A comparison of therapeutic hypothermia and strict therapeutic normothermia after cardiac arrest

A Systematic Literature Review to Assess Fever Management and the Quality of Targeted Temperature Management in Critically Ill Patients

Targeted temperature management (TTM) has been proposed to reduce mortality and improve neurological outcomes in postcardiac arrest and other critically ill patients. TTM implementation may vary considerably among hospitals, and "high-quality TTM" definitions are inconsistent. This systematic literature review in relevant critical care conditions evaluated the approaches to and definitions of TTM quality with respect to fever prevention and the maintenance of precise temperature control. Current evidence on the quality of fever management associated with TTM in cardiac arrest, traumatic brain injury, stroke, sepsis, and critical care more generally was examined. Searches were conducted in Embase and PubMed (2016 to 2021) following PRISMA guidelines. In total, 37 studies were identified and included, with 35 focusing on postarrest care. Frequently-reported TTM quality outcomes included the number of patients with rebound hyperthermia, deviation from target temperature, post-TTM body temperatures, and number of patients achieving target temperature. Surface and intravascular cooling were used in 13 studies, while one study used surface and extracorporeal cooling and one study used surface cooling and antipyretics. Surface and intravascular methods had comparable rates of achieving target temperature and maintaining temperature. A single study showed that patients with surface cooling had a lower incidence of rebound hyperthermia. This systematic literature review largely identified cardiac arrest literature demonstrating fever prevention with multiple TTM approaches. There was substantial heterogeneity in the definitions and delivery of quality TTM. Further research is required to define quality TTM across multiple elements, including achieving target temperature, maintaining target temperature, and preventing rebound hyperthermia.

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.

Recent developments and controversies in therapeutic hypothermia after cardiopulmonary resuscitation

Therapeutic hypothermia was recommended as the only neuroprotective treatment in comatose patients after return of spontaneous circulation (ROSC). With new evidence suggesting a similar neuroprotective effect of 36 °C and 33 °C, the term "therapeutic hypothermia" was substituted by "targeted temperature management" in 2011, which in turn was replaced by the term "temperature control" in 2022 because of new evidence of the similar effects of target normothermia and 33 °C. However, there is no clear consensus on the efficacy of therapeutic hypothermia. In this article, we provide an overview of the recent evidence from basic and clinical research related to therapeutic hypothermia and re-evaluate its application as a post-ROSC neuroprotective intervention in clinical settings.

Outcomes after decrease in hypothermia usage for out of Hospital Cardiac arrest after targeted temperature management study

OBJECTIVE

Evaluate trends in targeted temperature management with regards to temperature selection, its effect on neurologic outcomes at discharge, and compare this with recent large randomized controlled trial outcomes.

DESIGN

Retrospective cohort study between January 2010 and December 2019.

SETTING

Single large tertiary academic community hospital.

PATIENTS

634 adult non-traumatic patients presenting with out of hospital cardiac arrest with persistent comatose state treated with active targeted temperature management.

INTERVENTIONS, MEASUREMENTS, AND MAIN RESULTS

473 patients received hypothermia of 33 °C and were compared to 161 patients who received targeted normothermia of 36.5 °C. The primary outcome was Cerebral Performance Category (CPC) at hospital discharge, with levels 1 or 2 considered good outcomes. Mortality, ICU days, ventilator days, and overall hospital stay length were secondary outcomes. Patients receiving T33 had more favorable CPC outcomes when compared to patients receiving T36.5 (OR = 2.4 [1.3, 4.6], p = 0.006). Subgroup analysis of initial non-shockable rhythms demonstrated improved CPC scores (OR = 2.5, p = 0.04), however this was not maintained in the shockable rhythm group. T33 patients had a shorter length of stay. Mortality, ICU days, and ventilator days did not differ between the groups.

CONCLUSIONS

Out of hospital cardiac arrest patients with persistent comatose state treated with hypothermia of 33 °C had improved odds of discharge with good neurologic outcomes when compared to those treated with targeted normothermia. This improvement of outcomes appears to have been driven by the improved outcomes in the patients who had presented with non-shockable rhythm.

The Effects of Temperature Management on Brain Microcirculation, Oxygenation and Metabolism

Purpose: Target temperature management (TTM) is often used in patients after cardiac arrest, but the effects of cooling on cerebral microcirculation, oxygenation and metabolism are poorly understood. We studied the time course of these variables in a healthy swine model.Methods: Fifteen invasively monitored, mechanically ventilated pigs were allocated to sham procedure (normothermia, NT; n = 5), cooling (hypothermia, HT, n = 5) or cooling with controlled oxygenation (HT-Oxy, n = 5). Cooling was induced by cold intravenous saline infusion, ice packs and nasal cooling to achieve a body temperature of 33–35 °C. After 6 h, animals were rewarmed to baseline temperature (within 5 h). The cerebral microvascular network was evaluated (at baseline and 2, 7 and 12 h thereafter) using sidestream dark-field (SDF) video-microscopy. Cerebral blood flow (laser Doppler MNP100XP, Oxyflow, Oxford Optronix, Oxford, UK), oxygenation (PbtO₂, Licox catheter, Integra Lifesciences, USA) and lactate/pyruvate ratio (LPR) using brain microdialysis (CMA, Stockholm, Sweden) were measured hourly. Results: In HT animals, cerebral functional capillary density (FCD) and proportion of small-perfused vessels (PSPV) significantly decreased over time during the cooling phase; concomitantly, PbtO₂ increased and LPR decreased. After rewarming, all microcirculatory variables returned to normal values, except LPR, which increased during the rewarming phase in the two groups subjected to HT when compared to the group maintained at normothermia. Conclusions: In healthy animals, TTM can be associated with alterations in cerebral microcirculation during cooling and altered metabolism at rewarming.

Contemporary targeted temperature management: Clinical evidence and controversies

Advancements in cardiac arrest and post-cardiac arrest care have led to improved survival to hospital discharge. While survival to hospital discharge is an important clinical outcome, neurologic recovery is also a priority. With the advancement of targeted temperature management (TTM), the American Heart Association guidelines for post-cardiac arrest care recommend TTM in patients who remain comatose after return of spontaneous circulation (ROSC). Recently, the TTM2 randomized controlled trial found no significant difference in neurologic function and mortality at 6-months between traditional hypothermia to 33°C versus 37.5°C. While TTM has been evaluated for decades, current literature suggests that the use of TTM to 33° when compared to a protocol of targeted normothermia does not result in improved outcomes. Instead, perhaps active avoidance of fever may be most beneficial. Extracorporeal cardiopulmonary resuscitation and membrane oxygenation can provide a means of both hemodynamic support and TTM after ROSC. This review aims to describe the pathophysiology, physiologic aspects, clinical trial evidence, changes in post-cardiac arrest care, potential risks, as well as controversies of TTM.

Heat loss augmented by extracorporeal circulation is associated with overcooling in cardiac arrest survivors who underwent targeted temperature management

We investigated the association of extracorporeal circuit-based devices with temperature management and neurological outcome in out-of-hospital cardiac arrest survivors who underwent targeted temperature management. Patients with extracorporeal membrane oxygenation and/or continuous renal replacement therapy were classified as the extracorporeal group. We calculated the cooling rate during the induction period and time-weighted core temperatures (TWCT) during the maintenance period. We defined the sum of TWCT above or below 33 °C as positive and negative TWCT, respectively, and the sum of TWCT above 33.5 °C or below 32.5 °C as undercooling or overcooling, respectively. The primary outcome was the negative TWCT. The secondary outcomes were positive TWCT, cooling rate, undercooling, overcooling, and poor neurological outcomes, defined as Cerebral Performance Category 3–5. Among 235 patients, 150 (63.8%) had poor neurological outcomes and 52 (22.1%) were assigned to the extracorporeal group. The extracorporeal group (β, 0.307; p < 0.001) had increased negative TWCT, rapid cooling rate (1.77 °C/h [1.22–4.20] vs. 1.24 °C/h [0.77–1.79]; p = 0.005), lower positive TWCT (33.4 °C∙min [24.9–46.2] vs. 54.6 °C∙min [29.9–87.0]), and higher overcooling (5.01 °C min [0.00–10.08] vs. 0.33 °C min [0.00–3.78]). However, the neurological outcome was not associated with the use of extracorporeal devices (odds ratio, 1.675; 95% confidence interval, 0.685–4.094).

European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation and organ donation.

European Resuscitation Council and European Society of Intensive Care Medicine Guidelines 2021: Post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation, and organ donation.

Which Target Temperature for Post-Anoxic Brain Injury? A Systematic Review from "Real Life" Studies

There is a persistent debate on the optimal target temperature to use during cooling procedures in cardiac arrest survivors. A large randomized clinical trial (RCT) including more than 900 patients showed that targeted temperature management (TTM) at 33 °C had similar mortality and unfavorable neurological outcome (UO) rates as TTM at 36 °C in out-of-hospital cardiac arrest patients with any initial rhythm. Since then, several observational studies have been published on the effects of changes in target temperature (i.e., from 33 to 36 °C) on patients’ outcome. We performed a systematic literature search from 1 January 2014 to 4 December 2020 and identified ten retrospective studies (very low levels of certainty; high risk of bias), including 5509 patients, that evaluated TTM at 33 °C vs. TTM at 36 °C on the occurrence of UO (n = eight studies) and mortality (n = ten studies). TTM at 33 °C was associated with a lower risk of UO when studies assessing neurological outcome with the Cerebral Performance Categories were analyzed (OR 0.80 [95% CIs 0.72–0.98]; p = 0.03). No differences in mortality were observed within the two TTM strategies. These results suggest that an inappropriate translation of TTM protocols from large well-conducted randomized trials into clinical management may result in unexpected effects on patients’ outcome. As for all newly commercialized drugs, epidemiological studies and surveillance programs with an adequate follow-up on large databases are necessary to understand how RCTs are implemented into medical practice.

Temporal Changes in Targeted Temperature Management for Out-of-Hospital Cardiac Arrest-Examining the Effect of the Targeted Temperature Management Trial: A Retrospective Cohort Study

Targeted temperature management (TTM) is recommended after out-of-hospital cardiac arrest (OHCA). However, interpretation of the evidence and translation into clinical practice, to realize benefits to patient outcomes may be inconsistent. This study aims to compare compliance with the recommended targeted temperatures and the use of intravascular temperature management (IVTM), as well as 90-day survival, before and after publication of the TTM trial. A single-center retrospective cohort study was conducted from 2010 to 2017. All comatose patients admitted to the intensive care unit after OHCA, who survived for ≥24 hours, were included. IVTM use was measured and TTM adherence was defined as the percentage time the core temperature was (1) within the guideline-recommended temperature range (initially 32-34°C, later modified to 32-36°C) for the first 24 hours, and (2) ≤37.5°C between 24 and 72 hours following admission. Multiple logistic regression analyses were performed for the use of IVTM and survival at 90 days. Of the 302 patients identified, 136 (45%) were pre-TTM, and 166 (55%) post-TTM. Baseline characteristics were similar between the groups. IVTM use decreased significantly (77.9% vs. 51.8%, p < 0.001) after the publication of the TTM trial. Adherence to the 32-34°C and 32-36°C targets was higher pre-TTM as compared with the post-TTM cohort (33.3% [0-66.7%] vs. 0% [0-16.7%], p < 0.001 and 83.3% [50.0-100%] vs. 36.7% [16.7-66.7%], p < 0.001, respectively). Time with temperature ≥37.5°C in the first 24 hours was higher post-TTM (p = < 0.001) but not between 24 and 72 hours. Ninety-day survival was 54.4% in the pre-TTM cohort and 44.0% post-TTM, (odds ratio 1.52 [0.96-2.40], p = 0.083). Adherence with recommended TTM decreased significantly following publication of the TTM trial and this was explained by a significant decrease in IVTM use. However, this concerning trend did not result in a statistically significant difference in survival.

Increased protocol adherence and safety during controlled normothermia as compared to hypothermia after cardiac arrest

PURPOSE

This study aims to compare protocol adherence, neurological outcome and adverse effects associated with a controlled hypothermia versus a controlled normothermia protocol in patients successfully resuscitated after cardiac arrest.

METHODS

In this retrospective single-center study in a university intensive care unit in Switzerland, post-cardiac arrest patients were compared before and after a protocol change from targeted temperature management at 33 °C (TTM-33) to 36 °C (TTM-36) using an intravascular cooling device. Protocol adherence was assessed as the primary outcome. Secondary outcomes were in-hospital mortality, neurological outcome and adverse effects.

RESULTS

373 patients after cardiac arrest were screened, of whom a total of 133 patients were included. Protocol adherence was lower in the TTM-33 group (47% vs 87% of patients, p < 0.01). In-hospital mortality (59% vs 45%, p = 0.15) and neurological outcome (modified Rankin Score < 4 in 33% vs 39% and CPC-Score < 3 in 33% vs 39% of patients, p = 0.60 and 0.97) were similar. Overall incidence of adverse effects was comparable, with bradycardic arrhythmias occurring more frequently in the TTM-33 group.

CONCLUSION

Protocol adherence was higher in the TTM-36 group. In-hospital mortality and neurological outcome were similar, while bradycardic arrhythmias were encountered more often in TTM-33.

Association Between Target Temperature Variability and Neurologic Outcomes for Patients Receiving Targeted Temperature Management at 36°C After Cardiac Arrest: A Retrospective Cohort Study

Maintaining strict temperature control during the maintenance phase of targeted temperature management (TTM) after cardiac arrest may be an important component of clinical care. Temperature variability outside of the goal temperature range may lessen the benefit of TTM and worsen neurologic outcomes. The purpose of this retrospective study of 186 adult patients (70.4% males, mean age 53.8 ± 15.7 years) was to investigate the relationship between body temperature variability (at least one body temperature measurement outside of 36°C ± 0.5°C) during the maintenance phase of TTM at 36°C after cardiac arrest and neurologic outcome at hospital discharge. Patients with temperature variability (n = 124 [66.7%]) did not have significantly higher odds of poor neurologic outcome compared with those with no temperature variability (odds ratio [OR] = 1.01, 95% confidence interval [CI] = 0.36-2.82). Use of neuromuscular blocking agents (NMBAs) and having an initial shockable rhythm were associated with both higher odds of good neurologic outcome (shockable rhythm: OR = 10.77, 95% CI = 4.30-26.98; NMBA use: OR = 4.54, 95% CI = 1.34-15.40) and survival to hospital discharge (shockable rhythm: OR = 5.90, 95% CI = 2.65-13.13; NMBA use: OR = 3.03, 95% CI = 1.16-7.90). In this cohort of postcardiac arrest comatose survivors undergoing TTM at 36°C, having temperature variability during maintenance phase did not significantly impact neurologic outcome or survival.

A practical approach to the use of targeted temperature management after cardiac arrest

Among comatose survivors after cardiac arrest, target temperature management (TTM) is considered the most effective treatment to reduce the consequences of postanoxic brain injury. Several international guidelines have thus incorporated TTM in the management of the postresuscitation phase. However, despite extremely promising results in animal models and in randomized trials including selected patient cohorts, TTM benefits on neurological outcome have been questioned. Moreover, TTM potential side effects have raised some concerns on its wide application in all cardiac arrest patients in different healthcare systems. There is indeed still relatively large uncertainty concerning some practical aspects related to TTM application, such as: A) how to select patients who will benefit the most from TTM; B) the optimal time to initiate TTM; C) the best target temperature; D) the most effective methods to provide TTM; E) the length of the cooling phase; and F) the optimal rewarming rate and fever control strategies. The purpose of this manuscript is to review and discuss the most recent advances in TTM use after cardiac arrest and to give some proposals on how to deal with all these relevant practical questions.

The current temperature: A survey of post-resuscitation care across Australian and New Zealand intensive care units

Aim

Targeted temperature management (TTM) in post-resuscitation care has changed dramatically over the last two decades. However, uptake across Australian and New Zealand (NZ) intensive care units (ICUs) is unclear. We aimed to describe post-resuscitation care in our region, with a focus on TTM, and to gain insights into clinician's opinions about the level of evidence supporting TTM.

Methods

In December 2017, we sent an online survey to 163 ICU medical directors in Australia (n ​= ​141) and NZ (n ​= ​22).

Results

Sixty-one ICU medical directors responded (50 from Australia and 11 from NZ). Two respondents were excluded from analysis as their Private ICUs did not admit post-arrest patients. The majority of remaining respondents stated their ICU followed a post-resuscitation care clinical guideline (n ​= ​41/59, 70%). TTM was used in 57 (of 59, 97%) ICUs, of these only 64% had a specific TTM clinical guideline/policy and there was variation in the types of patients treated, temperatures targeted (range ​= ​33-37.5 ​°C), methods for cooling and duration of cooling (range ​= ​12-72 ​h). The majority of respondents stated that their ICU (n ​= ​45/57, 88%) changed TTM practice following the TTM trial: with 28% targeting temperatures >36 ​°C, and 23 (of 46, 50%) respondents expressed concerns with current level of evidence for TTM. Only 38% of post-resuscitation guidelines included prognostication procedures, few ICUs reported the use of electrophysiological tests.

Conclusions

In Australian and New Zealand ICUs there is widespread variation in post-resuscitation care, including TTM practice and prognostication. There also seems to be concerns with current TTM evidence and recommendations.

High Quality Targeted Temperature Management (TTM) After Cardiac Arrest

Targeted temperature management (TTM) is a complex intervention used with the aim of minimizing post-anoxic injury and improving neurological outcome after cardiac arrest. There is large variability in the devices used to achieve cooling and in protocols (e.g., for induction, target temperature, maintenance, rewarming, sedation, management of post-TTM fever). This variability can explain the limited benefits of TTM that have sometimes been reported. We therefore propose the concept of “high-quality TTM” as a way to increase the effectiveness of TTM and standardize its use in future interventional studies.

Temporal trends in the use of targeted temperature management after cardiac arrest and association with outcome: insights from the Paris Sudden Death Expertise Centre

Purpose

Recent doubts regarding the efficacy may have resulted in a loss of interest for targeted temperature management (TTM) in comatose cardiac arrest (CA) patients, with uncertain consequences on outcome. We aimed to identify a change in TTM use and to assess the relationship between this change and neurological outcome.

Methods

We used Utstein data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (capturing CA data from all secondary and tertiary hospitals located in the Great Paris area, France) between May 2011 and December 2017. All cases of non-traumatic OHCA patients with stable return of spontaneous circulation (ROSC) were included. After adjustment for potential confounders, we assessed the relationship between changes over time in the use of TTM and neurological recovery at discharge using the Cerebral Performance Categories (CPC) scale.

Results

Between May 2011 and December 2017, 3925 patients were retained in the analysis, of whom 1847 (47%) received TTM. The rate of good neurological outcome at discharge (CPC 1 or 2) was higher in TTM patients as compared with no TTM (33% vs 15%, P < 0.001). Gender, age, and location of CA did not change over the years. Bystander CPR increased from 55% in 2011 to 73% in 2017 (P < 0.001) and patients with a no-flow time longer than 3 min decreased from 53 to 38% (P < 0.001). The use of TTM decreased from 55% in 2011 to 37% in 2017 (P < 0.001). Meanwhile, the rate of patients with good neurological recovery remained stable (19 to 23%, P = 0.76). After adjustment, year of CA occurrence was not associated with outcome.

Conclusions

We report a progressive decrease in the use of TTM in post-cardiac arrest patients over the recent years. During this period, neurological outcome remained stable, despite an increase in bystander-initiated resuscitation and a decrease in “no flow” duration.

Changes in Temperature Management of Cardiac Arrest Patients Following Publication of the Target Temperature Management Trial

OBJECTIVES

To evaluate knowledge translation after publication of the target temperature management 33°C versus 36°C after out-of-hospital cardiac arrest trial and associated patient outcomes. Our primary hypothesis was that target temperature management at 36°C was rapidly adopted in Australian and New Zealand ICUs. Secondary hypotheses were that temporal reductions in mortality would be seen and would have accelerated after publication of the target temperature management trial.

DESIGN

Retrospective cohort study (January 2005 to December 2016).

SETTING

The Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation adult patient database containing greater than 2 million admission episodes from 186 Australian and New Zealand ICUs.

PATIENTS

Sixteen-thousand two-hundred fifty-two adults from 140 hospitals admitted to ICU after out-of-hospital cardiac arrest.

INTERVENTIONS

The primary exposure of interest was admission before versus after publication of the target temperature management trial.

MEASUREMENTS AND MAIN RESULTS

The primary outcome variable to evaluate changes in temperature management was lowest temperature in the first 24 hours in ICU. The primary clinical outcome variable of interest was inhospital mortality. Secondary outcomes included proportion of patients with fever in the first 24 hours in ICU. Mean ± SD lowest temperature in the first 24 hours in ICU in pre- and posttarget temperature management trial patients was 33.80 ± 1.71°C and 34.70 ± 1.39°C, respectively (absolute difference, 0.98°C [99% CI, 0.89-1.06°C]). Inhospital mortality rate decreased by 1.3 (99% CI, -1.8 to -0.9) percentage points per year from January 2005 until December 2013 and increased by 0.6 (99% CI, -1.4 to 2.6) percentage points per year from January 2014 until December 2016 (change in slope 1.9 percentage points per year [99% CI, -0.6 to 4.4]). Fever occurred in 568 (12.8%) of 4,450 pretarget temperature management trial patients and 853 (16.5%) of 5,184 posttarget temperature management trial patients (odds ratio, 1.35 [99% CI, 1.16-1.57]).

CONCLUSIONS

The average lowest temperature of postcardiac arrest patients in the first 24 hours in ICU rose after publication of the target temperature management trial. This change was associated with an increased frequency of fever not seen in the target temperature management trial.

Optimizing the Early Resuscitation After Out-of-Hospital Cardiac Arrest

Resuscitation after out-of-hospital cardiac arrest can be one of the most challenging scenarios in acute-care medicine. The devastating effects of postcardiac arrest syndrome carry a substantial morbidity and mortality that persist long after return of spontaneous circulation. Management of these patients requires the clinician to simultaneously address multiple emergent priorities including the resuscitation of the patient and the efficient diagnosis and management of the underlying etiology. This review provides a concise evidence-based overview of the core concepts involved in the early postcardiac arrest resuscitation. It will highlight the components of an effective management strategy including addressing hemodynamic, oxygenation, and ventilation goals as well as carefully considering cardiac catheterization and targeted temperature management. An organized approach is paramount to providing effective care to patients in this vulnerable time period.

Changes in cardiac arrest patients' temperature management after the publication of 2015 AHA guidelines for resuscitation in China

A survey was performed to assess the current management of targeted temperature management (TTM) in patients following cardiac arrest (CA) and whether healthcare providers will change target temperature after publication of 2015 American Heart Association guidelines for resuscitation in China. 52 hospitals were selected from whole of China between August to November 2016. All healthcare providers in EMs and/or ICUs of selected hospitals participated in the study. 1952 respondents fulfilled the survey (86.8%). TTM in CA patients was declared by 14.5% of physicians and 6.7% of the nurses. Only 4 of 64 departments, 7.8% of physicians and 5.7% of the nurses had implemented TH for CA patients. Since the publication of 2015 AHA guidelines, 33.6% of respondents declared no modification of target temperature, whereas 51.5% declared a target temperature's change in future practice. Respondents were more likely to choose 35∼36 °C-TTM (54.7%) after guidelines publication, as compared to that before guidelines publication they preferred 32∼34 °C-TTM (54.0%). TTM for CA patients was still in the early stage in China. Publication of 2015 resuscitation guidelines did have impact on choice of target temperature among healthcare providers. They preferred 35∼36 °C-TTM after guidelines publication.

Target temperature 34 vs. 36°C after out-of-hospital cardiac arrest - a retrospective observational study

BACKGROUND

Intensive care for comatose survivors of cardiac arrest includes targeted temperature management (TTM) to attenuate cerebral reperfusion injury. A recent multi-center clinical trial did not show any difference in mortality or neurological outcome between TTM targeting 33°C or 36°C after out-of-hospital-cardiac-arrest (OHCA). In our institution, the TTM target was changed accordingly from 34 to 36°C. The aim of this retrospective study was to analyze if this change had affected patient outcome.

METHODS

Intensive care registry and medical record data from 79 adult patients treated for OHCA with TTM during 2010 (n = 38; 34°C) and 2014 (n = 41; 36°C) were analyzed for mortality and neurological outcome were assessed as cerebral performance category. Student's t-test was used for continuous data and Fischer's exact test for categorical data, and multivariable logistic regression was applied to detect influence from patient factors differing between the groups.

RESULTS

Witnessed arrest was more common in 2010 (95%) vs. 2014 (76%) (P = 0.03) and coronary angiography was more common in 2014 (95%) vs. 2010 (76%) (P = 0.02). The number of patients awakening later than 72 h after the arrest did not differ. After adjusting for gender, hypertension, and witnessed arrest, neither 1-year mortality (P = 0.77), nor 1-year good neurological outcome (P = 0.85) differed between the groups.

CONCLUSION

Our results, showing no difference between TTM at 34°C and TTM at 36°C as to mortality or neurological outcome after OHCA, are in line with the previous TTM-trial results, supporting the use of either target temperature in our institution.

Neurologic Recovery After Cardiac Arrest: a Multifaceted Puzzle Requiring Comprehensive Coordinated Care

OPINION STATEMENT

Surviving cardiac arrest (CA) requires a longitudinal approach with multiple levels of responsibility, including fostering a culture of action by increasing public awareness and training, optimization of resuscitation measures including frequent updates of guidelines and their timely implementation into practice, and optimization of post-CA care. This clearly goes beyond resuscitation and targeted temperature management. Brain-directed physiologic goals should dictate the post-CA management, as accumulating evidence suggests that the degree of hypoxic brain injury is the main determinant of survival, regardless of the etiology of arrest. Early assessment of the need for further hemodynamic and electrophysiologic cardiac interventions, adjusting ventilator settings to avoid hyperoxia/hypoxia while targeting high-normal to mildly elevated PaCO₂, maintaining mean arterial blood pressures >65 mmHg, evaluating for and treating seizures, maintaining euglycemia, and aggressively pursuing normothermia are key steps in reducing the bioenergetic failure that underlies secondary brain injury. Accurate neuroprognostication requires a multimodal approach with standardized assessments accounting for confounders while recognizing the importance of a delayed prognostication when there is any uncertainty regarding outcome. The concept of a highly specialized post-CA team with expertise in the management of post-CA syndrome (mindful of the brain-directed physiologic goals during the early post-resuscitation phase), TTM, and neuroprognostication, guiding the comprehensive care to the CA survivor, is likely cost-effective and should be explored by institutions that frequently care for these patients. Finally, providing tailored rehabilitation care with systematic reassessment of the needs and overall goals is key for increasing independence and improving quality-of-life in survivors, thereby also alleviating the burden on families. Emerging evidence from multicenter collaborations advances the field of resuscitation at an incredible pace, challenging previously well-established paradigms. There is no more room for "conventional wisdom" in saving the survivors of cardiac arrest.