The Utility of Therapeutic Hypothermia for Post-Cardiac Arrest Syndrome Patients With an Initial Nonshockable Rhythm

Temperature Control in Acute Brain Injury: An Update

Temperature control in severe acute brain injury (SABI) is a key component of acute management. This manuscript delves into the complex role of temperature management in SABI, encompassing conditions like traumatic brain injury (TBI), acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), aneurysmal subarachnoid hemorrhage (aSAH), and hypoxemic/ischemic brain injury following cardiac arrest. Fever is a common complication in SABI and is linked to worse neurological outcomes due to increased inflammatory responses and intracranial pressure (ICP). Temperature management, particularly hypothermic temperature control (HTC), appears to mitigate these adverse effects primarily by reducing cerebral metabolic demand and dampening inflammatory pathways. However, the effectiveness of HTC varies across different SABI conditions. In the context of post-cardiac arrest, the impact of HTC on neurological outcomes has shown inconsistent results. In cases of TBI, HTC seems promising for reducing ICP, but its influence on long-term outcomes remains uncertain. For AIS, clinical trials have yet to conclusively demonstrate the benefits of HTC, despite encouraging preclinical evidence. This variability in efficacy is also observed in ICH, aSAH, bacterial meningitis, and status epilepticus. In pediatric and neonatal populations, while HTC shows significant benefits in hypoxic-ischemic encephalopathy, its effectiveness in other brain injuries is mixed. Although the theoretical basis for employing temperature control, especially HTC, is strong, the clinical outcomes differ among various SABI subtypes. The current consensus indicates that fever prevention is beneficial across the board, but the application and effectiveness of HTC are more nuanced, underscoring the need for further research to establish optimal temperature management strategies. Here we provide an overview of the clinical evidence surrounding the use of temperature control in various types of SABI.

Targeted Temperature Management After Out-of-Hospital Cardiac Arrest: Integrating Evidence Into Real World Practice

Targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA) has been a focus of debate in an attempt to improve post-arrest outcomes. Contemporary trials examining the role of TTM after cardiac arrest suggest that targeting normothermia should be the standard of care for initially comatose survivors of cardiac arrest. Differences in patient populations have been demonstrated across trials, and important subgroups may be under-represented in clinical trials compared with real-world registries. In this review, we aimed to describe the populations represented in international OHCA registries and to propose a pathway to integrate clinical trial evidence into practice. The patient case mix among registries including survivors to hospital admission was similar to the pivotal trials (shockable rhythm, witnessed arrest), suggesting reasonable external validity. Therefore, for the majority of OHCA, targeted normothermia should be the strategy of choice. There remains conflicting evidence for patients with a nonshockable rhythm, with no clear evidence-based justification for mild hypothermia over targeted normothermia.

Temperature Control After In-Hospital Cardiac Arrest: A Randomized Clinical Trial

BACKGROUND

This study was conducted to determine the effect of hypothermic temperature control after in-hospital cardiac arrest (IHCA) on mortality and functional outcome as compared with normothermia.

METHODS

An investigator initiated, open-label, blinded-outcome-assessor, multicenter, randomized controlled trial comparing hypothermic temperature control (32-34°C) for 24 h with normothermia after IHCA in 11 hospitals in Germany. The primary endpoint was all-cause mortality after 180 days. Secondary end points included in-hospital mortality and favorable functional outcome using the Cerebral Performance Category scale after 180 days. A Cerebral Performance Category score of 1 or 2 was defined as a favorable functional outcome.

RESULTS

A total of 1055 patients were screened for eligibility and 249 patients were randomized: 126 were assigned to hypothermic temperature control and 123 to normothermia. The mean age of the cohort was 72.6±10.4 years, 64% (152 of 236) were male, 73% (166 of 227) of cardiac arrests were witnessed, 25% (57 of 231) had an initial shockable rhythm, and time to return of spontaneous circulation was 16.4±10.5 minutes. Target temperature was reached within 4.2±2.8 hours after randomization in the hypothermic group and temperature was controlled for 48 hours at 37.0°±0.9°C in the normothermia group. Mortality by day 180 was 72.5% (87 of 120) in hypothermic temperature control arm, compared with 71.2% (84 of 118) in the normothermia group (relative risk, 1.03 [95% CI, 0.79-1.40]; P=0.822). In-hospital mortality was 62.5% (75 of 120) in the hypothermic temperature control as compared with 57.6% (68 of 118) in the normothermia group (relative risk, 1.11 [95% CI, 0.86-1.46, P=0.443). Favorable functional outcome (Cerebral Performance Category 1 or 2) by day 180 was 22.5% (27 of 120) in the hypothermic temperature control, compared with 23.7% (28 of 118) in the normothermia group (relative risk, 1.04 [95% CI, 0.78-1.44]; P=0.822). The study was prematurely terminated because of futility.

CONCLUSIONS

Hypothermic temperature control as compared with normothermia did not improve survival nor functional outcome at day 180 in patients presenting with coma after IHCA. The HACA in-hospital trial (Hypothermia After Cardiac Arrest in-hospital) was underpowered and may have failed to detect clinically important differences between hypothermic temperature control and normothermia.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique Identifier: NCT00457431.

Mild hypothermia and neurologic outcomes in patients undergoing venoarterial extracorporeal membrane oxygenation

BACKGROUND

Patients with venoarterial extracorporeal membrane oxygenation (VA-ECMO) are at risk of cerebral reperfusion injury after prolonged hypoperfusion and immediate restoration of systemic blood flow. We aimed to examine the impact of mild hypothermia during the first 24 h post-ECMO on neurological outcomes in VA-ECMO patients.

METHODS

This was a retrospective study of adult VA-ECMO patients from a tertiary care center. Mild hypothermia was defined as 32-36°C during the first 24 h post-ECMO. The primary outcome was a good neurological function at discharge measured by a modified Rankin Scale ≤3. Multivariable logistic regression analysis was performed for primary outcome adjusting for pre-specified covariates.

RESULTS

Overall, 128 consecutive patients with VA-ECMO support (median age: 60 years and 63% males) were included. Within the first 24 h of VA-ECMO cannulation, we found a median of 71 readings per patient (interquartile range 45-88). Eighty-eight patients (68.8%) experienced mild hypothermia within the first 24 h while 18 of those 88 patients (14.2%) had a mean temperature <36°C. ECMO indications included post-cardiotomy shock (39.8%), cardiac arrest (29.7%), and cardiogenic shock (26.6%). Duration of mild hypothermia, but not mean temperature, was independently associated with increased odds of good neurological outcome at discharge (odds ratio [OR] = 1.16, 95% confidence interval [CI] = 1.04-1.31, p = .01) after adjusting for age, the severity of illness, post-ECMO systemic hemorrhage, post-cardiotomy shock, acute brain injury, and mean 24-h PaO2 . Neither duration of mild hypothermia (OR = 0.93, CI = 0.84-1.03, p = .17) nor mean temperature (OR = 0.78, CI = 0.29-2.08, p = .62) was significantly associated with mortality. Similarly, duration of mild hypothermia (p = .47) and mean 24-h temperature (p = .76) were not significantly associated with the frequency of systemic hemorrhages.

CONCLUSIONS

In this single-center study, a longer duration of mild hypothermia during the first 24 h of ECMO support was significantly associated with improved neurological outcomes. Mild hypothermia was not associated with an increased risk of systemic hemorrhage or improved survival.

Impact of cooling method on the outcome of initial shockable or non-shockable out of hospital cardiac arrest patients receiving target temperature management: a nationwide multicentre cohort study

Background

Little is known about the effectiveness of surface cooling (SC) and endovascular cooling (EC) on the outcome of out-of-hospital cardiac arrest (OHCA) patients receiving target temperature management (TTM) according to their initial rhythm.

Methods

We retrospectively analysed data from the Japanese Association for Acute Medicine Out‐of‐Hospital Cardiac Arrest registry, a multicentre, prospective nationwide database in Japan. For our analysis, OHCA patients aged ≥ 18 years who were treated with TTM between June 2014 and December 2017 were included. The primary outcome was 30-day survival with favourable neurological outcome defined as a Glasgow–Pittsburgh cerebral performance category score of 1 or 2. Cooling methods were divided into the following groups: SC (ice packs, fans, air blankets, and surface gel pads) and EC (endovascular catheters and any dialysis technique). We investigated the efficacy of the two categories of cooling methods in two different patient groups divided according to their initially documented rhythm at the scene (shockable or non-shockable) using multivariable logistic regression analysis and propensity score analysis with inverse probability weighting (IPW).

Results

In the final analysis, 1082 patients were included. Of these, 513 (47.4%) had an initial shockable rhythm and 569 (52.6%) had an initial non-shockable rhythm. The proportion of patients with favourable neurological outcomes in SC and EC was 59.9% vs. 58.3% (264/441 vs. 42/72), and 11.8% (58/490) vs. 21.5% (17/79) in the initial shockable patients and the initial non-shockable patients, respectively. In the multivariable logistic regression analysis, differences between the two cooling methods were not observed among the initial shockable patients (adjusted odd ratio [AOR] 1.51, 95% CI 0.76–3.03), while EC was associated with better neurological outcome among the initial non-shockable patients (AOR 2.21, 95% CI 1.19–4.11). This association was constant in propensity score analysis with IPW (OR 1.40, 95% CI 0.83–2.36; OR 1.87, 95% CI 1.01–3.47 among the initial shockable and non-shockable patients, respectively).

Conclusion

We suggested that the use of EC was associated with better neurological outcomes in OHCA patients with initial non-shockable rhythm, but not in those with initial shockable rhythm. A TTM implementation strategy based on initial rhythm may be important.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00953-y.

Factors affecting outcomes in patients with cardiac arrest who receive target temperature management: The multi-center TIMECARD registry

BACKGROUND

Target temperature management (TTM) is a recommended therapy for patients after cardiac arrest (PCA). The TaIwan Network of Targeted Temperature ManagEment for CARDiac Arrest (TIMECARD) registry was established for PCA who receive TTM therapy in Taiwan. We aim to determine the variables that may affect neurologic outcomes in PCA who undergo TTM.

METHODS

We retrieved demographic variables, resuscitation variables, and cerebral performance category (CPC) scale score at hospital discharge from the TIMECARD registry. The primary outcome was a favorable neurologic outcome, defined as a CPC scale of 1 or 2 at discharge. A total of 540 PCA treated between January 2014 and September 2019 were identified from the registry. Univariate and multivariate analyses were performed to identify significant variables.

RESULTS

The mortality rate was 58.1% (314/540). Favorable neurologic outcomes were noted in 117 patients (21.7%). The factors significantly influencing the neurologic outcome (p < 0.05) were the presence of an initial shockable rhythm or pulseless electric activity, a witnessed cardiac-arrest event, bystander cardiopulmonary resuscitation, a smaller total dose of epinephrine, the diastolic blood pressure value at return of spontaneous circulation, a pre-arrest CPC score of 1, coronary angiography, new-onset seizure, and new-onset serious infection. Older patients and those with premorbid diabetes mellitus, chronic kidney disease, malignancy, obstructive lung disease, or cerebrovascular accident were more likely to have an unfavorable neurologic outcome.

CONCLUSIONS

In the TIMECARD registry, some PCA baseline characteristics, cardiac arrest events, cardiopulmonary resuscitation characteristics, and post-arrest management characteristics were significantly associated with neurologic outcomes.

Outcome Related to Level of Targeted Temperature Management in Postcardiac Arrest Syndrome of Low, Moderate, and High Severities: A Nationwide Multicenter Prospective Registry

OBJECTIVES

The optimal target temperature during targeted temperature management for patients after cardiac arrest remains under debate. The aim of this study was to evaluate the association between targeted temperature management at lower target temperatures and the neurologic outcomes among patients classified by the severity of postcardiac arrest syndrome.

DESIGN

A multicenter observational study from the out-of-hospital cardiac arrest registry of the Japanese Association for Acute Medicine, which is a nationwide prospective registry of out-of-hospital cardiac arrest patients.

SETTING

A total of 125 critical care medical centers or hospitals with an emergency care department across Japan.

PATIENTS

A total of 1,111 out-of-hospital cardiac arrest patients who had received targeted temperature management.

MEASUREMENTS AND MAIN RESULTS

We divided all 1,111 postcardiac arrest syndrome patients treated with targeted temperature management into two groups: those who received targeted temperature management at a lower target temperature (33-34°C) and those who received targeted temperature management at a higher target temperature (35-36°C). In regard to classification of the patients, we divided the patients into three categories of severity (low, moderate, and high severities) using the risk classification tool, post-Cardiac Arrest Syndrome for Therapeutic hypothermia, which was previously validated. The primary outcome was the percentage of patients with a good neurologic outcome at 30 days, and the secondary outcome was the survival rate at 30 days. Multivariate analysis showed that targeted temperature management at 33-34°C was significantly associated with a good neurologic outcome and survival at 30 days in the moderate severity (odds ratio, 1.70 [95% CI, 1.03-2.83] and 1.90 [95% CI, 1.15-3.16], respectively), but not in the patients of low or high severity (pinteraction = 0.033). Propensity score analysis also showed that targeted temperature management at 33-34°C was associated with a good neurologic outcome in the moderate-severity group (p = 0.022).

CONCLUSIONS

Targeted temperature management at 33-34°C was associated with a significantly higher rate of a good neurologic outcome in the moderate-severity postcardiac arrest syndrome group, but not in the low- or high-severity group.

Opioid-Associated Out-of-Hospital Cardiac Arrest: Distinctive Clinical Features and Implications for Health Care and Public Responses: A Scientific Statement From the American Heart Association

Opioid overdose is the leading cause of death for Americans 25 to 64 years of age, and opioid use disorder affects >2 million Americans. The epidemiology of opioid-associated out-of-hospital cardiac arrest in the United States is changing rapidly, with exponential increases in death resulting from synthetic opioids and linear increases in heroin deaths more than offsetting modest reductions in deaths from prescription opioids. The pathophysiology of polysubstance toxidromes involving opioids, asphyxial death, and prolonged hypoxemia leading to global ischemia (cardiac arrest) differs from that of sudden cardiac arrest. People who use opioids may also develop bacteremia, central nervous system vasculitis and leukoencephalopathy, torsades de pointes, pulmonary vasculopathy, and pulmonary edema. Emergency management of opioid poisoning requires recognition by the lay public or emergency dispatchers, prompt emergency response, and effective ventilation coupled to compressions in the setting of opioid-associated out-of-hospital cardiac arrest. Effective ventilation is challenging to teach, whereas naloxone, an opioid antagonist, can be administered by emergency medical personnel, trained laypeople, and the general public with dispatcher instruction to prevent cardiac arrest. Opioid education and naloxone distributions programs have been developed to teach people who are likely to encounter a person with opioid poisoning how to administer naloxone, deliver high-quality compressions, and perform rescue breathing. Current American Heart Association recommendations call for laypeople and others who cannot reliably establish the presence of a pulse to initiate cardiopulmonary resuscitation in any individual who is unconscious and not breathing normally; if opioid overdose is suspected, naloxone should also be administered. Secondary prevention, including counseling, opioid overdose education with take-home naloxone, and medication for opioid use disorder, is important to prevent recurrent opioid overdose.

Implementation of Targeted Temperature Management After Out-of-Hospital Cardiac Arrest: Observations From the Los Angeles County Regional System

Background

Despite the benefits of targeted temperature management (TTM) for out‐of‐hospital cardiac arrest), implementation within the United States remains low. The objective of this study was to evaluate the prevalence and factors associated with TTM use in a large, urban‐suburban regional system of care.

Methods and Results

This was a retrospective analysis from the Los Angeles County regional cardiac system of care serving a population of >10 million residents. All adult patients aged ≥18 years with non‐traumatic out‐of‐hospital cardiac arrest transported to a cardiac arrest center from April 2011 to August 2017 were included. Patients awake and alert in the emergency department and patients who died in the emergency department before consideration for TTM were excluded. The primary outcome measure was prevalence of TTM use. The secondary analysis were annual trends in TTM use over the study period and factors associated with TTM use. The study population included 8072 patients; 4154 patients (51.5%) received TTM and 3767 patients (46.7%) did not receive TTM. Median age was 67 years, 4780 patients (59.2%) were men, 4645 patients (57.5%) were non‐White, and the most common arrest location was personal residence in 4841 patients (60.0%). In the adjusted analysis, younger age, male sex, an initial shockable rhythm, witnessed arrest, and receiving coronary angiography were associated with receiving TTM.

Conclusions

Within this regional system of care, use of TTM was higher than previously reported in the literature at just over 50%. Use of integrated systems of care may be a novel method to increase TTM use within the United States.

Targeted Temperature Management at 33 Versus 36 Degrees: A Retrospective Cohort Study

OBJECTIVES

To determine the association between targeted temperature management goal temperature of 33°C versus 36°C and neurologic outcome after out-of-hospital cardiac arrest.

DESIGN

This was a retrospective, before-and-after, cohort study.

SETTING

Urban, academic, level 1 trauma center from 2010 to 2017.

PATIENTS

Adults with nontraumatic out-of-hospital cardiac arrest who received targeted temperature management.

INTERVENTIONS

Our primary exposure was targeted temperature management goal temperature, which was changed from 33°C to 36°C in April of 2014 at the study hospital. Primary outcome was neurologically intact survival to discharge. Secondary outcomes included hospital mortality and care processes.

MEASUREMENTS AND MAIN RESULTS

Of 782 out-of-hospital cardiac arrest patients transported to the study hospital, 453 (58%) received targeted temperature management. Of these, 258 (57%) were treated during the 33°C period (targeted temperature management 33°C) and 195 (43%) were treated during the 36°C period (targeted temperature management 36°C). Patients treated during targeted temperature management 33°C were older (57 vs 52 yr; p < 0.05) and had more arrests of cardiac etiology (45% vs 35%; p < 0.05), but otherwise had similar baseline characteristics, including initial cardiac rhythm. A total of 40% of patients treated during targeted temperature management 33°C survived with favorable neurologic outcome, compared with 30% in the targeted temperature management 36°C group (p < 0.05). After adjustment for demographic and cardiac arrest characteristics, targeted temperature management 33°C was associated with increased odds of neurologically intact survival to discharge (odds ratio, 1.79; 95% CI, 1.09-2.94). Targeted temperature management 33°C was not associated with significantly improved hospital mortality. Targeted temperature management was implemented faster (1.9 vs 3.5 hr from 911 call; p < 0.001) and more frequently in the emergency department during the targeted temperature management 33°C period (87% vs 55%; p < 0.001).

CONCLUSIONS

Comatose, adult out-of-hospital cardiac arrest patients treated during the targeted temperature management 33°C period had higher odds of neurologically intact survival to hospital discharge compared with those treated during the targeted temperature management 36°C period. There was no significant difference in hospital mortality.

The cold truth about postcardiac arrest targeted temperature management: 33°C vs. 36°C

This article provides nurses with up-to-date evidence to empower them in contributing to the 33°C versus 36°C discussion in postcardiac arrest targeted temperature management (TTM). Presented in debate format, this article addresses the pros and cons of various target temperatures, examines the evidence around TTM, and applies it to clinical scenarios.

Therapeutic hypothermia for cardiac arrest due to non-shockable rhythm: A protocol for systematic review and meta-analysis

BACKGROUND

The effectiveness of therapeutic hypothermia (TH) for patients following cardiac arrest with non-shockable rhythm is debated. We plan to conduct a systematic review and meta-analysis with all available randomized controlled trials (RCTs) to explore the efficacy and safety of TH in in this population.

METHODS

PubMed, EMBASE and Cochrane Library will be searched to identify RCTs published from inception through December 2020 without language restriction. Patients following cardiac arrest due to non-shockable rhythm will be included. The primary outcome is the hospital mortality. The secondary outcome is the favorable neurological outcome. The pooled effects will be analyzed as mean differences using the inverse-variance method for continuous data or as risk ratios using the Mantel-Haenszel method for dichotomous data. Subgroup and sensitivity analyses will be conducted. The Egger's test and/or the funnel plot will be used to test the publication bias. The grades of recommendation assessment, development, and evaluation (GRADE) methodology will be used to assess the quality of evidence. The trial sequential analysis will be used to test whether the meta-analysis is conclusive.

RESULTS

The RCTs on the effectiveness of TH for patients following cardiac arrest with non-shockable rhythm will be systematically reviewed and advance evidence will be provided.

CONCLUSION

Advanced evidence of TH for cardiac arrest due to non-shockable rhythm will be provided for physicians.

PROSPERO REGISTRATION NUMBER

CRD42020161823.

Early Initiation of Continuous Renal Replacement Therapy Induces Fast Hypothermia and Improves Post-Cardiac Arrest Syndrome in a Porcine Model

Rapid induction of hypothermia early after resuscitation can be an effective strategy against post-cardiac arrest syndrome (PCAS). Preliminary data suggested that continuous renal replacement therapy (CRRT) might be an efficient method to rapidly induce hypothermia. In this study, we investigated the efficacy of cooling induced by CRRT and its effects on the outcomes of PCAS in a porcine model.Thirty-two male domestic pigs weighing 36 ± 2 kg were randomized into 4 groups: sham control (n = 5), normothermia (n = 9), surface cooling (SC, n = 9), and CRRT (n = 9). Sham animals underwent the surgical preparation only. The animal model was established by 8 min of untreated ventricular fibrillation and then 5 min of cardiopulmonary resuscitation. At 5 min after resuscitation, the animals were cooled by either the combination of an earlier 8-h CRRT and later 16-h SC or the whole 24-h SC in the 2 hypothermic groups. For the other 2 groups, a normal temperature of 38.0 ± 0.5°C was maintained throughout the experiment.Blood temperature was decreased to 33°C within 28 min in animals treated with CRRT, which was significantly faster than that in the SC group requiring 185 min to achieve target temperature. Post-resuscitation myocardial dysfunction, brain injury, and systemic inflammation were significantly improved in the 2 hypothermic groups compared to the normothermia group. However, the improvement was significantly greater in the CRRT group than in the SC group.In conclusion, fast hypothermia was successfully induced by CRRT and significantly alleviated the severity of PCAS in a porcine model.

Targeted temperature management in cardiac arrest patients with a non-shockable rhythm: A national perspective

INTRODUCTION

Retrospective studies have shown conflicting benefit of utilizing targeted temperature management (TTM) in cardiac arrest (CA) patients with a non-shockable rhythm and presently there is only one randomized trial in this realm. We sought to determine trends and outcomes of TTM utilization in these patients from a large nationally representative United States population database.

METHODS AND RESULTS

Data were derived from National Inpatient Sample (NIS) from January 2006 to December 2013. All patients were identified using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes. Patients with evidence of shockable rhythm (ventricular tachycardia, ventricular flutter and ventricular fibrillation) were excluded. Trends in TTM utilization and mortality were assessed over our study period. Various outcomes were measured in patients receiving TTM and no TTM in unmatched and propensity matched cohorts. Logistic regression analysis was done to determine predictors of mortality. A total of 1,185,479 CA patients were identified in whom cause of arrest was a non-shockable rhythm. Overall, there was a steady increase in TTM utilization over our study period. In propensity-matched groups, mortality was higher in patients in whom TTM was utilized compared to non-TTM group (72.9% vs 68.7%, P < .01). In adjusted analysis, TTM remains an independent predictor of increased mortality in our group. Mortality remained high with TTM utilization regardless of location of CA.

CONCLUSIONS

TTM utilization was associated with increased mortality in CA patients with a non-shockable rhythm. These findings merit further confirmation in a large randomized trial before application into clinical practice.

Induced Hypothermia in Patients with Cardiac Arrest and a Non-shockable Rhythm: Meta-analysis and Trial Sequential Analysis

BACKGROUND

Controversy surrounds utilization of induced hypothermia (IHT) in comatose cardiac arrest (CA) survivors with a non-shockable rhythm.

METHODS

We conducted a meta-analysis and trial sequential analysis (TSA) comparing IHT with no IHT approaches in patients with CA and a non-shockable rhythm. The primary outcome of interest was favorable neurological outcomes (FNO) defined using the Cerebral Performance Category (CPC) score of 1 or 2. Secondary endpoints were survival at discharge and survival beyond 90 days.

RESULTS

A total of 9 studies with 10,386 patients were included. There was no difference between both groups in terms of FNO (13% vs. 13%, RR 1.34, 95% CI 0.96-1.89, p = 0.09, I² = 88%), survival at discharge (20% vs. 22%, RR 1.09, 95% CI 0.88-1.36, p = 0.42, I² = 76%), or survival beyond 90 days (16% vs. 15%, RR 0.92, 95% CI 0.61-1.40, p = 0.69, I² = 83%). The TSA showed firm evidence supporting the lack of benefit of IHT in terms of survival at discharge. However, the Z-curves failed to cross the conventional and TSA (futility) boundaries for FNO and survival beyond 90 days, indicating lack of sufficient evidence to draw firm conclusions regarding these outcomes.

CONCLUSION

In this meta-analysis of 9 studies, the utilization of IHT was not associated with a survival benefit at discharge. Although the meta-analysis showed lack of benefit of IHT in terms of FNO and survivals beyond 90 days, the corresponding TSA showed high probability of type-II statistical error, and therefore more randomized controlled trials powered for these outcomes are needed.

Targeted Temperature Management in Cardiac Arrest Patients With an Initial Non-Shockable Rhythm: A Systematic Review and Meta-Analysis

BACKGROUND

Targeted temperature management (TTM) is now recommended for patients presenting with an out-of-hospital cardiac arrest. However, there are limited data that support its use in patients with an initial non-shockable rhythm (NSR).

METHODS

A literature search of PubMed/MEDLINE, Cochrane Library, and Embase was conducted by two independent authors for studies that compared TTM along with standard care versus standard care alone in treating cardiac arrest with initial NSR. Outcomes were short-term and long-term survival, and a Cerebral Performance Category (CPC) score of 1 to 2 at the longest follow-up period. The Mantel-Haenszel random-effects model was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Trial sequential analysis (TSA) was performed on the randomized controlled trials (RCTs).

RESULTS

Thirty studies were included in the final analysis: 25 observational and five RCTs, totalling 10,703 patients, 4,023 of whom received TTM and 6,680 received standard care alone. Compared with standard care, patients who presented with an initial NSR cardiac arrest and received TTM (target of 32°C -34°C) had a significantly higher short-term survival (OR 1.44 95% CI 1.15-1.81; P = 0.002), long-term survival (OR 1.52 95% CI 1.03-2.26; P = 0.04), and CPC score of 1 to 2 (OR 1.63 95% CI 1.22-2.17; P = 0.0010). Sensitivity analyses by including only RCTs showed a trend, although not significant, toward better short-term survival (OR 1.25 95% CI 0.82-1.89; P = 0.30), long-term survival (OR 1.15 95% CI 0.80-1.66; P = 0.46), and neurologic outcomes (OR 1.51 95% CI 0.81-2.80; P = 0.19). However, TSA performed on the RCTs revealed that the results were inconclusive.

CONCLUSION

Among patients who survived cardiac arrest with an initial NSR, TTM is associated with a higher rate of survival and favorable neurological outcomes compared with no TTM. However, analyses from the included RCTs did not support this conclusion.

Targeted Temperature Management After Cardiac Arrest: The Montreal Heart Institute Experience

Background

Targeted temperature management (TTM) has been associated with an improvement in neurological function and survival in patients with cardiac arrest (CA) and an initially shockable rhythm. We report the Montreal Heart Institute (MHI) experience using TTM to evaluate mortality and neurological outcome in patients remaining in coma after CA, regardless of the initial rhythm.

Methods

We performed a retrospective review of all patients receiving TTM at the MHI between 2008 and 2015. Primary outcome was a composite of mortality and poor neurological outcome at hospital discharge. We also evaluated the long-term outcomes of those who initially survived to hospital discharge.

Results

A total of 147 patients (120 men, mean age 59.5 ± 12.5 years) underwent TTM at the MHI during the study period. Overall survival to hospital discharge with good neurological outcome was 45.6%. Shockable rhythm was associated with a better outcome (mortality odds ratio, 0.212; 95% confidence interval, 0.068-0.664; P = 0.008). Of the 11 initial survivors with a poor neurological status (Cerebral Performance Category ≥ 3), 4 died rapidly (within 1 month of hospital discharge), but 6 (54.5%) markedly improved their neurological status to Cerebral Performance Category 1. Long-term survival (mean follow-up of 38 ± 26 months) for those alive at hospital discharge (n = 76 patients) was 81.9%.

Conclusion

Our retrospective analysis of CA survivors treated with TTM at MHI showed good survival, similar to the published results from the landmark randomized controlled trials, despite enrolling patients with nonshockable rhythms. A significant proportion of survivors with poor neurological outcome at discharge improved at follow-up.

Targeted Temperature Management for Cardiac Arrest with Nonshockable Rhythm

BACKGROUND

Moderate therapeutic hypothermia is currently recommended to improve neurologic outcomes in adults with persistent coma after resuscitated out-of-hospital cardiac arrest. However, the effectiveness of moderate therapeutic hypothermia in patients with nonshockable rhythms (asystole or pulseless electrical activity) is debated.

METHODS

We performed an open-label, randomized, controlled trial comparing moderate therapeutic hypothermia (33°C during the first 24 hours) with targeted normothermia (37°C) in patients with coma who had been admitted to the intensive care unit (ICU) after resuscitation from cardiac arrest with nonshockable rhythm. The primary outcome was survival with a favorable neurologic outcome, assessed on day 90 after randomization with the use of the Cerebral Performance Category (CPC) scale (which ranges from 1 to 5, with higher scores indicating greater disability). We defined a favorable neurologic outcome as a CPC score of 1 or 2. Outcome assessment was blinded. Mortality and safety were also assessed.

RESULTS

From January 2014 through January 2018, a total of 584 patients from 25 ICUs underwent randomization, and 581 were included in the analysis (3 patients withdrew consent). On day 90, a total of 29 of 284 patients (10.2%) in the hypothermia group were alive with a CPC score of 1 or 2, as compared with 17 of 297 (5.7%) in the normothermia group (difference, 4.5 percentage points; 95% confidence interval [CI], 0.1 to 8.9; P = 0.04). Mortality at 90 days did not differ significantly between the hypothermia group and the normothermia group (81.3% and 83.2%, respectively; difference, -1.9 percentage points; 95% CI, -8.0 to 4.3). The incidence of prespecified adverse events did not differ significantly between groups.

CONCLUSIONS

Among patients with coma who had been resuscitated from cardiac arrest with nonshockable rhythm, moderate therapeutic hypothermia at 33°C for 24 hours led to a higher percentage of patients who survived with a favorable neurologic outcome at day 90 than was observed with targeted normothermia. (Funded by the French Ministry of Health and others; HYPERION ClinicalTrials.gov number, NCT01994772.).

Protective effect of extracorporeal membrane oxygenation on intestinal mucosal injury after cardiopulmonary resuscitation in pigs

The present study aimed to explore the protective effects of extracorporeal membrane oxygenation (ECMO) on intestinal mucosal injury following cardiopulmonary resuscitation (CPR), and to assess the potential mechanisms involved. A total of 24 healthy adult domestic pigs were selected as the study subjects. A ventricular fibrillation model was induced through programmed electric stimulation. Subsequently, the animals were randomly divided into conventional CPR and CPR+ECMO groups (n=12 per group). The mortality and hemodynamic parameters of the two groups were compared. The expression levels of inflammatory cytokines in the serum and intestinal mucosa were detected by ELISAs. The intestinal mucosa was subjected to hematoxylin and eosin, and immunohistochemical staining, followed by electron microscopy, to assess the degree of apoptosis and necrosis. The animals in both groups recovered from the programmed ventricular fibrillation. In the CPR group, two animals died at 2 h and two more animals died a further 2 h later, resulting in a 33.3% mortality rate, whereas no cases of mortality were observed in the CPR+ECMO group. Compared with the animals in the CPR group, the hemodynamic parameters of the animals in the CPR+ECMO group revealed significantly improved outcomes. Multiple inflammatory factors (tumor necrosis factor α, interleukin-1 and interleukin-6), myeloperoxidase and malondialdehyde levels were decreased, whereas Na/Ca-ATPase and superoxide dismutase levels were elevated in the intestinal mucosa of animals in the CPR+ECMO group compared with those in the CPR group. Additionally, pathological staining demonstrated that the intestinal mucosa tissue in the CPR+ECMO group exhibited less apoptosis, necrosis and inflammatory cell infiltration, which was further supported by a decrease in Bax expression and an increase in Bcl-2 expression. Overall, ECMO after CPR reduced the intestinal mucosal barrier injury after spontaneous circulation recovery, and the mechanism involved decreased inflammation and apoptosis.

Early administration of cold water and adipose derived mesenchymal stem cell derived exosome effectively protects the heart from ischemia-reperfusion injury

This study tested the hypothesis that early administration with cold water (CW)-assisted adipose-derived mesenchymal stem cell (ADMSC)-derived exosome (Exo) therapy was superior to either one on protecting the heart against ischemia-reperfusion (IR) (i.e., by ligation of 50 minutes and relieved by day 5 prior to euthanizing the animals) injury. Adult-male SD rats (n=30) were equally categorized into groups 1 (sham-operated control), 2 (IR), 3 (IR + CW), 4 (IR + Exo) and 5 (IR + CW-Exo). The left ventricular ejection fraction (LVEF) was highest in group 1, lowest in group 2, and significantly higher in group 5 than in groups 3 and 4, but no difference between groups 3 and 4 (all P<0.001). The protein expressions of oxidative-stress (NOX-1/NOX-2/NOX-4/oxidized protein), apoptotic/mitochondrial-damaged (mitochondrial-Bax/caspase 3/PARP/p53/cytosolic-cytochrome-C) and inflammatory (IL-1β/TNF-α/NF-κB/MMP-9) biomarkers, and cellular-stress response signaling (PI3K/Akt/GSK3β and p-m-TOR) showed an opposite pattern, whereas the anti-oxidants (SIRT1/SIRT3), anti-inflammation (IL-10) and IKB-α/p-AMKP/mitochondrial-cytochrome-C exhibited an identical pattern to the LVEF among the five groups (all P<0.0001). The cellular expressions of inflammation (CD68), total cellular ROS (i.e., stained by H₂DCFDA) and the LV infarct/fibrotic/collagen-deposition areas displayed an opposite pattern, whereas the cell gap junction (coonexin 43) and sarcomere length exhibited an identical pattern of LVEF among the five groups (all P<0.0001). Conclusion: Combined CW-exosome therapy markedly protected the heart against IR injury.

Risk of Mortality Associated With Therapeutic Hypothermia Among Sudden Cardiac Arrest Survivors With Known Heart Failure

Current guidelines do not inform about use of therapeutic hypothermia among heart failure (HF) patients who suffer from cardiac arrest. We assessed the risk of mortality associated with hypothermia among cardiac arrest survivors with HF. This analysis includes 1,416 comatose patients with cardiac arrest who achieved return of spontaneous circulation on admission and had a left ventricular ejection fraction (LVEF) assessment or HF admission within the previous year. HF was defined as either previous episode of HF or presence of left ventricular ejection fraction <50%. Hazard ratios (HR) and 95% confidence intervals (CI) for association of hypothermia and mortality among patients with and without HF were computed using Cox proportional hazard models adjusted for several risk factors. A propensity score matched analysis was also performed. There were 624 patients (44%) with pre-existing HF and 467 patients (33.0%) received hypothermia. The mortality rate was higher in HF patients treated with hypothermia compared with patients without hypothermia (75.4% vs 53.2%, p <0.0001). Hypothermia was associated with increased mortality among HF patients (HR 1.69; 95% CI 1.27, 2.24, p <0.001) and was not associated with mortality among non-HF patients (HR 1.21; 95% CI 0.93, 1.56, p = 0.15). The association of hypothermia with mortality was higher among HF patients who presented with shockable rhythm compared with nonshockable rhythm (interaction p value = 0.0495). Hypothermia is associated with increased mortality among cardiac arrest survivors with known HF.

Sequential Targeted Temperature Management: Case Report and Literature Review

We present the case of a 59-year-old gentleman with a history of nonmetastatic tonsillar malignancy and radiation chondronecrosis, who underwent targeted temperature management (TTM) in a sequential manner. The first time the patient underwent therapeutic cooling occurred after he developed a respiratory arrest followed by a cardiac arrest and prolonged hypoxemia after a diagnostic laryngoscopy. The patient was kept at 32°C for 24 hours, and 48 hours after rewarming woke up neurologically intact. However, six hours post-extubation, he suffered upper airway obstruction, followed by a prolonged cardiac arrest. Return of spontaneous circulation on this second episode was achieved after 45 minutes of resuscitation maneuvers. The patient was cooled again and kept at 32°C for 48 hours. Five days later, the patient recovered, with an intact neurologically function. This case stands out the importance of sequential TTM after repeat cardiac arrests with a return of spontaneous circulation (ROSC), demonstrating this process as a neuroprotective way of treatment.

Targeted temperature management for cardiac arrest

Therapeutic hypothermia, or targeted temperature management (TTM), is a strategy of reducing the core body temperature of survivors of sudden cardiac arrest (SCA) to minimize neurological damage caused by severe hypoxia. Initial clinical trials examining this technique demonstrated significant improvement in neurological function among survivors of out-of-hospital SCA with an initial shockable rhythm. Since then, TTM has become an integral part of the care provided to comatose survivors of SCA. However, multiple questions persist regarding the target cooling temperature, duration of cooling, and utility of TTM in patient populations such as survivors of out-of-hospital SCA with non-shockable rhythms or in-hospital SCA. This review article summarizes the current evidence regarding optimal application of TTM and compares the recommendations for TTM in current guidelines.

Targeted Temperature Management and Postcardiac arrest Care

Despite recent advances, care of the post-cardiac arrest patient remains a challenge. In this article, the authors discuss an approach to the initial care of post-cardiac arrest patients with particular focus on targeted temperature management (TTM). The article starts with history, physiologic rationale, and the major randomized controlled trials that have shaped guidelines for post-cardiac arrest care. It also reviews controversial topics, including TTM for nonshockable rhythms, TTM dose, and surface versus endovascular cooling. The article concludes with a brief review of other key aspects of post-arrest care: coronary angiography, hemodynamic optimization, ventilator management, and prognostication.

Impact of adrenaline dose and timing on out-of-hospital cardiac arrest survival and neurological outcomes

STUDY OBJECTIVE

The 2015 ILCOR Advanced Cardiovascular Life Support Guidelines recommend intravenous adrenaline (epinephrine) as a crucial pharmacologic treatment during cardiac arrest resuscitation. Some recent observational studies and clinical trials have questioned the efficacy of its use and suggested possible deleterious effects on overall survival and long-term outcomes. This study aimed to describe the association between time and dose of adrenaline on return of spontaneous circulation (ROSC) and neurologic function.

METHODS

We performed a retrospective analysis of the Penn Alliance for Therapeutic Hypothermia (PATH) data registry. The timing of the first dose of adrenaline and the total dose of adrenaline during cardiac arrests was compared between survivors to discharge and non-survivors for arrests lasting greater than 10 min.

RESULTS

The registry contained 5594 patients. After excluding patients with an in-hospital cardiac arrest, a non-shockable rhythm, or no adrenaline administration, 1826 were included in the final analysis. Survivors to discharge received adrenaline sooner (median 5.0 vs. 7.0 min, p = 0.022) and required a lower total dose than non-survivors (2.0 vs. 3.0 mg, p < 0.001). For survivors, there was no significant association between the time to first adrenaline dose and favorable neurological outcome as measured by Cerebral Performance Category (CPC). Among survivors, those that received less than 2 mg of adrenaline had a more favorable neurologic outcome than those administered > 3 mg. (CPC 1-2 16.6% vs. 12.5%, p = 0.004).

CONCLUSION

Early adrenaline administration is associated with a higher percentage of survival to discharge but not associated with favorable neurological outcome. Those patients with a favorable neurologic outcome received a lower total adrenaline dose prior to ROSC.

Effect of cancer history on post-resuscitation treatments in out-of-hospital cardiac arrest

OBJECTIVES

There is growing evidence that optimal post-resuscitation treatment is a significant factor for overall survival and neurological outcomes in out-of-hospital cardiac arrest (OHCA). However, there is also growing evidence of disparities in treatments in vulnerable populations such as elderly individuals or patients with underlying diseases, including cancer.

AIM

The aim of this study was to evaluate the influence of cancer status on post-resuscitation therapies among OHCA patients.

MATERIAL AND METHODS

This was a cross-sectional observational study based on a nationwide prospective OHCA registry database of Korea. All adult OHCA patients with presumed cardiac etiology and sustained return of spontaneous circulation (ROSC) from 2009 to 2016 were included in this study. Main exposure was history of cancer and primary outcome was post-resuscitation care, including percutaneous coronary intervention (PCI) and targeted temperature management (TTM). Multivariable logistic regression was used to analyze the association between cancer and post-resuscitation treatments.

RESULTS

A total of 33,760 patients were included for final analysis. Multivariable logistic analysis showed that cancer patients were significantly less likely to receive PCI and TTM compared to those without history of cancer with adjusted odds ratios of 0.29 (95% CI: 0.24-0.37) and 0.66 (0.58-0.77), respectively.

CONCLUSION

The results of this study suggest that a prior history of cancer may be associated with lower probability to receive potentially beneficial post-resuscitation treatments.

Critical Care of the Post-Cardiac Arrest Patient

The post-cardiac arrest syndrome is a highly inflammatory state characterized by organ dysfunction, systemic ischemia and reperfusion injury, and persistent precipitating pathology. Early critical care should focus on identifying and treating arrest etiology and minimizing further injury to the brain and other organs by optimizing perfusion, oxygenation, ventilation, and temperature. Patients should be treated with targeted temperature management, although the exact temperature goal is not clear. No earlier than 72 hours after rewarming, prognostication using a multimodal approach should inform discussions with families regarding likely neurologic outcome.

EAST Multicenter Trial on targeted temperature management for hanging-induced cardiac arrest

BACKGROUND

We sought to determine the outcome of suicidal hanging and the impact of targeted temperature management (TTM) on hanging-induced cardiac arrest (CA) through an Eastern Association for the Surgery of Trauma (EAST) multicenter retrospective study.

METHODS

We analyzed hanging patient data and TTM variables from January 1992 to December 2015. Cerebral performance category score of 1 or 2 was considered good neurologic outcome, while cerebral performance category score of 3 or 4 was considered poor outcome. Classification and Regression Trees recursive partitioning was used to develop multivariate predictive models for survival and neurologic outcome.

RESULTS

A total of 692 hanging patients from 17 centers were analyzed for this study. Their overall survival rate was 77%, and the CA survival rate was 28.6%. The CA patients had significantly higher severity of illness and worse outcome than the non-CA patients. Of the 175 CA patients who survived to hospital admission, 81 patients (46.3%) received post-CA TTM. The unadjusted survival of TTM CA patients (24.7% vs 39.4%, p < 0.05) and good neurologic outcome (19.8% vs 37.2%, p < 0.05) were worse than non-TTM CA patients. However, when subgroup analyses were performed between those with an admission Glasgow Coma Scale score of 3 to 8, the differences between TTM and non-TTM CA survival (23.8% vs 30.0%, p = 0.37) and good neurologic outcome (18.8% vs 28.7%, p = 0.14) were not significant. Targeted temperature management implementation and post-CA management varied between the participating centers. Classification and Regression Trees models identified variables predictive of favorable and poor outcome for hanging and TTM patients with excellent accuracy.

CONCLUSION

Cardiac arrest hanging patients had worse outcome than non-CA patients. Targeted temperature management CA patients had worse unadjusted survival and neurologic outcome than non-TTM patients. These findings may be explained by their higher severity of illness, variable TTM implementation, and differences in post-CA management. Future prospective studies are necessary to ascertain the effect of TTM on hanging outcome and to validate our Classification and Regression Trees models.

LEVEL OF EVIDENCE

Therapeutic study, level IV; prognostic study, level III.

Editor's Choice-Effects of targeted temperature management on mortality and neurological outcome: A systematic review and meta-analysis

AIMS

The purpose of this study was to conduct a systematic review, and where applicable meta-analyses, examining the evidence underpinning the use of targeted temperature management following resuscitation from cardiac arrest.

METHODS AND RESULTS

Multiple databases were searched for publications between January 2000-February 2016. Nine Population, Intervention, Comparison, Outcome questions were developed and meta-analyses were performed when appropriate. Reviewers extracted study data and performed quality assessments using Grading of Recommendations, Assessment, Development and Evaluation methodology, the Cochrane Risk Bias Tool, and the National Institute of Health Study Quality Assessment Tool. The primary outcomes for each Population, Intervention, Comparison, Outcome question were mortality and poor neurological outcome. Overall, low quality evidence demonstrated that targeted temperature management at 32-36°C, compared to no targeted temperature management, decreased mortality (risk ratio 0.76, 95% confidence interval 0.61-0.92) and poor neurological outcome (risk ratio 0.73, 95% confidence interval 0.60-0.88) amongst adult survivors of out-of-hospital cardiac arrest with an initial shockable rhythm. Targeted temperature management use did not benefit survivors of in-hospital cardiac arrest nor out-of-hospital cardiac arrest survivors with a non-shockable rhythm. Moderate quality evidence demonstrated no benefit of pre-hospital targeted temperature management initiation. Low quality evidence showed no difference between endovascular versus surface cooling targeted temperature management systems, nor any benefit of adding feedback control to targeted temperature management systems. Low quality evidence suggested that targeted temperature management be maintained for 18-24 h.

CONCLUSIONS

Low quality evidence supports the in-hospital initiation and maintenance of targeted temperature management at 32-36°C amongst adult survivors of out-of-hospital cardiac arrest with an initial shockable rhythm for 18-24 h. The effects of targeted temperature management on other populations, the optimal rate and method of cooling and rewarming, and effects of fever require further study.

Intubation is not a marker for coma after in-hospital cardiac arrest: A retrospective study

INTRODUCTION

In-hospital cardiac arrest (IHCA) strikes over 200,000 people in the United States annually. Targeted temperature management (TTM) is considered beneficial in other settings, but there is no prospective data for IHCA. Recent work on TTM and IHCA found an association between TTM and worse outcome. However, the authors used intubation as a marker for coma to determine eligibility for TTM. The validity of this approach is unexplored.

METHODS

Retrospective, single center study of adult patients with IHCA occurring in an intensive care unit, intubated prior to or during the event, or immediately after ROSC. We evaluated the percentage of patients documented as comatose after arrest, defined as Glasgow Comas Score (GCS) <8 for the primary analysis. We also evaluated the difference in hospital survival in patients with GCS <8 versus ≥8. Two sensitivity analyses using different methods for defining coma using post-ROSC GCS were conducted.

RESULTS

29/102 (28%) intubated patients had a post-ROSC GCS≥8, and 22 (22%) were documented as following commands. Survival in patients with GCS≥8 vs.<8 was 62% (18/29) vs. 37% (27/73) in unadjusted analysis (p=0.02). The adjusted odds ratio for survival to hospital discharge was 3.81 (95%CI: 1.37-10.61, p=0.01). Results were similar in both sensitivity analyses.

CONCLUSIONS

Intubation prior to or during IHCA was not a valid marker of coma after ROSC. Post-ROSC mental status was associated with hospital survival, and thus could be an important confounder when conducting observational studies on the association of TTM with outcomes in this patient population.

Thermoregulate, autoregulate and ventilate: brain-directed critical care for pediatric cardiac arrest

PURPOSE OF REVIEW

Cardiac arrest in childhood is associated with a high risk for mortality and poor long-term functional outcome. This review discusses the current evidence for neuroprotective therapies and goals for postarrest care in the context of the pathophysiology of hypoxic-ischemic injury, modalities for neurologic prognostication in these children and potential future monitoring paradigms for maximizing cerebral perfusion in the postarrest period.

RECENT FINDINGS

The recent publication of the in-hospital and out-of-hospital Therapeutic Hypothermia After Cardiac Arrest trials demonstrated a lack of statistically significant benefit for the use of postarrest therapeutic hypothermia. As a result, targeted normothermic temperature management has become standard of care. Continuous electroencephalographic monitoring during the acute postarrest period provides useful additional data for neurologic prognostication, in addition to its value for detection of seizures. Ongoing research into noninvasive monitoring of cerebrovascular autoregulation has the potential to individualize blood pressure goals in the postarrest period, maximizing cerebral perfusion in these patients.

SUMMARY

Therapeutic strategies after cardiac arrest seek to maximize cerebral perfusion while mitigating the effects of secondary brain injury and loss of autoregulation. Future research into new monitoring strategies and better long-term outcome measures may allow more precise targeting of therapies to these goals.

Recent developments in the management of patients resuscitated from cardiac arrest

Cardiac arrest is the leading cause of death in Europe and the United States. Many patients who are initially resuscitated die in the hospital, and hospital survivors often have substantial neurologic dysfunction. Most cardiac arrests are caused by coronary artery disease; patients with coronary artery disease likely benefit from early coronary angiography and intervention. After resuscitation, cardiac arrest patients remain critically ill and frequently suffer cardiogenic shock and multiorgan failure. Early cardiopulmonary stabilization is important to prevent worsening organ injury. To achieve best patient outcomes, comprehensive critical care management is needed, with primary goals of stabilizing hemodynamics and preventing progressive brain injury. Targeted temperature management is frequently recommended for comatose survivors of cardiac arrest to mitigate the neurologic injury that drives outcomes. Accurate neurologic assessment is central to managing care of cardiac arrest survivors and should combine physical examination with objective neurologic testing, with the caveat that delaying neurologic prognosis is essential to avoid premature withdrawal of supportive care. A combination of clinical findings and diagnostic results should be used to estimate the likelihood of functional recovery. This review focuses on recent advances in care and specific cardiac intensive care strategies that may improve morbidity and mortality for patients after cardiac arrest.

Neurology of cardiopulmonary resuscitation

This chapter aims to provide an up-to-date review of the science and clinical practice pertaining to neurologic injury after successful cardiopulmonary resuscitation. The past two decades have seen a major shift in the science and practice of cardiopulmonary resuscitation, with a major emphasis on postresuscitation neurologic care. This chapter provides a nuanced and thoughtful historic and bench-to-bedside overview of the neurologic aspects of cardiopulmonary resuscitation. A particular emphasis is made on the anatomy and pathophysiology of hypoxic-ischemic encephalopathy, up-to-date management of survivors of cardiopulmonary resuscitation, and a careful discussion on neurologic outcome prediction. Guidance to practice evidence-based clinical care when able and thoughtful, pragmatic suggestions for care where evidence is lacking are also provided. This chapter serves as both a useful clinical guide and an updated, thorough, and state-of-the-art reference on the topic for advanced students and experienced practitioners in the field.

Utilization of palliative care services for cardiac arrest patients undergoing therapeutic hypothermia: A retrospective analysis

BACKGROUND

Palliative care (PC) services are integral to the care of patients with advanced medical illnesses. Given the significant morbidity and mortality associated with cardiac arrest, we sought to measure the use and impact of PC in the care of patients treated with therapeutic hypothermia (TH).

METHODS

We conducted a retrospective study of 317 consecutive patients undergoing TH after cardiac arrest. We compared intensive care unit (ICU) characteristics and clinical outcomes of subjects who received PC consultation (n=125) to those who did not (n=192).

RESULTS

The proportion of TH patients with PC consultations increased to greater than 60% by 2013, corresponding to our institution's expansion of PC services, development of a dedicated PC unit, and integration of this service into our published TH protocol. In the TH population, time to return of spontaneous circulation (ROSC) was associated with higher inpatient mortality (p<0.001) and placement of a PC consult (p=0.011). TH patients who received PC consultation had longer ICU stays (p=0.034), more ventilator days (p<0.001), and higher inpatient mortality (p<0.001). When these measures were analyzed cohort-wide comparing all TH patients pre- and post-2013, at which time the frequency of PC consultation had dramatically increased, there were no statistically significant differences in ICU care or outcomes.

CONCLUSION

In our population of cardiac arrest patients undergoing TH, the utilization of PC services has increased over time, particularly for those patients with high morbidity and mortality. Future randomized studies may further delineate optimal patient selection for PC consultation to better facilitate goals of care discussions and timely medical decision-making.

Magnitude of temperature elevation is associated with neurologic and survival outcomes in resuscitated cardiac arrest patients with postrewarming pyrexia

PURPOSE

Avoidance of pyrexia is recommended in resuscitation guidelines, including after treatment with targeted temperature management (TTM). Which aspects of postresuscitation pyrexia are harmful and modifiable have not been conclusively determined.

MATERIALS AND METHODS

This retrospective multicenter registry study collected serial temperatures during 72 hours postrewarming to assess the relationship between 3 aspects of pyrexia (maximum temperature, pyrexia duration, timing of first pyrexia) and neurologic outcome (primary) and survival (secondary) at hospital discharge. Adult TTM-treated patients from 13 US hospitals between 2005 and 2015 were included.

RESULTS

One hundred seventy-nine of 465 patients had at least 1 temperature greater than or equal to 38°C. Pyrexic temperatures were associated with better survival than nonpyrexic temperatures (adjusted odds ratio [aOR], 1.54; 95% confidence interval [CI], 1.00-2.35). Higher maximum temperature was associated with worse outcome (neurologic aOR, 0.30 [95% CI, 0.10-0.84]; survival aOR, 0.25 [95% CI, 0.10-0.59]) in pyrexic patients. There was no significant relationship between pyrexia duration and outcomes unless duration was calculated as hours greater than or equal to 38.8°C, when longer duration was associated with worse outcomes (neurologic aOR, 0.86 [95% CI, 0.75-1.00]; survival aOR, 0.82 [95% CI, 0.72-0.93]).

CONCLUSIONS

In postarrest TTM-treated patients, pyrexia was associated with increased survival. Patients experiencing postrewarming pyrexia had worse outcomes at higher temperatures. Longer pyrexia duration was associated with worse outcomes at higher temperatures.

Outcomes of Adult In-Hospital Cardiac Arrest Treated with Targeted Temperature Management: A Retrospective Cohort Study

Aim

Targeted temperature management (TTM) for in-hospital cardiac arrest (IHCA) is given different recommendation levels within international resuscitation guidelines. We aimed to identify whether TTM would be associated with favourable outcomes following IHCA and to determine which factors would influence the decision to implement TTM.

Methods

We conducted a retrospective observational study in a single medical centre. We included adult patients suffering IHCA between 2006 and 2014. We used multivariable logistic regression analysis to evaluate associations between independent variables and outcomes.

Results

We included a total of 678 patients in our analysis; only 22 (3.2%) patients received TTM. Most (81.1%) patients met at least one exclusion criteria for TTM. In all, 144 (21.2%) patients survived to hospital discharge; among them, 60 (8.8%) patients displayed favourable neurological status at discharge. TTM use was significantly associated with favourable neurological outcome (OR: 3.74, 95% confidence interval [CI]: 1.19–11.00; p-value = 0.02), but it was not associated with survival (OR: 1.41, 95% CI: 0.54–3.66; p-value = 0.48). Arrest in the emergency department was positively associated with TTM use (OR: 22.48, 95% CI: 8.40–67.64; p value < 0.001) and having vasopressors in place at the time of arrest was inversely associated with TTM use (OR: 0.08, 95% CI: 0.004–0.42; p-value = 0.02).

Conclusion

TTM might be associated with favourable neurological outcome of IHCA patients, irrespective of arrest rhythms. The prevalence of proposed exclusion criteria for TTM was high among IHCA patients, but these factors did not influence the use of TTM in clinical practice or neurological outcomes after IHCA.

The Role of Targeted Temperature Management in Adult Patients Resuscitated from Nonshockable Cardiac Arrests: An Updated Systematic Review and Meta-Analysis

Routine targeted temperature management is recommended for comatose adult patients with return of spontaneous circulation after cardiac arrest. However, the role of targeted temperature management in patients resuscitated from nonshockable cardiac arrests remains uncertain. We conducted an updated systematic review and meta-analysis to evaluate the effects of targeted temperature management in this population. Medline, EMBASE, and Cochrane databases were systematically reviewed for studies published between January 2005 and March 2016, in which targeted temperature management was compared with standard care or normothermia for adult patients resuscitated from nonshockable cardiac arrests. A total of 25 trials that included 5715 patients were identified from 10985 relevant papers. Pooled data showed that targeted temperature management not only associated with improved short-term survival (RR = 1.42, 95% CI: 1.28-1.57) and neurological function (RR = 1.63, 95% CI: 1.39-1.91) but also associated with improved long-term survival (RR = 1.64, 95% CI: 1.27-2.12) and neurological recovery (RR = 1.42, 95% CI: 1.07-1.90) in observational cohort studies. However, more frequent infectious complications were reported in hypothermia-treated patients (RR = 1.46, 95% CI: 1.26-1.70) and the quality of the evidence ranged from moderate to very low.

Association Between Therapeutic Hypothermia and Survival After In-Hospital Cardiac Arrest

IMPORTANCE

Therapeutic hypothermia is used for patients following both out-of-hospital and in-hospital cardiac arrest. However, randomized trials on its efficacy for the in-hospital setting do not exist, and comparative effectiveness data are limited.

OBJECTIVE

To evaluate the association between therapeutic hypothermia and survival after in-hospital cardiac arrest.

DESIGN, SETTING, AND PATIENTS

In this cohort study, within the national Get With the Guidelines-Resuscitation registry, 26 183 patients successfully resuscitated from an in-hospital cardiac arrest between March 1, 2002, and December 31, 2014, and either treated or not treated with hypothermia at 355 US hospitals were identified. Follow-up ended February 4, 2015.

EXPOSURE

Induction of therapeutic hypothermia.

MAIN OUTCOMES AND MEASURES

The primary outcome was survival to hospital discharge. The secondary outcome was favorable neurological survival, defined as a Cerebral Performance Category score of 1 or 2 (ie, without severe neurological disability). Comparisons were performed using a matched propensity score analysis and examined for all cardiac arrests and separately for nonshockable (asystole and pulseless electrical activity) and shockable (ventricular fibrillation and pulseless ventricular tachycardia) cardiac arrests.

RESULTS

Overall, 1568 of 26 183 patients with in-hospital cardiac arrest (6.0%) were treated with therapeutic hypothermia; 1524 of these patients (mean [SD] age, 61.6 [16.2] years; 58.5% male) were matched by propensity score to 3714 non-hypothermia-treated patients (mean [SD] age, 62.2 [17.5] years; 57.1% male). After adjustment, therapeutic hypothermia was associated with lower in-hospital survival (27.4% vs 29.2%; relative risk [RR], 0.88 [95% CI, 0.80 to 0.97]; risk difference, -3.6% [95% CI, -6.3% to -0.9%]; P = .01), and this association was similar (interaction P = .74) for nonshockable cardiac arrest rhythms (22.2% vs 24.5%; RR, 0.87 [95% CI, 0.76 to 0.99]; risk difference, -3.2% [95% CI, -6.2% to -0.3%]) and shockable cardiac arrest rhythms (41.3% vs 44.1%; RR, 0.90 [95% CI, 0.77 to 1.05]; risk difference, -4.6% [95% CI, -10.9% to 1.7%]). Therapeutic hypothermia was also associated with lower rates of favorable neurological survival for the overall cohort (hypothermia-treated group, 17.0% [246 of 1443 patients]; non-hypothermia-treated group, 20.5% [725 of 3529 patients]; RR, 0.79 [95% CI, 0.69 to 0.90]; risk difference, -4.4% [95% CI, -6.8% to -2.0%]; P < .001) and for both rhythm types (interaction P = .88).

CONCLUSIONS AND RELEVANCE

Among patients with in-hospital cardiac arrest, use of therapeutic hypothermia compared with usual care was associated with a lower likelihood of survival to hospital discharge and a lower likelihood of favorable neurological survival. These observational findings warrant a randomized clinical trial to assess efficacy of therapeutic hypothermia for in-hospital cardiac arrest.

Glibenclamide Is Comparable to Target Temperature Management in Improving Survival and Neurological Outcome After Asphyxial Cardiac Arrest in Rats

Background

We previously have shown that glibenclamide (GBC), a sulfonylurea receptor 1–transient receptor potential M4 (SUR1‐TRPM4) channel inhibitor, improves survival and neurological outcome after asphyxial cardiac arrest and cardiopulmonary resuscitation (ACA/CPR). Here, we further compare the efficacy of GBC with target temperature management (TTM) and determine whether the efficacy of GBC is affected by TTM.

Methods and Results

Male Sprague‐Dawley rats (n=213) subjected to 10‐minute ACA/CPR were randomized to 4 groups after return of spontaneous circulation (ROSC): normothermia control (NT); GBC; TTM; and TTM+GBC. Survival, neurodeficit scores, histological injury, as well as the expressions of SUR1 and TRPM4 were evaluated. The 7‐day survival rate was 34.4% (11 of 32) in the NT group, 65% (13 of 20) in the GBC group, 50% (10 of 20) in the TTM group, and 70% (14 of 20) in the TTM+GBC group. Rats that received either GBC, TTM alone, or in combination showed less neurological deficit than NT control at 24, 48, and 72 hours and 7 days after ROSC. Moreover, TTM or GBC ameliorated neuronal degeneration and glial activation in the hippocampal CA1 region with similar efficacy, whereas the combination of them had a trend toward better effect. The subunits of SUR1‐TRPM4 heterodimers were both strongly upregulated after ACA/CPR and expressed in multiple types of brain cells, but partly suppressed by TTM.

Conclusions

GBC is comparable to TTM in improving survival and neurological outcome after ACA/CPR. When GBC is given along with TTM, less histological injury tended to be achieved.

Therapeutic hypothermia impacts leukocyte kinetics after cardiac arrest

BACKGROUND

Patients admitted to the hospital after primarily successful cardiopulmonary resuscitation (CPR) are at a very high risk for neurologic deficits and death. Targeted temperature management (TTM) for mild therapeutic hypothermia has been shown to improve survival compared to standard treatment. Acute cardiovascular events, such as myocardial infarction (MI), are a major cause for cardiac arrest (CA) in patients who undergo CPR. Recent findings have demonstrated the importance and impact of the leukocyte response following acute MI.

METHODS

In this retrospective, single center study we enrolled 169 patients with CA due to non-traumatic causes and primarily successful CPR. A total of 111 subjects (66%) underwent TTM aiming for a target temperature of 32-34 °C.

RESULTS

Analysis of 30 day follow up showed a significantly improved survival of all patients who received TTM compared to patients without hypothermia (P=0.0001). Furthermore TTM was an independent variable of good neurological outcome after 6 months (P=0.0030). Therapeutic hypothermia was found to be beneficial independent of differences in age and sex between both groups. While a higher rate of pneumonia was observed with TTM, this diagnosis had no additional impact on survival or neurological outcome. The beneficial effect on mortality remained significant in patients with the diagnosis of an acute cardiac event (P=0.0145). Next, we evaluated the kinetics of leukocytes in this group over the course of 7 days after CA. At presentation, patients showed a mean level of 16.5±6.7 of leukocytes per microliter. While this level stayed stable in the group of patients without hypothermia, patients who received TTM showed a significant decline of leukocyte levels resulting in significantly lower numbers of leukocytes on days 3 and 5 after CPR. Interestingly, these differences in leukocyte counts remained beyond the time period of TTM while C-reactive protein (CRP) levels were suppressed only during ongoing cooling, but differences between the groups were diminished after TTM was terminated (from day 3 on, P>0.2). Finally, patients who received TTM and showed a leukocyte count of less than 12.7/µL on day 3 had an improved survival (P=0.0214) and neurological outcome (P=0.0049) compared to patients above that level.

CONCLUSIONS

Our data underline the beneficial effects of TTM and demonstrate an impact of hypothermia on leukocyte counts after CA.