • AND the fundal height is at or above the umbilicus
  • OR the uterus is thought to be causing aortocaval compression
• Target: complete PMCD ideally within 5 minutes of cardiac arrest onset
• Technique
  • Preferred: cesarean delivery via vertical incision
  • For in-hospital cardiac arrest, perform PMCD where the patient is located (i.e., without attempting transfer to an OR).
  • After cesarean delivery, normal ACLS should continue for the mother.
  • See also “Neonatal resuscitation.”

Cardiac arrest in patients with trauma ^[57]

• Cardiac arrest due to trauma rarely responds to standard ACLS treatment.
• Management is primarily surgical, i.e., emergency chest decompression and/or emergency thoracotomy followed by operative intervention.
• See “Traumatic cardiac arrest” for details.

See “Neonatal resuscitation” for a structured approach to the care of neonates immediately after birth.

BLS in infants and children

Technique modifications ^[40]

• Compression rate: 100–120/minute
• Compression-to-breath ratio
  • Single rescuer: 30:2
  • Two rescuers: 15:2
• Postpubertal children/adolescents: Same CPR technique as for adults
• Children ≥ 1 year of age until puberty
  • Chest compressions: Deliver with one hand for smaller children.
  • Compression depth: 5 cm
• Infants < 1 year old ^[58]
  • Compression depth: 4 cm
  • Rescue breaths: Form a seal over both the nose and mouth.
• Defibrillation
  • Children 1–8 years old: If available, use an AED with pediatric attenuation (if no other device is available, use an adult AED).
  • Infants < 1 year old: If available, use a manual defibrillator (if no other device is available, use an adult AED). ^[58]

Greater emphasis is placed on ventilation compared to CPR in adults, as hypoxia is a more common cause of cardiac arrest in infants and children.

Algorithm modifications ^[15][40][59]

For simplification, similar algorithms are recommended for adults and children in North America, despite their physiological differences. ^[60][61]

• Initial steps (identical to BLS algorithm for adults): Assess scene safety and patient responsiveness, and call for help.
• Check for signs of life
  • Pulse present, no breathing
    • Administer rescue breaths: 1 breath every 2–3 seconds (20–30 breaths/minute)
    • If heart rate is ≤ 60 beats/minute: Start CPR.
  • No pulse, gasping, or no breathing: Start CPR.
• Single rescuer sequence
  • Perform 2 minutes of CPR (30:2 with a compression rate of 100–120/minute) before calling for help or retrieving an AED (if it requires leaving the patient's side).
  • If a cell phone is available, make an immediate emergency call and perform CPR with the phone on speaker.
• Two-rescuer sequence
  • Direct the second rescuer to call for help and retrieve a defibrillator.
  • Start CPR at a ratio of 30:2, changing to 15:2 when both rescuers are able to provide CPR.
  • If an advanced airway is in place, consider ventilating at a rate of 20–30/minute. ^[40]
• Rhythm assessment and defibrillation
  • Shockable rhythm: Defibrillate using pediatric AED pads for children 1–8 years old and continue CPR.
  • Nonshockable rhythm: Continue CPR immediately.
• Endpoints: identical to BLS algorithm for adults.

Pediatric modifications to advanced life support ^[40]

Advanced life support for children requires different drug and defibrillator dosages. The same algorithm for ACLS in adults should be followed for pediatric patients.

• Defibrillator dosage: If using a manual defibrillator, the shock dose should be set as follows.
  • First shock: 2 J/kg
  • Second shock: 4 J/kg
  • Subsequent shocks: ≥ 4 J/kg (max. dose 10 J/kg) or until the adult dose is reached
• Resuscitation medications: Drug dosages should be adapted as follows.
  • Epinephrine
    • Concentration: 0.1 mg/mL (1:10,000)
    • Dosage: 0.01 mg/kg (0.1 mL/kg) IV/IO every 3–5 minutes (max. dose 1 mg)
  • Lidocaine 1 mg/kg IV loading dose once ^[40]
  • Amiodarone 5 mg/kg IV bolus; may be repeated up to a maximum of 3 doses in shockable rhythms

Use the Broselow tape in pediatric patients to rapidly determine medication dosages, equipment sizing, and defibrillator shock dosages.

General principles

• Extracorporeal CPR (ECPR) is a form of extracorporeal life support (ECLS) which uses VA-ECMO for patients in cardiac arrest to support end-organ perfusion while underlying causes are treated.
• ECPR may be beneficial in selected patients with cardiac arrest refractory to standard ACLS in specialized centers with experienced providers. ^[22]
• If available, use validated protocols to mitigate unconscious bias in determining patient eligibility for ECLS.

Indications ^[3]

• Life-threatening respiratory failure due to refractory asthma exacerbation
• Cardiac arrest that occurs in the cardiac catheterization laboratory despite initial therapy
• Refractory cardiac arrest after cardiac surgery
• Hypothermic cardiac arrest
• Severe hypothermia requiring rewarming
• Life-threatening amniotic fluid embolism
• Cardiac arrest caused by suspected or confirmed pulmonary embolism
• Life-threatening refractory cardiovascular drug poisoning or poisoning-induced cardiogenic shock and/or arrhythmias, caused by, e.g.:
  • Beta blocker poisoning
  • Calcium channel blocker poisoning
  • Sodium channel blocker poisoning
  • Cocaine intoxication and/or other stimulant intoxication
  • Local anesthetic systemic toxicity

ECLS for organ and tissue donation ^[13]

• Consider organ and tissue donation for patients receiving ECLS who have been declared brain death or for whom withdrawal of LST is planned.
• Consider starting ECLS for DCD if CPR fails in patients with no chance of recovery from cardiac arrest.
• Consider transitioning from life-saving ECLS to ECLS for DCD only if both of the following conditions are met:
  • Exhaustive, high-quality resuscitation efforts have failed
  • The patient is at a specialized center of excellence where ECLS is accessible to all eligible patients without discrimination

• One-Minute Telegram 111-2024-2/3: Bone vs. vein: the race against time for drug delivery during cardiac arrest
• One-Minute Telegram 107-2024-1/3: Shocking news: defibrillator pad positioning may affect ROSC in cardiac arrest
• One-Minute Telegram 65-2022-2/3: Better outcomes with alternative defibrillation strategies
• One-Minute Telegram 57-2022-1/3: Cooling after out-of-hospital cardiac arrest mitigates the association between higher epinephrine doses and poor neurological outcomes
• One-Minute Telegram 37-2021-2/3: Vasopressin plus methylprednisolone for cardiac arrest: Can a cocktail save lives?

Interested in the newest medical research, distilled down to just one minute? Sign up for the One-Minute Telegram in “Tips and links” below.