The Brain after Cardiac Arrest Elmer, Jonathan; Callaway, Clifton W
Seminars in neurology
37, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Cardiac arrest is common and deadly. Most patients who are treated in the hospital after achieving return of spontaneous circulation still go on to die from the sequelae of anoxic brain injury. In ...this review, the authors provide an overview of the mechanisms and consequences of postarrest brain injury. Special attention is paid to potentially modifiable mechanisms of secondary brain injury including seizures, hyperpyrexia, cerebral hypoxia and hypoperfusion, oxidative injury, and the development of cerebral edema. Finally, the authors discuss the outcomes of cardiac arrest survivors with a focus on commonly observed patterns of injury as well as the scales used to measure patient outcome and their limitations.
Significant improvements have been achieved in cardiac arrest resuscitation and postarrest resuscitation care, but mortality remains high. Most of the poor outcomes and deaths of cardiac arrest ...survivors have been attributed to widespread brain injury. This brain injury, commonly manifested as a comatose state, is a marker of poor outcome and a major basis for unfavorable neurological prognostication. Accurate prognostication is important to avoid pursuing futile treatments when poor outcome is inevitable but also to avoid an inappropriate withdrawal of life-sustaining treatment in patients who may otherwise have a chance of achieving meaningful neurological recovery. Inaccurate neurological prognostication leading to withdrawal of life-sustaining treatment and deaths may significantly bias clinical studies, leading to failure in detecting the true study outcomes. The American Heart Association Emergency Cardiovascular Care Science Subcommittee organized a writing group composed of adult and pediatric experts from neurology, cardiology, emergency medicine, intensive care medicine, and nursing to review existing neurological prognostication studies, the practice of neurological prognostication, and withdrawal of life-sustaining treatment. The writing group determined that the overall quality of existing neurological prognostication studies is low. As a consequence, the degree of confidence in the predictors and the subsequent outcomes is also low. Therefore, the writing group suggests that neurological prognostication parameters need to be approached as index tests based on relevant neurological functions that are directly related to the functional outcome and contribute to the quality of life of cardiac arrest survivors. Suggestions to improve the quality of adult and pediatric neurological prognostication studies are provided.
Withdrawal of life-sustaining therapies for perceived poor neurological prognosis is the most common cause of death for patients hospitalized after resuscitation from cardiac arrest. Accurate ...neuroprognostication is challenging and high stakes, so guidelines recommend multimodality testing. We quantified the frequency and timing with which guideline recommended diagnostics were acquired prior to in-hospital death after cardiac arrest.
We performed a retrospective cohort study using the Optum® deidentified Electronic Health Record dataset for 2010 to 2021. We included in-hospital decedents admitted after resuscitation from non-traumatic cardiac arrest. We quantified the number of decedents who underwent head computed tomographic imaging, electroencephalography, somatosensory evoked potentials, brain magnetic resonance imaging, or evaluation by a neurologist, as well as the timing of these tests.
Of 34,585 included patients, median age was 66 interquartile range 53 – 79 years and 13,609 (39%) were female. Median hospital length of stay was 0 days 0–1 days, and only 16% of deaths occurred on or after day three. Only 3,245 patients (9%) had at least one neurodiagnostic test acquired and only 1,708 (5%) were evaluated by a neurologist. The most common neurological diagnostic test to be obtained was CT imaging, acquired in 3,004 (9%) of the overall cohort. Only 852 patients (2%) of patients had at least two diagnostic modalities obtained.
In this retrospective cohort, we found few patients hospitalized after out-of-hospital cardiac arrest underwent guideline-recommended prognostic testing. If validated in prospective cohorts with more granular clinical information, better guideline adherence and more frequent use of multimodality neuroprognostication offer an opportunity to improve quality of post-arrest care.
Targeted temperature management with mild hypothermia (TTM-hypothermia; 32-34 °C) is a treatment strategy for adult patients who are comatose after cardiac arrest. Robust preclinical data support the ...beneficial effects of hypothermia beginning within 4 hours of reperfusion and maintained during the several days of postreperfusion brain dysregulation. TTM-hypothermia increased survival and functional recovery after adult cardiac arrest in several trials and in realworld implementation studies. TTM-hypothermia also benefits neonates with hypoxic-ischemic brain injury. However, larger and methodologically more rigorous adult trials do not detect benefit. Reasons for inconsistency of adult trials include the difficulty delivering differential treatment between randomized groups within 4 hours and the use of shorter durations of treatment. Furthermore, adult trials enrolled populations that vary in illness severity and brain injury, with individual trials enriched for higher or lower illness severity. There are interactions between illness severity and treatment effect. Current data indicate that TTM-hypothermia implemented quickly for adult patients after cardiac arrest, may benefit select patients at risk of severe brain injury but not benefit other patients. More data are needed on how to identify treatment-responsive patients and on how to titrate the timing and duration of TTM-hypothermia.
Background
The occurrence of brain death in patients with hypoxic-ischaemic brain injury after resuscitation from cardiac arrest creates opportunities for organ donation. However, its prevalence is ...currently unknown.
Methods
Systematic review. MEDLINE via PubMed, ISI Web of Science and the Cochrane Database of Systematic Reviews were searched for eligible studies (2002–2016). The prevalence of brain death in adult patients resuscitated from cardiac arrest and the rate of organ donation among brain dead patients were summarised using a random effect model with double-arcsine transformation. The quality of evidence (QOE) was evaluated according to the GRADE guidelines.
Results
26 studies 16 on conventional cardiopulmonary resuscitation (c-CPR), 10 on extracorporeal CPR (e-CPR) included a total of 23,388 patients, 1830 of whom developed brain death at a mean time of 3.2 ± 0.4 days after recovery of circulation. The overall prevalence of brain death among patients who died before hospital discharge was 12.6 10.2–15.2 %. Prevalence was significantly higher in e-CPR vs. c-CPR patients (27.9 19.7–36.6 vs. 8.3 6.5–10.4 %;
p
< 0.0001). The overall rate of organ donation among brain dead patients was 41.8 20.2–51.0 % (9/26 studies, 1264 patients; range 0–100 %). The QOE was very low for both outcomes.
Conclusions
In patients with hypoxic-ischaemic brain injury following CPR, more than 10 % of deaths were due to brain death. More than 40 % of brain-dead patients could donate organs. Patients who are unconscious after resuscitation from cardiac arrest, especially when resuscitated using e-CPR, should be carefully screened for signs of brain death.
Functionally favorable survival remains low after out-of-hospital cardiac arrest. When initial interventions fail to achieve the return of spontaneous circulation, they are repeated with little ...incremental benefit. Patients without rapid return of spontaneous circulation do not typically survive with good functional outcome. Novel approaches to out-of-hospital cardiac arrest have yielded functionally favorable survival in patients for whom traditional measures had failed, but the optimal transition point from traditional measures to novel therapies is ill defined. Our objective was to estimate the dynamic probability of survival and functional recovery as a function of resuscitation effort duration to identify this transition point.
Retrospective cohort study of a cardiac arrest database at a single site. We included 1014 adult (≥18 years) patients experiencing nontraumatic out-of-hospital cardiac arrest between 2005 and 2011, defined as receiving cardiopulmonary resuscitation or defibrillation from a professional provider. We stratified by functional outcome at hospital discharge (modified Rankin scale). Survival to hospital discharge was 11%, but only 6% had a modified Rankin scale of 0 to 3. Within 16.1 minutes of cardiopulmonary resuscitation, 89.7% (95% confidence interval, 80.3%-95.8%) of patients with good functional outcome had achieved return of spontaneous circulation, and the probability of good functional recovery fell to 1%. Adjusting for prehospital and inpatient covariates, cardiopulmonary resuscitation duration (minutes) is independently associated with favorable functional status at hospital discharge (odds ratio, 0.84; 95% confidence interval, 0.72-0.98; P=0.02).
The probability of survival to hospital discharge with a modified Rankin scale of 0 to 3 declines rapidly with each minute of cardiopulmonary resuscitation. Novel strategies should be tested early after cardiac arrest rather than after the complete failure of traditional measures.
Antiarrhythmic drugs are used commonly in out-of-hospital cardiac arrest for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, but without proven survival benefit.
In ...this randomized, double-blind trial, we compared parenteral amiodarone, lidocaine, and saline placebo, along with standard care, in adults who had nontraumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia after at least one shock, and vascular access. Paramedics enrolled patients at 10 North American sites. The primary outcome was survival to hospital discharge; the secondary outcome was favorable neurologic function at discharge. The per-protocol (primary analysis) population included all randomly assigned participants who met eligibility criteria and received any dose of a trial drug and whose initial cardiac-arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia was refractory to shock.
In the per-protocol population, 3026 patients were randomly assigned to amiodarone (974), lidocaine (993), or placebo (1059); of those, 24.4%, 23.7%, and 21.0%, respectively, survived to hospital discharge. The difference in survival rate for amiodarone versus placebo was 3.2 percentage points (95% confidence interval CI, -0.4 to 7.0; P=0.08); for lidocaine versus placebo, 2.6 percentage points (95% CI, -1.0 to 6.3; P=0.16); and for amiodarone versus lidocaine, 0.7 percentage points (95% CI, -3.2 to 4.7; P=0.70). Neurologic outcome at discharge was similar in the three groups. There was heterogeneity of treatment effect with respect to whether the arrest was witnessed (P=0.05); active drugs were associated with a survival rate that was significantly higher than the rate with placebo among patients with bystander-witnessed arrest but not among those with unwitnessed arrest. More amiodarone recipients required temporary cardiac pacing than did recipients of lidocaine or placebo.
Overall, neither amiodarone nor lidocaine resulted in a significantly higher rate of survival or favorable neurologic outcome than the rate with placebo among patients with out-of-hospital cardiac arrest due to initial shock-refractory ventricular fibrillation or pulseless ventricular tachycardia. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT01401647.).
Managing temperature is an important part of post-cardiac arrest care. Fever or hyperthermia during the first few days after cardiac arrest is associated with worse outcomes in many studies. Clinical ...data have not determined any target temperature or duration of temperature management that clearly improves patient outcomes. Current guidelines and recent reviews recommend controlling temperature to prevent hyperthermia. Higher temperatures can lead to secondary brain injury by increasing seizures, brain edema and metabolic demand. Some data suggest that targeting temperature below normal could benefit select patients where this pathology is common. Clinical temperature management should address the physiology of heat balance. Core temperature reflects the heat content of the head and torso, and changes in core temperature result from changes in the balance of heat production and heat loss. Clinical management of patients after cardiac arrest should include measurement of core temperature at accurate sites and monitoring signs of heat production including shivering. Multiple methods can increase or decrease heat loss, including external and internal devices. Heat loss can trigger compensatory reflexes that increase stress and metabolic demand. Therefore, any active temperature management should include specific pharmacotherapy or other interventions to control thermogenesis, especially shivering. More research is required to determine whether individualized temperature management can improve outcomes.
Cardiac arrest systems of care are successfully coordinating community, emergency medical services, and hospital efforts to improve the process of care for patients who have had a cardiac arrest. As ...a result, the number of people surviving sudden cardiac arrest is increasing. However, physical, cognitive, and emotional effects of surviving cardiac arrest may linger for months or years. Systematic recommendations stop short of addressing partnerships needed to care for patients and caregivers after medical stabilization. This document expands the cardiac arrest resuscitation system of care to include patients, caregivers, and rehabilitative healthcare partnerships, which are central to cardiac arrest survivorship.
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