Approach

The main goal of treatment in sudden cardiac arrest is to achieve a return of spontaneous (as opposed to cardiopulmonary resuscitation [CPR]-mediated) circulation.[67] The algorithm of basic life support (BLS) and advanced cardiac life support (ACLS) provided by the American Heart Association (AHA) gives a systematic approach to the treatment of sudden cardiac arrest.[1] The methods vary slightly based on the underlying rhythm and cause of sudden cardiac arrest, but all rely on immediate attention to stabilising the patient's respiratory status, addressing airway management as needed, and providing medicines and other life-saving treatments aimed at correcting the unstable rhythm, as well as treating the underlying cause, all the while providing compressions to preserve vital organ perfusion.

After activation of emergency medical services, the first approach to sudden cardiac arrest is BLS, providing compressions (first priority), assessing the airway, and giving breaths. This C-A-B priority recommendation by the AHA for adults is a change in the guidelines from the A-B-C priority taught historically, in order to emphasise the importance of providing timely chest compressions.[1][68][69]​ Untrained lay-rescuers should perform compression-only CPR.[1] For rescuers trained in CPR using chest compressions and ventilation, it is reasonable to provide rescue breaths in addition to compressions.[1][51]

How to deliver chest compressions for an adult patient
How to deliver chest compressions for an adult patient

A paramedic demonstrates how to deliver chest compressions to an adult patient

How to deliver mouth to mouth to an adult patient
How to deliver mouth to mouth to an adult patient

A paramedic demonstrates how to deliver mouth to mouth to an adult patient

​​​​ In cases where it is suspected that opioid overdose has caused the cardiac arrest, naloxone should be administered.[37] Patients who require further treatment are then given ACLS by trained providers.[1]

At any given point in the provision of ACLS, the rhythm may change from pulseless ventricular tachycardia (VT)/ventricular fibrillation (VF) to pulseless electrical activity (PEA)/asystole, or vice versa. In such an event, the appropriate ACLS algorithm for the new rhythm should be followed.

Adrenaline (epinephrine) is recommended for both shockable and non-shockable rhythms.[1]​​​​[50][54]​ The use of adrenaline during cardiac arrest has been shown to increase the rate of achieving return of spontaneous circulation (ROSC) and to increase short-term survival.[70][71][72][73]​ However, adrenaline use during cardiac arrest has not been shown to lead to significantly improved neurological outcomes, and may lead to higher rates of severe neurological impairment among survivors.[70][71][72][73]​ One large randomised controlled trial (PARAMEDIC2) found no significant difference in the proportion of patients surviving to discharge with favourable neurological outcome.[70]

While performing ACLS, the care team will assess for and treat any suspected reversible causes of cardiac arrest. If poisoning is suspected or confirmed, timely consultation with a toxicologist or regional poison center should be undertaken to facilitate rapid and effective therapy. Treatment of cardiac arrest and life-threatening toxicity due to poisoning often requires specialised treatments that most clinicians do not use frequently, such as antidotes and venoarterial extracorporeal membrane oxygenation, in addition to effective basic and advanced life support. Guidelines have been published for the specific management of cardiac arrest due to critical poisoning from benzodiazepines, beta-blockers, calcium channel blockers, cocaine, cyanide, digoxin and related cardiac glycosides, local anaesthetics, methaemoglobinaemia, opioids, organophosphates and carbamates, sodium channel antagonists, and sympathomimetics.[35]

US guidelines published during the COVID-19 pandemic advise that chest compressions or defibrillation should not be delayed for providers to don personal protective equipment (PPE), but that initial resuscitation personnel should be relieved by providers wearing appropriate PPE as soon as possible.[74] If the patient cannot be placed supine, cardiopulmonary resuscitation may be provided in the prone position, particularly if the patient has advanced airway and circulatory support.[75]

UK guidance advises that for those working in healthcare settings, the use of FFP3 masks or respirators and eye protection is recommended when performing chest compressions for patients with suspected or confirmed COVID-19. PPE should be donned as swiftly as possible to avoid any delays in treatment.[76]

Shockable rhythms (pulseless VT and VF)

In the setting of pulseless VT/VF, the initial management is of BLS as described above (C-A-B method). Early provision of CPR, including compression-only CPR, by bystanders in out-of-hospital arrest increases the rate of survival.[7][77][78]​ 

Laypeople in the US initiated CPR in 40% of out-of-hospital cardiac arrests (OHCA) in 2022.[2]​​ Work has shown that compression-only resuscitation by bystanders for OHCA is equally, if not more, efficient in providing life-saving therapy, compared with conventional CPR with rescue breaths.[1][79]​​​ In a survey of 9022 people in the US in 2015, the prevalence of reported current training in CPR was 18%, and the prevalence of having CPR training at some point was 65%. The rates were lower in Hispanic/Latino people, older people, people with less formal education, and lower-income groups.[80]​ Research supports increasing the availability of public-access defibrillators and community training in BLS methods, including training for schoolchildren.[7][81]​​ BLS training should be particularly encouraged for likely rescuers of people at high risk of OHCA, such as those with cardiac disease, pulmonary disease, and drug-use disorder.[51]​ In Sweden, bystander CPR increased from 30.9% to 82.2% between 1990 and 2020, likely due to a 40-year campaign to educate the population about CPR.[82]

ACLS is commenced when trained providers arrive. If spontaneous circulation is not restored and a shockable rhythm is identified, one shock should be delivered (120-200 J for biphasic or 360 J for monophasic) followed by 5 cycles (2 minutes) of CPR.[1]​​ Intravenous (preferred) or intraosseous access is obtained without interrupting CPR.[1]

Intraosseous access
Intraosseous access

Demonstrates how to obtain intraosseous access.

​​​​

The pulse and rhythm are again assessed and, if the patient remains in pulseless VT/VF, another equivalent or higher-energy shock is delivered and adrenaline given followed by 5 cycles (2 minutes) of CPR.[1][54] If the rhythm is still pulseless VT/VF, another shock is delivered along with amiodarone [ Cochrane Clinical Answers logo ] ​ or lidocaine, and CPR is continued for 5 cycles (2 minutes). If the patient remains in a shockable rhythm, the algorithm restarts at the stage of adrenaline administration. This cycle continues until spontaneous circulation is achieved or resuscitative measures are terminated.

In situations of witnessed arrest, electrical defibrillation should be attempted as soon as possible, not necessarily after 5 cycles (2 minutes) of CPR.[1] Due to the importance of prompt defibrillation, the use of 'public access defibrillation' by lay-rescuers using automatic external defibrillators has gained favour and been found to increase the rate of sudden cardiac arrest patients surviving to hospital discharge.[7][84][85]​ Lay-rescuer public access defibrillation has been shown to have a higher impact on survival than defibrillation by emergency dispatched professional first responders.[86]

The International Liaison Committee on Resuscitation suggest that use of a double sequential defibrillation strategy or vector change defibrillation strategy may be considered for adults who remain in pulseless VT/VF after 3 or more consecutive shocks (this is a weak recommendation, based on very low certainty evidence).[87] If a double sequential defibrillation strategy is used, it is good practice for one single operator to activate the defibrillators in sequence.[87]​​

In patients with sudden cardiac arrest due to torsades de pointes, giving magnesium may restore a perfusing cardiac rhythm.[88][89]

Non-shockable rhythms (PEA and asystole)

In the setting of PEA/asystole, the initial provision is of BLS as described above (C-A-B method).

ACLS is commenced when trained providers arrive. If spontaneous circulation is not restored and a non-shockable rhythm is identified, 5 cycles (2 minutes) of CPR are provided.[1] Intravenous (preferred) or intraosseous access is obtained without interrupting CPR, and adrenaline (epinephrine) is given as soon as possible and every 3-5 minutes thereafter. The pulse and rhythm are assessed after every 5 cycles (2 minutes) of CPR, and if a pulseless non-shockable rhythm remains, CPR is continued.[1] This cycle of giving CPR and adrenaline continues until spontaneous circulation is attained or resuscitation is terminated. In addition, empirical treatment for likely reversible causes may be considered; for example, calcium bicarbonate for hyperkalaemia in patients with a history of renal failure. There is no evidence to suggest that transcutaneous pacing should be used in patients with asystolic arrest.[90]

Post-resuscitation care

If ROSC is achieved, post-resuscitation care should be instigated immediately. This involves continued monitoring, organ support, correction of electrolyte imbalances and acidosis, and safe transfer to a critical care environment. A thorough search for potential aetiologies should be conducted, and risk factors for sudden cardiac arrest should be modified or treated.

A 12-lead ECG is recommended immediately after ROSC to determine whether signs of ST-elevation myocardial infarction (STEMI) are present.[1] In patients with STEMI, emergency coronary angiography, with or without percutaneous coronary intervention, should be performed.[54]​ Emergency coronary angiography is also reasonable for select patients with suspected acute coronary syndrome without ST elevation, including those with haemodynamic/electrical instability or signs of ongoing ischaemia.​[54] It is not recommended over delayed angiography in patients with ROSC in the absence of ST elevation, shock, electrical instability, signs of significant myocardial damage, or ongoing ischaemia.​[54]

Anoxic brain injury is a frequent complication of sudden cardiac arrest. A systematic review of the literature demonstrates that targeted temperature management (TTM) protocols improve survival and neurological outcome following resuscitation from sudden cardiac arrest, with guidelines continuing to support their use.[1][91]​​​​​​ The American Heart Association (AHA) recommends that all patients unable to follow commands (i.e., are comatose) receive treatment that includes temperature control, regardless of their arrest location or presenting rhythm.[54]​ There is a range for the target temperature, with more recent evidence suggesting that maintaining normothermia (i.e., avoidance of fever) may be equivalent to targeting hypothermia. One large randomised controlled trial (TTM2) which studied patients with coma after OHCA found no difference in 6 month survival or neurological outcome in patients treated with hypothermia (target temperature of 33°C [91.4°F]) compared with normothermia (target temperature ≤37.5°C [≤99.5°F]).[92] An earlier trial (TTM) found that a targeted temperature of 33°C (91.4°F) conferred no benefit compared with 36°C (96.8°F).[93]

For comatose adult patients with ROSC, AHA guidelines recommend targeting a temperature between 32°C and 37.5°C (89.6°F and 99.5°F) for at least 24 hours, and avoiding fever after the initial temperature control phase.[54][94]​ The 2024 International Liaison Committee on Resuscitation guidelines recommend actively preventing fever by targeting a temperature of ≤37.5°C (≤99.5°F) for 36-72 hours, commenting that the benefits of targeting hypothermia between 32°C and 34°C (89.6° and 93.2°F) in selected sub-populations of patients remain uncertain.[87]​ European guidelines recommend targeting a temperature between 32°C and 36°C (89.6°F and 96.8°F).​[95]

TTM has three phases: induction, maintenance, and rewarming. Induction and/or maintenance can be achieved by:[95]

  • Simple ice packs with or without wet towels

  • Cooling blankets or pads

  • Water- or air-circulating blankets

  • Water-circulating gel-coated pads

  • Transnasal evaporative cooling

  • Intravascular heat exchanger

  • Extracorporeal circulation.

Routine pre-hospital cooling of patients after ROSC with rapid infusion of cold intravenous fluids is not recommended.[1][51][95]

Rewarming should be achieved slowly (0.25°C to 0.50°C [0.45°F to 0.90°F] of rewarming per hour) to avoid rebound hyperthermia, which is associated with worse neurological outcomes.[95]

There is evidence that patients who receive post-resuscitation care at specialised centres have higher rates of neurologically intact survival, suggesting that post-resuscitative treatment should ideally be performed in this setting.[96][97]​ Cardiac arrest centres have been shown to display higher coherence with guidelines compared with non-cardiac arrest centres.[98]​ In-patient neurological rehabilitation may be helpful for survivors who have suffered hypoxic-ischaemic brain injury, although specific guidelines and evidence are lacking in this patient population.[95]​ Many patients will also be eligible for cardiac rehabilitation programmes, which have been shown to reduce cardiovascular mortality and hospital admissions, and improve quality of life. They are mostly generic programmes, in which patients with different cardiac diseases, for example, post acute coronary syndrome, heart failure, or post-cardiac surgery, can participate. They involve exercise training, risk factor management, lifestyle advice, education, and psychological support.[95]

Long-term management focuses primarily on prevention of recurrence. Patients should abstain from toxic substances. Use of implantable cardioverter-defibrillators (ICD) has shown a significant reduction in mortality compared with anti-arrhythmic drug therapy in the secondary prevention of sudden cardiac arrest.[7][99]

Termination of resuscitation

This is an ethically challenging issue when treating patients for whom spontaneous circulation does not return in a timely fashion. There is no single factor that can determine when to terminate resuscitative efforts; rather it should be a decision of clinical judgement and respect for human dignity.[1]

In prehospital settings where Basic Life Support (BLS) Emergency Medical Services (EMS) are providing care, and Advanced Life Support (ALS) providers are not available or will be significantly delayed, resuscitation may be terminated based on a validated rule if all of the following criteria are met:[1][100][101]

  • EMS did not witness the arrest

  • The patient had no ROSC before transport

  • No shock was administered before transport.

In the prehospital setting where ALS EMS are providing care, resuscitation may be terminated based on a validated rule if all of the following criteria are met:[1]

  • Arrest was not witnessed

  • No bystander CPR was provided

  • The patient had no ROSC before transport

  • No shock was administered before transport.

In a meta-analysis, the BLS and ALS termination of resuscitation rules both had a low miss-rate (proportion recommended termination of resuscitation who nevertheless survived to discharge) of 0.13% and 0.01% respectively.[102]

Resuscitative measures should be terminated if there is documentation that the patient has a valid 'do not resuscitate' order. Terminating resuscitative measures may also be considered on the basis of the following parameters:[103]

  • Delayed initiation of CPR in unwitnessed cardiac arrest

  • Unsuccessful resuscitation after 20 minutes of ACLS guideline-directed therapy

  • Conditions that compromise the safety of the emergency care providers.

Advanced life support algorithm Opens in new window

Pocket mask ventilation animated demonstration
Pocket mask ventilation animated demonstration

How to use a pocket mask to deliver ventilation breaths to an adult patient.

After sudden OHCA with unsuccessful resuscitation, organ donation may be considered, but is commonly overlooked. Data from a single-centre study in the UK suggest that only 39% of patients who did not recover after OHCA were referred for organ donation. Of those who were referred, consent was obtained in only 68%, and 25% actually went on to donate an average of 1.9 organs per patient.[106]​ The AHA recommends that organ donation is considered in all resuscitated patients who meet the neurological criteria for death or before planned withdrawal of life-sustaining therapies.[54]​ A review by the International Liaison Committee on Resuscitation found that numerous barriers and logistical challenges exist to setting up systems that support organ donation after cardiac arrest; the authors recommend that all health systems should develop, implement, and evaluate protocols designed to optimise organ donation opportunities in this situation.[107]

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