When the heart comes back but the brain is lost—are we ready to predict brain death after cardiac arrest?

Abstract

Despite modest improvement in outcomes after out-of-hospital cardiac arrest (OHCA), mortality remains high with less than 20% of cardiac arrest victims surviving this event 1 Odom E. Nakajima Y. Vellano K. et al. Trends in EMS-attended out-of-hospital cardiac arrest survival, United States 2015–2019. Resuscitation. 2022; 179: 88-93 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar . The severity of hypoxic-ischemic brain injury is one of the main determinants of mortality 2 Laver S. Farrow C. Turner D. Nolan J. Mode of death after admission to an intensive care unit following cardiac arrest. Intensive Care Med. 2004; 30: 2126-2128 Crossref PubMed Scopus (676) Google Scholar . Withdrawal of life-sustaining therapies in the setting of predictions of poor neurologic outcome 2 Laver S. Farrow C. Turner D. Nolan J. Mode of death after admission to an intensive care unit following cardiac arrest. Intensive Care Med. 2004; 30: 2126-2128 Crossref PubMed Scopus (676) Google Scholar is the main driver of mortality, reaching 80% of deaths from neurologic causes 3 Mulder M. Gibbs H.G. Smith S.W. et al. Awakening and withdrawal of life-sustaining treatment in cardiac arrest survivors treated with therapeutic hypothermia*. Crit Care Med. 2014; 42: 2493-2499 Crossref PubMed Scopus (87) Google Scholar . Progression of catastrophic ischemic brain injury resulting in death by neurologic criteria (i.e., brain death) occurs in 10 to 29% of OHCA patients after successful cardiac resuscitation 4 Madelaine T. Cour M. Roy P. et al. Prediction of Brain Death After Out-of-Hospital Cardiac Arrest: Development and Validation of the Brain Death After Cardiac Arrest Score. Chest. 2021; 160: 139-147 Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar , 5 Sandroni C. D'Arrigo S. Callaway C.W. et al. The rate of brain death and organ donation in patients resuscitated from cardiac arrest: a systematic review and meta-analysis. Intensive Care Med. 2016; 42: 1661-1671 Crossref PubMed Scopus (78) Google Scholar , 6 Wittwer M.R. Armstrong T. Conway J. et al. In-hospital mode of death after out-of-hospital cardiac arrest. Resusc Plus. 2022; 10: 100229 Crossref PubMed Scopus (1) Google Scholar , 7 Lee B.K. Min J.H. Park J.S. Kang C. Lee B.K. Early identified risk factors and their predictive performance of brain death in out-of-hospital cardiac arrest survivors. Am J Emerg Med. 2022; 56: 117-123 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar . This number likely underreports the actual proportion of patients with brain injury severe enough to progress to brain death due to care limitations prior to occurrence and/or evaluation for brain death. The recognition of brain death as a distinct subset of cardiac arrest patients with a poor outcome (i.e., those who suffered irreversible cessation of all functions of the entire brain) has important downstream ramifications; yet accurate and timely prediction of this subset of patients remains a major challenge in resuscitation care and research.