Therapeutic hypothermia application vs standard support care in post resuscitated out-of-hospital cardiac arrest patients

Optimal Timing of Targeted Temperature Management for Post-Cardiac Arrest Syndrome: Is Sooner Better?

Targeted temperature management (TTM) is often considered to improve post-cardiac arrest patients’ outcomes. However, the optimal timing to initiate cooling remained uncertain. This retrospective analysis enrolled all non-traumatic post-cardiac arrest adult patients with either out-of-hospital cardiac arrest (OHCA) or in-hospital cardiac arrest (IHCA) who received TTM from July 2015 to July 2021 at our hospital. The values of time delay before TTM and time to target temperature were divided into three periods according to optimal cut-off values identified using receiver operating characteristic curve analysis. A total of 177 patients were enrolled. A shorter time delay before TTM (pre-induction time) was associated with a lower survival chance at 28 days (32.00% vs. 54.00%, p = 0.0279). Patients with a longer cooling induction time (>440 minis) had better neurological outcomes (1.58% vs. 1.05%; p = 0.001) and survival at 28 days (58.06% vs. 29.25%; p = 0.006). After COX regression analysis, the influence of pre-induction time on survival became insignificant, but patients who cooled slowest still had a better chance of survival at 28 days. In conclusion, a shorter delay before TTM was not associated with better clinical outcomes. However, patients who took longer to reach the target temperature had better hospital survival and neurological outcomes than those who were cooled more rapidly. A further prospective study was warranted to evaluate the appropriate time window of TTM.

Does One Size Fit All? External Validation of the rCAST Score to Predict the Hospital Outcomes of Post-Cardiac Arrest Patients Receiving Targeted Temperature Management

The revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) score was proposed to predict neurologic outcomes and mortality among out-of-hospital cardiac arrest (OHCA) patients. However, it has rarely been validated outside Japan. Therefore, this study aimed to investigate this issue. All adult patients admitted to our medical intensive care unit for targeted temperature management (TTM) between July 2015 and July 2021 were enrolled. Their medical records were retrieved, and rCAST scores were calculated. A total of 108 post-cardiac arrest syndrome (PCAS) patients who received TTM were analyzed. According to the rCAST score, 49.1%, 50.0%, and 0.9% of the patients were classified as low, moderate, and high severity, respectively. The areas under the curves for the rCAST score were 0.806 (95% confidence interval [CI]: 0.719-0.876) and 0.794 (95% CI: 0.706-0.866) to predict poor neurologic outcomes and mortality at day 28, respectively. In contrast to the original report, only low-severity patients had favorable neurologic outcomes. The rCAST score showed moderate accuracy in our OHCA patients with PCAS who received TTM to predict poor neurologic outcomes and mortality at day 28.

Effects of Extended Lower Extremity Cooling Following Zone 3 REBOA in a Porcine Hemorrhage Model

INTRODUCTION

External cooling of ischemic limbs has been shown to have a significant protective benefit for durations up to 4 hours.

MATERIALS AND METHODS

It was hypothesized that this benefit could be extended to 8 hours. Six swine were anesthetized and instrumented, then underwent a 25% total blood volume hemorrhage. Animals were randomized to hypothermia or normothermia followed by 8 hours of Zone 3 resuscitative endovascular balloon occlusion of the aorta, then resuscitation with shed blood, warming, and 3 hours of critical care. Physiologic parameters were continuously recorded, and laboratory specimens were obtained at regular intervals.

RESULTS

There were no significant differences between groups at baseline. There were no significant differences between creatine kinase in the hypothermia group when compared to the normothermia group (median [IQR] = 15,206 U/mL [12,476-19,987] vs 23,027 U/mL [18,745-26,843]); P = 0.13) at the end of the study. Similarly, serum myoglobin was also not significantly different in the hypothermia group after 8 hours (7,345 ng/mL [5,082-10,732] vs 5,126 ng/mL [4,720-5,298]; P = 0.28). No histologic differences were observed in hind limb skeletal muscle.

CONCLUSION

While external cooling during prolonged Zone 3 resuscitative endovascular balloon occlusion of the aorta appears to decrease ischemic muscle injury, this benefit appears to be time dependent. As the ischemic time approaches 8 hours, the benefit from hypothermia decreases.

Targeted Temperature Management for In-Hospital Cardiac Arrest: 6 Years of Experience

Targeted temperature management (TTM) is widely used for postcardiac arrest management of patients with out-of-hospital cardiac arrest. However, the use of TTM for patients with in-hospital cardiac arrest (IHCA) is controversial. The aim of this study was to investigate the role of TTM in the management of patients with IHCA. The medical records of all IHCA patients who were resuscitated and returned to spontaneous circulation from January 2011 to December 2016 were reviewed. After excluding patients with new do not resuscitate orders and those who died within 24 hours, 262 patients were eligible for analysis. Thirty-five of the 262 patients (13.3%) received TTM after IHCA. Patients who received TTM and standard supportive care (SSC) had similar baseline epidemiological status. The TTM patients were older and had a longer cardiac pulmonary resuscitation duration; however, the differences were not statistically significant. The 28-day survival rate was not significantly different between groups (12/35 in the TTM group [34%] vs. 114/225 in the SSC group [50%], p = 0.079). In the patients with good neurological status before arrest (Glasgow-Pittsburgh cerebral performance category [GP-CPC] scores: 1-2), there was no significant difference in the 28-day survival between groups (11/26 in the TTM group [42.3%] vs. 81/154 [52.6%] in the SSC group; p = 0.332). In this subgroup, the TTM patients had poorer neurological outcomes at discharge (GP-CPC score 1-2) than the SSC patients (1/26 in the TTM group [3.8%] vs. 57/154 in the SSC group [37%]; p = 0.001). TTM was not associated with better 28-day survival than usual care among the patients with IHCA in this study, and the TTM patients had less favorable neurological outcomes at discharge. Randomized clinical trials are needed to assess the efficacy of TTM for IHCA patients.

Lower extremity cooling reduces ischemia-reperfusion injury following Zone 3 REBOA in a porcine hemorrhage model

BACKGROUND

New strategies to mitigate ischemia during REBOA and to prolong its maximal duration are needed. We hypothesized that simple external cooling of the hind limbs would decrease ischemia-reperfusion injury following prolonged Zone 3 REBOA.

METHODS

Twelve swine were anesthetized, instrumented, splenectomized, and then underwent 15% total blood volume hemorrhage. Animals were randomized to hypothermia or control followed by 4 hours of Zone 3 REBOA, resuscitation with shed blood, and 3 hours of critical care. Physiologic parameters were continuously recorded, and laboratory specimens were obtained at regular intervals. Baseline and end-of-study muscle biopsies were obtained for histologic analysis.

RESULTS

There were no significant differences between groups at baseline or after hemorrhage. Maximum creatine kinase was significantly lower in the hypothermia group compared with the normothermia group (median [interquartile range] = 3,445 U/mL [3,380-4,402 U/mL] vs. 22,544 U/mL [17,030-24,981 U/mL]; p < 0.01). Maximum serum myoglobin was also significantly lower in the hypothermia group (1,792 ng/mL [1,250-3,668 ng/mL] vs. 21,186 ng/mL [14,181-24,779 ng/mL]; p < 0.01). Fascial compartment pressures were significantly lower during critical care in the hypothermia group (p = 0.03). No histologic differences were observed in hind limb skeletal muscle.

CONCLUSIONS

External cooling during prolonged Zone 3 REBOA decreased ischemic muscle injury and resulted in lower compartment pressures following reperfusion. Hypothermia may be a viable option to extend the tolerable duration of Zone 3 occlusion, beyond what is currently achievable. Future survival studies are required to assess functional outcomes.

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.

Therapeutic hypothermia in children after cardiac arrest: a systematic review and meta-analysis

BACKGROUND

Therapeutic hypothermia (TH) has been shown to be effective in resuscitation of some adults following cardiac arrest and infants with hypoxic ischemic encephalopathy, but has not been well studied in children.

OBJECTIVES

The purpose of this systematic review/meta-analysis was to examine mortality, neurologic outcomes, and adverse events in children following use of TH.

RESULTS

A search of PubMed, the Cumulative Index to Nursing and Allied Health Literature, and the Institute for Scientific Information's Web of Knowledge from 1946 to 2014 yielded 6 studies (3 retrospective and 3 prospective cohort studies) that met our inclusion criteria. Quantitative synthesis of mortality following TH (136 subjects) was 44% (95% confidence interval, 32-57) with 28% (95% confidence interval, 11-53) of survivors (42 subjects) demonstrating poor neurologic outcome. The most frequently reported adverse events were electrolyte imbalances and pneumonia.

CONCLUSIONS

Evidence is insufficient to support the advantage of TH compared with normothermia in pediatric resuscitation. The adverse event profile appears to be different than that reported in adults. Further studies are needed before TH may be considered a standard protocol for children after cardiac arrest.

Effects of in-hospital low targeted temperature after out of hospital cardiac arrest: A systematic review with meta-analysis of randomized clinical trials

OBJECTIVE

We performed this systematic review to evaluate the effectiveness of in-hospital low targeted temperature in adult patients after out of hospital cardiac arrest on survival and neurologic performance.

DATA SOURCE

We systematically searched MEDLINE and PUBMED from inception to April 2014.

STUDY SELECTION

Citations were screened for studies evaluating the effect of in-hospital low targeted temperature in patients following out of hospital cardiac arrest.

DATA EXTRACTION

We analyzed randomized control trials (RCTs) that included adult patients resuscitated from out of hospital cardiac arrest, reporting mortality at hospital discharge and comparing in-hospital low targeted temperature with a control group.

DATA SYNTHESIS

This meta-analysis included 6 RCTs and 1418 adult patients. In-hospital low targeted (low T) temperature was associated to a reduction in mortality at hospital discharge and at 6 months when compared with in-hospital targeted and not targeted temperature while there was no reduction in mortality comparing low and high targeted temperature. In patients with initial ventricular fibrillation/ventricular tachycardia rhythm of out of hospital cardiac arrest, low T was associated with a reduction in short and long-term mortality when compared with no targeted temperature while not when compared to high targeted temperature. Low T was associated with good neurologic performance at hospital discharge compared with in-hospital high or not targeted temperature.

CONCLUSION

In-hospital low targeted temperature (<4 °C) improved short and long-term mortality when compared to no targeted temperature. In contrast, low T did not improve outcome compared with a slightly higher targeted temperature (≈ 36 °C).

Modeling cardiac arrest and resuscitation in the domestic pig

Cardiac arrest remains a leading cause of death and permanent disability worldwide. Although many victims are initially resuscitated, they often succumb to the extensive ischemia-reperfusion injury inflicted on the internal organs, especially the brain. Cardiac arrest initiates a complex cellular injury cascade encompassing reactive oxygen and nitrogen species, Ca²⁺ overload, ATP depletion, pro- and anti-apoptotic proteins, mitochondrial dysfunction, and neuronal glutamate excitotoxity, which injures and kills cells, compromises function of internal organs and ignites a destructive systemic inflammatory response. The sheer complexity and scope of this cascade challenges the development of experimental models of and effective treatments for cardiac arrest. Many experimental animal preparations have been developed to decipher the mechanisms of damage to vital internal organs following cardiac arrest and cardiopulmonary resuscitation (CPR), and to develop treatments to interrupt the lethal injury cascades. Porcine models of cardiac arrest and resuscitation offer several important advantages over other species, and outcomes in this large animal are readily translated to the clinical setting. This review summarizes porcine cardiac arrest-CPR models reported in the literature, describes clinically relevant phenomena observed during cardiac arrest and resuscitation in pigs, and discusses numerous methodological considerations in modeling cardiac arrest/CPR. Collectively, published reports show the domestic pig to be a suitable large animal model of cardiac arrest which is responsive to CPR, defibrillatory countershocks and medications, and yields extensive information to foster advances in clinical treatment of cardiac arrest.