Cardiac Arrest

photo

Ona Wu, PhD FAHA

Associate Professor of Radiology, Harvard Medical School
Associate Neuroscientist, Massachusetts General Hospital
Director of Clinical Computational Neuroimaging, Athinoula A. Martinos Center for Biomedical Imaging, Dept of Radiology, Massachusetts General Hospital
The research goals of Dr. Wu’s group are to improve the diagnosis, prognosis and management of patients with brain injury by quantifying and monitoring... Read more about Ona Wu, PhD FAHA
p: 617-643-3873
Greer DM, Yang J, Scripko PD, Sims JR, Cash S, Kilbride R, Wu O, Hafler JP, Schoenfeld DA, Furie KL. Clinical examination for outcome prediction in nontraumatic coma. Crit Care Med 2012;40(4):1150-6.Abstract
OBJECTIVES: Determine the utility of the neurologic examination in comatose patients from nontraumatic causes in the modern era. DESIGN: Prospective observational study. SETTING: Single academic medical center. PATIENTS: Data from 500 patients in nontraumatic coma collected sequentially from 2000 to 2007 in the emergency department and neuroscience, medical, and cardiac intensive care units. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical data were collected on days 0, 1, 3, and 7. Outcome was assessed at 6 months; good outcome was determined at two levels by modified Rankin Scale, ≤3 as independence and ≤4 as moderate but not severe disability. A classification and regression tree analysis was performed to determine prognostic variables, creating predictive algorithms of good vs. poor outcome for each day. Patients with coma attributable to subarachnoid hemorrhage (4/80; 5%) or global hypoxic-ischemic injury (20/202, 10%) were more likely to achieve good outcomes. The pupillary reflex was an important determinant, regardless of day or modified Rankin Scale cut point (mean odds ratio 12.51, range [6.01, 22.56] for modified Rankin Scale ≤3; mean odds ratio 19.26, range [5.38, 42.26] for modified Rankin Scale ≤4). A less robust effect was seen for oculocephalic reflexes (mean odds ratio 62.61, range [2.24, 177] for modified Rankin Scale ≤3; mean odds ratio 34.13, range [4.95, 89.93] for modified Rankin Scale ≤4). The motor response was selected as a predictor of outcome only on day 0 (odds ratio 2.35, 95% confidence interval 0.64-5.74 for modified Rankin Scale ≤3; odds ratio 2.1, 95% confidence interval 0.81-4.24 for modified Rankin Scale score ≤4). Age was not associated with outcome. CONCLUSIONS: The clinical neurologic examination remains central to determining prognosis in nontraumatic coma. Additional clinical and diagnostic variables may also aid in outcome prediction for specific disease states.
Wu O, Sorensen GA, Benner T, Singhal AB, Furie KL, Greer DM. Comatose patients with cardiac arrest: predicting clinical outcome with diffusion-weighted MR imaging. Radiology 2009;252(1):173-81.Abstract
PURPOSE: To examine whether the severity and spatial distribution of reductions in apparent diffusion coefficient (ADC) are associated with clinical outcomes in patients who become comatose after cardiac arrest. MATERIALS AND METHODS: This was an institutional review board-approved, HIPAA-compliant retrospective study of 80 comatose patients with cardiac arrest who underwent diffusion-weighted magnetic resonance imaging. The need to obtain informed consent was waived except when follow-up phone calls were required; in those cases, informed consent was obtained from the families. Mean patient age was 57 years +/- 16 (standard deviation); 31 (39%) patients were women. ADC maps were semiautomatically segmented into the following regions: subcortical white matter; cerebellum; insula; frontal, occipital, parietal, and temporal lobes; caudate nucleus; putamen; and thalamus. Median ADCs were measured in these regions and in the whole brain and were compared (with a two-tailed Wilcoxon test) as a function of clinical outcome. Outcome was defined by both early eye opening in the 1st week after arrest (either spontaneously or in response to external stimuli) and 6-month modified Rankin scale score. RESULTS: Whole-brain median ADC was a significant predictor of poor outcome as measured by no eye opening (specificity, 100% [95% confidence interval {CI}: 86%, 100%]; sensitivity, 30% [95% CI: 18%, 45%]) or 6-month modified Rankin scale score greater than 3 (specificity, 100% [95% CI: 73%, 100%]; sensitivity, 41% [95% CI: 29%, 54%]), with patients with poor outcomes having significantly lower ADCs for both outcome measures (P
Greer DM, Rosenthal ES, Wu O. Neuroprognostication of hypoxic-ischaemic coma in the therapeutic hypothermia era. Nat Rev Neurol 2014;10(4):190-203.Abstract
Neurological prognostication after cardiac arrest has always been challenging, and has become even more so since the advent of therapeutic hypothermia (TH) in the early 2000s. Studies in this field are prone to substantial biases--most importantly, the self-fulfilling prophecy of early withdrawal of life-sustaining therapies--and physicians must be aware of these limitations when evaluating individual patients. TH mandates sedation and prolongs drug metabolism, and delayed neuronal recovery is possible after cardiac arrest with or without hypothermia treatment; thus, the clinician must allow an adequate observation period to assess for delayed recovery. Exciting advances have been made in clinical evaluation, electrophysiology, chemical biomarkers and neuroimaging, providing insights into the underlying pathophysiological mechanisms of injury, as well as prognosis. Some clinical features, such as pupillary reactivity, continue to provide robust information about prognosis, and EEG patterns, such as reactivity and continuity, seem promising as prognostic indicators. Evoked potential information is likely to remain a reliable prognostic tool in TH-treated patients, whereas traditional serum biomarkers, such as neuron-specific enolase, may be less reliable. Advanced neuroimaging techniques, particularly those utilizing MRI, hold great promise for the future. Clinicians should continue to use all the available tools to provide accurate prognostic advice to patients after cardiac arrest.
Greer DM, Yang J, Scripko PD, Sims JR, Cash S, Wu O, Hafler JP, Schoenfeld DA, Furie KL. Clinical examination for prognostication in comatose cardiac arrest patients. Resuscitation 2013;84(11):1546-51.Abstract
OBJECTIVE: To build new algorithms for prognostication of comatose cardiac arrest patients using clinical examination, and investigate whether therapeutic hypothermia influences the value of the clinical examination. METHODS: From 2000 to 2007, 500 consecutive patients in non-traumatic coma were prospectively enrolled, 200 of whom were post-cardiac arrest. Outcome was determined by modified Rankin Scale (mRS) score at 6 months, with mRS≤3 indicating good outcome. The clinical examination was performed on days 0, 1, 3 and 7 post-arrest, and clinical variables analyzed for importance in prognostication of outcome. A classification and regression tree analysis (CART) was used to develop a predictive algorithm. RESULTS: Good outcome was achieved in 9.9% of patients. In CART analysis, motor response was often chosen as a root node, and spontaneous eye movements, pupillary reflexes, eye opening and corneal reflexes were often chosen as splitting nodes. Over 8% of patients with absent or extensor motor response on day 3 achieved a good outcome, as did 2 patients with myoclonic status epilepticus. The odds of achieving a good outcome were lower in patients who suffered asystole (OR 0.187, 95% CI: 0.039-0.875, p=0.033) compared with ventricular fibrillation or non-perfusing ventricular tachycardia, but some still achieved good outcome. The absence of pupillary and corneal reflexes on day 3 remained highly reliable for predicting poor outcome, regardless of therapeutic hypothermia utilization. CONCLUSION: The clinical examination remains central to prognostication in comatose cardiac arrest patients in the modern area. Future studies should incorporate the clinical examination along with modern technology for accurate prognostication.
Greer DM, Scripko PD, Wu O, Edlow BL, Bartscher J, Sims JR, Camargo EEC, Singhal AB, Furie KL. Hippocampal magnetic resonance imaging abnormalities in cardiac arrest are associated with poor outcome. J Stroke Cerebrovasc Dis 2013;22(7):899-905.Abstract
BACKGROUND: The role of neuroimaging in assessing prognosis in comatose cardiac survivors appears promising, but little is known regarding the import of particular spatial patterns. We report a specific spatial imaging abnormality on magnetic resonance imaging (MRI) that portends a poor prognosis: bilateral hippocampal hyperintensities on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences. METHODS: Eighty sequential comatose cardiac arrest patients underwent MRI scans. Qualitative and quantitative regional analyses were performed. Patients were categorized as HIPPO(+) (n = 18) or HIPPO(-) (n = 62) based on whether they had bilateral hippocampal hyperintensities. Poor outcome was defined by a modified Rankin Scale (mRS) score ≥4 at 6 months. RESULTS: Patients with bilateral hippocampal abnormalities had a higher frequency of poor outcome (P = .032). HIPPO(+) patients suffered more severe cerebral injury, with lower whole brain apparent diffusion coefficient values (P = .043) and a greater number of affected regions on DWI (P = .001) and FLAIR (P = .001) than HIPPO(-) patients. The hippocampal approach was 100% specific for a poor prognosis; only 1 patient survived and remained in a vegetative state. CONCLUSIONS: Bilateral hippocampal hyperintensities on MRI may be a specific imaging finding that is indicative of poor prognosis in patients who suffer global hypoxic-ischemic injury. More research on the prognostic significance of this and similar neuroimaging patterns is indicated.
Wu O, Batista LM, Lima FO, Vangel MG, Furie KL, Greer DM. Predicting clinical outcome in comatose cardiac arrest patients using early noncontrast computed tomography. Stroke 2011;42(4):985-92.Abstract
BACKGROUND AND PURPOSE: Early assessment of the likelihood of neurological recovery in comatose cardiac arrest survivors remains challenging. We hypothesize that quantitative noncontrast computed tomography (NCCT) combined with neurological assessments, are predictive of outcome. METHODS: We analyzed data sets acquired from comatose cardiac arrest patients who underwent CT within 72 hours of arrest. Images were semiautomatically segmented into anatomic regions. Median Hounsfield units (HU) were measured regionally and in the whole brain (WB). Outcome was based on the 6-month modified Rankin Scale (mRS) score. Logistic regression was used to combine Glasgow Coma Scale (GCS) score measured on Day 3 post arrest (GCS_Day3) with imaging to predict poor outcome (mRS>4). RESULTS: WB HU (P=0.02) and the ratio of HU in the putamen to the posterior limb of the internal capsule (PLIC) (P=0.004) from 175 datasets from 151 patients were univariate predictors of poor outcome. Thirty-three patients underwent hypothermia treatment. Multivariate analysis showed that combining median HU in the putamen (P=0.0006) and PLIC (P=0.007) was predictive of poor outcome. Combining WB HU and GCS_Day3 resulted in 72% [61% to 80%] sensitivity and 100% [73% to 100%] specificity for predicting poor outcome in 86 patients with measurable GCS_Day3. This was an improvement over prognostic performance based on GCS_Day3≤8 (98% sensitive but 71% specific). DISCUSSION: Combining density changes on CT with GCS_Day3 may be useful for predicting poor outcome in comatose cardiac arrest patients who are neither rapidly improving nor deteriorating. Improved prognostication with CT compared with neurological assessments can be achieved in patients treated with hypothermia.
Hirsch KG, Mlynash M, Eyngorn I, Pirsaheli R, Okada A, Komshian S, Chen C, Mayer SA, Meschia JF, Bernstein RA, Wu O, Greer DM, Wijman CA, Albers GW. Multi-Center Study of Diffusion-Weighted Imaging in Coma After Cardiac Arrest. Neurocrit Care 2016;24(1):82-9.Abstract
BACKGROUND: The ability to predict outcomes in acutely comatose cardiac arrest survivors is limited. Brain diffusion-weighted magnetic resonance imaging (DWI MRI) has been shown in initial studies to be a simple and effective prognostic tool. This study aimed to determine the predictive value of previously defined DWI MRI thresholds in a multi-center cohort. METHODS: DWI MRIs of comatose post-cardiac arrest patients were analyzed in this multi-center retrospective observational study. Poor outcome was defined as failure to regain consciousness within 14 days and/or death during the hospitalization. The apparent diffusion coefficient (ADC) value of each brain voxel was determined. ADC thresholds and brain volumes below each threshold were analyzed for their correlation with outcome. RESULTS: 125 patients were included in the analysis. 33 patients (26%) had a good outcome. An ADC value of less than 650 × 10(-6) mm(2)/s in ≥10% of brain volume was highly specific [91% (95% CI 75-98)] and had a good sensitivity [72% (95% CI 61-80)] for predicting poor outcome. This threshold remained an independent predictor of poor outcome in multivariable analysis (p = 0.002). An ADC value of less than 650 × 10(-6) mm(2)/s in >22% of brain volume was needed to achieve 100% specificity for poor outcome. CONCLUSIONS: In patients who remain comatose after cardiac arrest, quantitative DWI MRI findings correlate with early recovery of consciousness. A DWI MRI threshold of 650 × 10(-6) mm(2)/s in ≥10% of brain volume can differentiate patients with good versus poor outcome, though in this patient population the threshold was not 100% specific for poor outcome.
Kamps MJA, Horn J, Oddo M, Fugate JE, Storm C, Cronberg T, Wijman CA, Wu O, Binnekade JM, Hoedemaekers CWE. Prognostication of neurologic outcome in cardiac arrest patients after mild therapeutic hypothermia: a meta-analysis of the current literature. Intensive Care Med 2013;39(10):1671-82.Abstract
PURPOSE: To assess the sensitivity and false positive rate (FPR) of neurological examination and somatosensory evoked potentials (SSEPs) to predict poor outcome in adult patients treated with therapeutic hypothermia after cardiopulmonary resuscitation (CPR). METHODS: MEDLINE and EMBASE were searched for cohort studies describing the association of clinical neurological examination or SSEPs after return of spontaneous circulation with neurological outcome. Poor outcome was defined as severe disability, vegetative state and death. Sensitivity and FPR were determined. RESULTS: A total of 1,153 patients from ten studies were included. The FPR of a bilaterally absent cortical N20 response of the SSEP could be calculated from nine studies including 492 patients. The SSEP had an FPR of 0.007 (confidence interval, CI, 0.001-0.047) to predict poor outcome. The Glasgow coma score (GCS) motor response was assessed in 811 patients from nine studies. A GCS motor score of 1-2 at 72 h had a high FPR of 0.21 (CI 0.08-0.43). Corneal reflex and pupillary reactivity at 72 h after the arrest were available in 429 and 566 patients, respectively. Bilaterally absent corneal reflexes had an FPR of 0.02 (CI 0.002-0.13). Bilaterally absent pupillary reflexes had an FPR of 0.004 (CI 0.001-0.03). CONCLUSIONS: At 72 h after the arrest the motor response to painful stimuli and the corneal reflexes are not a reliable tool for the early prediction of poor outcome in patients treated with hypothermia. The reliability of the pupillary response to light and the SSEP is comparable to that in patients not treated with hypothermia.
Greer DM, Wu O. Neuroimaging in Cardiac Arrest Prognostication. Semin Neurol 2017;37(1):66-74.Abstract
Neuroimaging is commonly utilized in the evaluation of post-cardiac arrest patients, providing a unique ability to visualize and quantify structural brain injury that can complement clinical and electrophysiologic data. Despite its lack of validation, we would advocate that neuroimaging is a valuable prognostication tool, worthy of further study, and an essential part of the armamentarium when used in combination with other modalities in the assessment of the post-cardiac arrest patient. Herein, we discuss the data and its limitations for neuroimaging to date and how it is being studied prospectively. We present current guidelines recommendations for prognostication after global hypoxic-ischemic injury, focusing primarily on computed tomography (CT) and magnetic resonance imaging (MRI), as they are the most widely used modalities. We present promising results from advanced neuroimaging techniques, and provide practical advice for the clinician caring for these patients in the real world.