Brain injury after cardiac arrest

doi:10.1016/S0140-6736(21)00953-3

The Lancet

Volume 398, Issue 10307, 2–8 October 2021, Pages 1269-1278

https://doi.org/10.1016/S0140-6736(21)00953-3 Get rights and content

Summary

As more people are surviving cardiac arrest, focus needs to shift towards improving neurological outcomes and quality of life in survivors. Brain injury after resuscitation, a common sequela following cardiac arrest, ranges in severity from mild impairment to devastating brain injury and brainstem death. Effective strategies to minimise brain injury after resuscitation include early intervention with cardiopulmonary resuscitation and defibrillation, restoration of normal physiology, and targeted temperature management. It is important to identify people who might have a poor outcome, to enable informed choices about continuation or withdrawal of life-sustaining treatments. Multimodal prediction guidelines seek to avoid premature withdrawal in those who might survive with a good neurological outcome, or prolonging treatment that might result in survival with severe disability. Approximately one in three admitted to intensive care will survive, many of whom will need intensive, tailored rehabilitation after discharge to have the best outcomes.

Introduction

When cardiac arrest occurs, circulation to the brain ceases and consciousness is lost within seconds. Left untreated, irreversible brain damage and death will rapidly follow. The chance of survival with a favourable neurological outcome declines rapidly the longer someone remains in cardiac arrest.¹ As the heart is more tolerant of ischaemia than the brain, up to 70% of people admitted to hospital die from the effects of brain injury after cardiac arrest, even when initial resuscitation efforts are successful.2, 3, 4 The ultimate goal of resuscitation is to restore cardiac and cerebral function to that before the cardiac arrest. Early initiation of high-quality cardiopulmonary resuscitation (CPR) and rapid defibrillation to reduce primary brain injury increase the odds of favourable neurological outcome by two to four times.⁵ Following return of spontaneous circulation (ROSC), post-cardiac arrest care focuses on minimising secondary brain injury and optimising the chances of recovery. Prediction tools are used to assess the likelihood of a poor neurological outcome, which might lead to withdrawal of treatment or organ donation. After discharge from intensive care, intensive, individualised rehabilitation is required to deliver the best outcomes (figure 1). The aim of this Series paper is to summarise contemporary knowledge about the epidemiology, pathophysiology, treatment, prognostication, long-term outcome, and rehabilitation for brain injury after cardiac arrest.

Section snippets

Epidemiology

A review of global cardiac arrest registries identified that over 500 000 people receive treatment for out-of-hospital cardiac arrest (OHCA) each year, with an annual incidence between 30 and 97 per 100 000 people⁶ (equivalent to 10% of the number of people with myocardial infarctions). ROSC is achieved by the time of hospital handover in approximately a third of patients.⁷ Higher rates of ROSC are seen in North America, Australasia, and Europe than in Asia.⁷ The majority of cardiac arrests

Pathophysiology

Although the severity and duration of ischaemia during cardiac arrest determines the primary neurological injury (no flow), secondary damage occurs during CPR (low flow), and after ROSC (reperfusion). The physiology and molecular consequences associated with brain injury after cardiac arrest have been described in detail previously¹⁸ and are summarised in panel 2 and figure 3.

Interventions to reduce brain injury after cardiac arrest

The European Resuscitation Council and European Society of Intensive Care Medicine guidelines provide comprehensive information on the care of patients following ROSC.²³ Guidelines specifically targeting brain injury after cardiac arrest include targeted temperature management (TTM), treatment of seizures, and maintenance of normal physiology.

Prognostication

Prediction of either a favourable or unfavourable outcome among comatose patients after cardiac arrest improves communication with patients' families who usually seek some indication of the likelihood of a good recovery. When a favourable outcome is predicted, it provides justification for continuation of multi-organ support. And when an unfavourable neurological outcome (eg, survival with severe disability requiring ongoing care from others, unresponsive wakefulness syndrome, or death) is

Clinical and patient focused outcomes

Patients and the public involved in developing a core outcome set for cardiac arrest highlighted the importance of outcomes beyond survival and gross assessments of neurological function.⁶⁰ Common sequelae of brain injury after cardiac arrest include impairments in cognition, emotional wellbeing, physical function, pain, fatigue, participation, and return to work, which reduce health-related quality of life.⁶⁰

Rehabilitation

At present, there are no widely accepted rehabilitation care pathways for patients with brain injury after cardiac arrest, unlike for stroke, traumatic brain injury,⁷² or myocardial infarction.⁷³ Depending on the cause of cardiac arrest, patients might be included in rehabilitation pathways designed for other patient groups, such as post-myocardial infarction or brain injury rehabilitation. However, many patients receive little or no rehabilitation.

Conclusion

Brain injury after cardiac arrest remains a substantial cause of morbidity and mortality. Early recognition and response to cardiac arrest, which includes high-quality bystander CPR and rapid defibrillation, can mitigate the devastating consequences of brain injury after cardiac arrest. Most people admitted to hospital have impaired consciousness and require admission to intensive care where the best supportive care comprises TTM, normalising physiology and allowing sufficient time for

Search strategy and selection criteria

We searched MEDLINE for papers from Jan 1, 2000, to Sept 1, 2020, with the terms “post cardiac arrest brain injury”, “post cardiac arrest syndrome”, “cardiac arrest”, and “brain injury” and relevant section headings (epidemiology, pathophysiology, treatment, rehabilitation). The International Liaison Committee on Resuscitation Consensus on Science and Treatment Recommendations database (costr.ilcor.org) was also searched for relevant systematic reviews. No language restrictions were applied. We

Declaration of interests

GDP reports grants from the UK National Institute for Health Research (NIHR), NIHR Applied Research Collaboration West Midlands, British Heart Foundation, and Resuscitation Council UK. CWC reports grants from the US National Institutes of Health and a US patent (6 174 875 B1). MBS reports personal fees from BARD Medical. JPN reports grants from NIHR, MJR reports grants from NIHR and a UK patent (1062957.7). All other authors declare no competing interests. All authors have or previously held

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