Comatose Post-cardiac Arrest Patients Research Articles

Potassium disorders at intensive care unit admission and functional outcomes after cardiac arrest

BackgroundAbnormal serum potassium levels are commonly found in the intensive care unit (ICU) population. We aimed to determine the prevalence of potassium disorders at ICU admission and its association with functional outcomes in comatose patients resuscitated from cardiac arrest. MethodsWe performed a post hoc analysis of pooled data from four randomised clinical trials involving comatose post-cardiac arrest patients admitted to ICU after return of spontaneous circulation (ROSC). Reference serum potassium levels were defined as between 3.0 and 4.9 mmol/L. An unfavourable functional outcome was defined as a cerebral performance category of 3 to 5 at 180 days. We compared potassium disturbances categorically in a mixed effects logistic regression model including initial rhythm, delay from collapse to return of spontaneous circulation, bystander cardiopulmonary resuscitation, lactate and urea at ICU admission, with normokalaemia set as the reference group. ResultsWe included 1133 patients (557 from the HYPERION, 346 from the TTH48, 120 from the COMACARE, and 110 from the Xe-HYPOTHECA trials) with a median age of 64 years (interquartile range 55–72) and a predominance of males (72 %); a total of 712 (64 %) patients had unfavourable functional outcomes. On admission, 221 patients (19.5 %) experienced hyperkalaemia and 35 (3.1 %) patients experienced hypokalaemia. Fewer patients in the normokalaemia group (513/877, 58.5 %) had an unfavourable functional outcome compared to the hypokalaemia (24/35, 68.6 %) and hyperkalaemia groups (180/221, 81.4 %; p < 0.001). Hyperkalaemia was associated with higher odds for an unfavourable functional outcome (adjusted odds ratio (OR) 1.85, 95 % confidence interval (CI) 1.10–3.12, p = 0.02), while hypokalaemia was not (OR 1.36 95 % CI 0.51–3.60, p = 0.53). The associations were not significant in a subgroup analysis adjusted for the modified cardiac arrest hospital prognosis score in 833 patients (OR 1.74, 95 % CI 0.91–3.34, p = 0.10 for hyperkalaemia and OR 1.48, 95 % CI 0.40–5.44, p = 0.55 for hypokalaemia). ConclusionsOf the comatose patients admitted to ICU after cardiac arrest, one in five experienced a potassium disorder on ICU admission. Hyperkalaemia was associated with unfavourable functional outcomes at 180 days, while hypokalaemia was not.

Abstract Su907: Post-Cardiac Arrest Potassium Abnormalities Associated With Unfavorable Functional Outcome

Background: Abnormal potassium levels are common findings in the intensive care unit (ICU) population. We aimed to determine the incidence of dyskalemias at ICU admission and their association with functional outcome in comatose patients resuscitated from cardiac arrest. Hypothesis: We hypothesized that both hypokalemia and hyperkalemia are associated with unfavorable functional outcome. Methods: Pooled data from four randomized clinical trials in comatose post-cardiac arrest patients admitted to ICU after return of spontaneous circulation (ROSC). Reference potassium levels were defined as between 3 and 4.9 mmol/L, as proposed in the Simplified Acute Physiology Score II. Favorable functional outcome was defined as a Cerebral Performance Category of 1 or 2 at 180 days. Results: We included 1133 patients (557 from HYPERION, 346 from TTH48, 120 from COMACARE and 110 from Xe-HYPOTHECA) with a median age of 64 (IQR: 55-72) years and a predominance of males (72%). Overall, 421 (36%) patients had favorable functional outcome. On admission, 221 (19.5%) patients experienced hyperkalemia and 35 (3.1%) patients experienced hypokalemia. More patients in the normokalemia group (364/877, 41.5%) had a favorable functional outcome, as compared to the hypokalemia (11/35, 31.4%) and hyperkalemia (41/221, 18.6%) groups p&lt;0.001). In a mixed-effects logistic regression model including initial rhythm, delay from collapse to ROSC, bystander cardiopulmonary resuscitation, lactate, and urea and with normokalemia as reference group, hyperkalemia was associated with higher odds for unfavorable functional outcome (OR 1.85, 95% CI 1.10-3.12, p=0.02) whereas hypokalemia was not (OR 1.36 95% CI 0.51-3.60, p=0.53). Conclusions: One fifth of unconscious cardiac arrest patients experienced dyskalemia on ICU admission. Hyperkalemia was associated with unfavorable functional outcome at 180 days compared to normokalemia, whereas hypokalemia was not an independent predictor of outcome.

Quantitative pupillometry for neuroprognostication in comatose post-cardiac arrest patients: A protocol for a predefined sub-study of the Blood pressure and Oxygenations Targets after Out-of-Hospital Cardiac Arrest (BOX)-trial

BackgroundResuscitation guidelines propose a multimodal prognostication strategy algorithm at ≥72 hours after the return of spontaneous circulation to evaluate neurological outcome for unconscious cardiac arrest survivors. Even though guidelines suggest quantitative pupillometry for assessing pupillary light reflex, threshold values are not yet validated.This study aims to validate pre-specified thresholds of quantitative pupillometry by quantitatively assessing the percentage reduction of pupillary size (qPLR) <4% and Neurological Pupil index (NPi) ≤2 and in predicting unfavorable neurological outcome. Both as an isolated predictor and combined with guideline-suggested neuron-specific enolase (NSE) threshold >60 μg L−1 in the current prognostication strategy algorithm. MethodsWe conduct this pre-planned diagnostic sub-study in the randomized, controlled, multicenter clinical trial “Blood Pressure and Oxygenation Targets after Out-of-Hospital Cardiac Arrest-trial”. Blinded to treating physicians and outcome assessors, measurements of qPLR and NPi are obtained from cardiac arrest survivors at time points (±6 hours) of admission, after 24, 48, and 72 hours, or until the time of awakening or death. DiscussionThis study will be the largest prospective study investigating the predictive performance of automated quantitative pupillometry in unconscious patients resuscitated from cardiac arrest. We will test specific threshold values of NPi ≤2 and qPLR <4% to predict unfavorable outcome following cardiac arrest. The validation of pupillometry alone and combined with NSE with the criteria of the current prognostication strategy algorithm will hopefully increase the level of evidence and support clinical neuroprognostication with automated quantitative pupillometry in unconscious post-cardiac arrest patients. Trial registrationRegistered March 30, 2017, at ClinicalTrials.gov (Identifier: NCT03141099).

Myoclonus in comatose patients with electrographic status epilepticus after cardiac arrest: Corresponding EEG patterns, effects of treatment and outcomes

ObjectiveTo clarify the significance of any form of myoclonus in comatose patients after cardiac arrest with rhythmic and periodic EEG patterns (RPPs) by analyzing associations between myoclonus and EEG pattern, response to anti-seizure medication and neurological outcome. DesignPost hoc analysis of the prospective randomized Treatment of ELectroencephalographic STatus Epilepticus After Cardiopulmonary Resuscitation (TELSTAR) trial. SettingEleven ICUs in the Netherlands and Belgium. PatientsOne hundred and fifty-seven adult comatose post-cardiac arrest patients with RPPs on continuous EEG monitoring. InterventionsAnti-seizure medication vs no anti-seizure medication in addition to standard care. Measurements and Main ResultsOf 157 patients, 98 (63%) had myoclonus at inclusion. Myoclonus was not associated with one specific RPP type. However, myoclonus was associated with a smaller probability of a continuous EEG background pattern (48% in patients with vs 75% without myoclonus, odds ratio (OR) 0.31; 95% confidence interval (CI) 0.16–0.64) and earlier onset of RPPs (24% vs 9% within 24 hours after cardiac arrest, OR 3.86;95% CI 1.64–9.11). Myoclonus was associated with poor outcome at three months, but not invariably so (poor neurological outcome in 96% vs 82%, p = 0.004). Anti-seizure medication did not improve outcome, regardless of myoclonus presence (6% good outcome in the intervention group vs 2% in the control group, OR 0.33; 95% CI 0.03–3.32). ConclusionsMyoclonus in comatose patients after cardiac arrest with RPPs is associated with poor outcome and discontinuous or suppressed EEG. However, presence of myoclonus does not interact with the effects of anti-seizure medication and cannot predict a poor outcome without false positives.

Temperature control after cardiac arrest: friend or foe.

Most patients who are successfully resuscitated after cardiac arrest are initially comatose and require mechanical ventilation and other organ support in an ICU. Best practice has been to cool these patients and control their temperature at a constant value in the range of 32-36 oC for at least 24 h. But the certainty of the evidence for this practice is increasingly being challenged. This review will summarize the evidence on key aspects of temperature control in comatose postcardiac arrest patients. The Targeted Temperature Management 2 (TTM-2) trial documented no difference in 6-month mortality among comatose postcardiac arrest patients managed at 33 oC vs. targeted normothermia. A systematic review and meta-analysis completed by the Advanced Life Support (ALS) Task Force of the International Liaison Committee on Resuscitation (ILCOR) concluded that temperature control with a target of 32-34 °C did not improve survival or favourable functional outcome after cardiac arrest. Two observational studies have documented an association between predicted moderate hypoxic-ischaemic brain injury and better outcome with temperature control at 33-34 oC compared with 35-36 oC. We suggest actively preventing fever by targeting a temperature 37.5 oC or less for those patients who remain comatose following return of spontaneous circulation (ROSC) after cardiac arrest.

Targeted temperature management after out of hospital cardiac arrest: quo vadis?

Targeted temperature management (TTM) has become a cornerstone in the treatment of comatose post-cardiac arrest patients over the last two decades. Belief in the efficacy of this intervention for improving neurologically intact survival was based on two trials from 2002, one truly randomized-controlled and one small quasi-randomized trial, without clear confirmation of that finding. Subsequent large randomized trials reported no difference in outcomes between TTM at 33 vs. 36°C and no benefit of TTM at 33°C as compared with fever control alone. Given that these results may help shape post-cardiac arrest patient care, we sought to review the history and rationale as well as trial evidence for TTM, critically review the TTM2 trial, and highlight gaps in knowledge and research needs for the future. Finally, we provide contemporary guidance for the use of TTM in daily clinical practice.

Effects of targeted temperature management at 33 °C vs. 36 °C on comatose patients after cardiac arrest stratified by the severity of encephalopathy

ObjectivesTo assess neurological outcome after targeted temperature management (TTM) at 33 °C vs. 36 °C, stratified by the severity of encephalopathy based on EEG-patterns at 12 and 24 h. DesignPost hoc analysis of prospective cohort study. SettingFive Dutch Intensive Care units. Patients479 adult comatose post-cardiac arrest patients. InterventionsTTM at 33 °C (n = 270) or 36 °C (n = 209) and continuous EEG monitoring. Measurements and main resultsOutcome according to the cerebral performance category (CPC) score at 6 months post-cardiac arrest was similar after 33 °C and 36 °C. However, when stratified by the severity of encephalopathy based on EEG-patterns at 12 and 24 h after cardiac arrest, the proportion of good outcome (CPC 1–2) in patients with moderate encephalopathy was significantly larger after TTM at 33 °C (66% vs. 45%; Odds Ratios 2.38, 95% CI = 1.32–4.30; p = 0.004). In contrast, with mild encephalopathy, there was no statistically significant difference in the proportion of patients with good outcome between 33 °C and 36 °C (88% vs. 81%; OR 1.68, 95% CI = 0.65–4.38; p = 0.282). Ordinal regression analysis showed a shift towards higher CPC scores when treated with TTM 33 °C as compared with 36 °C in moderate encephalopathy (cOR 2.39; 95% CI = 1.40–4.08; p = 0.001), but not in mild encephalopathy (cOR 0.81 95% CI = 0.41–1.59; p = 0.537). Adjustment for initial cardiac rhythm and cause of arrest did not change this relationship. ConclusionsEffects of TTM probably depend on the severity of encephalopathy in comatose patients after cardiac arrest. These results support inclusion of predefined subgroup analyses based on EEG measures of the severity of encephalopathy in future clinical trials.

Therapeutic Hypothermia Is Associated With a Decrease in All-cause Mortality in Cardiac Arrest Due to Shockable Rhythm.

The benefits of therapeutic hypothermia (TH) in comatose patients postcardiac arrest remain uncertain. While some studies have shown benefit, others have shown equivocal results. We pooled data from randomized controlled trials to better study the outcomes of TH. Electronic research databases were queried up till September 21, 2021. Randomized controlled trials comparing TH (32-34 °C) with control (normothermia or temperature ≥36 °C) in comatose postcardiac arrest patients were included. The study included 10 randomized controlled trials with 3988 subjects (1999 in the TH arm and 1989 in the control arm). There was no difference in all-cause mortality between TH and control (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.66-1.05; P = 0.08; I2 = 41%). There was no difference in the odds of poor neurological outcomes (OR, 0.78; 95% CI, 0.61-1.01; P = 0.07; I2 = 43%). Subgroup analysis showed a decrease in all-cause mortality and poor neurological outcomes with TH in shockable rhythms (OR, 0.55; 95% CI, 0.37-0.80; P = 1.00; I2 = 0% and OR, 0.48; 95% CI, 0.32-0.72; P = 0.92; I2 = 0%, respectively). TH may be beneficial in reducing mortality and poor neurological outcomes in comatose postcardiac arrest patients with shockable rhythms.

Abstract 13082: Region-Specific Diffusion-Weighted Imaging Predicts Neurological Outcome in Comatose Post-Cardiac Arrest Patients

Introduction &amp; Hypothesis: Diffusion-weighted imaging (DWI), a technique sensitive to acute brain ischemia, may hold utility in predicting neurological outcome in comatose post-cardiac arrest patients. Outcome studies are biased by early withdrawal of life sustaining therapy (WLST), leading to a self-fulfilling prophecy. This creates a need to reassess the use of DWI as a neuroprognostic tool in patients who have not undergone WLST. We hypothesize that DWI abnormalities is a robust predictor of poor neurological outcome in our WLST - controlled cohort. Methods: We leveraged the MOCHA database, a registry of over 300 comatose post-cardiac arrest patients, to retrospectively examine neurological outcomes in a cohort of patients who did not undergo WLST. A good outcome was defined by a cerebral performance category (CPC) score at discharge of 1 - 3, while a poor outcome CPC 4 - 5 (n=43). We first examined the relationship between the number of brain regions with DWI abnormalities and CPC score using a linear regression. We then examined how DWI abnormalities in specific brain regions correlated with CPC score outcome groups using a fisher exact test. DWI abnormalities were qualitatively determined by two vascular neurologists. Results: We found a positive correlation between the number of brain regions with DWI abnormalities and CPC score ( linear regression , R 2 =0.572, p=2.670x10 -9 ). Interestingly, the association between DWI abnormalities and CPC score exhibited brain region-specific variability. DWI abnormalities exhibited the strongest association with poor neurological outcome in the occipital lobe ( fisher exact test , p=7.413x10 -10 ), parietal lobe (p=9.125x10 -9 ), frontal lobe (p=5.385x10 -9 ), temporal lobe (p=3.904x10 -8 ) and basal ganglia (p=2.342x10 -7 ); and the weakest association in the white matter (p=1.000) and brain stem (p=6.612x10 -2 ). Conclusion: Our preliminary results suggest that the region of ischemia is an important factor to consider in predicting neurological outcome. This warrants a larger scale WLST-controlled study examining region-specific DWI abnormalities and neurological outcome - the findings of which would improve our neuroprognostication capabilities in comatose post-cardiac arrest patients.

Differences in the gray-to-white matter ratio according to different computed tomography scanners for outcome prediction in post-cardiac arrest patients receiving target temperature management.

The gray-to-white matter ratio (GWR) has been used to identify brain damage in comatose patients after cardiac arrest. However, Hounsfield units (HUs), the measurement of brain density on computed tomography (CT) images, may vary depending on the machine type or parameter. Therefore, differences in CT scanners may affect the GWR in post-cardiac arrest patients. We performed a retrospective study on comatose post-cardiac arrest patients who visited the hospital from 2007 to 2017. Two CT, Lightspeed and SOMATOM, scanners were used. Two observers independently measured the HUs of the caudate nucleus, putamen, posterior internal capsule, and corpus callosum using regions of interest. We compared the GWR calculated from the HUs measured at different CT scanners. The analysis of different scanners showed statistically significant differences in the measured HUs and GWR. The HUs and GWR of Lightspeed were measured lower than SOMATOM. The difference between the two CT scanners was also evident in groups divided by neurological prognosis. The area under the curve of the receiver operating characteristic curve to predict poor outcomes of Lightspeed was 0.798, and the cut-off value for 100% specificity was 1.172. The SOMATOM was 0.855, and the cut-off value was 1.269. The difference in scanners affects measurements and performance characteristics of the GWR in post-cardiac arrest patients. Therefore, when applying the results of the GWR study to clinical practice, reference values for each device should be presented, and an integrated plan should be prepared.

Postresuscitation care and prognostication.

Most patients who are successfully resuscitated after cardiac arrest are initially comatose and require mechanical ventilation and other organ support in an ICU. Knowledge about the optimal strategy for treating these patients is evolving rapidly. This review will summarize the evidence on key aspects of postarrest care and prognostication, with a focus on actionable parameters that may impact patient survival and neurologic outcomes. Optimal targets for arterial blood oxygen and carbon dioxide in comatose postcardiac arrest patients remain uncertain. Observational data are conflicting and the few randomized controlled trials to date have failed to show that different ranges of blood oxygen and carbon dioxide values impact on biomarkers of neurological injury. The Targeted Temperature Management 2 (TTM-2) trial has documented no difference in 6-month mortality among comatose postcardiac arrest patients managed at 33 oC versus controlled normothermia. An extensive systematic review of the evidence on prognostication of outcome among comatose postcardiac arrest patients underpins new prognostication guidelines. Clinical guidelines for postresuscitation care have recently been updated and incorporate all the available science supporting the treatment of postcardiac arrests. At a minimum, fever should be strictly avoided in comatose postcardiac patients. Prognostication must involve multiple modalities and should not be attempted until assessment confounders have been sufficiently excluded.

Intra-burst Theta During Burst-suppression Pattern in Comatose Post-cardiac Arrest Patients Correlates with Outcome; a Prospective Study (1316)

Intra-burst Theta During Burst-suppression Pattern in Comatose Post-cardiac Arrest Patients Correlates with Outcome; a Prospective Study (1316)

Somatosensory Evoked Potentials and Neuroprognostication After Cardiac Arrest.

Improved understanding of post-cardiac arrest syndrome and clinical practices such as targeted temperature management have led to improved mortality in this cohort. Attention has now been placed on development of tools to aid in predicting functional outcome in comatose cardiac arrest survivors. Current practice uses a multimodal approach including physical examination, neuroimaging, and electrophysiologic data, with a primary utility in predicting poor functional outcome. These modalities remain confounded by self-fulfilling prophecy and the withdrawal of life-sustaining therapies. To date, a reliable measure to predict good functional outcome has not been established or validated, but the use of quantitative somatosensory evoked potential (SSEP) shows potential for this use. MEDLINE and EMBASE search using words "Cardiac Arrest" and "SSEP," "Somato sensory evoked potentials," "qSSEP," "quantitative SSEP," "targeted temperature management in cardiac arrest" was conducted. Relevant recent studies on targeted temperature management in cardiac arrest, plus studies on SSEP in cardiac arrest in the setting of hypothermia and without hypothermia, were included. In addition, animal studies evaluating the role of different components of SSEP in cardiac arrest were reviewed. SSEP is a specific indicator of poor outcomes in post-cardiac arrest patients but lacks sensitivity and has not clinically been established to foresee good outcomes. Novel methods of analyzing quantitative SSEP (qSSEP) signals have shown potential to predict good outcomes in animal and human studies. In addition, qSSEP has potential to track cerebral recovery and guide treatment strategy in post-cardiac arrest patients. Lying beyond the current clinical practice of dichotomized absent/present N20 peaks, qSSEP has the potential to emerge as one of the earliest predictors of good outcome in comatose post-cardiac arrest patients. Validation of qSSEP markers in prospective studies to predict good and poor outcomes in the cardiac arrest population in the setting of hypothermia could advance care in cardiac arrest. It has the prospect to guide allocation of health care resources and reduce self-fulfilling prophecy.

Hydrogen gas inhalation alleviates oxidative stress in patients with post-cardiac arrest syndrome.

Oxidative stress plays a key role in the pathophysiology of post-cardiac arrest syndrome. Molecular hydrogen reduces oxidative stress and exerts anti-inflammatory effects in an animal model of cardiac arrest. However, its effect on human post-cardiac arrest syndrome is unclear. We consecutively enrolled five comatose post-cardiac arrest patients (three males; mean age, 65 ± 15 years; four cardiogenic, one septic cardiac arrest) and evaluated temporal changes in oxidative stress markers and cytokines with inhaled hydrogen. All patients were treated with target temperature management. Hydrogen gas inhalation (2% hydrogen with titrated oxygen) was initiated upon admission for 18 h. Blood hydrogen concentrations, plasma and urine oxidative stress markers (derivatives of reactive oxygen metabolites, biological antioxidant potential, 8-hydroxy-2'-deoxyguanosine, Nɛ-hexanoyl-lysine, lipid hydroperoxide), and cytokines (interleukin-6 and tumor necrosis factor-α) were measured before and 3, 9, 18, and 24 h after hydrogen gas inhalation. Arterial hydrogen concentration was measurable and it was equilibrated with inhaled hydrogen. Oxidative stress was reduced and cytokine levels were unchanged in cardiogenic patients, whereas oxidative stress was unchanged and cytokine levels were diminished in the septic patient. The effect of inhaled hydrogen on oxidative stress and cytokines in comatose post-cardiac arrest patients remains indefinite because of methodological weaknesses.

Sinus Bradycardia During Targeted Temperature Management: A Systematic Review and Meta-Analysis.

The beneficial effect of sinus bradycardia during targeted temperature management (TTM) in cardiac arrest patients remains doubtful. We aimed to investigate the impact of sinus bradycardia on survival and neurological outcome. MEDLINE (PubMed), Cochrane, Google Scholar, and ClinicalTrials.gov databases were searched for studies reporting on comatose postcardiac arrest patients presenting sinus bradycardia during TTM. Outcomes were the 180-day survival and final neurologic function assessed by the Cerebral Performance Category scale. The effect size on study outcomes is presented as odds ratio (OR) with 95% confidence interval (CI). Two studies with 681 patients were included. Compared to no-sinus bradycardia group, in patients with sinus bradycardia below 50 bpm, a significant effect of sinus bradycardia on reduction of 180-day mortality was reported (OR = 0.42; 95% CI: 0.29-0.59). No heterogeneity was detected. Sinus bradycardia below 50 bpm during TTM may be protective and should be considered in comatose postcardiac arrest patients.

Evoked potentials improve multimodal prognostication after cardiac arrest

AimPredicting recovery in comatose post-cardiac arrest patients requires multiple modalities of prognostic assessment. In isolation, absent N20 cortical responses in somatosensory evoked potentials (SSEPs) are a specific predictor of poor outcome. It is unknown whether SSEP results, when assessed in the context of prior knowledge (demographic and clinical information), change the pretest predicted probability of recovery. MethodsIn a single center retrospective study, a cohort of 323 patients admitted to post-cardiac arrest service at a tertiary care center were classified into a group based on SSEP testing. We built adjusted logistic regression models including clinical examination findings on the day SSEPs were recorded to generate a pre-test outcome probability for awakening, withdrawal of life-sustaining therapy (WLST) and survival to discharge. We then added the upper extremity N20 cortical response results to the model to obtain updated outcome probabilities. ROC curve was used to determine the additive effect of using SSEPs to the model. Survival to discharge, awakening, and WLST due to neurological reasons were designated as primary, secondary and tertiary outcomes, respectively. ResultsAnalyses showed that evoked potentials are ordered in sicker patients. Adding SSEP to the model increased the proportion of patients with less than 1% and 5% chance of survival, as well as the proportion of patients with over 95% chance of WLST. AUC for survival increased from 0.85 to 0.93 when SSEP was included (p = 0.006). ConclusionAdding the N20 SSEP response results to prior knowledge changed the predicted probability of WLST and survival to discharge in comatose post-arrest patients.

Spectral Content of Electroencephalographic Burst-Suppression Patterns May Reflect Neuronal Recovery in Comatose Post-Cardiac Arrest Patients.

To assess the potential biologic significance of variations in burst-suppression patterns (BSPs) after cardiac arrest in relation to recovery of consciousness. In the context of recent theoretical models of BSP, bursting frequency may be representative of underlying network dynamics; discontinuous activation of membrane potential during impaired cellular energetics may promote neuronal rescue. We reviewed a database of 73 comatose post-cardiac arrest patients who underwent therapeutic hypothermia to assess for the presence of BSP and clinical outcomes. In a subsample of patients with BSP (n = 14), spectral content of burst and suppression periods were quantified using multitaper method. Burst-suppression pattern was seen in 45/73 (61%) patients. Comparable numbers of patients with (31.1%) and without (35.7%) BSP regained consciousness by the time of hospital discharge. In addition, in two unique cases, BSP initially resolved and then spontaneously reemerged after completion of therapeutic hypothermia and cessation of sedative medications. Both patients recovered consciousness. Spectral analysis of bursts in all patients regaining consciousness (n = 6) showed a prominent theta frequency (5-7 Hz) feature, but not in age-matched patients with induced BSP who did not recover consciousness (n = 8). The prognostic implications of BSP after hypoxic brain injury may vary based on the intrinsic properties of the underlying brain state itself. The presence of theta activity within bursts may index potential viability of neuronal networks underlying recovery of consciousness; emergence of spontaneous BSP in some cases may indicate an innate neuroprotective mechanism. This study highlights the need for better characterization of various BSP patterns after cardiac arrest.

Preliminary experience with point-of-care EEG in post-cardiac arrest patients

ObjectiveAbnormal electroencephalography (EEG) patterns are common after resuscitation from cardiac arrest and have clinical and prognostic importance. Bedside continuous EEGs are not available in many institutions. We tested the feasibility of using a point-of-care system for EEG acquisition. MethodsWe prospectively enrolled a convenience sample of post-cardiac arrest patients between 9/2015–1/2017. Upon hospital arrival, a limited EEG montage was applied. We tested both continuous EEG (cEEG) and this point-of-care EEG (eEEG). A board-certified epileptologist and a board-certified neurointensivist jointly reviewed all EEGs. Cohen’s kappa coefficient evaluated agreement between eEEG and cEEG and Fisher’s exact test evaluated their associations with survival to hospital discharge and proximate cause of death. ResultsWe studied 95 comatose post-cardiac arrest patients. Mean age was 59 (SD17) years. Most (61%) were male, few (N = 22; 23%) demonstrated shockable rhythms, and PCAC IV illness severity was present in 58 (61%). eEEG was interpretable in 57 (60%) subjects. The most common eEEG interpretations were: continuous (21%), generalized suppression (14%), burst-suppression (12%) and burst-suppression with identical bursts (10%). Seizures were detected in 2 eEEG subjects (2%). No patient with seizure or burst-suppression with identical bursts survived. cEEG demonstrated generalized suppression (31%), burst-suppression with identical bursts (27%), continuous (18%) and seizure (4%). The eEEG and cEEG demonstrated fair agreement (kappa = 0.27). Neither eEEG nor cEEG was associated with survival (p = 0.19; p = 0.11) or proximate cause of death (p = 0.14; p = 0.8) ConclusionseEEG is feasible, although artifact often precludes interpretation. eEEG is fairly associated with cEEG and may facilitate post-cardiac arrest care.

Comparison of three haemodynamic monitoring methods in comatose post cardiac arrest patients*

Objectives. Haemodynamic monitoring during post arrest care is important to optimise treatment. We compared stroke volume measured by minimally-invasive monitoring devices with or without thermodilution calibration, and transthoracic echocardiography (TTE), and hypothesised that thermodilution calibration would give stroke volume index (SVI) more in agreement with TTE during targeted temperature management (TTM). Design. Comatose out-of-hospital cardiac arrest survivors receiving TTM (33 °C for 24 hrs) underwent haemodynamic monitoring with arterial pulse contour analyses with (PiCCO2®) and without (FloTrac®/Vigileo® monitor®) transpulmonary thermodilution calibration. Haemodynamic parameters were collected simultaneously every fourth hour during TTM (hypothermia) and (normothermia). SVI was measured with TTE during hypothermia and normothermia. Bland-Altman analyses were used for determination of SVI bias (±1SD). Results. Twenty-six patients were included, of whom 77% had initial shockable rhythm and 52% discharged with good outcome. SVI (bias ±2SD) between PiCCO (after thermodilution calibration) vs FloTrac/Vigileo, TTE vs FloTrac/Vigileo and TTE vs PiCCO were 1.4 (±25.8), −1.9 (±19.8), 0.06 (±18.5) ml/m2 during hypothermia and 9.7 (±23.9), 1.0 (±17.4), −7.2 (±12.8) ml/m2 during normothermia. Continuous SVI measurements between PiCCO and FloTrac/Vigileo during hypothermia at reduced SVI (<35 ml/m2) revealed low bias and relatively narrow limits of agreement (0.5 ± 10.2 ml/m2). Conclusion. We found low bias, but relatively wide limits of agreement in SV with PiCCO, FloTrac/Vigileo and TTE during TTM treatment. The methods are not interchangeable. Precision was not improved by transpulmonary thermodilution calibration during hypothermia.

Effect of target temperature management at 32–34 °C in cardiac arrest patients considering assessment by regional cerebral oxygen saturation: A multicenter retrospective cohort study

AimTarget temperature management (TTM) is used in comatose post-cardiac arrest patients, but the recommended temperature range is wide. This study aimed to assess the effectiveness of TTM at 32–34 °C while considering the degree of cerebral injury and cerebral circulation, as assessed by regional cerebral oxygen saturation (rSO2). MethodsThis is a secondary analysis of prospectively collected registry data from comatose patients who were transferred to 15 hospitals in Japan after out-of-hospital cardiac arrest (OHCA) from 2011 to 2013. The primary outcome was all-cause mortality at 90 days after OHCA, and the secondary outcome was favorable neurological outcomes as evaluated according to the Cerebral Performance Category. We monitored rSO2 noninvasively with near-infrared spectroscopy, which could assess cerebral perfusion and the balance of oxygen delivery and uptake. ResultsWe stratified 431 study patients into three groups according to rSO2 on hospital arrival: rSO2 ≤40% (n = 296), rSO2 41–60% (n = 67), and rSO2 ≥61% (n = 68). Propensity score analysis revealed that TTM at 32–34 °C decreased all-cause mortality in patients with rSO2 41–60% (average treatment effect on treated [ATT] by propensity score matching [PSM] −0.51, 95%CI −0.70 to −0.33; ATT by inverse probability of treatment weighting [IPW] −0.52, 95%CI −0.71 to −0.34), and increased favorable neurological outcomes in patients with rSO2 41–60% (ATT by PSM 0.50, 95%CI 0.32–0.68; ATT by IPW 0.52, 95%CI 0.35–0.69). ConclusionTTM at 32–34 °C effectively decreased all-cause mortality in comatose OHCA patients with rSO2 41–60% on hospital arrival in Japan.