Therapeutic hypothermia is associated with improved neurologic outcome and survival in cardiac arrest survivors of non-shockable rhythms

Survival and Neurologic Outcomes From Pharmacologic Peptide Administration During Cardiopulmonary Resuscitation of Pulseless Electrical Activity

BACKGROUND

Outcomes from cardiopulmonary resuscitation (CPR) following sudden cardiac arrest are suboptimal. Postresuscitation targeted temperature management has been shown to have benefit in subjects with sudden cardiac arrest due to ventricular fibrillation, but there are few data for outcomes from sudden cardiac arrest due to pulseless electrical activity. In addition, intra-CPR cooling is more effective than postresuscitation cooling. Physical cooling is associated with increased protein kinase B activity. Therefore, our group developed a novel peptide, TAT-PHLPP9c, which regulates protein kinase B. We hypothesized that when given during CPR, TAT-PHLPP9c would improve survival and neurologic outcomes following pulseless electrical activity arrest.

METHODS AND RESULTS

In 24 female pigs, pulseless electrical activity was induced by inflating balloon catheters in the right coronary and left anterior descending arteries for ≈7 minutes. Advanced life support was initiated. In 12 control animals, epinephrine was given after 1 and 3 minutes. In 12 peptide-treated animals, 7.5 mg/kg TAT-PHLPP9c was also administered at 1 and 3 minutes of CPR. The balloons were removed after 2 minutes of support. Animals were recovered and neurologically scored 24 hours after return of spontaneous circulation. Return of spontaneous circulation was more common in the peptide group, but this difference was not significant (8/12 control versus 12/12 peptide; P=0.093), while fully intact neurologic survival was significantly more common in the peptide group (0/12 control versus 11/12 peptide; P<0.00001). TAT-PHLPP9c significantly increased myocardial nicotinamide adenine dinucleotide levels.

CONCLUSIONS

TAT-PHLPP9c resulted in improved survival with full neurologic function after sudden cardiac arrest in a swine model of pulseless electrical activity, and the peptide shows potential as an intra-CPR pharmacologic agent.

Targeted Temperature Management in Cardiac Arrest: An Updated Narrative Review

The established benefits of cooling along with development of sophisticated methods to safely and precisely induce, maintain, monitor, and reverse hypothermia have led to the development of targeted temperature management (TTM). Early trials in human subjects showed that hypothermia conferred better neurological outcomes when compared to normothermia among survivors of cardiac arrest, leading to guidelines recommending targeted hypothermia in this patient population. Multiple studies have sought to explore and compare the benefit of hypothermia in various subgroups of patients, such as survivors of out-of-hospital cardiac arrest versus in-hospital cardiac arrest, and survivors of an initial shockable versus non-shockable rhythm. Larger and more recent trials have shown no statistically significant difference in neurological outcomes between patients with targeted hypothermia and targeted normothermia; further, aggressive cooling is associated with a higher incidence of multiple systemic complications. Based on this data, temporal trends have leaned towards using a lenient temperature target in more recent times. Current guidelines recommend selecting and maintaining a constant target temperature between 32 and 36 °C for those patients in whom TTM is used (strong recommendation, moderate-quality evidence), as soon as possible after return of spontaneous circulation is achieved and airway, breathing (including mechanical ventilation), and circulation are stabilized. The comparative benefit of lower (32-34 °C) versus higher (36 °C) temperatures remains unknown, and further research may help elucidate this. Any survivor of cardiac arrest who is comatose (defined as unarousable unresponsiveness to external stimuli) should be considered as a candidate for TTM regardless of the initial presenting rhythm, and the decision to opt for targeted hypothermia versus targeted normothermia should be made on a case-by-case basis.

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.

Ventilatory settings in the initial 72 h and their association with outcome in out-of-hospital cardiac arrest patients: a preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial

PURPOSE

The optimal ventilatory settings in patients after cardiac arrest and their association with outcome remain unclear. The aim of this study was to describe the ventilatory settings applied in the first 72 h of mechanical ventilation in patients after out-of-hospital cardiac arrest and their association with 6-month outcomes.

METHODS

Preplanned sub-analysis of the Target Temperature Management-2 trial. Clinical outcomes were mortality and functional status (assessed by the Modified Rankin Scale) 6 months after randomization.

RESULTS

A total of 1848 patients were included (mean age 64 [Standard Deviation, SD = 14] years). At 6 months, 950 (51%) patients were alive and 898 (49%) were dead. Median tidal volume (V_T) was 7 (Interquartile range, IQR = 6.2-8.5) mL per Predicted Body Weight (PBW), positive end expiratory pressure (PEEP) was 7 (IQR = 5-9) cmH₂0, plateau pressure was 20 cmH₂0 (IQR = 17-23), driving pressure was 12 cmH₂0 (IQR = 10-15), mechanical power 16.2 J/min (IQR = 12.1-21.8), ventilatory ratio was 1.27 (IQR = 1.04-1.6), and respiratory rate was 17 breaths/minute (IQR = 14-20). Median partial pressure of oxygen was 87 mmHg (IQR = 75-105), and partial pressure of carbon dioxide was 40.5 mmHg (IQR = 36-45.7). Respiratory rate, driving pressure, and mechanical power were independently associated with 6-month mortality (omnibus p-values for their non-linear trajectories: p < 0.0001, p = 0.026, and p = 0.029, respectively). Respiratory rate and driving pressure were also independently associated with poor neurological outcome (odds ratio, OR = 1.035, 95% confidence interval, CI = 1.003-1.068, p = 0.030, and OR = 1.005, 95% CI = 1.001-1.036, p = 0.048). A composite formula calculated as [(4*driving pressure) + respiratory rate] was independently associated with mortality and poor neurological outcome.

CONCLUSIONS

Protective ventilation strategies are commonly applied in patients after cardiac arrest. Ventilator settings in the first 72 h after hospital admission, in particular driving pressure and respiratory rate, may influence 6-month outcomes.

Ventilation management and outcomes in out-of-hospital cardiac arrest: a protocol for a preplanned secondary analysis of the TTM2 trial

INTRODUCTION

Mechanical ventilation is a fundamental component in the management of patients post cardiac arrest. However, the ventilator settings and the gas-exchange targets used after cardiac arrest may not be optimal to minimise post-anoxic secondary brain injury. Therefore, questions remain regarding the best ventilator management in such patients.

METHODS AND ANALYSIS

This is a preplanned analysis of the international randomised controlled trial, targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (OHCA)-target temperature management 2 (TTM2). The primary objective is to describe ventilatory settings and gas exchange in patients who required invasive mechanical ventilation and included in the TTM2 trial. Secondary objectives include evaluating the association of ventilator settings and gas-exchange values with 6 months mortality and neurological outcome. Adult patients after an OHCA who were included in the TTM2 trial and who received invasive mechanical ventilation will be eligible for this analysis. Data collected in the TTM2 trial that will be analysed include patients' prehospital characteristics, clinical examination, ventilator settings and arterial blood gases recorded at hospital and intensive care unit (ICU) admission and daily during ICU stay.

ETHICS AND DISSEMINATION

The TTM2 study has been approved by the regional ethics committee at Lund University and by all relevant ethics boards in participating countries. No further ethical committee approval is required for this secondary analysis. Data will be disseminated to the scientific community by abstracts and by original articles submitted to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02908308.

Cardiopulmonary Resuscitation and Rescue Therapies

The history of cardiopulmonary resuscitation and the Society of Critical Care Medicine have much in common, as many of the founders of the Society of Critical Care Medicine focused on understanding and improving outcomes from cardiac arrest. We review the history, the current, and future state of cardiopulmonary resuscitation.

Outcomes of Targeted Temperature Management for In-Hospital and Out-Of-Hospital Cardiac Arrest: A Matched Case-Control Study Using the National Database of Taiwan Network of Targeted Temperature Management for Cardiac Arrest (TIMECARD) Registry

BACKGROUND This study aimed to compare outcomes of targeted temperature management (TTM) for patients with in-hospital and out-of-hospital cardiac arrest using the national database of TaIwan network of targeted temperature ManagEment for CARDiac arrest (TIMECARD) registry. MATERIAL AND METHODS A retrospective, matched, case-control study was conducted. Patients with in-hospital cardiac arrest (IHCA) treated with TTM after the return of spontaneous circulation (ROSC) were selected as the case group and controls were defined as the same number of patients with out-of-hospital cardiac arrest (OHCA), matched for sex, age, Charlson comorbidity index, and cerebral performance category. Neurological outcome and survival at hospital discharge were the primary outcome measures. RESULTS Data of 103 patients with IHCA and matched controls with OHCA were analyzed. Patients with IHCA were more likely to experience witnessed arrest and bystander cardiopulmonary resuscitation (CPR). The duration from collapse to the beginning of CPR, CPR time, and the duration from ROSC to initiation of TTM were shorter in the IHCA group but their initial arterial blood pressure after ROSC was lower. Overall, 88% of patients survived to completion of TTM and 43% survived to hospital discharge. Hospital survival (42.7% vs 42.7%, P=1.00) and favorable neurological outcome at discharge (19.4% vs 12.7%, P=0.25) did not differ between the 2 groups. CONCLUSIONS The findings from the national TIMECARD registry showed that clinical outcomes following TTM for patients with IHCA were not significantly different from OHCA when baseline factors were matched.

Gender differences and survival after an out-of-hospital cardiac arrest: a systematic review and meta-analysis

Patients who experience out-of-hospital cardiac arrest (OHCA) have unacceptably high mortality rates. It remains unclear whether gender has an association with survival in this regard. Hence, we aimed to investigate the association between gender and survival by conducting a systematic review and meta-analysis. The databases of PubMed, Embase, and Cochrane Database of Systematic Reviews were searched from inception to 17 March, 2020. Studies assessing the association between gender and survival to discharge or 30-day survival after OHCA were included. Two reviewers independently assessed the eligibility of the identified studies. The random-effects model was used to pool data, and the outcome was reported as odds ratios (ORs) and 95% confidence intervals, as the relative measure of association. Twenty-three eligible studies enrolling 897,805 patients were included in this systematic review. Overall, women were older and less likely to experience arrest in public places. When arrest occurred, women had less initial shockable rhythm, were less likely to be witnessed by bystanders, and were less likely provided with CPR compared with men. After admission, women underwent less coronary angiography, percutaneous coronary angiography, and targeted temperature management therapy. Eleven studies with ORs were pooled, showing a significant survival benefit in women (OR = 1.08, p < 0.05, I² = 52.3%). In the subgroup analysis, both premenopausal women (< 50 years) (OR = 1.42, p < 0.001, I² = 0%) and postmenopausal women (≥ 50 years) (OR = 1.07, p < 0.05, I² = 16.4%) had higher odds of survival compared with age-matched men. Despite the unfavorable factors, the pooled results showed a significant survival benefit in women after OHCA, especially in premenopausal women.

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.

Assessing the impact of resuscitation residents on the treatment of cardiopulmonary resuscitation patients

BACKGROUND

The management of cardiac arrest patients receiving cardiopulmonary resuscitation (CPR) is an essential aspect of emergency medicine (EM) training. At our institution, we have a 1-month Resuscitation Rotation designed to augment resident training in managing critical patients. The objective of this study is to compare 30-day mortality between cardiac arrest patients with resuscitation resident (RR) involvement versus patients without. Our secondary outcome is to determine if RR involvement altered rates of initiating targeted temperature management (TTM).

METHODS

This study was conducted at a single site tertiary care Level-1 trauma center with an Emergency Department (ED) census of nearly 130,000 visits per year. Data was collected from 01/01/2015 to 01/01/2018 using electronic medical records via query. Patients admitted with cardiac arrest were separated into two groups, one with RR involvement and one without. Initial rhythm of ventricular fibrillation/tachycardia (VFIB/VTACH), 30-day mortality, history of coronary artery disease (CAD), and initiation of TTM were compared. Statistical analysis was performed.

RESULTS

Out of 885 patient encounters, 91 (10.28%) had RR participation. There was no statistical difference in 30-day mortality between patients with RR involvement compared to those without (71.42% vs 66.36%; P = 0.3613). However, TTM was initiated more in the RR group (20.70% vs 8.86%; P = 0.0025). Patients who received TTM also had a lower 30-day mortality compared to those without TTM (52.94% vs 70.87%; P = 0.0020). Patients who were older and had no history of CAD were also noted to have a statistically significant higher 30-day mortality. All other variables were not statistically significant.

CONCLUSION

Resuscitation resident involvement with the care of cardiac arrest patients had no impact in 30-day mortality. However, the involvement of RR was associated with a statistically significant increase in the initiation of TTM. One limitation is that RR participated in 10.28% of the cases analyzed herein, thus the two arms are unbalanced in size. Future work may investigate if the increase in TTM in the RR involved cases may portend improved rates of neurologically intact survival or more rapid achievement of goal temperatures.

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.

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.

[Therapeutic Hypothermia in a Cardiac Arrest: Complicated Questions and Unsolved Problems]

The article aims to review the main trials, meta-analyses and guidelines regarding to various practical aspects and unsolved questions of an appliance of the therapeutic hypothermia in out-of-hospital and in-hospital cardiac arrest.

Predicting the probability of survival with mild or moderate neurological dysfunction after in-hospital cardiopulmonary arrest: The GO-FAR 2 score

BACKGROUND

The Good Outcome Following Attempted Resuscitation (GO-FAR) Score uses pre-arrest factors to predict survival after In-Hospital Cardiac Arrest (IHCA) with minimal neurological dysfunction, (cerebral performance category (CPC) ≤1). Moderate neurological dysfunction (CPC ≤2) may be a more acceptable outcome.

OBJECTIVE

To predict survival after IHCA with mild or moderate neurological dysfunction based on pre-arrest factors.

METHODS

52,468 patients with IHCA from 2012-2017. Data was divided into training (44%), testing (22%), and validation (34%) sets. Univariate analysis was used to identify variables with >3% difference in survival with CPC ≤2. These variables carried forward to the multivariate logistic regression model. The most parsimonious model that best classified patients as having a very poor (≤5%), below average (≤10%), average (11%-30%), or above average (>30%) likelihood of survival with CPC ≤2 was chosen.

RESULTS

Age >85, admission CPC <2, and non-surgical admission were strongly association with poor survival (-12.1%, -14.4%, and -18%, respectively). Nine variables were included in the logistic regression analysis. The final updated model, GO FAR 2, categorized 6.2% of patients with a very poor predicted survival, 24.8% of patients with a below average predicted survival, and 11.3% with above average predicted survival. The observed survival among those with very poor predicted survival was 4.5%.

CONCLUSION

The GO FAR 2 score provides clinicians with a prognostic estimate of the likelihood of a good outcome after IHCA based on pre-arrest patient factors. Future research is required to validate the GO-FAR 2 score.

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.

Initial arterial pH as a predictor of neurologic outcome after out-of-hospital cardiac arrest: A propensity-adjusted analysis

BACKGROUND

Lower pH after out-of-hospital cardiac arrest (OHCA) has been associated with worsening neurologic outcome, with <7.2 identified as an "unfavorable resuscitation feature" in consensus treatment algorithms despite conflicting data. This study aimed to describe the relationship between decremental post-resuscitation pH and neurologic outcomes after OHCA.

METHODS

Consecutive OHCA patients treated with targeted temperature management (TTM) at multiple US centers from 2008 to 2017 were evaluated. Poor neurologic outcome at hospital discharge was defined as cerebral performance category ≥3. The exposure was initial arterial pH after return of spontaneous circulation (ROSC) analyzed in decremental 0.05 thresholds. Potential confounders (demographics, history, resuscitation characteristics, initial studies) were defined a priori and controlled for via ATT-weighting on the inverse propensity score plus direct adjustment for the linear propensity score.

RESULTS

Of 723 patients, 589 (80%) experienced poor neurologic outcome at hospital discharge. After propensity-adjustment with excellent covariate balance, the adjusted odds ratios for poor neurologic outcome by pH threshold were: ≤7.3: 2.0 (1.0-4.0); ≤7.25: 1.9 (1.2-3.1); ≤7.2: 2.1 (1.3-3.3); ≤7.15: 1.9 (1.2-3.1); ≤7.1: 2.4 (1.4-4.1); ≤7.05: 3.1 (1.5-6.3); ≤7.0: 4.5 (1.8-12).

CONCLUSIONS

No increased hazard of progressively poor neurologic outcomes was observed in resuscitated OHCA patients treated with TTM until the initial post-ROSC arterial pH was at least ≤7.1. This threshold is more acidic than in current guidelines, suggesting the possibility that post-arrest pH may be utilized presently as an inappropriately-pessimistic prognosticator.

Understanding therapeutic hypothermia

Therapeutic hypothermia is a relatively new protocol that can improve patients' chances of favorable neurologic outcomes after cardiac arrest. However, implementation rates remain low nationwide. This article describes recommendations for and benefits of therapeutic hypothermia in postresuscitation care.

Out-of-hospital cardiac arrest with Do-Not-Resuscitate orders signed in hospital: Who are the survivors?

BACKGROUND

Signing Do-Not-Resuscitate orders is an important element contributing to a worse prognosis for out-of-hospital cardiac arrest (OHCA). However, our data showed that some of those OHCA patients with Do-Not-Resuscitate orders signed in hospital survived to hospital discharge, and even recovered with favorable neurological function. In this study, we described their clinical features and identified those factors that were associated with better outcomes.

METHODS

A retrospective, observational analysis was performed on all adult non-traumatic OHCA who were enrolled in the Resuscitation Outcomes Consortium (ROC) PRIMED study but signed Do-Not-Resuscitate orders in hospital after admission. We reported their demographics, characteristics, interventions and outcomes of all enrolled cases. Patients surviving and not surviving to hospital discharge, as well as those who did and did not obtain favorable neurological recovery, were compared. Logistic regression models assessed those factors which might be prognostic to survival and favorable neurological outcomes at discharge.

RESULTS

Of 2289 admitted patients with Do-Not-Resuscitate order signed in hospital, 132(5.8%) survived to hospital discharge and 28(1.2%) achieved favorable neurological recovery. Those factors, including witnessed arrest, prehospital shock delivered, Return of Spontaneous Circulation (ROSC) obtained in the field, cardiovascular interventions or procedures applied, and no prehospital adrenaline administered, were independently associated with better outcomes.

CONCLUSIONS

We suggest that some factors should be taken into considerations before Do-Not-Resuscitate decisions are made in hospital for those admitted OHCA patients.

General anesthetics protects against cardiac arrest-induced brain injury by inhibiting calcium wave propagation in zebrafish

Cardiac arrest is a leading cause of death and disability worldwide. Although many victims are initially resuscitated, they often suffer from serious brain injury, even leading to a “persistent vegetative state”. Therefore, it is need to explore therapies which restore and protect brain function after cardiac arrest. In the present study, using Tg (HuC:GCaMP5) zebrafish as a model, we found the zebrafish brain generated a burst of Ca²⁺ wave after cardiac arrest by in vivo time-lapse confocal imaging. The Ca²⁺ wave was firstly initiated at hindbrain and then sequentially propagated to midbrain and telencephalon, the neuron displayed Ca²⁺ overload after Ca²⁺ wave propagation. Consistent with this, our study further demonstrated neuronal apoptosis was increased in cardiac arrest zebrafish by TUNEL staining. The cardiac arrest-induced Ca²⁺ wave propagation can be prevented by general anesthetics such as midazolam or ketamine pretreatment. Moreover, midazolam or ketamine pretreatment dramatically decreased the neuronal apoptosis and improved the survival rate in CA zebrafish. Taken together, these findings provide the first in vivo evidence that general anesthetics pretreatment protects against cardiac arrest-induced brain injury by inhibiting calcium wave propagation in zebrafish.

Patient Outcomes After Palliative Care Consultation Among Patients Undergoing Therapeutic Hypothermia

OBJECTIVES

To compare the clinical outcomes of patients who did and did not receive palliative care consultation among those who experienced out-of-hospital cardiac arrest and underwent therapeutic hypothermia.

METHODS

We identified patients at a single academic medical center who had undergone therapeutic hypothermia after out-of-hospital cardiac arrest between 2009 and 2013. We performed a retrospective chart review for demographic data, hospital and critical care length of stay, and clinical outcomes of care.

RESULTS

We reviewed the charts of 62 patients, of which 35 (56%) received a palliative care consultation and 27 (44%) did not. Palliative care consultation occurred an average of 8.3 days after admission. Patients receiving palliative care consultation were more likely to have a do-not-resuscitate (DNR) order placed (odds ratio: 2.3, P < .001). The mean length of stay in the hospital was similar for patients seen by palliative care or not (16.7 vs 17.1 days, P = .90). Intensive care length of stay was also similar (11.3 vs 12.6 days, P = .55).

CONCLUSIONS

Palliative care consultation was underutilized and utilized late in this cohort. Palliative consultation was associated with DNR orders but did not affect measures of utilization such as hospital and intensive care length of stay.

Accuracy of Zero-Heat-Flux Cutaneous Temperature in Intensive Care Adults

OBJECTIVES

To compare accuracy of a continuous noninvasive cutaneous temperature using zero-heat-flux method to esophageal temperature and arterial temperature.

DESIGN

Prospective study.

SETTING

ICU and NeuroICU, University Hospital.

PATIENTS

Fifty-two ICU patients over a 4-month period who required continuous temperature monitoring were included in the study, after informed consent.

INTERVENTIONS

All patients had esophageal temperature probe and a noninvasive cutaneous device to monitor their core temperature continuously. In seven patients who required cardiac output monitoring, continuous iliac arterial temperature was collected. Simultaneous core temperatures were recorded from 1 to 5 days. Comparison to the esophageal temperature, considered as the reference in this study, used the Bland and Altman method with adjustment for multiple measurements per patient.

MEASUREMENTS AND MAIN RESULTS

The esophageal temperature ranged from 33°C to 39.7°C, 61,298 pairs of temperature using zero-heat-flux and esophageal temperature were collected and 1,850 triple of temperature using zero-heat-flux, esophageal temperature, and arterial temperature. Bias and limits of agreement for temperature using zero-heat-flux were 0.19°C ± 0.53°C compared with esophageal temperature with an absolute difference of temperature pairs equal to or lower than 0.5°C of 92.6% (95% CI, 91.9-93.4%) of cases and equal to or lower than 1°C for 99.9% (95% CI, 99.7-100.0%) of cases. Compared with arterial temperature, bias and limits of agreement were -0.00°C ± 0.36°C with an absolute difference of temperature pairs equal to or lower than 0.5°C of 99.8% (95% CI, 95.3-100%) of cases. All absolute difference of temperature pairs between temperature using zero-heat-flux and arterial temperature and between arterial temperature and esophageal temperature were equal to or lower than 1°C. No local or systemic serious complication was observed.

CONCLUSIONS

These results suggest a comparable reliability of the cutaneous sensor using the zero-heat-flux method compared with esophageal or iliac arterial temperatures measurements.

Targeted temperature management in the ICU: Guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term "targeted temperature management" (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de réanimation de langue française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société francaise d'anesthésie réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société française de médecine d'urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe francophone de réanimation et urgences pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association nationale de neuro-anesthésie réanimation française [ANARLF]), and the French Neurovascular Society (Société française neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts' opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Targeted temperature management in the ICU: guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term “targeted temperature management” (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société Francaise d’Anesthésie Réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société Française de Médecine d’Urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe Francophone de Réanimation et Urgences Pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association Nationale de Neuro-Anesthésie Réanimation Française [ANARLF]), and the French Neurovascular Society (Société Française Neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts’ opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

C-GRApH: A Validated Scoring System for Early Stratification of Neurologic Outcome After Out-of-Hospital Cardiac Arrest Treated With Targeted Temperature Management

Background

Out‐of‐hospital cardiac arrest (OHCA) results in significant morbidity and mortality, primarily from neurologic injury. Predicting neurologic outcome early post‐OHCA remains difficult in patients receiving targeted temperature management.

Methods and Results

Retrospective analysis was performed on consecutive OHCA patients receiving targeted temperature management (32–34°C) for 24 hours at a tertiary‐care center from 2008 to 2012 (development cohort, n=122). The primary outcome was favorable neurologic outcome at hospital discharge, defined as cerebral performance category 1 to 2 (poor 3–5). Patient demographics, pre‐OHCA diagnoses, and initial laboratory studies post‐resuscitation were compared between favorable and poor neurologic outcomes with multivariable logistic regression used to develop a simple scoring system (C‐GRApH). The C‐GRApH score ranges 0 to 5 using equally weighted variables: (C): coronary artery disease, known pre‐OHCA; (G): glucose ≥200 mg/dL; (R): rhythm of arrest not ventricular tachycardia/fibrillation; (A): age >45; (pH): arterial pH ≤7.0. A validation cohort (n=344) included subsequent patients from the initial site (n=72) and an external quaternary‐care health system (n=272) from 2012 to 2014. The c‐statistic for predicting neurologic outcome was 0.82 (0.74–0.90, P<0.001) in the development cohort and 0.81 (0.76–0.87, P<0.001) in the validation cohort. When subdivided by C‐GRApH score, similar rates of favorable neurologic outcome were seen in both cohorts, 70% each for low (0–1, n=60), 22% versus 19% for medium (2–3, n=307), and 0% versus 2% for high (4–5, n=99) C‐GRApH scores in the development and validation cohorts, respectively.

Conclusions

C‐GRApH stratifies neurologic outcomes following OHCA in patients receiving targeted temperature management (32–34°C) using objective data available at hospital presentation, identifying patient subsets with disproportionally favorable (C‐GRApH ≤1) and poor (C‐GRApH ≥4) prognoses.

Practice guideline summary: Reducing brain injury following cardiopulmonary resuscitation: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

To assess the evidence and make evidence-based recommendations for acute interventions to reduce brain injury in adult patients who are comatose after successful cardiopulmonary resuscitation.

METHODS

Published literature from 1966 to August 29, 2016, was reviewed with evidence-based classification of relevant articles.

RESULTS AND RECOMMENDATIONS

For patients who are comatose in whom the initial cardiac rhythm is either pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF) after out-of-hospital cardiac arrest (OHCA), therapeutic hypothermia (TH; 32-34°C for 24 hours) is highly likely to be effective in improving functional neurologic outcome and survival compared with non-TH and should be offered (Level A). For patients who are comatose in whom the initial cardiac rhythm is either VT/VF or asystole/pulseless electrical activity (PEA) after OHCA, targeted temperature management (36°C for 24 hours, followed by 8 hours of rewarming to 37°C, and temperature maintenance below 37.5°C until 72 hours) is likely as effective as TH and is an acceptable alternative (Level B). For patients who are comatose with an initial rhythm of PEA/asystole, TH possibly improves survival and functional neurologic outcome at discharge vs standard care and may be offered (Level C). Prehospital cooling as an adjunct to TH is highly likely to be ineffective in further improving neurologic outcome and survival and should not be offered (Level A). Other pharmacologic and nonpharmacologic strategies (applied with or without concomitant TH) are also reviewed.

Initiation of Therapeutic Hypothermia in the Emergency Department: A Quality Improvement Project

Therapeutic hypothermia (TH) postresuscitation has been recommended by the American Heart Association (AHA) since 2005. Early initiation of TH and fast achievement of goal temperatures have been associated with better neurological outcomes. The objective of this study was to evaluate the effectiveness of a specific TH protocol for the emergency department (ED) in increasing ED use of TH and decreasing the time from return of spontaneous circulation (ROSC) to initiation of cooling measures. An ED protocol for TH as recommended by the AHA was implemented. A random sample of 10 patients who received TH prior to the implementation of an ED protocol were analyzed and compared with the first 10 patients who received TH after the ED protocol was implemented. The time from ROSC to initiation of cooling measures and survival to discharge rates were analyzed. After implementation of the ED protocol, 7 of the 10 patients were treated with the ED protocol. The mean time to initiation of TH for the preimplementation group was 127.8 min (SD = 52.9) compared with 15.71 min (SD = 9.552) for the postimplementation group. The difference in initiation time between the pre- and postimplementation study groups was statistically significant, t(9.826) = 6.55, p < 0.05. Survival to discharge rates were 30% for the preimplementation group and 20% for the postimplementation group. The difference was not statistically significant, χ (1, N = 20) = 0.73, p = 0.78. Implementation of an ED protocol for TH reduced mean time to initiation of therapy. Additional study is warranted to determine whether differences in survival and functional recovery for ED patients receiving TH were influenced by age, comorbidities, and total resuscitation time.

Therapeutic Hypothermia After Resuscitation From a Non-Shockable Rhythm Improves Outcomes in a Regionalized System of Cardiac Arrest Care

OBJECTIVE

Therapeutic hypothermia (TH) improves neurologic outcome in patients resuscitated from ventricular fibrillation. The purpose of this study was to evaluate TH effects on neurologic outcome in patients resuscitated from a non-shockable out-of-hospital cardiac arrest rhythm.

DESIGN AND SETTING

This is a retrospective cohort study of data reported to a registry in an emergency medical system in a large metropolitan region. Patients achieving field return of spontaneous circulation are transported to designated hospitals with TH protocols.

PATIENTS

Patients with an initial non-shockable rhythm were identified. Patients were excluded if awake in the Emergency Department or if TH was withheld due to preexisting coma or death prior to initiation. The decision to initiate TH was determined by the treating physician.

MEASUREMENTS

The primary outcome was survival with good neurologic outcome defined by a cerebral performance category of 1 or 2.

MAIN RESULTS

Of the 2772 patients treated for cardiac arrest during the study period, there were 1713 patients resuscitated from cardiac arrest with an initial non-shockable rhythm and 1432 patients met inclusion criteria. The median age was 69 years [IQR 59-82]; 802 (56%) male. TH was induced in 596 (42%) patients. Survival with good neurologic outcome was 14% in the group receiving TH, compared with 5% in those not treated with TH (risk difference = 8%, 95% CI 5-12%). The adjusted OR for a CPC 1 or 2 with TH was 2.9 (95% CI 1.9-4.4).

CONCLUSION

Analyzing the data collected from the registry of the standard practice in a large metropolitan region, TH is associated with improved neurologic outcome in patients resuscitated from initial non-shockable rhythms in a regionalized system for post-resuscitation care.

Similar long-term survival of consecutive in-hospital and out-of-hospital cardiac arrest patients treated with targeted temperature management

Objective

The long-term survival of in-hospital cardiac arrest (IHCA) patients treated with targeted temperature management (TTM) is poorly described. The aim of this study was to compare the outcomes of consecutive IHCA with out-of-hospital cardiac arrest (OHCA) patients treated with TTM.

Design, setting, and patients

Retrospectively collected data on all consecutive adult patients treated with TTM at a university tertiary heart center between 2005 and 2011 were analyzed.

Measurements

Primary endpoints were survival to hospital discharge and long-term survival. Secondary endpoint was neurological outcome assessed using the Pittsburgh cerebral performance category (CPC).

Results

A total of 282 patients were included in this study; 233 (83%) OHCA and 49 (17%) IHCA. The IHCA group presented more often with asystole, received bystander cardiopulmonary resuscitation (CPR) in all cases, and had shorter time to return of spontaneous circulation (ROSC). Survival to hospital discharge was 54% for OHCA and 53% for IHCA (adjusted odds ratio 0.98 [95% confidence interval {CI}; 0.43–2.24]). Age ≤60 years, bystander CPR, time to ROSC ≤10 min, and shockable rhythm at presentation were associated with survival to hospital discharge. Good neurologic outcome among survivors was achieved by 86% of OHCA and 92% of IHCA (P=0.83). After a median follow-up time of >5 years, 83% of OHCA and 77% of IHCA were alive (adjusted hazard ratio [HR] 1.51 [95% CI; 0.59–3.91]). Age ≤60 years was the only factor associated with long-term survival (adjusted HR 2.73 [95% CI; 1.36–5.52]).

Conclusion

There was no difference in short- and long-term survival and no difference in neurologic outcome to hospital discharge between IHCA and OHCA patients treated with TTM despite higher frequency of asystole in IHCA.

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.

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.

Application of a novel rectal cooling device in hypothermia therapy after cerebral hypoxia-ischemia in rats

BACKGROUND

A new rectal cooling device for therapeutic hypothermia (TH) therapy is designed and is applied in TH treatment of SD rats with ischemic-hypoxic brain damage.

METHODS

Healthy adult SD rats (n = 45) were randomly assigned into four groups: the healthy control group (n = 5), the ischemia and hypoxia group (n = 10), the rectal TH cooling group (n = 18), and the ice blanket TH cooling group (n = 11). The rats in the rectal cooling and ice blanket TH groups received 12 h treatment after hypoxic-ischemic brain damage had been established, while those in the ischemia and hypoxia group did not. Taking the start of TH as the zero point, rats were sacrificed after 24 h and the brain and rectum tissues were sampled for histological analysis.

RESULTS

The TH induction time (37.3 ± 14.7 min) in the rectal cooling group was significantly shorter (F = 4.937, P < 0.05) than that in the ice blanket cooling group (75.6 ± 27.2 min). The HE and NISSL staining results showed that rats in the rectal TH cooling group had significantly decreased (P < 0.01) positive neurons cell count compared to those in ischemia and hypoxia group. In addition, TUNEL staining indicated that the number of apoptotic cells (3.9 ± 1.8 cells / × 400 field) and the apoptosis index (4.4 % ± 1.5) were significantly lower in rectal TH cooling group (P < 0.05) than in ischemia and hypoxia group (23.2 ± 12.1 cells / × 400 field, 26.6 % ± 12.1). Also, no rectal frostbite or inflammatory infiltration was observed in rats in the rectal TH treatment groups.

CONCLUSION

Our new cooling device realized rapid TH induction in SD rats with ischemic-hypoxic brain damage, inhibited the apoptosis of cells in the hippocampal CAl region, and did not cause histological damage to the rectal tissues.

Inducing Therapeutic Hypothermia in Cardiac Arrest Caused by Lightning Strike

Only limited clinical scenarios are grounds for induction of therapeutic hypothermia. Its use in traumatic cardiac arrests, including those from lightning strikes, is not well studied. Nonshockable cardiac arrest rhythms have only recently been included in resuscitation guidelines. We report a case of full neurological recovery with therapeutic hypothermia after a lightning-induced pulseless electrical activity cardiac arrest in an 18-year-old woman. We also review the important pathophysiology of lightning-induced cardiac arrest and neurologic sequelae, elaborate upon the mechanism of therapeutic hypothermia, and add case-based evidence in favor of the use of targeted temperature management in lightning-induced cardiac arrest.

Therapeutic hypothermia in the intensive cardiac care unit

Therapeutic hypothermia has demonstrated to improve both survival and neurological outcome in patients who experienced an out-of-hospital cardiac arrest. Nevertheless, many aspects of its clinical application are still controversial. Current guidelines recommend to cool patients who survive a cardiac arrest due to either ventricular fibrillation or ventricular tachycardia, whereas the beneficial effect of lowering body temperature in nonshockable rhythms is still questionable due to the lack of randomized controlled trial involving this subgroup of patients. Although therapeutic hypothermia is often begun before hospital arrival, the optimal time to start cooling is still a matter of debate. Furthermore, different methods are available to low body temperature, but no direct comparisons are available to establish which device performs better than others, and a combination of external and endovascular cooling is usually preferred. The present review is aimed at summarizing the available evidence supporting the use in clinical practice of mild hypothermia in comatose survivors from cardiac arrest and at evaluating its adverse events and their treatment.

Effect of therapeutic hypothermia on the outcomes after out-of-hospital cardiac arrest according to initial ECG rhythm and witnessed status: A nationwide observational interaction analysis

BACKGROUND

The use of mild therapeutic hypothermia (TH) in out-of-hospital cardiac arrest (OHCA) with shockable rhythms is recommended and widely used. However, it is unclear whether TH is associated with better outcomes in non-shockable rhythms.

METHODS

This is a retrospective observational study using a national OHCA cohort database composed of emergency medical services (EMS) and hospital data. We included adult EMS-treated OHCA patients of presumed cardiac etiology who were admitted to the hospital during Jan. 2008 to Dec. 2013. Patients without hospital outcome data were excluded. The primary outcome was good neurological outcome at discharge; secondary outcome was survival to discharge. The primary exposure was TH. We compared outcomes between TH and non-TH groups using multivariable logistic regression, adjusting for individual and Utstein factors. Interactions of initial ECG rhythm and witnessed status on the effect of TH on outcomes were tested.

RESULTS

There were 11,256 patients in the final analysis. TH was performed in 1703 patients (15.1%). Neurological outcome was better in TH (23.5%) than non-TH (15.0%) (Adjusted OR=1.25, 95% CI 1.05-1.48). The effect of TH on the odds for good neurological outcome was highest in the witnessed PEA group (Adjusted OR=3.91, 95% CI 1.87-8.14). Survival to discharge was significantly higher in the TH group (55.1%) than non-TH (35.9%) (Adjusted OR=1.76, 95% CI 1.56-2.00).

CONCLUSIONS

In a nationwide observational study, TH is associated with better neurological outcome and higher survival to discharge. The effect of TH is greatest in witnessed OHCA patients with PEA as the initial ECG rhythm.

Effect of Therapeutic Hypothermia on Survival to Hospital Discharge in Out-of-hospital Cardiac Arrest Secondary to Nonshockable Rhythms

OBJECTIVES

Therapeutic hypothermia has been shown to improve neurologic outcome and survival in out-of-hospital cardiac arrest (OHCA) following return of spontaneous circulation (ROSC), and current guidelines recommend therapeutic hypothermia for all comatose survivors of OHCA. However, recommendations for nonshockable rhythms are not as strongly supported. Our study aims to provide further evidence on the use of therapeutic hypothermia in nonshockable rhythms.

METHODS

A multivariate analysis with propensity score matching was performed using a cardiac arrest registry maintained by the Houston Fire Department. The analysis was limited to adult patients achieving ROSC following OHCA secondary to nonshockable rhythm in Houston from 2007 to 2012 with definitive information regarding the implementation of therapeutic hypothermia. The primary outcome was survival to hospital discharge.

RESULTS

Of 9,479 records identified for analysis, 7,839 had an initial nonshockable rhythm. Of these, 2,609 (33.3%) had sustained ROSC and 1,768 (22.6%) were admitted to the hospital. Data on therapeutic hypothermia use were available for 696 patients, with 335 (48.1%) receiving therapeutic hypothermia. Propensity score matching yielded 260 case/control pairs. The odds of survival to hospital discharge was an odds ratio of 1.07 (95% confidence interval = 0.71 to 1.60) for those in the therapeutic hypothermia group versus the nontherapeutic hypothermia group (p = 0.79).

CONCLUSIONS

Based on this retrospective study, therapeutic hypothermia is not associated with improved survival in patients with OHCA secondary to nonshockable rhythms. Given the limitations of our study, further prospective trials to assess the effect of therapeutic hypothermia for OHCA with nonshockable rhythms are warranted.

The impact of body mass index on patient survival after therapeutic hypothermia after resuscitation

OBJECTIVES

Therapeutic hypothermia improves survival in patients after cardiac arrest, yet the impact of body mass index (BMI) on survival is lesser known. We hypothesized that nonobese patients would have greater survival post-therapeutic hypothermia than obese patients.

METHODS

We retrospectively evaluated 164 patients who underwent therapeutic hypothermia after resuscitation for cardiac arrest from January 2012 to September 2014. Logistic regression analysis was used to assess for survival based upon BMI and comorbidities (odds ratio, 95% confidence interval).

RESULTS

Forty-one percent of patients were obese. Obese patients presented less frequently with ventricular fibrillation (P=.046) but had similar rates of pulseless electrical activity (P=.479) and ventricular tachycardia (P=.262) to nonobese patients. In multivariable analysis, BMI less than 30 kg/m(2), hypertension, presence of pacemaker/implantable cardioverter-defibrillator, high glomerular filtration rate, and low neuron-specific enolase were all associated with increased survival post-therapeutic hypothermia, respectively: 0.36 (0.16-0.78), 0.28 (0.12-0.66), 0.23 (0.08-0.62), 0.25 (0.11-0.56), and 0.37 (0.14-0.96). Other comorbidities demonstrated no association with survival.

CONCLUSIONS

Body mass index at least 30 kg/m(2) compared with BMI less than 30 kg/m(2) was a significant risk factor for mortality post-therapeutic hypothermia protocol. Absence of history of hypertension, lack of pacemaker/implantable cardioverter-defibrillator, high neuron-specific enolase, and renal disease had greater associations with death. Larger studies will be needed to validate these findings.

Measuring outcome after cardiac arrest: construct validity of Cerebral Performance Category

INTRODUCTION

Approximately half of the survivors of cardiac arrest have cognitive impairments due to hypoxic brain injury. To describe the outcome after a cardiac arrest, the Cerebral Performance Category (CPC) is frequently used. Although widely used, its validity is still debatable.

OBJECTIVE

To investigate the construct validity of the Cerebral Performance Category in survivors of a cardiac arrest. Participants were 18 years and older that survived a cardiac arrest more than six months.

METHODS

Cross-sectional design. A method to administer the CPC in a structured and reproducible manner was developed. This 'Structured CPC' was administered by a structured interview. Construct variables were Cognitive Failure Questionnaire (CFQ), Barthel Index (BI), Frenchay Activity Index (FAI), Community Integration Questionnaire (CIQ) and Quality of Life after Brain Injury (Qolibri). Associations were tested based on Spearman correlation coefficients.

RESULTS

A total of 62 participants responded. In 58 (94%) patients the CPC was determined, resulting in CPC 1 (48%), CPC 2 (23%) and CPC 3 (23%). The CPC-scoring correlated significantly with the CFQ (r=-0.40); BI (r=-0.57); FAI (r=-0.65), CIQ (r=-0.53) and Qolibri (r=-0.67).

DISCUSSION AND CONCLUSIONS

In this study we developed the 'Structured CPC' to improve the transparency and reproducibility of the original CPC. A moderate correlation between the 'Structured CPC' and the constructs 'activities', 'participation' and 'quality of life' confirmed the validity of the 'Structured CPC'.

CLINICAL MESSAGE

The 'Structured CPC' can be used as an instrument to measure the level of functioning after cardiac arrest.

Cardiac Arrest Disrupts Caspase-1 and Patterns of Inflammatory Mediators Differently in Skin and Muscle Following Localized Tissue Injury in Rats: Insights from Data-Driven Modeling

BACKGROUND

Trauma often cooccurs with cardiac arrest and hemorrhagic shock. Skin and muscle injuries often lead to significant inflammation in the affected tissue. The primary mechanism by which inflammation is initiated, sustained, and terminated is cytokine-mediated immune signaling, but this signaling can be altered by cardiac arrest. The complexity and context sensitivity of immune signaling in general has stymied a clear understanding of these signaling dynamics.

METHODOLOGY/PRINCIPAL FINDINGS

We hypothesized that advanced numerical and biological function analysis methods would help elucidate the inflammatory response to skin and muscle wounds in rats, both with and without concomitant shock. Based on the multiplexed analysis of inflammatory mediators, we discerned a differential interleukin (IL)-1α and IL-18 signature in skin vs. muscle, which was suggestive of inflammasome activation in the skin. Immunoblotting revealed caspase-1 activation in skin but not muscle. Notably, IL-1α and IL-18, along with caspase-1, were greatly elevated in the skin following cardiac arrest, consistent with differential inflammasome activation.

CONCLUSION/SIGNIFICANCE

Tissue-specific activation of caspase-1 and the NLRP3 inflammasome appear to be key factors in determining the type and severity of the inflammatory response to tissue injury, especially in the presence of severe shock, as suggested via data-driven modeling.

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

BACKGROUND

Therapeutic hypothermia (TH) attenuates reperfusion injury in comatose survivors of cardiac arrest. The utility of TH in patients with nonshockable initial rhythms has not been widely accepted. We sought to determine whether TH improved neurological outcome and survival in postarrest patients with nonshockable rhythms.

METHODS AND RESULTS

We identified 519 patients after in- and out-of-hospital cardiac arrest with nonshockable initial rhythms from the Penn Alliance for Therapeutic Hypothermia (PATH) registry between 2000 and 2013. Propensity score matching was used. Patient and arrest characteristics used to estimate the propensity to receive TH were age, sex, location of arrest, witnessed arrest, and duration of arrest. To determine the association between TH and outcomes, we created 2 multivariable logistic models controlling for confounders. Of 201 propensity score-matched pairs, mean age was 63 ± 17 years, 51% were male, and 60% had an initial rhythm of pulseless electric activity. Survival to hospital discharge was greater in patients who received TH (17.6% versus 28.9%; P < 0.01), as was a discharge Cerebral Performance Category of 1 to 2 (13.7% versus 21.4%; P = 0.04). In adjusted analyses, patients who received TH were more likely to survive (odds ratio, 2.8; 95% confidence interval, 1.6-4.7) and to have better neurological outcome (odds ratio, 3.5; 95% confidence interval, 1.8-6.6) than those that did not receive TH.

CONCLUSIONS

Using propensity score matching, we found that patients with nonshockable initial rhythms treated with TH had better survival and neurological outcome at hospital discharge than those who did not receive TH. Our findings further support the use of TH in patients with initial nonshockable arrest rhythms.

Glibenclamide Improves Survival and Neurologic Outcome After Cardiac Arrest in Rats

OBJECTIVES

Glibenclamide confers neuroprotection in animal models as well as in retrospective clinical studies. This study determines whether glibenclamide improves outcome after cardiac arrest in rats.

DESIGN

Prospective randomized laboratory study.

SETTING

University research laboratory.

SUBJECTS

Male Sprague-Dawley rats (n = 126).

INTERVENTIONS

Rats successfully resuscitated from 8-minute asphyxial cardiac arrest were randomized to glibenclamide or vehicle group. Rats in the glibenclamide group were intraperitoneally administered glibenclamide with a loading dose of 10 μg/kg at 10 minutes and a maintenance dose of 1.2 μg at 6, 12, 18, and 24 hours after return of spontaneous circulation, whereas rats in the vehicle group received equivalent volume of vehicle solution.

MEASUREMENTS AND MAIN RESULTS

Survival was recorded every day, and neurologic deficit scores were assessed at 24, 48, and 72 hours and 7 days after return of spontaneous circulation (n = 22 in each group). Results showed that glibenclamide treatment increased 7-day survival rate, reduced neurologic deficit scores, and prevented neuronal loss in the hippocampal cornu ammonis 1 region. To investigate the neuroprotective effects of glibenclamide in acute phase, we observed neuronal injury at 24 hours after return of spontaneous circulation and found that glibenclamide significantly decreased the rate of neuronal necrosis and apoptosis. In addition, glibenclamide reduced the messenger RNA expression of tumor necrosis factor-α and monocyte chemoattractant protein-1 in the cortex after return of spontaneous circulation. Furthermore, the sulfonylurea receptor 1 and transient receptor potential M4 heteromers, the putative therapeutic targets of glibenclamide, were up-regulated after cardiac arrest and cardiopulmonary resuscitation, indicating that they might be involved in neuroprotective effect of glibenclamide.

CONCLUSIONS

Glibenclamide treatment substantially improved survival and neurologic outcome throughout a 7-day period after return of spontaneous circulation. The salutary effects of glibenclamide were associated with suppression of neuronal necrosis and apoptosis, as well as inflammation in the brain.