Application of therapeutic hypothermia in the intensive care unit. Opportunities and pitfalls of a promising treatment modality--Part 2: Practical aspects and side effects

Cardiogenic Shock Intravascular Cooling Trial (CHILL-SHOCK)

BACKGROUND

Cardiogenic shock (CS) is complicated by high mortality rates. Targeted temperature control (TTC) has been proposed as an adjunct therapy in CS. This study aims to examine the safety of TTC in patients presenting with CS.

METHODS AND RESULTS

In this open-label, randomized controlled pilot trial, 20 patients with hemodynamic criteria for CS were assigned to standard of care plus TTC vs standard of care alone. The primary outcome was a composite safety outcome, including well-described complications of TTC. Secondary outcomes included mortality at 90 days, invasive hemodynamic and echocardiographic parameters, electrocardiographic measurements, and inotrope dosing. There were no significant differences in the composite analysis of prespecified safety outcomes (3 events in the TTC group vs 0 events in the control group; P = 0.24). Patients randomized to TTC demonstrated a statistically significant increase in cardiac index and cardiac power index compared to the control group at 48-96 hours after randomization (3.6 [3.1, 3.9] L/min/m2 vs 2.6 [2.5, 3.15] L/min/m2; P = 0.029 and 0.61 [0.55, 0.7] W/m2 vs 0.53 [0.435, 0.565] W/m2; P = 0.029, respectively).

CONCLUSION

TTC may be a safe adjunct therapy for patients presenting with CS and may yield improvement in specific hemodynamic parameters.

Targeted Temperature Management for Patients with Acute Ischemic Stroke: A Literature Review

Despite significant advances in medical imaging, thrombolytic therapy, and mechanical thrombectomy, acute ischemic strokes (AIS) remain a major cause of mortality and morbidity globally. Targeted temperature management (TTM) has emerged as a potential therapeutic intervention, aiming to mitigate neuronal damage and improve outcomes. This literature review examines the efficacy and challenges of TTM in the context of an AIS. A comprehensive literature search was conducted using databases such as PubMed, Cochrane, Web of Science, and Google Scholar. Studies were selected based on relevance and quality. We identified key factors influencing the effectiveness of TTM such as its timing, depth and duration, and method of application. The review also highlighted challenges associated with TTM, including increased pneumonia rates. The target temperature range was typically between 32 and 36 °C, with the duration of cooling from 24 to 72 h. Early initiation of TTM was associated with better outcomes, with optimal results observed when TTM was started within the first 6 h post-stroke. Emerging evidence indicates that TTM shows considerable potential as an adjunctive treatment for AIS when implemented promptly and with precision, thereby potentially mitigating neuronal damage and enhancing overall patient outcomes. However, its application is complex and requires the careful consideration of various factors.

Temperature Monitoring and Thermal Support in Exotic Animal Critical Care

Body temperature measurement is one of the most important parameters to assess the health of a patient. In small exotic mammals, rectal temperature is obtained via a similar process as in dogs or cats, with a few specific differences. In reptiles and birds, measurement of body temperature can provide important information, albeit its accuracy may be limited. In most animals, temperature should be taken at the beginning of the examination to not artificially elevate the temperature during the physical exam. Heat support is typically indicated any time a patient's temperature is below the accepted core temperature range and cooling may be indicated whenever a patient's temperature exceeds a critical point.

ATP-induced hypothermia improves burn injury and relieves burn pain in mice

Thermal burn injury is a severe and life-threatening form of trauma that presents a significant challenge to clinical therapy. Therapeutic hypothermia has been shown to be beneficial in various human pathologies. Adenosine triphosphate (ATP) induces a hypothermic state that resembles hibernation-like suspended animation in mammals. This study investigates the potential protective role of ATP-induced hypothermia in thermal burn injury. Male C57BL/6 mice underwent a sham procedure or third-degree burn, and ATP-induced hypothermia was applied immediately or 1 h after burn injury. Our results show that ATP-induced hypothermia significantly improved burn depth progression and reduced collagen degradation. Moreover, hypothermia induced by ATP alleviated burn-induced hyperinflammatory responses and oxidative stress. Metabolomic profiling revealed that ATP-induced hypothermia reversed the shifts of metabolic profiles of the skin in burn mice. In addition, ATP-induced hypothermia relieved nociceptive and inflammatory pain, as observed in the antinociceptive test. Our findings suggest that ATP-induced hypothermia attenuates burn injury and provides new insights into first-aid therapy after thermal burn injury.

Circulating Galectin-3 in Patients with Cardiogenic Shock Complicating Acute Myocardial Infarction Treated with Mild Hypothermia: A Biomarker Sub-Study of the SHOCK-COOL Trial

Background: Galectin-3 (Gal-3) is considered a potential cardiovascular inflammatory marker that may provide additional risk stratification for patients with acute heart failure. It is unknown whether mild therapeutic hypothermia (MTH) impacts Gal-3 levels. Therefore, this biomarker study aimed to investigate the effect of MTH on Gal-3. Methods: In the randomized SHOCK-COOL trial, 40 patients with cardiogenic shock (CS) complicating acute myocardial infraction (AMI) were randomly assigned to the MTH (33 °C) or control group in a 1:1 ratio. Blood samples were collected on the day of admission/day 1, day 2, and day 3. Gal-3 level kinetics throughout these time points were compared between the MTH and control groups. Additionally, potential correlations between Gal-3 and clinical patient characteristics were assessed. Multiple imputations were performed to account for missing data. Results: In the control group, Gal-3 levels were significantly lower on day 3 than on day 1 (day 1 vs. day 3: 3.84 [IQR 2.04−13.3] vs. 1.79 [IQR 1.23−3.50] ng/mL; p = 0.049). Gal-3 levels were not significantly different on any day between the MTH and control groups (p for interaction = 0.242). Spearman’s rank correlation test showed no significant correlation between Gal-3 levels and sex, age, smoking, body mass index (BMI), and levels of creatine kinase-MB, creatine kinase, C-reactive protein, creatinine, and white blood cell counts (all p > 0.05). Patients with lower Gal-3 levels on the first day after admission demonstrated a higher risk of all-cause mortality at 30 days (hazard ratio, 2.67; 95% CI, 1.11−6.42; p = 0.029). In addition, Gal-3 levels on day 1 had a good predictive value for 30-day all-cause mortality with an area under the receiver operating characteristic curve of 0.696 (95% CI: 0.513−0.879), with an optimal cut-off point of less than 3651 pg/mL. Conclusions: MTH has no effect on Gal-3 levels in patients with CS complicating AMI compared to the control group. In addition, Gal-3 is a relatively stable biomarker, independent of age, sex, and BMI, and Gal-3 levels at admission might predict the risk of 30-day all-cause mortality.

Effects of temperature and humidity on peritonsillar abscess volume of emergency patients

Climate and temperature have long been considered in relation to human diseases and mortality. In this study, we investigated whether daily temperature and humidity and patients' personal history affect the volume of peritonsillar abscesses (PTAs). We included 52 patients with PTAs who were admitted to the emergency department of the study hospital; their computed tomography data were analyzed, and PTA volume was measured. We investigated the possible correlation between PTA volume and mean/minimum/maximum temperature and humidity. Furthermore, we obtained personal history data, including information on drinking status, smoking status, dental problems, and patients' treatment experiences at local clinics before visiting the emergency department. The mean PTA volume was 3.93 mL, which was significantly correlated with temperature differences between 1 and 2 days before hospitalization and the day of hospitalization (P < .05) and also with a lack of treatment experience at local clinics (P < .001). However, no significant correlation was noted between PTA volume and the mean/minimum/maximum temperature and humidity on the day of hospitalization (P > .05). Similar findings were obtained for drinking status, smoking status, and dental problems (P > .1). PTA volume appears to be strongly associated with temperature differences between 1 and 2 days before hospitalization and the day of hospitalization. Patients with treatment experience at local clinics exhibited substantial increases in PTA volume. Thus, an increased PTA volume may be observed in patients who visit the emergency department without any treatment experience at local clinics or from environments that differ considerably from their current environment in terms of temperature.

Therapeutic hypothermia for stroke: Unique challenges at the bedside

Therapeutic hypothermia has shown promise as a means to improving neurological outcomes at several neurological conditions. At the clinical level, it has been shown to improve outcomes in comatose survivors of cardiac arrest and in neonatal hypoxic ischemic encephalopathy, but has yet to be convincingly demonstrated in stroke. While numerous preclinical studies have shown benefit in stroke models, translating this to the clinical level has proven challenging. Major obstacles include cooling patients with typical stroke who are awake and breathing spontaneously but often have significant comorbidities. Solutions around these problems include selective brain cooling and cooling to lesser depths or avoiding hyperthermia. This review will cover the mechanisms of protection by therapeutic hypothermia, as well as recent progress made in selective brain cooling and the neuroprotective effects of only slightly lowering brain temperature. Therapeutic hypothermia for stroke has been shown to be feasible, but has yet to be definitively proven effective. There is clearly much work to be undertaken in this area.

Hemodynamics and vasopressor support during targeted temperature management after cardiac arrest with non-shockable rhythm: A post hoc analysis of a randomized controlled trial

Background

Patients admitted after cardiac arrest with non-shockable rhythm frequently experience hemodynamic instability. This study assessed the hemodynamic consequences of TTM in this sub population.

Methods

This is a post hoc analysis of the HYPERION trial (NCT01994772), that randomized patients to either hypothermia or normothermia after non-shockable rhythm related cardiac arrest. Patients with no, moderate or severe circulatory failure were identified with cardiovascular Sequential Organ Failure Assessment at randomization. Primary outcome was the number of patients at day 7 with resolution of shock, accounting for the risk of death (competing risk analysis). Secondary endpoint included neurological outcome and death at day-90.

Results

584 patients were included in the analysis: 195 (34%), 46 (8%) and 340 (59%) had no, moderate and severe circulatory failure, respectively. Resolution of circulatory failure at day 7 was more frequently observed in the normothermia group than in the TTM group (60% [95 %CI 54-66] versus 53% [95 %CI 46-60], Gray-test: p = 0.016). The severity of circulatory failure at randomization was associated with its less frequent resolution at day 7 accounting for the risk of death (76 % [62-86] versus 54% [49-59] for patients with moderate versus severe circulatory failure, Gray test, p < 0.001, respectively). At day 90, the proportion of patients with Cerebral Performance Category score of 1 or 2 was lower in patients presenting severe circulatory failure (p = 0.038).

Conclusion

Circulatory failure is frequent after CA with non-shockable rhythm. Its severity at admission and TTM were associated with delayed resolution of circulatory failure.

Second- and Third-Tier Therapies for Severe Traumatic Brain Injury

Intracranial hypertension is a common finding in patients with severe traumatic brain injury. These patients need treatment in the intensive care unit, where intracranial pressure monitoring and, whenever possible, multimodal neuromonitoring can be applied. A three-tier approach is suggested in current recommendations, in which higher-tier therapies have more significant side effects. In this review, we explain the rationale for this approach, and analyze the benefits and risks of each therapeutic modality. Finally, we discuss, based on the most recent recommendations, how this approach can be adapted in low- and middle-income countries, where available resources are limited.

Mild hypothermia ameliorates hepatic ischemia reperfusion injury by inducing RBM3 expression

Liver ischemia reperfusion injury (IRI) is a serious complication of certain liver surgeries, and it is difficult to prevent. As a potential drug-free treatment, mild hypothermia has been shown to promote positive outcomes in patients with IRI. However, the protective mechanism remains unclear. We established in vivo and in vitro models of hepatic ischemia reperfusion (IR) and mild hypothermia pretreatment. Hepatocytes were transfected with RNA-binding motif protein 3 (RBM3) overexpression plasmids, and IR was performed. Cell, culture medium, blood and tissue samples were collected to assess hepatic injury, oxidative stress, apoptosis and changes in RBM3 expression in the liver. Upregulation of RBM3 expression by mild hypothermia reduced the aminotransferase release, liver tissue injury and mitochondrial injury induced by liver IR. Hepatic IR-induced p38 and c-Jun N-terminal kinase (JNK) signaling pathway activation, oxidative stress injury and apoptosis could be greatly reversed by mild hypothermia. Overexpression of RBM3 mimicked the hepatoprotective effect of mild hypothermia. Mild hypothermia protects the liver from ischemia reperfusion-induced p38 and JNK signaling pathway activation, oxidative stress injury and apoptosis through the upregulation of RBM3 expression.

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.

Neuromonitoring in Severe Traumatic Brain Injury: A Bibliometric Analysis

Traumatic brain injury (TBI) is the leading cause of mortality and disability among trauma-related injuries. Neuromonitoring plays an essential role in the management and prognosis of patients with severe TBI. Our bibliometric study aimed to identify the knowledge base, define the research front, and outline the social networks on neuromonitoring in severe TBI. We conducted an electronic search for articles related to neuromonitoring in severe TBI in Scopus. A descriptive analysis retrieved evidence on the most productive authors and countries, the most cited articles, the most frequently publishing journals, and the most common author's keywords. Through a three-step network extraction process, we performed a collaboration analysis among universities and countries, a cocitation analysis, and a word cooccurrence analysis. A total of 1884 records formed the basis of our bibliometric study. We recorded an increasing scientific interest in the use of neuromonitoring in severe TBI. Czosnyka, Hutchinson, Menon, Smielewski, and Stocchetti were the most productive authors. The most cited document was a review study by Maas et al. There was an extensive collaboration among universities. The most common keywords were "intracranial pressure," with an increasing interest in magnetic resonance imaging and cerebral perfusion pressure monitoring. Neuromonitoring constitutes an area of active research. The present findings indicate that intracranial pressure monitoring plays a pivotal role in the management of severe TBI. Scientific interest shifts to magnetic resonance imaging and individualized patient care on the basis of optimal cerebral perfusion pressure.

Optimal Time of Collapse to Return of Spontaneous Circulation to Apply Targeted Temperature Management for Cardiac Arrest: A Bayesian Network Meta-Analysis

Background: Both the American Heart Association (AHA) and European Resuscitation Council (ERC) have strongly recommended targeted temperature management (TTM) for patients who remain in coma after return of spontaneous circulation (ROSC). However, the role of TTM, especially hypothermia, in cardiac arrest patients after TTM2 trials has become much uncertain.

Methods: We searched four online databases (PubMed, Embase, CENTRAL, and Web of Science) and conducted a Bayesian network meta-analysis. Based on the time of collapse to ROSC and whether the patient received TTM or not, we divided this analysis into eight groups (<20 min + TTM, <20 min, 20–39 min + TTM, 20–39 min, 40–59 min + TTM, 40–59 min, ≥60 min + TTM and ≥60 min) to compare their 30-day and at-discharge survival and neurologic outcomes.

Results: From an initial search of 3,023 articles, a total of 9,005 patients from 42 trials were eligible and were included in this network meta-analysis. Compared with other groups, patients in the <20 min + TTM group were more likely to have better survival and good neurologic outcomes (probability = 46.1 and 52.5%, respectively). In comparing the same time groups with and without TTM, only the survival and neurologic outcome of the 20–39 min + TTM group was significantly better than that of the 20–39 min group [odds ratio = 1.41, 95% confidence interval (1.04–1.91); OR = 1.46, 95% CI (1.07–2.00) respectively]. Applying TTM with <20 min or more than 40 min of collapse to ROSC did not improve survival or neurologic outcome [ <20 min vs. <20 min + TTM: OR = 1.02, 95% CI (0.61–1.71)/OR = 1.03, 95% CI (0.61–1.75); 40–59 min vs. 40–59 min + TTM: OR = 1.50, 95% CI (0.97–2.32)/OR = 1.40, 95% CI (0.81–2.44); ≧60 min vs. ≧60 min + TTM: OR = 2.09, 95% CI (0.70–6.24)/OR = 4.14, 95% CI (0.91–18.74), respectively]. Both survival and good neurologic outcome were closely related to the time from collapse to ROSC.

Conclusion: Survival and good neurologic outcome are closely associated with the time of collapse to ROSC. These findings supported that 20–40 min of collapse to ROSC should be a more suitable indication for TTM for cardiac arrest patients. Moreover, the future trials should pay more attention to these patients who suffer from moderate injury.

Systematic Review Registration: [https://inplasy.com/?s=202180027], identifier [INPLASY202180027]

Hemodynamic response to thermal stress varies with sex and age: a murine MRI study

PURPOSE

The cardiovascular (CV) system plays a vital role in thermoregulation because of its influence on heat transfer via forced convection and conduction by changes in blood distribution, blood velocity, and proximity of vessels to surrounding tissues. To fully understand the cardiovascular system's role in thermoregulation, blood distribution (influenced by cardiac output, vessel size, blood flow, and pressure) must be quantified, ideally across sex and age. Additionally, wall shear stress is quantified because it is an important metric in cardiovascular disease localization and progression. By investigating the effect of thermal conditions on wall shear stress at a healthy baseline, researchers can begin to study the confluence of thermal condition with pathology or exercise. The purpose of this study is to determine the influence of sex and age on the CV response to temperature. In this work, the effect of core body temperature on hemodynamics of the murine arterial and venous systems has been studied non-invasively, at multiple locations across age and sex.

METHODS

Male and female, adult and aged, mice (n = 20) were anesthetized and underwent MRI at 7 T. Data were acquired from four co-localized vessel pairs (the neck [carotid/jugular], torso [suprarenal and infrarenal aorta/inferior vena cava (IVC)], periphery [femoral artery/vein]) at core temperatures of 35, 36, 37, and 38 °C. Sixteen CINE, ECG-gated, phase contrast frames with one-directional velocity encoding (through plane) were acquired perpendicular to each vessel. Each frame was analyzed to quantify blood velocity and volumetric flow using a semi-automated in-house MATLAB script. Wall shear stress (WSS) was calculated using the Hagen-Poiseulle formula. A multivariable regression for WSS in the femoral artery was fitted with temperature, sex, age, body weight, and heart rate as variables.

RESULTS

Blood velocity and volumetric flow were quantified in eight vessels at four core body temperatures. Flow in the infrarenal IVC linearly increased with temperature for all groups (p = .002; adjusted means of slopes: male vs. female, 0.37 and 0.28 cm/(s × °C); adult vs. aged, 0.22 and 0.43 cm/(s × °C)). Comparing average volumetric flow response to temperature, groups differed for the suprarenal aorta (adult < aged, p < .05), femoral artery (adult < aged, p < .05), and femoral vein (adult male < aged male, p < .001). The two-way interaction terms of temperature and body weight and temperature and sex had the largest effect on wall shear stress.

CONCLUSIONS

Age, in particular, had a significant impact on hemodynamic response as measured by volumetric flow (e.g., aged males > adult males) and WSS at peak-systole (e.g., aged males < adult males). The hemodynamic data can provide physiologically-relevant parameters, including sex and age difference, to computational fluid dynamics models and provide baseline data for the healthy murine vasculature to use as a benchmark for investigations of a variety of physiological (thermal stress) and pathophysiological conditions of the cardiovascular system.

Tier-three therapies for refractory intracranial hypertension in adult head trauma

Refractory intracranial hypertension after traumatic brain injury (TBI) is defined as recurrent increase of intracranial pressure (ICP) above 20-22 mmHg for sustained period of time (10-15 min), despite conventional therapies, such as osmotic therapy, cerebral spinal fluid drainage and mild hyperventilation. As such, more aggressive treatments should be taken into consideration. In particular, therapeutic hypothermia, barbiturates administration and decompressive craniectomy are considered as tier-three or "salvage" interventions, as they have shown to be able to control refractory hypertension, but are also associated with an increased risk of significant side effects. The aim of this review is therefore to describe the evidence supporting the use of these tier-three therapies in the management of refractory intracranial hypertension in TBI patients.

Pharmacological Approach for Neuroprotection After Cardiac Arrest-A Narrative Review of Current Therapies and Future Neuroprotective Cocktail

Cardiac arrest (CA) results in global ischemia-reperfusion injury damaging tissues in the whole body. The landscape of therapeutic interventions in resuscitation medicine has evolved from focusing solely on achieving return of circulation to now exploring options to mitigate brain injury and preserve brain function after CA. CA pathology includes mitochondrial damage and endoplasmic reticulum stress response, increased generation of reactive oxygen species, neuroinflammation, and neuronal excitotoxic death. Current non-pharmacologic therapies, such as therapeutic hypothermia and extracorporeal cardiopulmonary resuscitation, have shown benefits in protecting against ischemic brain injury and improving neurological outcomes post-CA, yet their application is difficult to institute ubiquitously. The current preclinical pharmacopeia to address CA and the resulting brain injury utilizes drugs that often target singular pathways and have been difficult to translate from the bench to the clinic. Furthermore, the limited combination therapies that have been attempted have shown mixed effects in conferring neuroprotection and improving survival post-CA. The global scale of CA damage and its resultant brain injury necessitates the future of CA interventions to simultaneously target multiple pathways and alleviate the hemodynamic, mitochondrial, metabolic, oxidative, and inflammatory processes in the brain. This narrative review seeks to highlight the current field of post-CA neuroprotective pharmaceutical therapies, both singular and combination, and discuss the use of an extensive multi-drug cocktail therapy as a novel approach to treat CA-mediated dysregulation of multiple pathways, enhancing survival, and neuroprotection.

Targeted temperature management at 33 degrees Celsius in patients with high-grade aneurysmal subarachnoid hemorrhage: a protocol for a multicenter randomized controlled study

Background

Studies on the use of therapeutic hypothermia (TH) to improve the outcome of high-grade aneurysmal subarachnoid hemorrhage (aSAH), show promising, though conflicting results because of the lack of high-quality trials. The aim of this study is to evaluate the safety and efficacy of TH (maintaining bladder temperature at 33 °C for ≥72 h) to treat patients with high-grade aSAH (Hunt-Hess grade IV-V).

Methods

A multicenter, randomized, controlled clinical trial will be conducted for October 2020 to September 2024 involving 10 clinics. Patients who meet the inclusion criteria will be randomized 1:1 to a TH group and a normothermia group. The trial will enroll 96 participants in TH group and normothermia one, respectively. The trial was registered with ClinicalTrials.gov (NCT03442608) on February 22, 2018. Following conventional treatment for aSAH, patients will undergo either TH for at least 72 h or normothermia. The primary endpoint is the Glasgow outcome scale at 6 months after bleeding. The secondary endpoints are: (I) mortality at 6 months after bleeding; (II) intracranial pressure; (III) intensive care unit stay; and (IV) hospital stay. The safety endpoints include neurological, infectious, intestinal, circulatory, coagulation, and bleeding complications, electrolyte disorders, and other complications.

Discussion

If the study hypothesis is confirmed, TH at 33 °C in patients with high-grade aSAH may become a promising treatment strategy for improving 6-month outcome.

Trial registration

The trial has been registered at ClinicalTrials.gov (ID: NCT03442608).

Cheap and simple, could it get even cooler? Mild hypothermia and COVID-19

Purpose

The pathophysiology theories of COVID-19 attach the injury of target organs to faulty immune responses and occasionally hyper-inflammation. The damage frequently extends beyond the respiratory system, accompanying cardiovascular, renal, central nervous system, and/or coagulation derangements. Tumor necrosis factor-α (TNF-α) and interleukins (IL)-1 and − 6 suppression may improve outcomes, as experimentally shown. Targeted therapies have been proposed, but mild therapeutic hypothermia—a more multifaceted approach—could be suitable.

Findings

According to evidence derived from previous applications, therapeutic hypothermia diminishes the release of IL-1, IL-6, and TNF-α in serum and at the tissue level. PaCO2 is reduced and the PaO2/FiO2 ratio is increased, possibly lasting after rewarming. Cooling might mitigate both ventilator and infectious-induced lung injury, and suppress microthrombi development, enhancing V/Q mismatch. Improvements in microhemodynamics and tissue O2 diffusion, along with the ischemia-tolerance heightening of tissues, could be reached. Arrhythmia incidence diminishes. Moreover, hypothermia may address the coagulopathy, promoting normalization of both hypo- and hyper-coagulability patterns, which are apparently sustained after a return to normothermia.

Conclusions

As per prior therapeutic hypothermia literature, the benefits regarding inflammatory response and organic damage might be seen. Following the safety-cornerstones of the technique, the overall infection rate and infection-related mortality are not expected to rise, and increased viral replication does not seem to be a concern. Therefore, the possibility of a low cost and widely available therapy being capable of improving COVID-19 outcomes deserves further study.

A Clinical Test for a Newly Developed Direct Brain Cooling System for the Injured Brain and Pattern of Cortical Brainwaves in Cooling, Noncooling, and Dead Brain

To ensure the direct delivery of therapeutic hypothermia at a selected constant temperature to the injured brain, a newly innovated direct brain cooling system was constructed. The practicality, effectiveness, and safety of this system were clinically tested in our initial series of 14 patients with severe head injuries. The patients were randomized into two groups: direct brain cooling at 32°C and the control group. All of them received intracranial pressure (ICP), focal brain oxygenation, brain temperature, and direct cortical brainwave monitoring. The direct brain cooling group did better in the Extended Glasgow Outcome Scale at the time of discharge and at 6 months after trauma. This could be owing to a trend in the monitored parameters; reduction in ICP, increment in cerebral perfusion pressure, optimal brain redox regulation, near-normal brain temperature, and lessening of epileptic-like brainwave activities are likely the reasons for better outcomes in the cooling group. Finally, this study depicts interesting cortical brainwaves during a transition time from being alive to dead. It is believed that the demonstrated cortical brainwaves follow the principles of quantum physics.

Perioperative care of the adult diabetic patient

The prevalence of diabetes mellitus is rapidly increasing in the UK, presenting greater complexity in its management when in the presence of other comorbidities. In the care of the adult perioperative patient with diabetes mellitus not only can symptoms can be difficult to attribute to one specific cause but also the onset of complications can be rapid. This article discusses the aetiology and key concerns during the perioperative pathway of care for successful management of the adult diabetic patient.

Comparison Between Two Pharmacologic Strategies to Alleviate Rewarming Shock: Vasodilation vs. Inodilation

Rewarming from hypothermia is often challenged by coexisting cardiac dysfunction, depressed organ blood flow (OBF), and increased systemic vascular resistance. Previous research shows cardiovascular inotropic support and vasodilation during rewarming to elevate cardiac output (CO). The present study aims to compare the effects of inodilatation by levosimendan (LS) and vasodilation by nitroprusside (SNP) on OBF and global oxygen transport during rewarming from hypothermia. We used an in vivo experimental rat model of 4 h 15°C hypothermia and rewarming. A stable isotope-labeled microsphere technique was used to determine OBF. Cardiac and arterial pressures were monitored with fluid-filled pressure catheters, and CO was measured by thermodilution. Two groups were treated with either LS (n = 7) or SNP (n = 7) during the last hour of hypothermia and throughout rewarming. Two groups served as hypothermic (n = 7) and normothermic (n = 6) controls. All hypothermia groups had significantly reduced CO, oxygen delivery, and OBF after rewarming compared to their baseline values. After rewarming, LS had elevated CO significantly more than SNP (66.57 ± 5.6/+30% vs. 54.48 ± 5.2/+14%) compared to the control group (47.22 ± 3.9), but their ability to cause elevation of brain blood flow (BBF) was the same (0.554 ± 0.180/+81 vs. 0.535 ± 0.208/+75%) compared to the control group (0.305 ± 0.101). We interpret the vasodilator properties of LS and SNP to be the primary source to increase organ blood flow, superior to the increase in CO.

The Effects of Pharmacological Hypothermia Induced by Neurotensin Receptor Agonist ABS 201 on Outcomes of CPR

Neurotensin is an endogenous tridecapeptide that binds to neurotensin receptors in the brain, which induce hypothermia. The aim of this study was to investigate whether the receptor agonist ABS 201 could induce therapeutic hypothermia and improve postresuscitation outcomes in a ventricular fibrillation cardiac arrest (VFCA) rat model. VF was electrically induced in 12 rats. Defibrillation was achieved after 6 min of cardiopulmonary resuscitation. After successful resuscitation, animals were randomized to receive ABS 201 (8 mg/kg/h) or placebo. Postresuscitation myocardial function and neurological deficit scores (NDS) were assessed, and postresuscitation survival duration was observed for up to 72 h. After administration of ABS 201, blood temperature decreased significantly from 37°C to 34°C, and was maintained for 2.5 h. There was a significant improvement of postresuscitation myocardial dysfunction, NDS, and survival duration in animals treated with ABS 201. These results demonstrated that ABS 201 induces therapeutic hypothermia in a VFCA rat model, ameliorates postresuscitation myocardial-neurological dysfunction, and prolongs survival duration. ABS 201 may therefore be an alternative method to induce therapeutic hypothermia with current cooling methods and improve postresuscitation outcomes.

Ketamine-dexmedetomidine combination and controlled mild hypothermia for the treatment of long-lasting and super-refractory status epilepticus in 3 dogs suffering from idiopathic epilepsy

OBJECTIVE

To describe the use of a ketamine-dexmedetomidine combination and mild hypothermia for the treatment of status epilepticus in 3 dogs that did not respond to GABAergic medication.

CASE SERIES SUMMARY

Three dogs, each with a diagnosis of idiopathic epilepsy, were presented to the emergency department in a state of status epilepticus. The dogs were treated unsuccessfully with benzodiazepine as a first-line therapy that was followed by IV propofol anesthesia maintained for at least 12 hours. When general anesthesia was discontinued, seizures reoccurred. All 3 dogs then received a bolus of ketamine (1 mg/kg, IV) over a period of 5 minutes that was followed by a bolus of dexmedetomidine (3 μg/kg, IV) over the same time period and then followed by a continuous infusion for 12 hours of ketamine at a constant rate of 1 mg/kg/h and dexmedetomidine at a variable rate of 3-7 μg/kg/h. Body temperature was maintained between 36.7 and 37.7°C at a state of mild hypothermia throughout treatment. The dogs recovered uneventfully over 48 hours after treatment was discontinued with no evidence of seizures. No notable alterations in physiological parameters were observed during the drug infusions. All dogs were discharged following examinations that showed normal neurological function.

NEW OR UNIQUE INFORMATION PROVIDED

This case series highlights the potential benefits of a ketamine-dexmedetomidine infusion combined with mild hypothermia for the treatment of status epilepticus refractory to GABAergic therapy in dogs suffering from idiopathic epilepsy. After the dogs were weaned from the ketamine-dexmedetomidine infusion, all dogs experienced complete recovery. Thus, this case series introduces a novel approach to treat this intense condition.

Inducing Brain Cooling Without Core Temperature Reduction in Pigs Using a Novel Nasopharyngeal Method: An Effectiveness and Safety Study

BACKGROUND

Acute brain lesions constitute an alarming public health concern. Neuroprotective therapies have been implemented to stabilize, prevent, or reduce brain lesions, thus improving neurological outcomes and survival rates. Hypothermia is the most effective approach, mainly attributed to the reduction in cellular metabolic activity. Whole-body cooling is currently implemented by healthcare professionals; however, adverse events are frequent, limiting the potential benefits of therapeutic hypothermia. Therefore, selective methods have been developed to reduce adverse events while delivering neuroprotection. Nasopharyngeal approaches are the safest and most effective methods currently considered. Our primary objective was to determine the effects of a novel nasopharyngeal catheter on the brain temperature of pigs.

METHODS

In this prospective, non-randomized, interventional experimental trial, 10 crossbred pigs underwent nasopharyngeal cooling for 60 min followed by 15 min of rewarming. Nasopharyngeal catheters were inserted into the left nostril and properly positioned at the nasopharyngeal cavity.

RESULTS

Nasopharyngeal cooling was associated with a decrease in brain temperature, which was more significant in the left cerebral hemisphere (p = 0.01). There was a reduction of 1.47 ± 0.86 °C in the first 5 min (p < 0.001), 2.45 ± 1.03 °C within 10 min (p < 0.001), and 4.45 ± 1.36 °C after 1 h (p < 0.001). The brain-core gradient was 4.57 ± 0.87 °C (p < 0.001). Rectal, esophageal, and pulmonary artery temperatures and brain and systemic hemodynamic parameters, remained stable during the procedure. Following brain cooling, values of oxygen partial pressure in brain tissue significantly decreased. No mucosal lesions were detected during nasal, pharyngeal, or oral inspection after nasopharyngeal catheter removal.

CONCLUSIONS

In this study, a novel nasopharyngeal cooling catheter effectively induced and maintained exclusive brain cooling when combined with effective counter-warming methods. Exclusive brain cooling was safe with no device-related local or systemic complications and may be desired in selected patient populations.

Assessing structural and functional response of murine vasculature to acute β-adrenergic stimulation in vivo during hypothermic and hyperthermic conditions

Background: Because of the importance of adrenoreceptors in regulating the cardiovascular (CV) system and the role of the CV system in thermoregulation, understanding the response to these two stressors is of interest. The purpose of this study was to assess changes of arterial geometry and function in vivo during thermal and β-adrenergic stress induced in mice and quantified by MRI.Methods: Male mice were anesthetized and imaged at 7 T. Anatomical and functional data were acquired from the neck (carotid artery), torso (suprarenal and infrarenal aorta and iliac artery) and periphery (femoral artery). Intravenous dobutamine (tail vein catheter, 40 µg/kg/min, 0.12 mL/h) was used as β-adrenergic stressor. Baseline and dobutamine data were acquired at minimally hypothermic (35 °C) and minimally hyperthermic (38 °C) core temperatures. Cross-sectional vessel area and maximum cyclic strain were measured across the cardiac cycle.Results: Vascular response varied by location and by core temperature. For minimally hypothermic conditions (35 °C), average, maximum and minimum areas decreased with dobutamine only at the suprarenal aorta (avg: -17.9%, max: -13.5%, min: -21.4%). For minimally hyperthermic conditions (38 °C), vessel areas decreased between baseline and dobutamine at the carotid (avg: -19.6%, max: -15.5%, min: -19.3%) and suprarenal aorta (avg: -24.2%, max: -17.4%, min: -17.3%); whereas, only the minimum vessel area decreased for the iliac artery (min: -14.4%). Maximum cyclic strain increased between baseline and dobutamine at the iliac artery for both conditions and at the suprarenal aorta at hyperthermic conditions.Conclusions: At hypothermic conditions, the vessel area response to dobutamine is diminished compared to hyperthermic conditions where the vessel area response mimics normothermic dobutamine conditions. The varied response emphasizes the need to monitor and control body temperature during medical conditions or treatments that may be accompanied by hypothermia, especially when vasoactive agents are used.

Selective Thermal Stimulation Delays the Progression of Vasoconstriction During Body Cooling

The objective of this study was to test the feasibility of Selective Thermal Stimulation (STS) as a method to upregulate glabrous skin blood flow. STS is accomplished by mild surface heating along the spinal cord. 4 healthy subjects were tested in this study. Each participated in a control experiment and an intervention experiment (STS). Both experiments included establishing a maximum level of vasodilation, considered unique to a subject on a test day, and then cooling to a maximum level of vasoconstriction. Perfusion was measured by a laser Doppler flow probe on the index fingertip. The percent of perfusion in the range of minimum to maximum was the primary outcome variable. The data was fit to a linear mixed effects model to determine if STS had a significant influence on perfusion during whole body cooling. STS had a statistically significant effect on perfusion and increased glabrous skin blood flow by 16.3% (P<.001, CI [13.1%, 19.5%]) as skin temperature was decreased. This study supports the theory that STS improves the heat exchanger efficiency of palmar and plantar surfaces by increasing the blood flow.

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.

Pediatric Post–Cardiac Arrest Care: A Scientific Statement From the American Heart Association

Successful resuscitation from cardiac arrest results in a post–cardiac arrest syndrome, which can evolve in the days to weeks after return of sustained circulation. The components of post–cardiac arrest syndrome are brain injury, myocardial dysfunction, systemic ischemia/reperfusion response, and persistent precipitating pathophysiology. Pediatric post–cardiac arrest care focuses on anticipating, identifying, and treating this complex physiology to improve survival and neurological outcomes. This scientific statement on post–cardiac arrest care is the result of a consensus process that included pediatric and adult emergency medicine, critical care, cardiac critical care, cardiology, neurology, and nursing specialists who analyzed the past 20 years of pediatric cardiac arrest, adult cardiac arrest, and pediatric critical illness peer-reviewed published literature. The statement summarizes the epidemiology, pathophysiology, management, and prognostication after return of sustained circulation after cardiac arrest, and it provides consensus on the current evidence supporting elements of pediatric post–cardiac arrest care.

Therapeutic hypothermia: Applications in adults with acute ischemic stroke

The advent of mechanical thrombectomy and increasing alteplase use have transformed the care of patients with acute ischemic stroke. Patients with major arterial occlusions with poor outcomes now have a chance of returning to independent living in more than half of the cases. However, many patients with these severe strokes suffer major disability despite these therapies. The search is ongoing for agents that can be combined with thrombectomy to achieve better recovery through halting infarct growth and mitigating injury after ischemic stroke. Several studies in animals and humans have demonstrated that therapeutic hypothermia (TH) offers potential to interrupt the ischemic cascade, reduce infarct volume, and improve functional independence. We performed a literature search to look up recent advances in the use of TH surrounding the science, efficacy, and feasibility of inducing TH in modern stroke treatments. While protocols remain controversial, there is a real opportunity to combine TH with the existing therapies to improve outcome in adults with acute ischemic stroke.

Therapeutic hypothermia to reduce intracranial pressure after traumatic brain injury: the Eurotherm3235 RCT

BACKGROUND

Traumatic brain injury (TBI) is a major cause of disability and death in young adults worldwide. It results in around 1 million hospital admissions annually in the European Union (EU), causes a majority of the 50,000 deaths from road traffic accidents and leaves a further ≈10,000 people severely disabled.

OBJECTIVE

The Eurotherm3235 Trial was a pragmatic trial examining the effectiveness of hypothermia (32-35 °C) to reduce raised intracranial pressure (ICP) following severe TBI and reduce morbidity and mortality 6 months after TBI.

DESIGN

An international, multicentre, randomised controlled trial.

SETTING

Specialist neurological critical care units.

PARTICIPANTS

We included adult participants following TBI. Eligible patients had ICP monitoring in place with an ICP of > 20 mmHg despite first-line treatments. Participants were randomised to receive standard care with the addition of hypothermia (32-35 °C) or standard care alone. Online randomisation and the use of an electronic case report form (CRF) ensured concealment of random treatment allocation. It was not possible to blind local investigators to allocation as it was obvious which participants were receiving hypothermia. We collected information on how well the participant had recovered 6 months after injury. This information was provided either by the participant themself (if they were able) and/or a person close to them by completing the Glasgow Outcome Scale - Extended (GOSE) questionnaire. Telephone follow-up was carried out by a blinded independent clinician.

INTERVENTIONS

The primary intervention to reduce ICP in the hypothermia group after randomisation was induction of hypothermia. Core temperature was initially reduced to 35 °C and decreased incrementally to a lower limit of 32 °C if necessary to maintain ICP at < 20 mmHg. Rewarming began after 48 hours if ICP remained controlled. Participants in the standard-care group received usual care at that centre, but without hypothermia.

MAIN OUTCOME MEASURES

The primary outcome measure was the GOSE [range 1 (dead) to 8 (upper good recovery)] at 6 months after the injury as assessed by an independent collaborator, blind to the intervention. A priori subgroup analysis tested the relationship between minimisation factors including being aged < 45 years, having a post-resuscitation Glasgow Coma Scale (GCS) motor score of < 2 on admission, having a time from injury of < 12 hours and patient outcome.

RESULTS

We enrolled 387 patients from 47 centres in 18 countries. The trial was closed to recruitment following concerns raised by the Data and Safety Monitoring Committee in October 2014. On an intention-to-treat basis, 195 participants were randomised to hypothermia treatment and 192 to standard care. Regarding participant outcome, there was a higher mortality rate and poorer functional recovery at 6 months in the hypothermia group. The adjusted common odds ratio (OR) for the primary statistical analysis of the GOSE was 1.54 [95% confidence interval (CI) 1.03 to 2.31]; when the GOSE was dichotomised the OR was 1.74 (95% CI 1.09 to 2.77). Both results favoured standard care alone. In this pragmatic study, we did not collect data on adverse events. Data on serious adverse events (SAEs) were collected but were subject to reporting bias, with most SAEs being reported in the hypothermia group.

CONCLUSIONS

In participants following TBI and with an ICP of > 20 mmHg, titrated therapeutic hypothermia successfully reduced ICP but led to a higher mortality rate and worse functional outcome.

LIMITATIONS

Inability to blind treatment allocation as it was obvious which participants were randomised to the hypothermia group; there was biased recording of SAEs in the hypothermia group. We now believe that more adequately powered clinical trials of common therapies used to reduce ICP, such as hypertonic therapy, barbiturates and hyperventilation, are required to assess their potential benefits and risks to patients.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN34555414.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 45. See the NIHR Journals Library website for further project information. The European Society of Intensive Care Medicine supported the pilot phase of this trial.

Energetic Trade-Offs and Hypometabolic States Promote Disease Tolerance

Host defenses against pathogens are energetically expensive, leading ecological immunologists to postulate that they might participate in energetic trade-offs with other maintenance programs. However, the metabolic costs of immunity and the nature of physiologic trade-offs it engages are largely unknown. We report here that activation of immunity causes an energetic trade-off with the homeothermy (the stable maintenance of core temperature), resulting in hypometabolism and hypothermia. This immunity-induced physiologic trade-off was independent of sickness behaviors but required hematopoietic sensing of lipopolysaccharide (LPS) via the toll-like receptor 4 (TLR4). Metabolomics and genome-wide expression profiling revealed that distinct metabolic programs supported entry and recovery from the energy-conserving hypometabolic state. During bacterial infections, hypometabolic states, which could be elicited by competition for energy between maintenance programs or energy restriction, promoted disease tolerance. Together, our findings suggest that energy-conserving hypometabolic states, such as dormancy, might have evolved as a mechanism of tissue tolerance.

Hypothermic neuroprotection during reperfusion following exposure to aglycemia in central white matter is mediated by acidification

Hypoglycemia is a common iatrogenic consequence of type 1 diabetes therapy that can lead to central nervous system injury and even death if untreated. In the absence of clinically effective neuroprotective drugs we sought to quantify the putative neuroprotective effects of imposing hypothermia during the reperfusion phase following aglycemic exposure to central white matter. Mouse optic nerves (MONs), central white matter tracts, were superfused with oxygenated artificial cerebrospinal fluid (aCSF) containing 10 mmol/L glucose at 37°C. The supramaximal compound action potential (CAP) was evoked and axon conduction was assessed as the CAP area. Extracellular lactate was measured using an enzyme biosensor. Exposure to aglycemia, simulated by omitting glucose from the aCSF, resulted in axon injury, quantified by electrophysiological recordings, electron microscopic analysis confirming axon damage, the extent of which was determined by the duration of aglycemia exposure. Hypothermia attenuated injury. Exposing MONs to hypothermia during reperfusion resulted in improved CAP recovery compared with control recovery measured at 37°C, an effect attenuated in alkaline aCSF. Hypothermia decreases pH implying that the hypothermic neuroprotection derives from interstitial acidification. These results have important clinical implications demonstrating that hypothermic intervention during reperfusion can improve recovery in central white matter following aglycemia.

Intravascular versus surface cooling for targeted temperature management after out-of-hospital cardiac arrest: an analysis of the TTH48 trial

Background

The aim of this study was to explore the performance and outcomes for intravascular (IC) versus surface cooling devices (SFC) for targeted temperature management (TTM) after out-of-hospital cardiac arrest.

Methods

A retrospective analysis of data from the Time-differentiated Therapeutic Hypothermia (TTH48) trial (NCT01689077), which compared whether TTM at 33 °C for 48 h results in better neurologic outcomes compared with standard 24-h duration. Devices were assessed for the speed of cooling and rewarming rates. Precision was assessed by measuring temperature variability (TV), i.e., the standard deviation (SD) of all temperature measurements in the cooling phase. Main outcomes were overall mortality and poor neurological outcome, including death, severe disability, or vegetative status.

Results

A total of 352 patients had available data and were included in the analysis; of those, 218 (62%) were managed with IC. A total of 114/218 (53%) patients with IC and 61/134 (43%) with SFC were cooled for 48 h (p = 0.22). Time to target temperature (≤ 34 °C) was significantly shorter for patients treated with endovascular devices (2.2 [1.1–4.0] vs. 4.2 [2.7–6.0] h, p < 0.001), but temperature was also lower on admission (35.0 [34.2–35.6] vs. 35.3 [34.5–35.8]°C; p = 0.02) and cooling rate was similar (0.4 [0.2–0.8] vs. 0.4 [0.2–0.6]°C/h; p = 0.14) when compared to SFC. Temperature variability was significantly lower in the endovascular device group when compared with SFC methods (0.6 [0.4–0.9] vs. 0.7 [0.5–1.0]°C; p = 0.007), as was rewarming rate (0.31 [0.22–0.44] vs. 0.37 [0.29–0.49]°C/hour; p = 0.02). There was no statistically significant difference in mortality (endovascular 65/218, 29% vs. others 43/134, 32%; p = 0.72) or poor neurological outcome (endovascular 69/218, 32% vs. others 51/134, 38%; p = 0.24) between type of devices.

Conclusions

Endovascular cooling devices were more precise than SFC methods in patients cooled at 33 °C after out-of-hospital cardiac arrest. Main outcomes were similar with regard to the cooling methods.

Clinicopathological prognostic indicators of survival and pathological findings in cold-stressed Florida manatees Trichechus manatus latirostris

Cold-stress syndrome (CSS) is a leading natural cause of mortality in free-ranging Florida manatees Trichechus manatus latirostris, but comprehensive investigations into blood analyte derangements and prognostic indicators in CSS are lacking. The objectives of this study were to (1) compare admission blood analyte data of manatees pre and post rehabilitation for CSS to identify clinicopathological derangements, (2) identify blood analyte prognostic indicators for survival, and (3) correlate post-mortem anatomic pathological changes with clinicopathological findings to improve the understanding of CS pathophysiology. CSS manatees admitted to a rehabilitation facility between 2007 and 2017 were included: 59 manatees with data for clinicopathological analysis (7 non-survivors and 49 survivors) and 14 manatees with necropsy data (7 with and 7 without blood analyte data). Main interpretive clinicopathological findings indicated systemic inflammation, bone marrow damage, diuresis, malnutrition, tissue necrosis, fat mobilization, hepatic impairment, acid-base imbalances, and gastrointestinal ulceration. The best diagnostically performing prognostic indicators for survival included platelet concentration, aspartate aminotransferase, calcium, and blood urea nitrogen. The main anatomic pathological findings were cutaneous lesions (n = 14), lipid depletion (n = 12), upper gastrointestinal ulceration and/or hemorrhage (n = 9), and pneumonia (n = 5). Based on the identified blood prognostic indicators interpreted in the context of anatomic pathological findings, multi-organ tissue injury, gastrointestinal ulceration and/or hemorrhage, and hemodynamic and platelet derangements are the presumptive major factors of CSS manatee mortality. These results contribute to the understanding of the complex CSS pathophysiology and offer the use of blood analyte prognostic indicators as a clinically applicable tool for the medical care of manatees during rehabilitation, thereby contributing to increased rehabilitation success and conservation of the Florida manatee.

Comparison between Gel Pad Cooling Device and Water Blanket during Target Temperature Management in Cardiac Arrest Patients

Background:

Target temperature management (TTM) improves neurological outcomes for comatose survivors of out-of-hospital cardiac arrest. We compared the efficacy and safety of a gel pad cooling device (GP) and a water blanket (WB) during TTM.

Methods:

We performed a retrospective analysis in a single hospital, wherein we measured the time to target temperature (<34℃) after initiation of cooling to evaluate the effectiveness of the cooling method. The temperature farthest from 33℃ was selected every hour during maintenance. Generalized estimation equation analysis was used to compare the absolute temperature differences from 33℃ during the maintenance period. If the selected temperature was not between 32℃ and 34℃, the hour was considered a deviation from the target. We compared the deviation rates during hypothermia maintenance to evaluate the safety of the different methods.

Results:

A GP was used for 23 patients among of 53 patients, and a WB was used for the remaining. There was no difference in baseline temperature at the start of cooling between the two patient groups (GP, 35.7℃ vs. WB, 35.6℃; P=0.741). The time to target temperature (134.2 minutes vs. 233.4 minutes, P=0.056) was shorter in the GP patient group. Deviation from maintenance temperature (2.0% vs. 23.7%, P<0.001) occurred significantly more frequently in the WB group. The mean absolute temperature difference from 33℃ during the maintenance period was 0.19℃ (95% confidence interval [CI], 0.17℃ to 0.21℃) in the GP group and 0.76℃ (95% CI, 0.71℃ to 0.80℃) in the WB group. GP significantly decreased this difference by 0.59℃ (95% CI, 0.44℃ to 0.75℃; P<0.001).

Conclusions:

The GP was superior to the WB for strict temperature control during TTM.

Out-of-hospital initiation of hypothermia in ST-segment elevation myocardial infarction: a randomised trial

Objective

To evaluate the effect of prereperfusion hypothermia initiated in the out-of-hospital setting in awake patients with ST-segment elevation myocardial infarction (STEMI) on myocardial salvage measured by cardiac MRI (CMR).

Methods

Hypothermia was initiated within 6 hours of symptom onset by the emergency medical service with surface cooling pads and cold saline, and continued in the cath lab with endovascular cooling (target temperature: ≤35°C at time of reperfusion). Myocardial salvage index (using CMR) was compared in a randomised, controlled, open-label, endpoint blinded trial to a not-cooled group of patients at day 4±2 after the event.

Results

After postrandomisation exclusion of 19 patients a total of 101 patients were included in the intention-to-treat analysis (control group: n=54; hypothermia group: n=47). Target temperature was reached in 38/47 patients (81%) in the intervention group. Study-related interventions resulted in a delay in time from first medical contact to reperfusion of 14 min (control group 89±24 min; hypothermia group 103±21 min; p<0.01). Myocardial salvage index was 0.37 (±0.26) in the control group and 0.43 (±0.27) in the hypothermia group (p=0.27). No differences in cardiac biomarkers or clinical outcomes were found. In a CMR follow-up 6 months after the initial event no significant differences were detected.

Conclusion

Out-of-hospital induced therapeutic hypothermia as an adjunct to primary percutaneous coronary intervention did not improve myocardial salvage in patients with STEMI.

Trial registration number

NCT01777750

Understanding therapeutic hypothermia

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

Cross-sectional areas of deep/core veins are smaller at lower core body temperatures

The cardiovascular system plays a crucial role in thermoregulation. Deep core veins, due to their large size and role in returning blood to the heart, are an important part of this system. The response of veins to increasing core temperature has not been adequately studied in vivo. Our objective was to noninvasively quantify in C57BL/6 mice the response of artery-vein pairs to increases in body temperature. Adult male mice were anesthetized and underwent magnetic resonance imaging. Data were acquired from three colocalized vessel pairs (the neck [carotid/jugular], torso [aorta/inferior vena cava (IVC)], periphery [femoral artery/vein]) at core temperatures of 35, 36, 37, and 38°C. Cross-sectional area increased with increasing temperature for all vessels, excluding the carotid. Average area of the jugular, aorta, femoral artery, and vein linearly increased with temperature (0.10, 0.017, 0.017, and 0.027 mm2 /°C, respectively; P < 0.05). On average, the IVC has the largest venous response for area (18.2%/°C, vs. jugular 9.0 and femoral 10.9%/°C). Increases in core temperature from 35 to 38 °C resulted in an increase in contact length between the aorta/IVC of 29.3% (P = 0.007) and between the femoral artery/vein of 28.0% (P = 0.03). Previously unidentified increases in the IVC area due to increasing core temperature are biologically important because they may affect conductive and convective heat transfer. Vascular response to temperature varied based on location and vessel type. Leveraging noninvasive methodology to quantify vascular responses to temperature could be combined with bioheat modeling to improve understanding of thermoregulation.

Cerebral venous thrombosis requiring invasive treatment for elevated intracranial pressure in women with combined hormonal contraceptive intake: risk factors, anatomical distribution, and clinical presentation

OBJECTIVE Women taking combined hormonal contraceptives (CHCs) are generally considered to be at low risk for cerebral venous thrombosis (CVT). When it does occur, however, intensive care and neurosurgical management may, in rare cases, be needed for the control of elevated intracranial pressure (ICP). The use of nonsurgical strategies such as barbiturate coma and induced hypothermia has never been reported in this context. The objective of this study is to determine predictive factors for invasive or surgical ICP treatment and the potential complications of nonsurgical strategies in this population. METHODS The authors conducted a 2-center, retrospective chart review of 168 cases of CVT in women between 2000 and 2012. Eligible patients were classified as having had a mild or a severe clinical course, the latter category including all patients who underwent invasive or surgical ICP treatment and all who had an unfavorable outcome (modified Rankin Scale score ≥ 3 or Glasgow Outcome Scale score ≤ 3). The Mann-Whitney U-test was used for continuous parameters and Fisher's exact test for categorical parameters, and odds ratios were calculated with statistical significance set at p ≤ 0.05. RESULTS Of the 168 patients, 57 (age range 16-49 years) were determined to be eligible for the study. Six patients (10.5%) required invasive or surgical ICP treatment. Three patients (5.3%) developed refractory ICP > 30 mm Hg despite early surgical decompression; 2 of them (3.5%) were treated with barbiturate coma and induced hypothermia, with documented infectious, thromboembolic, and hemorrhagic complications. Coma on admission, thrombosis of the deep venous system with consecutive hydrocephalus, intraventricular hemorrhage, and hemorrhagic venous infarction were associated with a higher frequency of surgical intervention. Coma, quadriparesis on admission, and hydrocephalus were more commonly seen among women with unfavorable outcomes. Thrombosis of the transverse sinus was less common in patients with an unfavorable outcome, with similar distribution in patients needing invasive or surgical ICP treatment. CONCLUSIONS The need for invasive or surgical ICP treatment in women taking CHCs who have CVT is partly predictable on the basis of the clinical and radiological findings on admission. The use of nonsurgical treatments for refractory ICP, such as barbiturate coma and induced hypothermia, is associated with systemic infectious and hematological complications and may worsen morbidity in this patient population. The significance of these factors should be studied in larger multicenter cohorts.

Hypothesis: Fever control, a niche for alpha-2 agonists in the setting of septic shock and severe acute respiratory distress syndrome?

During severe septic shock and/or severe acute respiratory distress syndrome (ARDS) patients present with a limited cardio-ventilatory reserve (low cardiac output and blood pressure, low mixed venous saturation, increased lactate, low PaO2/FiO2 ratio, etc.), especially when elderly patients or co-morbidities are considered. Rescue therapies (low dose steroids, adding vasopressin to noradrenaline, proning, almitrine, NO, extracorporeal membrane oxygenation, etc.) are complex. Fever, above 38.5-39.5°C, increases both the ventilatory (high respiratory drive: large tidal volume, high respiratory rate) and the metabolic (increased O2 consumption) demands, further limiting the cardio-ventilatory reserve. Some data (case reports, uncontrolled trial, small randomized prospective trials) suggest that control of elevated body temperature ("fever control") leading to normothermia (35.5-37°C) will lower both the ventilatory and metabolic demands: fever control should simplify critical care management when limited cardio-ventilatory reserve is at stake. Usually fever control is generated by a combination of general anesthesia ("analgo-sedation", light total intravenous anesthesia), antipyretics and cooling. However general anesthesia suppresses spontaneous ventilation, making the management more complex. At variance, alpha-2 agonists (clonidine, dexmedetomidine) administered immediately following tracheal intubation and controlled mandatory ventilation, with prior optimization of volemia and atrio-ventricular conduction, will reduce metabolic demand and facilitate normothermia. Furthermore, after a rigorous control of systemic acidosis, alpha-2 agonists will allow for accelerated emergence without delirium, early spontaneous ventilation, improved cardiac output and micro-circulation, lowered vasopressor requirements and inflammation. Rigorous prospective randomized trials are needed in subsets of patients with a high fever and spiraling toward refractory septic shock and/or presenting with severe ARDS.

Therapeutic temperature management (TTM): post-resuscitation care for adult cardiac arrest, with recommendations from the National TTM Workgroup

Therapeutic temperature management (TTM) was strongly recommended by the 2015 International Liaison Committee on Resuscitation as a component of post-resuscitation care. It has been known to be effective in improving the survival rate and neurologic functional outcome of patients after cardiac arrest. In an effort to increase local adoption of TTM as a standard of post-resuscitation care, this paper discusses and makes recommendations on the treatment for local providers.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.