Mild therapeutic hypothermia in cardiogenic shock syndrome. Crit Care Med. 2012;40:1715-1723. [PMID: 22487996 DOI: 10.1097/ccm.0b013e318246b820]

Hypothermia as an Adjunctive Therapy in Cardiogenic Shock: A Systematic Review and Meta-Analysis

In the setting of out-of-hospital cardiac arrest, therapeutic hypothermia (TH) has been shown to improve clinical outcomes. However, trials showing the advantage of TH did not include patients with cardiogenic shock (CS). We performed a comprehensive literature search for studies that evaluated the efficacy and safety of adjunctive TH compared with the standard of care (SOC) in patients with CS. The primary outcome was the mortality rate (in-hospital, short-, and mid-term). The secondary outcomes were the TH-related complications, duration of Intensive Care Unit (ICU) stay, duration of mechanical ventilation (MV-days), and improvement in cardiac function. Relative risk (RR) or the standardized mean difference (SMD) and corresponding 95% confidence intervals (CIs) were calculated using the random-effects model. A total of 7 clinical studies (3 RCTs included), and 712 patients (341 in the TH group and 371 in the SOC group) were included. As compared with the SOC, TH was not associated with a statistically significant improvement in the in-hospital (RR: 0.73%, 95% CI: 0.51-1.03; p = 0.08), short-term (RR: 0.90%, 95% CI: 0.75-1.06; p = 0.21), or mid-term (RR: 0.93%, 95% CI: 0.78-1.10; p = 0.38) mortality rates. Despite the improvement in the cardiac function in the TH group (SMD: 1.08, 95% CI: 0.02-2.1; p = 0.04), the TH strategy did not significantly shorten the MV days, or the ICU stay (p-values >0.05). Finally, there was a trend toward higher risks for infection, major bleeding, and the need for blood transfusion in the TH group. According to our meta-analysis of published clinical studies, TH is not beneficial in patients with CS and has a marginal safety profile. Larger-scale RCTs are needed to further clarify our results.

MILD THERAPEUTIC HYPOTHERMIA REDUCES ISCHEMIA-REPERFUSION INJURY AFTER ZONE 1 REBOA IN A SWINE HEMORRHAGIC SHOCK MODEL

ABSTRACT

Background: Resuscitative balloon occlusion of the aorta (REBOA) is an endovascular hemostasis method used for the management of traumatic abdominal and pelvic hemorrhages. However, REBOA-associated ischemia-reperfusion injury complication limits its blocking time. We hypothesized that mild therapeutic hypothermia would relieve ischemia-reperfusion injury caused by prolonged zone 1 REBOA. Methods: Ten pigs were anesthetized, intubated, and subsequently struck with the experimental sliding-chamber ballistic gun to inflict liver damage. Animals were randomized to hypothermia (60 min of zone 1 REBOA with external cooling for 180 min, n = 5) or control (60 min of zone 1 REBOA with no external cooling, n = 5). Physiological and laboratory parameters were monitored and assessed. Distal organs were obtained for histologic analysis. Results: At 180 min, compared with the control, the hypothermia animals exhibited significantly increased pH and significantly reduced lactate, hemoglobin, and hematocrit (all P < 0.05). The change of lactate from 0 to 180 min in hypothermia animals was less than that in the control ( P = 0.02). The total bleeding in the control group was significantly less than the hypothermia ( P < 0.01). In the hypothermia group, prothrombin time at 120 and 180 min was significantly longer than that at baseline (all P < 0.05). Compared with the control, animals in the hypothermia group showed slighter pathological injury of the distal organs and significantly lower overall injury score (all P < 0.05). Conclusions: Mild therapeutic hypothermia during prolonged zone 1 REBOA offered extraordinary distal organ preservation and decreased metabolic acidosis.

External validation of the CREST model to predict early circulatory-etiology death after out-of-hospital cardiac arrest without initial ST-segment elevation myocardial infarction

BACKGROUND

The CREST model is a prediction model, quantitating the risk of circulatory-etiology death (CED) after cardiac arrest based on variables available at hospital admission, and intend to guide the triage of comatose patients without ST-segment-elevation myocardial infarction after successful cardiopulmonary resuscitation. This study assessed performance of the CREST model in the Target Temperature Management (TTM) trial cohort.

METHODS

We retrospectively analyzed data from resuscitated out-of-hospital cardiac arrest (OHCA) patients in the TTM-trial. Demographics, clinical characteristics, and CREST variables (history of coronary artery disease, initial heart rhythm, initial ejection fraction, shock at admission and ischemic time > 25 min) were assessed in univariate and multivariable analysis. The primary outcome was CED. The discriminatory power of the logistic regression model was assessed using the C-statistic and goodness of fit was tested according to Hosmer-Lemeshow.

RESULTS

Among 329 patients eligible for final analysis, 71 (22%) had CED. History of ischemic heart disease, previous arrhythmia, older age, initial non-shockable rhythm, shock at admission, ischemic time > 25 min and severe left ventricular dysfunction were variables associated with CED in univariate analysis. CREST variables were entered into a logistic regression model and the area under the curve for the model was 0.73 with adequate calibration according to Hosmer-Lemeshow test (p = 0.602).

CONCLUSIONS

The CREST model had good validity and a discrimination capability for predicting circulatory-etiology death after resuscitation from cardiac arrest without ST-segment elevation myocardial infarction. Application of this model could help to triage high-risk patients for transfer to specialized cardiac centers.

Influence of Culprit Lesion Intervention on Outcomes in Infarct-Related Cardiogenic Shock With Cardiac Arrest

BACKGROUND

Cardiac arrest (CA) is common in patients with infarct-related cardiogenic shock (CS).

OBJECTIVES

The goal of this study was to identify the characteristics and outcomes of culprit lesion percutaneous coronary intervention (PCI) of patients with infarct-related CS stratified according to CA in the CULPRIT-SHOCK (Culprit Lesion Only PCI Versus Multivessel PCI in Cardiogenic Shock) randomized trial and registry.

METHODS

Patients with CS with and without CA from the CULPRIT-SHOCK study were analyzed. All-cause death or severe renal failure leading to renal replacement therapy within 30 days and 1-year death were assessed.

RESULTS

Among 1,015 patients, 550 (54.2%) had CA. Patients with CA were younger, more frequently male, had lower rates of peripheral artery disease, a glomerular filtration rate <30 mL/min, and left main disease, and they presented more often with clinical signs of impaired organ perfusion. The composite of all-cause death or severe renal failure within 30 days occurred in 51.2% of patients with CA vs 48.5% in non-CA patients (P = 0.39) and 1-year death in 53.8% vs 50.4% (P = 0.29), respectively. In a multivariate analysis, CA was an independent predictor of 1-year mortality (HR: 1.27; 95% CI: 1.01-1.59). In the randomized trial, culprit lesion-only PCI was superior to immediate multivessel PCI in patients both with and without CA (P for interaction = 0.6).

CONCLUSIONS

More than 50% of patients with infarct-related CS had CA. These patients with CA were younger and had fewer comorbidities, but CA was an independent predictor of 1-year mortality. Culprit lesion-only PCI is the preferred strategy, both in patients with and without CA. (Culprit Lesion Only PCI Versus Multivessel PCI in Cardiogenic Shock [CULPRIT-SHOCK]; NCT01927549).

Outcomes of mild-to-moderate postresuscitation shock after non-shockable cardiac arrest and association with temperature management: a post hoc analysis of HYPERION trial data

BACKGROUND

Outcomes of postresuscitation shock after cardiac arrest can be affected by targeted temperature management (TTM). A post hoc analysis of the "TTM1 trial" suggested higher mortality with hypothermia at 33 °C. We performed a post hoc analysis of HYPERION trial data to assess potential associations linking postresuscitation shock after non-shockable cardiac arrest to hypothermia at 33 °C on favourable functional outcome.

METHODS

We divided the patients into groups with vs. without postresuscitation (defined as the need for vasoactive drugs) shock then assessed the proportion of patients with a favourable functional outcome (day-90 Cerebral Performance Category [CPC] 1 or 2) after hypothermia (33 °C) vs. controlled normothermia (37 °C) in each group. Patients with norepinephrine or epinephrine > 1 µg/kg/min were not included.

RESULTS

Of the 581 patients included in 25 ICUs in France and who did not withdraw consent, 339 had a postresuscitation shock and 242 did not. In the postresuscitation-shock group, 159 received hypothermia, including 14 with a day-90 CPC of 1-2, and 180 normothermia, including 10 with a day-90 CPC of 1-2 (8.81% vs. 5.56%, respectively; P = 0.24). After adjustment, the proportion of patients with CPC 1-2 also did not differ significantly between the hypothermia and normothermia groups (adjusted hazards ratio, 1.99; 95% confidence interval, 0.72-5.50; P = 0.18). Day-90 mortality was comparable in these two groups (83% vs. 86%, respectively; P = 0.43).

CONCLUSIONS

After non-shockable cardiac arrest, mild-to-moderate postresuscitation shock at intensive-care-unit admission did not seem associated with day-90 functional outcome or survival. Therapeutic hypothermia at 33 °C was not associated with worse outcomes compared to controlled normothermia in patients with postresuscitation shock. Trial registration ClinicalTrials.gov, NCT01994772.

Basic mechanisms in cardiogenic shock: part 2 - biomarkers and treatment options

Cardiogenic shock mortality rates remain high despite significant advances in cardiovascular medicine and the widespread uptake of mechanical circulatory support systems. Except for early invasive angiography and percutaneous coronary intervention of the infarct-related artery, all other widely used therapeutic measures are based on low-quality evidence. The grim prognosis and lack of high-quality data warrant further action. Within Part 2 of this two-part educational review on basic mechanisms in cardiogenic shock, we aimed to highlight the current status of translating our understanding of the pathophysiology of cardiogenic shock into clinical practice. We summarize the current status of biomarker research in risk stratification and therapy guidance. In addition, we summarized the current status of translating the findings from bench-, bedside, and biomarker studies into treatment options. Several large randomized controlled trials (RCTs) are underway, providing a huge opportunity to study contemporary cardiogenic shock patients. Finally, we call for translational, homogenous, biomarker-based, international RCTs testing novel treatment approaches to improve the outcome of our patients.

Effect of Moderate Hypothermia vs Normothermia on 30-Day Mortality in Patients With Cardiogenic Shock Receiving Venoarterial Extracorporeal Membrane Oxygenation: A Randomized Clinical Trial

IMPORTANCE

The optimal approach to the use of venoarterial extracorporeal membrane oxygenation (ECMO) during cardiogenic shock is uncertain.

OBJECTIVE

To determine whether early use of moderate hypothermia (33-34 °C) compared with strict normothermia (36-37 °C) improves mortality in patients with cardiogenic shock receiving venoarterial ECMO.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial of patients (who were eligible if they had been endotracheally intubated and were receiving venoarterial ECMO for cardiogenic shock for <6 hours) conducted in the intensive care units at 20 French cardiac shock care centers between October 2016 and July 2019. Of 786 eligible patients, 374 were randomized. Final follow-up occurred in November 2019.

INTERVENTIONS

Early moderate hypothermia (33-34 °C; n = 168) for 24 hours or strict normothermia (36-37 °C; n = 166).

MAIN OUTCOMES AND MEASURES

The primary outcome was mortality at 30 days. There were 31 secondary outcomes including mortality at days 7, 60, and 180; a composite outcome of death, heart transplant, escalation to left ventricular assist device implantation, or stroke at days 30, 60, and 180; and days without requiring a ventilator or kidney replacement therapy at days 30, 60, and 180. Adverse events included rates of severe bleeding, sepsis, and number of units of packed red blood cells transfused during venoarterial ECMO.

RESULTS

Among the 374 patients who were randomized, 334 completed the trial (mean age, 58 [SD, 12] years; 24% women) and were included in the primary analysis. At 30 days, 71 patients (42%) in the moderate hypothermia group had died vs 84 patients (51%) in the normothermia group (adjusted odds ratio, 0.71 [95% CI, 0.45 to 1.13], P = .15; risk difference, -8.3% [95% CI, -16.3% to -0.3%]). For the composite outcome of death, heart transplant, escalation to left ventricular assist device implantation, or stroke at day 30, the adjusted odds ratio was 0.61 (95% CI, 0.39 to 0.96; P = .03) for the moderate hypothermia group compared with the normothermia group and the risk difference was -11.5% (95% CI, -23.2% to 0.2%). Of the 31 secondary outcomes, 30 were inconclusive. The incidence of moderate or severe bleeding was 41% in the moderate hypothermia group vs 42% in the normothermia group. The incidence of infections was 52% in both groups. The incidence of bacteremia was 20% in the moderate hypothermia group vs 30% in the normothermia group.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial involving patients with refractory cardiogenic shock treated with venoarterial ECMO, early application of moderate hypothermia for 24 hours did not significantly increase survival compared with normothermia. However, because the 95% CI was wide and included a potentially important effect size, these findings should be considered inconclusive.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02754193.

Targeted high volume hemofiltration could avoid extracorporeal membrane oxygenation in some patients with severe Hantavirus cardiopulmonary syndrome

Background

Hantavirus cardiopulmonary syndrome (HCPS) has a high lethality. Severe cases may be rescued by venoarterial extracorporeal membrane oxygenation (VA ECMO), alongside substantial complications. High volume hemofiltration (HVHF) is a depurative technique that provides homeostatic balance allowing hemodynamic stabilization in some critically ill patients.

Methods

We implemented HVHF before VA ECMO consideration in the last five severe HCPS patients requiring mechanical ventilation and vasoactive drugs admitted to our intensive care unit. Patients were considered HVHF‐responders if VA ECMO was avoided and HVHF‐nonresponders if VA ECMO support was needed despite HVHF. A targeted‐HVHF strategy compounded by aggressive hyperoncotic albumin, sodium bicarbonate, and calcium supplementation plus ultrafiltration to avoid fluid overload was implemented on three patients.

Results

Patients had maximum serum lactate of 8.8 (8.7–12.8) mmol/L and a lowest cardiac index of 1.8 (1.8–1.9) L/min/m². The first two required VA ECMO. They were connected later to HVHF, displayed progressive tachycardia and declining stroke volume. The opposite was true for HVHF‐responders who received targeted‐HVHF. All patients survived, but one of the VA ECMO patients suffered a vascular complication.

Conclusion

HVHF may contribute to support severe HCPS patients avoiding the need for VA ECMO in some. Early connection and targeted‐HVHF may increase the chance of success.

Severe or critical hypotension during post cardiac arrest care is associated with factors available on admission - a post hoc analysis of the TTH48 trial

PURPOSE

We explored whether severe or critical hypotension can be predicted, based on patient and resuscitation characteristics in out-of-hospital cardiac arrest (OHCA) patients. We also explored the association of hypotension with mortality and neurological outcome.

MATERIALS AND METHODS

We conducted a post hoc analysis of the TTH48 study (NCT01689077), where 355 out-of-hospital cardiac arrest (OHCA) patients were randomized to targeted temperature management (TTM) treatment at 33 °C for either 24 or 48 h. We recorded hypotension, according to four severity categories, within four days from admission. We used multivariable logistic regression analysis to test association of admission data with severe or critical hypotension.

RESULTS

Diabetes mellitus (OR 3.715, 95% CI 1.180-11.692), longer ROSC delay (OR 1.064, 95% CI 1.022-1.108), admission MAP (OR 0.960, 95% CI 0.929-0.991) and non-shockable rhythm (OR 5.307, 95% CI 1.604-17.557) were associated with severe or critical hypotension. Severe or critical hypotension was associated with increased mortality and poor neurological outcome at 6 months.

CONCLUSIONS

Diabetes, non-shockable rhythm, longer delay to ROSC and lower admission MAP were predictors of severe or critical hypotension. Severe or critical hypotension was associated with poor outcome.

Postresuscitation Care after Out-of-hospital Cardiac Arrest: Clinical Update and Focus on Targeted Temperature Management

Out-of-hospital cardiac arrest is a major cause of mortality and morbidity worldwide. With the introduction of targeted temperature management more than a decade ago, postresuscitation care has attracted increased attention. In the present review, we discuss best practice hospital management of unconscious out-of-hospital cardiac arrest patients with a special focus on targeted temperature management. What is termed post-cardiac arrest syndrome strikes all organs and mandates access to specialized intensive care. All patients need a secured airway, and most patients need hemodynamic support with fluids and/or vasopressors. Furthermore, immediate coronary angiography and percutaneous coronary intervention, when indicated, has become an essential part of the postresuscitation treatment. Targeted temperature management with controlled sedation and mechanical ventilation is the most important neuroprotective strategy to take. Targeted temperature management should be initiated as quickly as possible, and according to international guidelines, it should be maintained at 32° to 36°C for at least 24 h, whereas rewarming should not increase more than 0.5°C per hour. However, uncertainty remains regarding targeted temperature management components, warranting further research into the optimal cooling rate, target temperature, duration of cooling, and the rewarming rate. Moreover, targeted temperature management is linked to some adverse effects. The risk of infection and bleeding is moderately increased, as is the risk of hypokalemia and magnesemia. Circulation needs to be monitored invasively and any deviances corrected in a timely fashion. Outcome prediction in the individual patient is challenging, and a self-fulfilling prophecy poses a real threat to early prognostication based on clinical assessment alone. Therefore, delayed and multimodal prognostication is now considered a key element of postresuscitation care. Finally, modern postresuscitation care can produce good outcomes in the majority of patients but requires major diagnostic and therapeutic resources and specific training. Hence, recent international guidelines strongly recommend the implementation of regional prehospital resuscitation systems with integrated and specialized cardiac arrest centers.

Protocol for a multicentre randomised controlled trial evaluating the effects of moderate hypothermia versus normothermia on mortality in patients with refractory cardiogenic shock rescued by venoarterial extracorporeal membrane oxygenation (VA-ECMO) (HYPO-ECMO study)

INTRODUCTION

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is widely used to support the most severe forms of cardiogenic shock (CS). Nevertheless, despite extracorporeal membrane oxygenation (ECMO) use, mortality still remains high (50%). Moderate hypothermia (MH) (33°C-34°C) may improve cardiac performance and decrease ischaemia-reperfusion injuries. The use of MH during VA-ECMO is strongly supported by experimental and preliminary clinical data.

METHODS AND ANALYSIS

The Hypothermia-Extracorporeal Membrane Oxygenation (HYPO-ECMO) study is a multicentre, prospective, controlled randomised trial between an MH group (33°C≤T°C≤34°C) and normothermia group (36°C≤T°C≤37°C). The primary endpoint is all-cause mortality at day 30 following randomisation. The study will also assess as secondary endpoints the effects of targeted temperature management strategies on (1) mortality rate at different time points, (2) organ failure and supportive treatment use and (3) safety. All intubated adults with refractory CS supported with VA-ECMO will be screened. Exclusion criteria are patients having undergone cardiac surgery for heart transplantation or left or biventricular assist device implantation, acute poisoning with cardiotoxic drugs, pregnancy, uncontrolled bleeding and refractory cardiac arrest.Three-hundred and thirty-four patients will be randomised and followed up to 6 months to detect a 15% difference in mortality. Data analysis will be intention to treat. The differences between the two study groups in the risk of all-cause mortality at day 30 following randomisation will be studied using logistic regression analysis adjusted for postcardiotomy setting, prior cardiac arrest, prior myocardial infarction, age, vasopressor dose, Sepsis-related Organ Failure Assessment (SOFA) score and lactate at randomisation.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Comité de Protection des Personnes Est III Ethics Committee. The trial has been approved by the French Health Authorities (Agence Nationale de la Sécurité du Médicament et des Produits de Santé). Dissemination of results will be performed via journal articles and presentations at national and international conferences. Since this study is also the first step in the constitution of an 'ECMO Trials Group', its results will also be disseminated by the aforementioned group.

TRIAL REGISTRATION NUMBER

NCT02754193.

Physiological Factor Evaluation of the Warm Humidification of Anesthetic Gas Nursing Care

Objective:

This study aimed to evaluate the effects of warm humidification of anesthetic gas nursing care on physiological factors in elderly patients during laparoscopic cancer surgery.

Methods:

Sixty elderly laparoscopic surgical patients were recruited from a medical center in Korea. The participants’ physiological factors (blood pressure, body temperature, and leukocyte and neutrophil counts) were measured four times.

Results:

After warm humidification of anesthetic gas nursing care, there were significant differences in body temperatures.

Conclusions:

These findings indicate that warm humidification of anesthetic gas nursing care is effective in maintaining body temperature. Thus, this type of nursing care can be effective in elderly cancer patients undergoing laparoscopic surgery.

Malignant Arrhythmias During Induction of Target Temperature Management After Cardiac Arrest

The aim of this study was to evaluate the incidence and determinants of malignant arrhythmias (MA) in patients with shock following out-of-hospital cardiac arrest (OHCA) treated with targeted temperature management. Risk factors for the development of MA were prospectively analyzed in patients after OHCA. MA were defined as ventricular tachycardia or fibrillation with a duration >30 seconds, which had to be terminated by defibrillation. All patients were treated with therapeutic hypothermia for 24 hours. Demographics, OHCA details, interventions, and intensive care unit (ICU) treatment were recorded. A total of 55 patients were included, 11 (20%) of whom developed MA during the ICU stay. All MA occurred within the first 18 hours after admission. Patients who developed MA showed a stronger decrease in body temperature (Δ -2.4°C ± 0.8°C vs. Δ -1.3°C ± 1.3°C; p = 0.016) and in serum potassium levels (Δ -0.9 ± 1 mmol/L vs. Δ -0.3 ± 0.6 mmol/L; p = 0.037) during the cooling period compared with patients without MA. In the multivariable analysis, fast temperature decline as well as lower potassium levels were associated with MA. In addition, higher number of shocks during resuscitation and higher ICU epinephrine use were independent predictors of MA in patients with OHCA. The use of epinephrine as well as hypokalemia in context with intense cooling may increase the incidence of MA in patients with shock after cardiac arrest. Therefore, these therapeutic strategies should be applied with caution in this vulnerable group of patients.

Pre-arrest hypothermia improved cardiac function of rats by ameliorating the myocardial mitochondrial injury after cardiac arrest

This study investigated the effects of hypothermia induced before cardiac arrest or after return of spontaneous circulation (ROSC) on cardiac function and myocardial mitochondrial injury after ROSC in a rat cardiac arrest model. Sixty healthy, male Wistar rats were randomly divided into the Normothermia group, pre-arrest hypothermia (Pre-HT) group, and post-resuscitation hypothermia (Post-HT) group. The rats underwent 8 min of untreated ventricular fibrillation followed by cardiopulmonary resuscitation. Twelve rats in each group were used to evaluate the left ventricular ejection fraction before ventricular fibrillation and 4 h after ROSC. Survival was determined at 24 h after ROSC. The remaining eight rats in each group were used to detect for heart malondialdehyde, reduced glutathione, adenosine triphosphate levels and mitochondrial histology. Oxygen consumption rate and mitochondrial membrane potential were evaluated 4 h after ROSC; 10 of 12 rats in Pre-HT group, 5 of 12 in Post-HT group, and 6 of 12 in normothermia group were successfully resuscitated. The survival rate of each group was 66.7%, 33.3%, and 25%, respectively. Rats in the Pre-HT group showed less alteration of the mitochondrial ultrastructure and oxidative stress injury, better maintenance of adenine nucleotides, and more preservation of the mitochondrial membrane potential and respiratory function when compared with rats in the Post-HT and normothermia groups. Transient hypothermia is an effective preconditioning stimulus to induce ischemic tolerance in a cardiac arrest model and worthy of further evaluation for potential clinical use.

Impact statement

In this paper, we investigated the effects of hypothermia induced before ischemia or after ROSC on cardiac function, oxidative stress damage, and myocardial mitochondrial ischemia–reperfusion injury after cardiac arrest in a rat model with VF. We demonstrated that pre-arrest hypothermia conferred greater cardio-protective benefits than delayed post-resuscitation hypothermia, reduced the number of defibrillations required and dosages of epinephrine during CPR, decreased oxidative stress, ameliorated mitochondrial dysfunction, and subsequently improved survival rate.

Cardiac Shock Care Centers: JACC Review Topic of the Week

Despite advances over the past decade, the incidence of cardiogenic shock secondary to acute myocardial infarction has increased, with an unchanged mortality near 50%. Recent trials have not clarified the best strategies in treatment. While dedicated cardiac shock centers are being established, there are no standardized agreements on the utilization of mechanical circulatory support and the timeliness of percutaneous coronary intervention strategies. In some centers and prospective registries, outcomes after placement of advanced mechanical circulatory support prior to reperfusion therapy with percutaneous coronary intervention have been encouraging with improved survival. Here, we suggest systems of care with a treatment pathway for patients with acute myocardial infarction complicated by cardiogenic shock.

One year experience with fast track algorithm in patients with refractory out-of-hospital cardiac arrest

BACKGROUND

Overall prognosis in patients with out-of-hospital cardiac arrest (OHCA) remains poor, especially when return of spontaneous circulation (ROSC) cannot be achieved at the scene. It is unclear if rapid transport to the hospital with ongoing cardiopulmonary resuscitation (CPR) improves outcome in patients with refractory OHCA (rOHCA). The aim of this study was to evaluate the effect of a novel fast track algorithm (FTA) in patients with rOHCA.

METHODS

This prospective single-center study analysed outcome in rOHCA patients treated with FTA. Historical patients before FTA-implementation served as controls. rOHCA was defined as: persistent shockable rhythm after three shocks and 300mg of amiodarone or persistent non-shockable rhythm and continuous CPR for 10min without ROSC after exclusion of treatable arrest causes.

RESULTS

110 consecutive patients with rOHCA (mean age 56±14 years) were included. 40 patients (36%) were treated with FTA, 70 patients (64%) served as historical controls. Pre-hospital time was significantly shorter after FTA implementation (69±18 vs. 79±24min, p=0.02). Favourable neurological outcome (defined as cerebral performance categories Score 1 or 2) was significantly more frequent in FTA patients (27.5% vs. 11.4%, p=0.038). FTA-implementation showed a trend towards improved mortality (70.0% vs. 82.9%, p=0.151). Extracorporeal Life Support was similar between the two groups.

CONCLUSION

Our study suggests that a rapid transport algorithm with ongoing CPR is feasible, improves neurological outcome and may improve survival in carefully selected patients with rOHCA.

Impact of hypothermia on cardiac performance during targeted temperature management after cardiac arrest

INTRODUCTION

Targeted temperature management (TTM) is a well-accepted neuro-protective intervention in the management of comatose survivors of cardiac arrest (CA). However, the impact of TTM on cardiac performance has not been adequately evaluated.

METHODS

We reviewed data on consecutive CA survivors undergoing TTM at a quaternary cardiac intensive care unit between January 2015 and June 2017. Enrollment was restricted to cases with invasive hemodynamics (iHDs) at TTM initiation, every 8 h at target temperature (32-34 °C) and at completion of rewarming (>36 °C), unless precluded by mortality. Cardiac index and cardiac index-derived variables were adjusted for a decreased oxygen consumption during hypothermia. We assessed the serial impact of cooling on iHDs and cardiac performance utilizing longitudinal data analysis accounting for the effects of time as surrogate for the expected change from the post arrest syndrome and instituted treatments. A Frank-Starling construct was used to evaluate changes in cardiac contractility.

RESULTS

We evaluated the effects of cooling on iHDs and cardiac performance in 46 CA survivors. Heart rate decreased with cooling (p < 0.001), to return to baseline after rewarming (p = 0.6). Mean arterial pressure and pulmonary wedge pressure decreased by cooling (p < 0.001 for both), with sustained improvement after rewarming (p < 0.001 for both). Systemic vascular resistance was unaffected by hypothermia (p > 0.05). Left stroke work index increased with cooling (p < 0.001), with return to baseline after rewarming (p = 0.6). Cooling was associated with a left-upward shift in the Frank-Starling curve indicative of increased contractility.

CONCLUSION

Mild hypothermia in CA survivors appears associated to positive changes in iHDs and cardiac performance, including a potential increase in cardiac contractility. Larger studies are needed to conclusively confirm these findings.

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.

Therapeutic hypothermia after paediatric cardiac arrest: Pooled randomized controlled trials

BACKGROUND

Separate trials to evaluate therapeutic hypothermia after paediatric cardiac arrest for out-of-hospital and in-hospital settings reported no statistically significant differences in survival with favourable neurobehavioral outcome or safety compared to therapeutic normothermia. However, larger sample sizes might detect smaller clinical effects. Our aim was to pool data from identically conducted trials to approximately double the sample size of the individual trials yielding greater statistical power to compare outcomes.

METHODS

Combine individual patient data from two clinical trials set in forty-one paediatric intensive care units in USA, Canada and UK. Children aged at least 48 h up to 18 years old, who remained comatose after resuscitation, were randomized within 6 h of return of circulation to hypothermia or normothermia (target 33.0 °C or 36.8 °C). The primary outcome, survival 12 months post-arrest with Vineland Adaptive Behaviour Scales, Second Edition (VABS-II) score at least 70 (scored from 20 to 160, higher scores reflecting better function, population mean = 100, SD = 15), was evaluated among patients with pre-arrest scores ≥70.

RESULTS

624 patients were randomized. Among 517 with pre-arrest VABS-II scores ≥70, the primary outcome did not significantly differ between hypothermia and normothermia groups (28% [75/271] and 26% [63/246], respectively; relative risk, 1.08; 95% confidence interval [CI], 0.81 to 1.42; p = 0.61). Among 602 evaluable patients, the change in VABS-II score from baseline to 12 months did not differ significantly between groups (p = 0.20), nor did, proportion of cases with declines no more than 15 points or improvement from baseline [22% (hypothermia) and 21% (normothermia)]. One-year survival did not differ significantly between hypothermia and normothermia groups (44% [138/317] and 38% [113/ 297], respectively; relative risk, 1.15; 95% CI, 0.95 to 1.38; p = 0.15). Incidences of blood-product use, infection, and serious cardiac arrhythmia adverse events, and 28-day mortality, did not differ between groups.

CONCLUSIONS

Analysis of combined data from two paediatric cardiac arrest targeted temperature management trials including both in-hospital and out-of-hospital cases revealed that hypothermia, as compared with normothermia, did not confer a significant benefit in survival with favourable functional outcome at one year.

Myocardial dysfunction after out-of-hospital cardiac arrest: predictors and prognostic implications

We aim to determine the incidence of early myocardial dysfunction after out-of-hospital cardiac arrest, risk factors associated with its development, and association with outcome. A retrospective chart review was performed among consecutive out-of-hospital cardiac arrest (OHCA) patients who underwent echocardiography within 24 h of return of spontaneous circulation at three urban teaching hospitals. Our primary outcome is early myocardial dysfunction, defined as a left ventricular ejection fraction < 40% on initial echocardiogram. We also determine risk factors associated with myocardial dysfunction using multivariate analysis, and examine its association with survival and neurologic outcome. A total of 190 patients achieved ROSC and underwent echocardiography within 24 h. Of these, 83 (44%) patients had myocardial dysfunction. A total of 37 (45%) patients with myocardial dysfunction survived to discharge, 39% with intact neurologic status. History of congestive heart failure (OR 6.21; 95% CI 2.54-15.19), male gender (OR 2.27; 95% CI 1.08-4.78), witnessed arrest (OR 4.20; 95% CI 1.78-9.93), more than three doses of epinephrine (OR 6.10; 95% CI 1.12-33.14), more than four defibrillations (OR 4.7; 95% CI 1.35-16.43), longer duration of resuscitation (OR 1.06; 95% CI 1.01-1.10), and therapeutic hypothermia (OR 3.93; 95% CI 1.32-11.75) were associated with myocardial dysfunction. Cardiopulmonary resuscitation immediately initiated by healthcare personnel was associated with lower odds of myocardial dysfunction (OR 0.40; 95% CI 0.17-0.97). There was no association between early myocardial dysfunction and mortality or neurological outcome. Nearly half of OHCA patients have myocardial dysfunction. A number of clinical factors are associated with myocardial dysfunction, and may aid providers in anticipating which patients need early diagnostic evaluation and specific treatments. Early myocardial dysfunction is not associated with neurologically intact survival.

TIMP-2/IGFBP7 predicts acute kidney injury in out-of-hospital cardiac arrest survivors

Background

Acute kidney injury (AKI) is a common complication after cardiopulmonary resuscitation (CPR) and predicts in-hospital mortality. To which extent post-resuscitation disease or the initial event of cardiac arrest and the duration of insufficient cardiac output triggers AKI is challenging to discriminate. Knowledge on molecular mediators of AKI is scarce. Early identification of patients at high risk of AKI is hampered by the low sensitivity of the established tests in clinical routine practice. The present study aimed to determine the diagnostic utility of the novel urine biomarkers tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) for the early recognition of AKI in patients with non-traumatic shock.

Methods

The performance of [TIMP-2]·[IGFBP7] was prospectively analysed in 48 patients with shock following out-of-hospital cardiac arrest (OHCA). All patients were treated with target temperature management (TTM) for 24 h. Urinary [TIMP-2]·[IGFBP7] samples were collected at 3 and 24 h after determination of OHCA.

Results

Patients (n = 31 (65%)) developed AKI after an average of 26 ± 12 h. Patients who developed AKI had significantly higher [TIMP-2]·[IGFBP7] compared to individuals that did not develop AKI (1.52 ± 0.13 vs. 0.13 ± 0.14; p < 0.05) as early as 3 h after determination of OHCA,. For urine [TIMP-2]*[IGFBP7], the area under the curve (AUC) for the development of AKI was 0.97 (CI 0.90–1.00) at 3 h after OHCA. The optimal [TIMP-2]·[IGFBP7] cut-off value for the prediction of AKI was 0.24. The sensitivity was 96.8% and specificity was 94.1%.

Conclusions

Urinary [TIMP-2]•[IGFBP7] reliably predicts AKI in high-risk patients only 3 h after determination of OHCA with a cut-off at 0.24. This novel test may help to identify patients at high risk of AKI to enrol into clinical studies to further elucidate the pathophysiology of AKI and devise targeted interventions in the future.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2042-9) contains supplementary material, which is available to authorized users.

Moderate Hypothermia Improves Cardiac and Vascular Function in a Pig Model of Ischemic Cardiogenic Shock Treated With Veno-Arterial ECMO

Cardiogenic shock (CS) patients treated with extracorporeal membrane oxygenation (ECMO) have severe cardiac failure, associated with ischemia-reperfusion. The use of moderate hypothermia during ischemia-reperfusion syndrome is supported by experimental data. We therefore studied the effects of moderate hypothermia on cardiac and vascular function in pig ischemic CS treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). CS was induced in 12 anesthetized pigs by coronary ligation. After 1 h of CS, VA-ECMO was initiated and pigs were randomized to normothermia (38°C) or moderate hypothermia (34°C) during 8 h. Intrinsic cardiac function was measured using a left ventricular conductance catheter. At the end of the experiment, tissues were harvested for Western blotting. ECMO associated with norepinephrine infusion and volume resuscitation increased mean arterial pressure, mixed venous oxygen saturation as well as carotid, renal, and coronary blood flow without any differences between normothermia and hypothermia. Hypothermia was associated with less fluid and less norepinephrine infusion, lower lactate level, and higher urinary output. Vascular reactivity was superior in hypothermia comparatively to normothermia as expressed using norepinephrine dose-response curves. Pressure development during isovolumic contraction, left ventricular ejection fraction, and prerecruitable stroke work index were higher in the hypothermia group. There were no differences between normothermia and hypothermia with regard to carotid and mesenteric protein expression for iNOs, eNOS, and phospho AKt/AKt measured at the end of the experimentation. The incidence of surgical bleeding and coagulation disorders was the same in both groups. In conclusion, moderate and rapid hypothermia improves hemodynamics and cardiac and vascular function in a pig model of ischemic CS treated with ECMO.

Left Ventricle Function During Therapeutic Hypothermia with Beta1-Adrenergic Receptor Blockade

Therapeutic hypothermia is an established treatment in patients resuscitated from cardiac arrest. It is usually well-tolerated circulatory, but hypothermia negatively effects myocardial contraction and relaxation velocities and increases diastolic filling restrictions. A significant proportion of resuscitated patients are treated with long-acting beta-receptor blocking agents' prearrest, but the combined effects of hypothermia and beta-blockade on left ventricle (LV) function are not previously investigated. We hypothesized that beta₁-adrenergic receptor blockade (esmolol infusion) exacerbates the negative effects of hypothermia on active myocardial motions, affecting both systolic and diastolic LV function. A pig (n = 10) study was performed to evaluate the myocardial effects of esmolol during hypothermia (33°C) and during normothermia, at spontaneous and pacing-increased heart rates (HRs). LV function was assessed by a LV pressure transducer, an epicardial ultrasonic transducer (wall thickness, wall thickening/thinning velocity) and an aortic ultrasonic flow-probe (stroke volume, cardiac output). The data were compared using a paired two-tailed Students t-test, and also analyzed using a linear mixed model to handle dependencies introduced by repeated measurements within each subject. The significance level was p ≤ 0.05. The effects of hypothermia and beta blockade were distinct and additive. Hypothermia reduced myocardial motion velocities and increased diastolic filling restrictions, but end-systolic wall thickness increased, and stroke volume and dP/dt_max (pumping function) were maintained. In contrast, esmolol predominantly affected systolic pumping function, by a negative inotropic effect. In combination, hypothermia and esmolol reduced myocardial velocities in systole and diastole by ∼40%, compared with normothermia without esmolol, inducing in combination both systolic and diastolic LV function impairment. The cardiac dysfunction deteriorated at increased HRs during hypothermia. Beta₁-adrenergic receptor blockade (esmolol) exacerbates the negative effects of hypothermia on active myocardial contraction and relaxation. The combination of hypothermia with beta-blockade induces both systolic and diastolic LV function impairment.

Optimal course of treatment in acute cardiogenic shock complicating myocardial infarction

INTRODUCTION

About 5% of patients with myocardial infarction suffer from cardiogenic shock as a complication, with a mortality of ≥30%. Primary percutaneous coronary intervention as soon as possible is the most successful therapeutic approach. Prognosis depends not only on the extent of infarction, but also - and even more - on organ hypoperfusion with consequent development of multiple organ dysfunction syndrome. Areas covered: This review covers diagnostic, monitoring and treatment concepts relevant for caring patients with cardiogenic shock complicating myocardial infarction. All major clinical trials have been selected for review of the recent data. Expert commentary: For optimal care, not only primary percutaneous intervention of the occluded coronary artery is necessary, but also best intensive care medicine avoiding the development of multiple organ dysfunction syndrome and finally death. On contrary, intra-aortic balloon pump - though used for decades - is unable to reduce mortality of patients with cardiogenic shock complicating myocardial infarction.

Contemporary Management of Cardiogenic Shock: A Scientific Statement From the American Heart Association

Cardiogenic shock is a high-acuity, potentially complex, and hemodynamically diverse state of end-organ hypoperfusion that is frequently associated with multisystem organ failure. Despite improving survival in recent years, patient morbidity and mortality remain high, and there are few evidence-based therapeutic interventions known to clearly improve patient outcomes. This scientific statement on cardiogenic shock summarizes the epidemiology, pathophysiology, causes, and outcomes of cardiogenic shock; reviews contemporary best medical, surgical, mechanical circulatory support, and palliative care practices; advocates for the development of regionalized systems of care; and outlines future research priorities.

Mild hypothermia ameliorates muscle wasting in septic rats associated with hypothalamic AMPK-induced autophagy and neuropeptides

Sepsis, always developing muscle wasting, contributes to serious complications and mortality. Mild hypothermia has been reported to have protective effects on the prognosis of septic patients. However, the underlying mechanisms remain unclear. We therefore hypothesized that mild hypothermia could ameliorate muscle wasting during sepsis and whether it was associated with hypothalamus AMPK-induced autophagy and neuropeptides. Adult male Sprague-Dawley rats were intraperitoneally injected with lipopolysaccharide (LPS) (5 mg/kg) or saline. Mild hypothermia was instantly induced at 33 °C for 3h after LPS injected. Meanwhile, the control and sepsis groups were simultaneously placed on the thermal mattress to maintain the a normal temperature in control group whatever the changes induced by anesthesia. Twenty-four hours after injection, skeletal muscle and hypothalamus tissues were obtained. Muscle wasting was measured by the mRNA expression of two muscle atrophic genes, muscle ring finger 1 (MuRF-1) and muscle atrophy F-box (MAFbx), as well as 3-methylhistidine (3-MH) and tyrosine release. Hypothalamic AMPK-induced autophagy markers and neuropeptides expression were also detected. Results showed that LPS administration significantly decreased hypothalamic AMPK-induced autophagy together with muscle wasting. Also, increased hypothalamic neuropeptides, proopiomelanocortin (POMC), cocaine and amphetamine-related transcript (CART) and neuro-peptides Y (NPY) and decreased agouti-related protein (AgRP) were observed. Mild hypothermia significantly increased hypothalamic AMPK-induced autophagy and ameliorated LPS-induced muscle wasting, and attenuated the alteration of neuropeptides, POMC, CART and NPY. In conclusion, mild hypothermia could alleviate muscle wasting by LPS injection, which was associated with reversing the level of hypothalamic AMPK-induced autophagy and the alteration of neuropeptides. These results suggested that mild hypothermia could be a potential treatment concept and a novel mechanism in management of muscle wasting in critically ill patients.

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 Whole-body Hypothermia Protects Remote Lung, Liver, and Kidney Injuries after Blast Limb Trauma in Rats

BACKGROUND

Severe blast limb trauma (BLT) induces distant multiple-organ injuries. In the current study, the authors determined whether whole-body hypothermia (WH) and its optimal duration (if any) afford protection to the local limb damage and distant lung, liver, and kidney injuries after BLT in rats.

METHODS

Rats with BLT, created by using chartaceous electricity detonators, were randomly treated with WH for 30 min, 60 min, 3 h, and 6 h (n = 12/group). Rectal temperature and arterial blood pressure were monitored throughout. Blood and lung, liver, and kidney tissue samples were harvested for measuring tumor necrosis factor-α, interleukin-6 and interleukin-10, myeloperoxidase activity, hydrogen sulfide, and biomarkers of oxidative stress at 6 h after BLT. The pathologic lung injury and the water content of the lungs, liver, and kidneys and blast limb tissue were assessed.

RESULTS

Unlike WH for 30 min, WH for 60 min reduced lung water content, lung myeloperoxidase activity, and kidney myeloperoxidase activity by 10, 39, and 28% (all P < 0.05), respectively. WH for 3 h attenuated distant vital organs and local traumatic limb damage and reduced myeloperoxidase activity, hydrogen peroxide and malondialdehyde concentration, and tumor necrosis factor-α and interleukin-6 levels by up to 49% (all P < 0.01). Likewise, WH for 6 h also provided protection to such injured organs but increased blood loss from traumatic limb.

CONCLUSIONS

Results of this study indicated that WH may provide protection for distant organs and local traumatic limb after blast trauma, which warrants further study.

Does therapeutic hypothermia during extracorporeal cardiopulmonary resuscitation preserve cardiac function?

Background

Extracorporeal cardiopulmonary resuscitation (E-CPR) is increasingly used as a rescue method in the management of cardiac arrest and provides the opportunity to rapidly induce therapeutic hypothermia. The survival after a cardiac arrest is related to post-arrest cardiac function, and the application of therapeutic hypothermia post-arrest is hypothesized to improve cardiac outcome. The present animal study compares normothermic and hypothermic E-CPR considering resuscitation success, post-arrest left ventricular function and magnitude of myocardial injury.

Methods

After a 15-min untreated ventricular fibrillation, the pigs (n = 20) were randomized to either normothermic (38 °C) or hypothermic (32–33 °C) E-CPR. Defibrillation terminated ventricular fibrillation after 5 min of E-CPR, and extracorporeal support continued for 2 h, followed by warming, weaning and a stabilization period. Magnetic resonance imaging and left ventricle pressure measurements were used to assess left ventricular function pre-arrest and 5 h post-arrest. Myocardial injury was estimated by serum concentrations of cardiac TroponinT and Aspartate transaminase (ASAT).

Results

E-CPR resuscitated all animals and the hypothermic strategy induced therapeutic hypothermia within minutes without impairment of the resuscitation success rate. All animals suffered a severe global systolic left ventricular dysfunction post-arrest with 50–70% reductions in stroke volume, ejection fraction, wall thickening, strain and mitral annular plane systolic excursion. Serum concentrations of cardiac TroponinT and ASAT increased considerably post-arrest. No significant differences were found between the two groups.

Conclusions

Two-hour therapeutic hypothermia during E-CPR offers an equal resuscitation success rate, but does not preserve the post-arrest cardiac function nor reduce the magnitude of myocardial injury, compared to normothermic E-CPR.

Trial registration FOTS 4611/13 registered 25 October 2012

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1099-y) contains supplementary material, which is available to authorized users.

Editor's Choice- Inside the cold heart: A review of therapeutic hypothermia cardioprotection

Targeted temperature management has been originally used to reduce neurological injury and improve outcome in patients after out-of-hospital cardiac arrest. Myocardial infarction remains a major cause of death in the world and several investigators are studying the effect of mild therapeutic hypothermia during an acute cardiac ischemic injury. A search on MEDLINE, Scopus and EMBASE databases was conducted to obtain data regarding the cardioprotective properties of therapeutic hypothermia. Preclinical studies have shown that therapeutic hypothermia provides a cardioprotective effect in animals. The proposed pathways for the cardioprotective effects of therapeutic hypothermia include stabilization of mitochondrial permeability, production of nitric oxide, equilibration of reactive oxygen species, and calcium channels homeostasis. Clinical trials in humans have yielded controversial results. Current trials are therefore seeking to combine therapeutic hypothermia with other treatment modalities in order to improve the outcomes of patients with acute ischemic injury. This article provides a review of the hypothermia effects on the cardiovascular system, from the basic science of physiological changes in the human body and molecular mechanisms of cardioprotection to the bench of clinical trials with therapeutic hypothermia in patients with acute ischemic injury.

Inotropic Effects of Experimental Hyperthermia and Hypothermia on Left Ventricular Function in Pigs-Comparison With Dobutamine

OBJECTIVES

The results from the recent Targeted Temperature Management trial raised the question whether cooling or merely the avoidance of fever mediates better neurologic outcome in resuscitated patients. As temperature per se is a major determinant of cardiac function, we characterized the effects of hyperthermia (40.5°C), normothermia (38.0°C), and mild hypothermia (33.0°C) on left ventricular contractile function in healthy pigs and compared them with dobutamine infusion.

DESIGN

Animal study.

SETTING

Large animal facility, Medical University of Graz, Graz, Austria.

SUBJECTS

Nine anesthetized and mechanically ventilated closed-chest Landrace pigs (67 ± 2 kg).

INTERVENTIONS

Core body temperature was controlled using an intravascular device. At each temperature step, IV dobutamine was titrated to double maximum left ventricular dP/dt (1.8 ± 0.1 µg/kg/min at normothermia). Left ventricular pressure-volume relationships were assessed during short aortic occlusions. Left ventricular contractility was assessed by the calculated left ventricular end-systolic volume at an end-systolic left ventricular pressure of 100 mm Hg.

MEASUREMENTS AND MAIN RESULTS

Heart rate (98 ± 4 vs 89 ± 4 vs 65 ± 2 beats/min; all p < 0.05) and cardiac output (6.7 ± 0.3 vs 6.1 ± 0.3 vs 4.4 ± 0.2 L/min) decreased with cooling from hyperthermia to normothermia and mild hypothermia, whereas left ventricular contractility increased (left ventricular end-systolic volume at a pressure of 100 mm Hg: 74 ± 5 mL at hyperthermia, 52 ± 4 mL at normothermia, and 41 ± 3 mL at mild hypothermia; all p < 0.05). The effect of cooling on left ventricular end-systolic volume at a pressure of 100 mm Hg (hyperthermia to normothermia: -28% ± 3% and normothermia to mild hypothermia: -20% ± 5%) was of comparable effect size as dobutamine at a given temperature (hyperthermia: -28% ± 4%, normothermia: -27% ± 6%, and mild hypothermia: -27% ± 9%).

CONCLUSIONS

Cooling from hyperthermia to normothermia and from normothermia to mild hypothermia increased left ventricular contractility to a similar degree as a significant dose of dobutamine in the normal porcine heart. These data indicate that cooling can reduce the need for positive inotropes and that lower rather than higher temperatures are appropriate for the resuscitated failing heart.

Asian Targeted Temperature Management Task Panel Report

In the fields of emergency and critical care, targeted temperature management has become a critical issue and particularly popular in clinical practices throughout Asia. As more research is carried out, evidence and concepts about targeted temperature management continue to evolve. Areas of interest include new 2015 resuscitation guidelines, temperature management in pediatrics, and integrated care and neurological monitoring for cardiac arrest patients. The Asian Targeted Temperature Management task panel includes colleagues from various Asian countries and allows them to exchange experiences in a professional environment. Some of the key issues include optimal therapeutic hypothermia temperature for postcardiac arrest syndrome pursuant to 2015 guidelines, an integral approach to postcardiac arrest syndrome with hemodynamic monitoring and stabilization, roles of percutaneous coronary intervention and extracorporeal membrane oxygenation, and temperature management for neonatal hypoxic-ischemic encephalopathy. Panel experts reviewed all of the aforementioned issues and discussed the feasibility and effectiveness of targeted temperature management based on the Asian population. These discussions can expand the perspectives with regard to applying targeted temperature management all over the world.

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.

Advanced monitoring of systemic hemodynamics in critically ill patients with acute brain injury

Hemodynamic monitoring is widely used in critical care; however, the impact of such intervention in patients with acute brain injury (ABI) remains unclear. Using PubMed, a systematic review was performed (1966-August 2013), and 118 studies were included. Data were extracted using the PICO approach. The evidence was classified, and recommendations were developed according to the GRADE system. Electrocardiography and invasive monitoring of arterial blood pressure should be the minimal hemodynamic monitoring required in unstable or at-risk patients in the intensive care unit. Advanced hemodynamic monitoring (i.e., assessment of preload, afterload, cardiac output, and global systemic perfusion) could help establish goals that take into account cerebral blood flow and oxygenation, which vary depending on diagnosis and disease stage. Choice of techniques for assessing preload, afterload, cardiac output, and global systemic perfusion should be guided by specific evidence and local expertise. Hemodynamic monitoring is important and has specific indications among ABI patients. Further data are necessary to understand its potential for therapeutic interventions and prognostication.

Safety of therapeutic hypothermia in children on veno-arterial extracorporeal membrane oxygenation after cardiac surgery

OBJECTIVE

The aim of this study was to evaluate whether the use of therapeutic hypothermia in patients receiving extracorporeal membrane oxygenation after paediatric cardiac surgery is associated with increased complication rates.

METHODS

We undertook a retrospective study to compare the complication rates and clinical course of children after cardiac surgery in two groups – extracorporeal membrane oxygenation without therapeutic hypothermia (group 1) and extracorporeal membrane oxygenation with therapeutic hypothermia (group 2). Therapeutic hypothermia was performed via the extracorporeal membrane oxygenation circuit heater-cooler device.

RESULTS

A total of 96 patients were included in this study (59 in group 1 and 37 in group 2). Complications were comparable between group 1 and group 2, except that more patients with therapeutic hypothermia had hypertension while on extracorporeal membrane oxygenation. Therapeutic hypothermia was not independently associated with in-hospital mortality (adjusted odds ratio 1.16, 95% CI: 0.33-4.03; p=0.82).

CONCLUSION

Therapeutic hypothermia can be safely provided to children on extracorporeal membrane oxygenation after cardiac surgery without an increase in complication rates.

Myocardial Dysfunction and Shock after Cardiac Arrest

Postarrest myocardial dysfunction includes the development of low cardiac output or ventricular systolic or diastolic dysfunction after cardiac arrest. Impaired left ventricular systolic function is reported in nearly two-thirds of patients resuscitated after cardiac arrest. Hypotension and shock requiring vasopressor support are similarly common after cardiac arrest. Whereas shock requiring vasopressor support is consistently associated with an adverse outcome after cardiac arrest, the association between myocardial dysfunction and outcomes is less clear. Myocardial dysfunction and shock after cardiac arrest develop as the result of preexisting cardiac pathology with multiple superimposed insults from resuscitation. The pathophysiology involves cardiovascular ischemia/reperfusion injury and cardiovascular toxicity from excessive levels of inflammatory cytokine activation and catecholamines, among other contributing factors. Similar mechanisms occur in myocardial dysfunction after cardiopulmonary bypass, in sepsis, and in stress-induced cardiomyopathy. Hemodynamic stabilization after resuscitation from cardiac arrest involves restoration of preload, vasopressors to support arterial pressure, and inotropic support if needed to reverse the effects of myocardial dysfunction and improve systemic perfusion. Further research is needed to define the role of postarrest myocardial dysfunction on cardiac arrest outcomes and identify therapeutic strategies.