Effect of cooling methods and target temperature on outcomes in comatose patients resuscitated from cardiac arrest: Systematic review and network meta-analysis of randomized trials

Intravascular vs. surface cooling in out-of-hospital cardiac arrest patients receiving hypothermia after hospital arrival: a post hoc analysis of the TTM2 trial

PURPOSE

To compare the performance of targeted temperature management (TTM) at 33 °C using intravascular (IC) vs. surface-cooling (SFC) devices after out-of-hospital cardiac arrest (OHCA).

METHODS

A post hoc analysis including OHCA patients randomized to hypothermia in the TTM2-trial (NCT02908308) comparing hypothermia with normothermia. The main outcome was cooling performance, defined as the proportion of patients reaching target temperature < 33.5 °C within 4 h, time outside temperature ranges during maintenance, rewarming rate and post-TTM fever. Exploratory outcomes included survival and good functional outcome, defined as modified Rankin Scale (mRS) scores of 0-3 at 6 months, analyzed using Inverse Probability Treatment Weighting (IPTW).

RESULTS

Among 930 patients randomized to hypothermia, 876 were treated with a cooling device and included in this study. Of those, 27.3% received IC devices, while 72.7% received SFC devices. The proportion reaching target temperature within 4 h was higher with IC (IC: 69.6% vs. SFC: 49.2%; p < 0.001). Temperature outside ranges during the cooling period and post-TTM fever were lower with IC compared to SFC (17.2% vs. 39.6%; p < 0.001 and 0% vs. 6.3%; p < 0.001, respectively). In the exploratory IPTW analysis, 6-month survival rates were 55.2% in the IC group and 50.2% in the SFC group (OR 1.22, 95% CI 0.89-1.68) and survival with good functional outcome at 6 months was 51.1% patients in the IC group and 44.9% in the SFC (OR 1.28, 95% CI 0.93-1.77).

CONCLUSIONS

Among OHCA patients randomized to hypothermia in the TTM2 study, intravascular cooling, compared with surface cooling, was associated with better cooling performance.

Ghrelin for neuroprotection in post-cardiac arrest coma: a 1-year follow-up of cognitive and psychosocial outcomes

AIMS

Effective treatments to improve brain recovery after cardiac arrest are needed. Ghrelin showed efficacy in experimental models and was associated with lower neuron-specific enolase levels in the clinical Ghrelin in Coma (GRECO) trial. Here, we present cognitive and psychosocial outcomes at 1-year follow-up.

METHODS AND RESULTS

GRECO was a Phase 2 multicentre, double-blind, randomized, placebo-controlled trial in comatose patients after cardiac arrest. The intervention was intravenous acyl-ghrelin 600 μg twice daily or placebo for 1 week, starting within 12 h after the arrest. Patients were assessed after 1 year using cognitive tests and questionnaires measuring participation, health-related quality of life, mood, and caregiver strain. Composite z-scores of the cognitive tests were computed by comparing the scores with those of a norm population and averaging the tests for memory, attention, and executive functioning separately. Groups were compared based on composite z-scores and cut-off scores for psychosocial outcomes. Of the 160 participants originally included, 66 of the 85 participants who survived to 1 year after OHCA completed the psychosocial and cognitive follow-up. The intervention group scored numerically higher across the cognitive domains compared with the control group, but the differences were not statistically significant (memory median = -0.850 vs. -1.385, U = 424.5, P = 0.587; attention median = -0.733 vs. -0.717, U = 420.5, P = 0.548; and executive functioning median = -0.311 vs. -0.482, U = 408.5, P = 0.323). There were significantly fewer signs of depression in the intervention group (U = 322.5, P = 0.014).

CONCLUSION

This predefined secondary analysis found that ghrelin treatment was associated with non-significantly but consistently better cognitive outcomes and significantly fewer signs of depression. This is in line with the primary outcomes.

CLINICAL TRIAL REGISTRATION

Clinicaltrialsregister.eu: EUCTR2018-000005-23-NL.

Description of current status of implementation and management of cardiac arrest in China

Variation in the incidence, survival rate and factors associated with survival after cardiac arrest in China is reported. Some studies have tried to fill the knowledge gap regarding the epidemiology of cardiac arrest in China but were unable to identify reasons for the reported differences. Therefore, the purpose of this study was to describe Chinese management of cardiac arrest, particularly from the perspective of compression, ventilation, monitoring, treatment, and extracorporeal cardiopulmonary resuscitation. An online questionnaire with 56 questions was designed about demographic characteristics, management of cardiac arrest, compression, ventilation, treatment and medicine, as well as advanced life support and resuscitation skill training. A total of 814 copies of questionnaire were received from 23 provinces, 4 autonomous regions and 4 municipalities of China. Results were combined with official information on population density. Throughout China, hospitals resuscitate according to the guideline, however, there are still differences varies in implement with regard to chest compression, ventilation, medicine, monitoring, as well as advanced life support and resuscitation skills training because of economical and developmental level from different regions. All the startup of chest compression is manual, whereas mechanical compression instruments are increasingly involved in sequential resuscitation. Most of clinicians rotate during resuscitation every five cycles other than the guideline recommends every 2 min or when they are tired. About half of the participants don't build the advanced airway rather than use bag valve mask to ventilate, and 75% of the rest use mechanical ventilation whether they succeed to ROSC. Most of rescuers choose endotracheal intubation which is consistent with many other clinical trials results. Various compression feedback devices play increasingly significant roles in assessment of ROSC. More and more regional hospitals have access to ECPR and implement TTM, but still lead to various divergences. Thus, more elaborate clinical trials need to be designed to verify and explore every procedure in the CPR life cycle.

Temperature Control in the Era of Personalized Medicine: Knowledge Gaps, Research Priorities, and Future Directions

Hypoxic-ischemic brain injury (HIBI) is the leading cause of death and disability after cardiac arrest. To date, temperature control is the only intervention shown to improve neurologic outcomes in patients with HIBI. Despite robust preclinical evidence supporting hypothermia as neuroprotective therapy after cardiac arrest, there remains clinical equipoise regarding optimal core temperature, therapeutic window, and duration of therapy. Current guidelines recommend continuous temperature monitoring and active fever prevention for at least 72 h and additionally note insufficient evidence regarding temperature control targeting 32 °C-36 °C. However, population-based thresholds may be inadequate to support the metabolic demands of ischemic, reperfused, and dysregulated tissue. Promoting a more personalized approach with individualized targets has the potential to further improve outcomes. This review will analyze current knowledge and evidence, address research priorities, explore the components of high-quality temperature control, and define critical future steps that are needed to advance patient-centered care for cardiac arrest survivors.

Temperature Control After Cardiac Arrest: A Narrative Review

Cardiac arrest (CA) is a critical public health issue affecting more than half a million Americans annually. The main determinant of outcome post-CA is hypoxic-ischemic brain injury (HIBI), and temperature control is currently the only evidence-based, guideline-recommended intervention targeting secondary brain injury. Temperature control is a key component of a post-CA care bundle; however, conflicting evidence challenges its wide implementation across the vastly heterogeneous population of CA survivors. Here, we critically appraise the available literature on temperature control in HIBI, detail how the evidence has been integrated into clinical practice, and highlight the complications associated with its use and the timing of neuroprognostication after CA. Future clinical trials evaluating different temperature targets, rates of rewarming, duration of cooling, and identifying which patient phenotype benefits from different temperature control methods are needed to address these prevailing knowledge gaps.

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.