Timing for fever-related brain damage in acute ischemic stroke

Hyperthermia and Early Growth of Cerebral Infarct: The Potential Role of Blood-Brain Barrier Permeability

Hyperthermia within the first 24 h following ischemic stroke (IS) has been associated with poor outcomes. We sought to determine whether blood-brain barrier (BBB) permeability contributes to the relationship between hyperthermia and early infarct growth (EIG). A retrospective analysis was conducted on a prospective stroke biobank. EIG was defined as the percentage difference between the initial volume (mL) determined by the diffusion-weighted imaging at admission and the volume (mL) from the control CT image on the 4 th-7 th day. Hyperthermia was defined as an axillary body temperature ≥ 37.5 °C within the first 24 h. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) serum levels were measured by ELISA. One-hundred and two (19.7%) patients showed EIG from a cohort of 519 patients (45.6% females). Linear correlation was observed for axillar body temperature and EIG (Pearson's r = 0.46; p < 0.001). sTWEAK serum levels showed a c-statistic of 0.74 (95% CI: 0.69-0.79), with an optimal cut-off point > 3000 pg/mL for EIG prediction. Moreover, microalbuminuria levels strongly correlated with sTWEAK levels (Pearson's r = 0.75; p < 0.001). In the multivariate analysis for EIG was observed an independent association with hyperthermia (adjusted OR 24.21; 95% CI: 12.03-39.12), sTWEAK levels > 3000 pg/mL (adjusted OR 16.43; 95% CI: 3.71-72.70), leukoaraiosis (adjusted OR 10.42; 95% CI: 2.68-39.08), and microalbuminuria (adjusted OR 1.02; 95% CI: 1.00-1.12). In our cohort, hyperthermia was independently associated with EIG after IS. The fact that microalbuminuria, leukoaraiosis, and sTWEAK were also associated with EIG suggests a relationship with increased BBB permeability.

Pulmonary consequences of experimentally induced stroke: differences between global and focal cerebral ischemia

Introduction

Cerebral ischemia leads to multiple organ dysfunctions, with the lungs among the most severely affected. Although adverse pulmonary consequences contribute significantly to reduced life expectancy after stroke, the impact of global or focal cerebral ischemia on respiratory mechanical parameters remains poorly understood.

Methods

Rats were randomly assigned to undergo surgery to induce permanent global cerebral ischemia (2VO) or focal cerebral ischemia (MCAO), or to receive a sham operation (SHAM). Three days later, end-expiratory lung volume, airway and respiratory tissue mechanics were measured at positive end-expiratory pressure (PEEP) levels of 0, 3 and 6 cmH2O. Bronchial responsiveness to methacholine, lung cytokine levels, wet-to-dry ratio, blood gas parameters and cerebral stroke markers were also evaluated.

Results

Global and focal cerebral ischemia had no significant effect on end-expiratory lung volume, bronchial responsiveness, and arterial blood gas levels. No change in respiratory mechanics and inflammatory response was evident after 2VO. Conversely, MCAO decreased airway resistance at PEEP 0, deteriorated respiratory tissue damping and elastance at all PEEP levels, and elevated Hct and Hgb. MCAO also caused lung edema and augmented IL-1β and TNF-α in the lung tissue without affecting IL-6 and IL-8 levels.

Discussion

Our findings suggest that global cerebral ischemia has no major pulmonary consequences. However, deteriorations in the respiratory tissue mechanics develop after permanent focal ischemia due to pulmonary edema formation, hemoconcentration and cytokine production. This respiratory mechanical defect can compromise lung distension at all PEEP levels, which warrants consideration in optimizing mechanical ventilation.

Impact of fever on the outcome non-anoxic acute brain injury patients: a systematic review and meta-analysis

BACKGROUND

Fever is a common condition in intensive care unit (ICU) patients, with an incidence between 30 and 50% in non-neurological ICU patients and up to 70-90% in neurological ICU patients. We aim to perform systematic review and meta-analysis of current literature to assess impact of fever on neurological outcomes and mortality of acute brain injury patients.

METHODS

We searched PubMed/Medline, Scopus and Embase databases following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, and we included both retrospective and prospective observational studies, interventional studies, and randomized clinical trials that had data on body temperature and fever during ICU admission. The primary endpoints were neurological outcome and mortality at any time. Secondary outcomes included: early neurological deterioration, delayed cerebral ischemia (DCI, only for patients with subarachnoid hemorrhage), large infarct or hemorrhage size, hemorrhagic transformation (only for patients with ischemic stroke). This study was registered in PROSPERO (CRD42020155903).

RESULTS

180 studies from 14692 records identified after the initial search were included in the final analysis, for a total of 460,825 patients. Fever was associated with an increased probability of unfavorable neurological outcome (pooled OR 2.37 [95% CI 2.08-2.71], I2:92%), death (pooled OR 1.31 [95% CI 1.28-1.34], I2:93%), neurological deterioration (pooled OR 1.10 [95% CI 1.05-1.15]), risk of DCI (pooled OR 1.96 [95% CI 1.73-2.22]), large infarct size (pooled OR 2.94 [95% CI 2.90-2.98]) and hemorrhagic transformation (pooled OR 1.63 [95% CI 1.34-1.97]) and large hemorrhagic volume (pooled OR 2.38 [95% CI 1.94-2.93]).

CONCLUSION

Fever was associated with poor neurological outcomes and mortality in patients with acute brain injury. Whether normothermia should be targeted in the management of all neuro critically ill patients warrants specific research.

Cisternal Blood Clearance Attenuates Systemic Inflammatory Response After Subarachnoid Hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (SAH) frequently triggers systemic inflammatory response syndrome (SIRS). SIRS has been associated with inferior outcomes and, specifically, delayed cerebral infarction after aneurysmal SAH. Here, we assess the impact of intracranial blood clearance through stereotactic catheter ventriculocisternostomy on SIRS in patients with aneurysmal SAH.

METHODS

We assessed daily SIRS criteria (heart rate > 90 beats/min, respiratory rate > 20 breaths/min or abnormal respiratory coefficient, temperature > 38 °C or < 36 °C, white blood cell count < 4000 or > 12,000 cells/mm3) between admission and day 21 in 80 consecutive patients who underwent cisternal lavage through stereotactic catheter ventriculocisternostomy from 2015 to 2022. These patients were compared with 80 matched controls who received treatment at our institution between 2010 and 2015. We conducted a mixed effects model analysis using restricted maximum likelihood estimation to assess the effects of treatment groups on the SIRS rate while accounting for repeated measures. Additionally, Bonferroni's correction was employed to examine specific differences between groups at different time points.

RESULTS

The mean percentages of patients meeting SIRS criteria during the first 21 days after aneurysmal SAH were 23% in the matched cohort group and 14% in patients who underwent cisternal lavage (p < 0.001). Additionally, significant differences were observed in the mean leukocyte count (p = 0.047), mean heart rate (p = 0.019), and mean respiratory rate (p = 0.0018) between the two groups. However, there was no significant difference in mean body temperature (p = 0.36).

CONCLUSIONS

Intracranial blood clearance and cisternal lavage after aneurysmal SAH is associated with a decline in SIRS prevalence and severity.

Transient Changes in Cerebral Tissue Oxygen, Glucose, and Temperature by Microstrokes: A Computational Study

OBJECTIVE

This study focuses on evaluating the disruptions in key physiological parameters during microstroke events to assess their severity.

METHODS

A mathematical model was developed to simulate the changes in cerebral tissue pO2, glucose concentration, and temperature due to blood flow interruptions. The model considers variations in baseline cerebral blood flow (CBF), capillary density, and blood oxygen/glucose levels, as well as ambient temperature changes.

RESULTS

Simulations indicate that complete blood flow obstruction still allows for limited glucose availability, supporting nonoxidative metabolism and potentially exacerbating lactate buildup and acidosis. Partial obstructions decrease tissue pO2, with minimal impact on glucose level, which can remain almost unchanged or even slightly increase. Reduced CBF, capillary density, or blood oxygen due to aging or disease enhances hypoxia risk at lower obstruction levels, with capillary density having a significant effect on stroke severity by influencing both pO2 and glucose levels. Conditions could lead to co-occurrence of hypoxia/hypoglycemia or hypoxia/hyperglycemia, each worsening outcomes. Temperature effects were minimal in deep brain regions but varied near the skull by 0.2-0.8°C depending on ambient temperature.

CONCLUSIONS

The model provides insights into the conditions driving severe stroke outcomes based on estimated levels of hypoxia, hypoglycemia, hyperglycemia, and temperature changes.

Body temperature in the acute phase and clinical outcomes after acute ischemic stroke

BACKGROUND

This study aimed to examine whether post-stroke early body temperature is associated with neurological damage in the acute phase and functional outcomes at three months.

METHODS

We included 7,177 patients with acute ischemic stroke within 24 h of onset. Axillary temperature was measured daily in the morning for seven days. Mean body temperature was grouped into five quintiles (Q1: 35.1‒36.5°C, Q2: 36.5‒36.7°C, Q3: 36.7‒36.8°C, Q4: 36.8‒37.1°C, and Q5: 37.1‒39.1°C). Clinical outcomes included neurological improvement during hospitalization and poor functional outcome (modified Rankin scale score, 3-6) at three months. A logistic regression analysis was performed to evaluate the association between body temperature and clinical outcomes.

RESULTS

The patient's mean (SD) age was 70.6 (12.3) years, and 35.7% of patients were women. Mean body temperature was significantly associated with less neurological improvement from Q2 (odds ratios [95% confidence interval], 0.77 [0.65-0.99] vs. Q1) to Q5 (0.33 [0.28-0.40], P for trend <0.001) even after adjusting for potential confounders, including baseline neurological severity, C-reactive protein levels, and post-stroke acute infections. The multivariable-adjusted risk of poor functional outcome linearly increased from Q2 (1.36 [1.03-1.79]) to Q5 (6.44 [5.19-8.96], P for trend <0.001). These associations were maintained even in the analyses excluding patients with acute infectious diseases. Multivariable-adjusted risk of poor functional outcome was higher in patients with early body temperature elevation on days 1-3 and with longer duration with body temperature >37.0°C.

CONCLUSIONS

Post-stroke early high body temperature is independently associated with unfavorable outcomes following acute ischemic stroke.

Current and Emerging Endovascular and Neurocritical Care Management Strategies in Large-Core Ischemic Stroke

The volume of infarcted tissue in patients with ischemic stroke is consistently associated with increased morbidity and mortality. Initial studies of endovascular thrombectomy for large-vessel occlusion excluded patients with established large-core infarcts, even when large volumes of salvageable brain tissue were present, due to the high risk of hemorrhagic transformation and reperfusion injury. However, recent retrospective and prospective studies have shown improved outcomes with endovascular thrombectomy, and several clinical trials were recently published to evaluate the efficacy of endovascular management of patients presenting with large-core infarcts. With or without thrombectomy, patients with large-core infarcts remain at high risk of in-hospital complications such as hemorrhagic transformation, malignant cerebral edema, seizures, and others. Expert neurocritical care management is necessary to optimize blood pressure control, mitigate secondary brain injury, manage cerebral edema and elevated intracranial pressure, and implement various neuroprotective measures. Herein, we present an overview of the current and emerging evidence pertaining to endovascular treatment for large-core infarcts, recent advances in neurocritical care strategies, and their impact on optimizing patient outcomes.

Factors influencing the surveillance of re-emerging intracranial infections in elective neurosurgical patients: A single-center retrospective study

BACKGROUND

At present, many studies have reported the risk factors for postoperative intracranial reinfection, including age, sex, time to surgery, duration of postoperative catheterization, emergency procedures, type of disease and cerebrospinal fluid leakage, but the academic community has not reached a unified conclusion.

AIM

To find factors influencing the surveillance of re-emerging intracranial infections in elective neurosurgical patients.

METHODS

Ninety-four patients who underwent elective craniotomy from January 1, 2015 to December 31, 2022 in the Department of Neurosurgery, First Hospital of Jilin University, were included in this study. Of those, 45 patients were enrolled in the infection group, and 49 were enrolled in the control group. The clinical data of the patients were collected and divided into three categories, including preoperative baseline conditions, intraoperative characteristics and postoperative infection prevention. The data were analyzed using SPSS 26.0 software.

RESULTS

There were 23 males and 22 females in the infection group with a mean age of 52.8 ± 15.1 years and 17 males and 32 females in the control group with a mean age of 48.9 ± 15.2 years. The univariate analysis showed that the infection group had higher systolic blood pressures and postoperative temperatures, fewer patients who underwent a supratentorial craniotomy, more patients with a history of hypertension and higher initial postoperative white blood cell counts than the control group, with statistically significant differences (P < 0.05). The multifactorial logistic regression analysis showed that a history of hypertension and a high postoperative body temperature were independent risk factors for postoperative infection in neurosurgical patients.

CONCLUSION

The results obtained in this study indicated that a history of hypertension and a high postoperative body temperature were independent risk factors for postoperative neurological symptoms.

Approaches to neuroprotection in pediatric neurocritical care

Acute neurologic injuries represent a common cause of morbidity and mortality in children presenting to the pediatric intensive care unit. After primary neurologic insults, there may be cerebral brain tissue that remains at risk of secondary insults, which can lead to worsening neurologic injury and unfavorable outcomes. A fundamental goal of pediatric neurocritical care is to mitigate the impact of secondary neurologic injury and improve neurologic outcomes for critically ill children. This review describes the physiologic framework by which strategies in pediatric neurocritical care are designed to reduce the impact of secondary brain injury and improve functional outcomes. Here, we present current and emerging strategies for optimizing neuroprotective strategies in critically ill children.

Influence of Temperature Chronobiology on Stroke Outcome

The circadian system regulates numerous physiological variables, including body temperature. Additionally, a circadian patter has been described in stroke onset. Considering this, we hypothesised that the chronobiology of temperature may have an impact on stroke onset and functional outcomes. We also studied the variation of blood biomarkers according to stroke onset time. This is a retrospective observational study. Of the patients included, 2763 had a stroke between midnight and 8:00 h; 1571 between 8:00-14:00 h; and 655 between 14:00 h and midnight. Axillary temperature was measured at admission. At this time, blood samples were collected for biomarker analysis (TNF-α, IL-1β, IL-6, IL-10, and glutamate). Temperature was higher in patients admitted from 8:00 h to midnight (p < 0.0001). However, the percentage of poor outcome at 3 months was highest in patients from midnight to 8:00 h (57.7%, p < 0.001). The association between temperature and mortality was highest during night time (OR: 2.79; CI 95%: 2.36-3.28; p < 0.001). These patients exhibited high glutamate (220.2 ± 140.2 µM), IL-6 (32.8 ± 14.3 pg/mL) and low IL-10 (9.7 ± 14.3 pg/mL) levels. Therefore, temperature chronobiology could have a significant impact on stroke onset and functional outcome. Superficial body hyperthermia during sleep seems to be more dangerous than during wakefulness. Further studies will be necessary to confirm our data.

[Craniocerebral hypothermia in the acute period of ischemic stroke]

OBJECTIVE

To determine the effect of craniocerebral hypothermia (CCH) on neurological deficit regression, hemodynamics, fever and functional outcome of therapy in patients with moderate ischemic stroke (IS).

MATERIAL AND METHODS

This study included 60 patients with IS (the first day). The main group consisted of 30 patients who underwent CCH, and the comparison (control) group consisted of 30 patients without CCH. The National Institutes of Health Stroke Scale (NIHSS), the Glasgow Coma Scale (GCS), the modified Rankin Scale (mRs) were used. Recorded parameters were mortality, heart rate (HR), blood pressure (BP), axial temperature, cerebral temperature of the frontal cortex. Cerebral temperature was obtained noninvasively by using a RTM-01-RES radiothermometer (Russia). CCH (for 24 hours) in the main group was implemented by ATG-01 device (Russia). Results were recorded on the day of admission, after 24 hours and at discharge. In both groups, basic neuroprotective, hypotensive, antiplatelet and antiedemic therapy was administered.

RESULTS

No fatal outcomes were reported in both groups. Side-effects and complications of CCH were not recorded. In the main group, neurological deficit assessed by NIHSS decreased by 75% after the CCH procedure and by 93.75% at the time of discharge from the hospital. In patients of the comparison group, regression of neurological deficit was 35% on the second day and 55% at the day of discharge. The use of CCH suppressed systemic and cerebral hyperthermia. Functional outcome of therapy in the main group was higher compared to the comparison one. The dynamics in blood pressure and heart rate didn't differ in both groups.

CONCLUSION

A pronounced positive effect of CCH on the course of the acute period and therapy results in patients with IS was demonstrated.

Lithium Biological Action Mechanisms after Ischemic Stroke

Lithium is a source of great scientific interest because although it has such a simple structure, relatively easy-to-analyze chemistry, and well-established physical properties, the plethora of effects on biological systems—which influence numerous cellular and molecular processes through not entirely explained mechanisms of action—generate a mystery that modern science is still trying to decipher. Lithium has multiple effects on neurotransmitter-mediated receptor signaling, ion transport, signaling cascades, hormonal regulation, circadian rhythm, and gene expression. The biochemical mechanisms of lithium action appear to be multifactorial and interrelated with the functioning of several enzymes, hormones, vitamins, and growth and transformation factors. The widespread and chaotic marketing of lithium salts in potions and mineral waters, always at inadequate concentrations for various diseases, has contributed to the general disillusionment with empirical medical hypotheses about the therapeutic role of lithium. Lithium salts were first used therapeutically in 1850 to relieve the symptoms of gout, rheumatism, and kidney stones. In 1949, Cade was credited with discovering the sedative effect of lithium salts in the state of manic agitation, but frequent cases of intoxication accompanied the therapy. In the 1960s, lithium was shown to prevent manic and also depressive recurrences. This prophylactic effect was first demonstrated in an open-label study using the “mirror” method and was later (after 1970) confirmed by several placebo-controlled double-blind studies. Lithium prophylaxis was similarly effective in bipolar and also unipolar patients. In 1967, the therapeutic value of lithemia was determined, included in the range of 0.5–1.5 mEq/L. Recently, new therapeutic perspectives on lithium are connected with improved neurological outcomes after ischemic stroke. The effects of lithium on the development and maintenance of neuroprotection can be divided into two categories: short-term effects and long-term effects. Unfortunately, the existing studies do not fully explain the lithium biological action mechanisms after ischemic stroke.

Acute Hospital Management of Pediatric Stroke

The field of pediatric stroke has historically been hampered by limited evidence and small patient cohorts. However the landscape of childhood stroke is rapidly changing due in part to increasing awareness of the importance of pediatric stroke and the emergence of dedicated pediatric stroke centers, care pathways, and alert systems. Acute pediatric stroke management hinges on timely diagnosis confirmed by neuroimaging, appropriate consideration of recanalization therapies, implementation of neuroprotective measures, and attention to secondary prevention. Because pediatric stroke is highly heterogenous in etiology, management strategies must be individualized. Determining a child's underlying stroke etiology is essential to appropriately tailoring hyperacute stroke management and determining best approach to secondary prevention. Herein, we review the methods of recognition, diagnosis, management, current knowledge gaps and promising research for pediatric stroke.

Temperature Management in the ICU

OBJECTIVE

Temperature abnormalities are recognized as a marker of human disease, and the therapeutic value of temperature is an attractive treatment target. The objective of this synthetic review is to summarize and critically appraise evidence for active temperature management in critically ill patients.

DATA SOURCES

We searched MEDLINE for publications relevant to body temperature management (including targeted temperature management and antipyretic therapy) in cardiac arrest, acute ischemic and hemorrhagic stroke, traumatic brain injury, and sepsis. Bibliographies of included articles were also searched to identify additional relevant studies.

STUDY SELECTION

English-language systematic reviews, meta-analyses, randomized trials, observational studies, and nonhuman data were reviewed, with a focus on the most recent randomized control trial evidence.

DATA EXTRACTION

Data regarding study methodology, patient population, temperature management strategy, and clinical outcomes were qualitatively assessed.

DATA SYNTHESIS

Temperature management is common in critically ill patients, and multiple large trials have been conducted to elucidate temperature targets, management strategies, and timing. The strongest data concerning the use of therapeutic hypothermia exist in comatose survivors of cardiac arrest, and recent trials suggest that appropriate postarrest temperature targets between 33°C and 37.5°C are reasonable. Targeted temperature management in other critical illnesses, including acute stroke, traumatic brain injury, and sepsis, has not shown benefit in large clinical trials. Likewise, trials of pharmacologic antipyretic therapy have not demonstrated improved outcomes, although national guidelines do recommend treatment of fever in patients with stroke and traumatic brain injury based on observational evidence associating fever with worse outcomes.

CONCLUSIONS

Body temperature management in critically ill patients remains an appealing therapy for several illnesses, and additional studies are needed to clarify management strategies and therapeutic pathways.

Associations between RNA-Binding Motif Protein 3, Fibroblast Growth Factor 21, and Clinical Outcome in Patients with Stroke

Background: RNA-binding motif protein 3 (RBM3) is a cold-induced marker of good functional outcome of ischemic stroke that is promising as a protective target. Fibroblast growth factor 21 (FGF21) is an obesity- and temperature-related hormone that upregulates the expression of RBM3, which is beneficial as a recombinant treatment and has been tested under different experimental pathological conditions, including stroke. However, the interaction between RBM3 and FGF21 has not yet been tested for clinical stroke conditions. Methods: In a sample of 66 stroke patients, we analyzed the associations between the FGF21 and RBM3 serum concentrations on admission and at 72 h, body weight, maximum temperature during the first 24 h, and the outcome of patients at 3 months. We also analyzed their association with biomarkers of obesity (adiponectin and leptin) and inflammation (interleukin-6 (IL-6) and interleukin (IL-10)). Results: Higher concentrations of FGF21 on admission and RBM3 at 72 h were associated with good outcomes. Serum FGF21 and RBM3 were directly related to body mass index and inversely related to the maximum temperature during the first 24 h. We found a positive association between the FGF21 concentrations in obese patients with leptin and a negative correlation with adiponectin in non-obese participants. Conclusions: This clinical study demonstrates the association between RBM3 and FGF21 levels and the outcome of stroke patients. Although further investigations are required, these data support the pharmacological induction of RBM3 as a promising protective therapy.

Relationship Between Body Temperature and Early Neurological Deterioration after Endovascular Thrombectomy for Acute Ischemic Stroke with Large Vessel Occlusion

BACKGROUND

Early neurological deterioration (END) after endovascular thrombectomy (EVT) is strongly associated with poor prognosis in patients with large vessel occlusion. The relationship between body temperature and END after EVT is unknown, which we aimed to investigate in this study.

METHODS

END was defined as an increase of four or more points on the National Institutes of Health Stroke Scale score compared with the baseline assessment within 24 h. Logistic regression and restricted cubic spline models were used to assess the relationship between body temperature and END.

RESULTS

Among 7741 consecutive patients with ischemic stroke, 406 patients with large vessel occlusion who underwent EVT were enrolled. In total, 88 (21.7%) patients developed END. Logistic regression showed that the maximum body temperature within 24 h (odds ratio [OR] = 1.97 per °C, 95% confidence interval [CI] 1.17-3.32, p = 0.010) was independently associated with END. This association was nonlinear and J shaped (p for nonlinearity = 0.010), and the risk of END increased when the maximum body temperature within 24 h was lower or higher than 37.0 °C. Fever burden is also independently associated with END (OR = 1.06 per °C  × hour, 95% CI 1.01-1.11, p = 0.012). In addition, the timing of fever onset was independently associated with END, and the highest risk of END was associated with fever onset within 6 h after EVT (OR = 3.92, 95% CI 1.25-12.27, p = 0.019).

CONCLUSIONS

In summary, there is a J-shaped association between the maximum body temperature within 24 h after EVT and END. Moreover, the risk of END differed according to the timing of fever onset.

Brain Temperature Influences Intracranial Pressure and Cerebral Perfusion Pressure After Traumatic Brain Injury: A CENTER-TBI Study

Background

After traumatic brain injury (TBI), fever is frequent. Brain temperature (BT), which is directly linked to body temperature, may influence brain physiology. Increased body and/or BT may cause secondary brain damage, with deleterious effects on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and outcome.

Methods

Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI), a prospective multicenter longitudinal study on TBI in Europe and Israel, includes a high resolution cohort of patients with data sampled at a high frequency (from 100 to 500 Hz). In this study, simultaneous BT, ICP, and CPP recordings were investigated. A mixed-effects linear model was used to examine the association between different BT levels and ICP. We additionally focused on changes in ICP and CPP during the episodes of BT changes (Δ BT ≥ 0.5 °C lasting from 15 min to 3 h) up or downward. The significance of ICP and CPP variations was estimated with the paired samples Wilcoxon test (also known as Wilcoxon signed-rank test).

Results

Twenty-one patients with 2,435 h of simultaneous BT and ICP monitoring were studied. All patients reached a BT of 38 °C and experienced at least one episode of ICP above 20 mm Hg. The linear mixed-effects model revealed an association between BT above 37.5 °C and higher ICP levels that was not confirmed for lower BT. We identified 149 episodes of BT changes. During BT elevations (n = 79) ICP increased, whereas CPP was reduced; opposite ICP and CPP variations occurred during episodes of BT reduction (n = 70). All these changes were of moderate clinical relevance (increase of ICP of 4.5 and CPP decrease of 7.5 mm Hg for BT rise, and ICP reduction of 1.7 and CPP elevation of 3.7 mm Hg during BT defervescence), even if statistically significant (p < 0.0001). It has to be noted, however, that a number of therapeutic interventions against intracranial hypertension was documented during those episodes.

Conclusions

Patients after TBI usually develop BT > 38 °C soon after the injury. BT may influence brain physiology, as reflected by ICP and CPP. An association between BT exceeding 37.5 °C and a higher ICP was identified but not confirmed for lower BT ranges. The relationship between BT, ICP, and CPP become clearer during rapid temperature changes. During episodes of temperature elevation, BT seems to have a significant impact on ICP and CPP.

Prognostic significance of early pyrexia in acute intracerebral haemorrhage: The INTERACT2 study

INTRODUCTION

Uncertainty exists over the prognostic significance of pyrexia in acute intracerebral haemorrhage (ICH). We aimed to determine the association of elevated body temperature with clinical and imaging outcomes among participants of the main Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2).

METHODS

Post-hoc analyses of INTERACT2, an international open, blinded outcome assessed, randomised trial of 2839 patients with spontaneous ICH (<6 h of onset) and elevated systolic blood pressure (SBP, 150-220 mmHg) randomly assigned to intensive (SBP target <140 mmHg) or guideline-recommended (SBP target < 180 mmHg) BP management. Multivariable logistic regression was used to determine associations of elevated baseline body temperature (<37.5 vs. ≥37.5 °C) and 90-day clinical outcome defined on the modified Rankin scale (mRS). Analysis of covariance determined relations of body temperature and haematoma and perihaematomal oedema (PHE) volumes, at baseline and 24 h post-randomisation.

RESULTS

Of 2792 participants with data available at admission, 39 (1.4%) patients had elevated body temperature ≥ 37.5 °C. Elevated body temperature was significantly associated with 90-day mortality (adjusted odds ratio 2.44; 95% confidence interval 1.02-5.82; P = .044) but not with major disability alone (mRS scores 3-5) and combination death or major disability (mRS scores 3-6). Elevated body temperature was also associated with larger PHE volume at baseline (10.89 vs. 3.14 cm³, P < .001;) and 24 h (12.43 vs 5.76 cm³, P = .018) but not with haematoma volumes at these time points.

CONCLUSION

Early pyrexia in mild to moderate ICH is associated with greater mortality and larger PHE volume, suggesting an early inflammatory-mediated reaction.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov (NCT00716079).

Transient forebrain ischemia under hyperthermic condition accelerates memory impairment and neuronal death in the gerbil hippocampus by increasing NMDAR1 expression

Altered expression levels of N‑methyl‑D‑aspartate receptor (NMDAR), a ligand‑gated ion channel, have a harmful effect on cellular survival. Hyperthermia is a proven risk factor of transient forebrain ischemia (tFI) and can cause extensive and severe brain damage associated with mortality. The objective of the present study was to investigate whether hyperthermic preconditioning affected NMDAR1 immunoreactivity associated with deterioration of neuronal function in the gerbil hippocampal CA1 region following tFI via histological and western blot analyses. Hyperthermic preconditioning was performed for 1 h before tFI, which was developed by ligating common carotid arteries for 5 min. tFI‑induced cognitive impairment under hyperthermia was worse compared with that under normothermia. Loss (death) of pyramidal neurons in the CA1 region occurred fast and was more severe under hyperthermia compared with that under normothermia. NMDAR1 immunoreactivity was not observed in the somata of pyramidal neurons of sham gerbils with normothermia. However, its immunoreactivity was strong in the somata and processes at 12 h post‑tFI. Thereafter, NMDAR1 immunoreactivity decreased with time after tFI. On the other hand, NMDAR1 immunoreactivity under hyperthermia was significantly increased in the somata and processes at 6 h post‑tFI. The change pattern of NMDAR1 immunoreactivity under hyperthermia was different from that under normothermia. Overall, accelerated tFI‑induced neuronal death under hyperthermia may be closely associated with altered NMDAR1 expression compared with that under normothermia.

Inhibition of cyclooxygenase-1 does not reduce mortality in post-ischemic stroke rats

BACKGROUND

Ischemic stroke is one of the leading causes of mortality and morbidity. The currently available non-invasive therapeutic options are not sufficiently efficacious. Post-ischemic brain is characterized by a prominent inflammatory response. Little is known about the involvement of cyclooxygenase (COX)-1 in the pathophysiology of ischemic stroke.

OBJECTIVE

This study was undertaken to examine the effects of a highly selective COX-1 inhibitor - mofezolac - on clinical outcomes and brain inflammatory markers in post-stroke rats.

METHODS

Stroke was induced by subjecting rats to permanent middle cerebral artery occlusion (MCAO). Control rats underwent a sham surgery. Rats were treated with mofezolac (50 mg/kg, intraperitoneally [ip]) once daily for 14 days. Control animals were treated with vehicle. Body temperature (BT), neurological score (NS) and cumulative mortality were monitored at different time points. At the end of the experiment, rats were euthanized and three brain regions (hypothalamus, hippocampus and frontal cortex) were extracted. Levels of interleukin (IL)-6, prostaglandin (PG)E₂ and tumor necrosis factor (TNF)-α in these brain regions were determined by ELISA kits.

RESULTS

BT, NS and cumulative mortality were all significantly higher in post-MCAO rats than in sham-operated rats, irrespective of the treatment given. BT, NS and mortality rate did not differ significantly between mofezolac-treated and vehicle-treated sham-operated animals. BT was significantly lower in mofezolac-treated as compared to vehicle-treated post-MCAO rats. Mofezolac did not significantly alter NS in post-MCAO rats at any time-point. Cumulative 14-day mortality was non-significantly higher in mofezolac-treated as compared to vehicle-treated post-MCAO rats (48 % vs. 21 %, respectively; P =  0.184). Mostly, IL-6 and TNF-α levels did not differ between post-MCAO and sham-operated rats and were not affected by mofezolac treatment. In contrast, mofezolac significantly decreased PGE₂ levels in post-MCAO rats' brains.

CONCLUSION

Overall, these results suggest that chronic treatment with the selective COX-1 inhibitor mofezolac did not reduce morbidity or mortality in post-stroke rats.

Mild fever as a catalyst for consumption of the ischaemic penumbra despite endovascular reperfusion

Cerebrovascular ischaemia is potentiated by hyperthermia, and even mild temperature elevation has proved detrimental to ischaemic brain. Infarction progression following endovascular reperfusion relates to multiple patient-specific and procedural variables; however, the potential influence of mild systemic temperature fluctuations is not fully understood. This study aims to assess the relationship between systemic temperatures in the early aftermath of acute ischaemic stroke and the loss of at-risk penumbral tissues, hypothesizing consumption of the ischaemic penumbra as a function of systemic temperatures, irrespective of reperfusion status. A cross-sectional, retrospective evaluation of a single-institution, prospectively collected endovascular therapy registry was conducted. Patients with anterior circulation, large vessel occlusion acute ischaemic stroke who underwent initial CT perfusion, and in whom at least four-hourly systemic temperatures were recorded beginning from presentation and until the time of final imaging outcome were included. Initial CT perfusion core and penumbra volumes and final MRI infarction volumes were computed. Systemic temperature indices including temperature maxima were recorded, and pre-defined temperature thresholds varying between 37°C and 38°C were examined in unadjusted and adjusted regression models which included glucose, collateral status, reperfusion status, CT perfusion-to-reperfusion delay, general anaesthesia and antipyretic exposure. The primary outcome was the relative consumption of the penumbra, reflecting normalized growth of the at-risk tissue volume ≥10%. The final study population comprised 126 acute ischaemic stroke subjects (mean 63 ± 14.5 years, 63% women). The primary outcome of penumbra consumption ≥10% occurred in 51 (40.1%) subjects. No significant differences in baseline characteristics were present between groups, with the exception of presentation glucose (118 ± 26.6 without versus 143.1 ± 61.6 with penumbra consumption, P = 0.009). Significant differences in the likelihood of penumbra consumption relating to systemic temperature maxima were observed [37°C (interquartile range 36.5 − 37.5°C) without versus 37.5°C (interquartile range 36.8 − 38.2°C) with penumbra consumption, P = 0.001]. An increased likelihood of penumbra consumption was observed for temperature maxima in unadjusted (odds ratio 3.57, 95% confidence interval 1.65 − 7.75; P = 0.001) and adjusted (odds ratio 3.06, 95% confidence interval 1.33 − 7.06; P = 0.009) regression models. Significant differences in median penumbra consumption were present at a pre-defined temperature maxima threshold of 37.5°C [4.8 ml (interquartile range 0 − 11.5 ml) versus 21.1 ml (0 − 44.7 ml) for subjects not reaching or reaching the threshold, respectively, P = 0.007]. Mild fever may promote loss of the ischaemic penumbra irrespective of reperfusion, potentially influencing successful salvage of at-risk tissue volumes following acute ischaemic stroke.

Temperature-Induced Changes in Reperfused Stroke: Inflammatory and Thrombolytic Biomarkers

Although hyperthermia is associated with poor outcomes in ischaemic stroke (IS), some studies indicate that high body temperature may benefit reperfusion therapies. We assessed the association of temperature with effective reperfusion (defined as a reduction of ≥8 points in the National Institute of Health Stroke Scale (NIHSS) within the first 24 h) and poor outcome (modified Rankin Scale (mRS) > 2) in 875 retrospectively-included IS patients. We also studied the influence of temperature on thrombolytic (cellular fibronectin (cFn); matrix metalloproteinase 9 (MMP-9)) and inflammatory biomarkers (tumour necrosis factor-alpha (TNF-α), interleukin 6 (IL-6)) and their relationship with effective reperfusion. Our results showed that a higher temperature at 24 but not 6 h after stroke was associated with failed reperfusion (OR: 0.373, p = 0.001), poor outcome (OR: 2.190, p = 0.005) and higher IL-6 levels (OR: 0.958, p < 0.0001). Temperature at 6 h was associated with higher MMP-9 levels (R = 0.697; p < 0.0001) and effective reperfusion, although this last association disappeared after adjusting for confounding factors (OR: 1.178, p = 0.166). Our results suggest that body temperature > 37.5 °C at 24 h, but not at 6 h after stroke, is correlated with reperfusion failure, poor clinical outcome, and infarct size. Mild hyperthermia (36.5–37.5 °C) in the first 6 h window might benefit drug reperfusion therapies by promoting clot lysis.

Cold stress protein RBM3 responds to hypothermia and is associated with good stroke outcome

RNA-binding motif protein 3 is a molecular marker of hypothermia that has proved neuroprotective in neurodegenerative disease models. However, its relationship to the well-recognized therapeutic effect of hypothermia in ischaemic stroke had not been studied. In this work, the expression of RNA-binding motif protein 3 was investigated in ischaemic animal models subjected to systemic and focal brain hypothermia, specifically the effects of RNA-binding motif protein 3 silencing and overexpression on ischaemic lesions. Moreover, the association of RNA-binding motif protein 3 levels with body temperature and clinical outcome was evaluated in two independent cohorts of acute ischaemic stroke patients (n = 215); these levels were also determined in a third cohort of 31 patients derived from the phase III EuroHYP-1 trial of therapeutic cooling in ischaemic stroke. The preclinical data confirmed the increase of brain RNA-binding motif protein 3 levels in ischaemic animals subjected to systemic and focal hypothermia; this increase was selectively higher in the cooled hemisphere of animals undergoing focal brain hypothermia, thus confirming the direct effect of hypothermia on RNA-binding motif protein 3 expression, while RNA-binding motif protein 3 up-regulation in ischaemic brain regions led to functional recovery. Clinically, patients with body temperature <37.5°C in the first two cohorts had higher RNA-binding motif protein 3 values at 24 h and good outcome at 3 months post-ischaemic stroke, while RNA-binding motif protein 3 levels in the cooled third cohort tended to exceed those in placebo-treated patients. These results make RNA-binding motif protein 3 a molecular marker associated with the effect of hypothermia in ischaemic stroke and suggest its potential application as a promising protective target.

Systemic Inflammatory Response Syndrome (SIRS) Score Independently Predicts Poor Outcome in Isolated Traumatic Brain Injury

INTRODUCTION

Systemic inflammatory response syndrome (SIRS) is frequently observed after various types of acute cerebral injury and has been linked to clinical deterioration in non-traumatic brain injury (TBI). SIRS scores have also been shown to be predictive of length of stay and mortality in trauma patients. We aimed to determine the prognostic utility of SIRS present at admission in trauma patients with isolated TBI.

METHODS

This was a 5-year retrospective cohort study of adults (≥18 years) with isolated TBI admitted to a Level II trauma center. The prognostic value of SIRS, total SIRS scores, and each SIRS criterion was examined by Χ ² and logistic regression analyses.

RESULTS

Of the 330 patients identified, 50 (15.2%) met SIRS criteria. SIRS was significantly associated with poor outcome (P < 0.001). Relative risk of poor outcome was 2.7 times higher in patients with a SIRS score of 2 on admission (P = 0.007) and increased significantly to 6.5 times in patients with a SIRS score of 3 (P = 0.002). Logistic regression demonstrated SIRS and each criterion to be significant independent prognostic factors (SIRS, P = 0.030; body temperature, P = 0.006; tachypnea, P = 0.022, tachycardia P = 0.023).

CONCLUSION

SIRS at admission is an independent predictor of poor outcome in isolated TBI patients. These data demonstrate SIRS to be an important clinical tool that may be used in facilitating prognostication, particularly in elderly trauma patients. Future prospective studies aimed at therapeutic interventions to mitigate SIRS in TBI patients are warranted.

LEVEL OF EVIDENCE

Prognostic, Level III.

The impact of hyperthermia after acute carbon monoxide poisoning on neurological sequelae

This study investigated whether hyperthermia within the first 24 h after presentation was associated with long-term neurological outcomes after acute carbon monoxide (CO) poisoning. This retrospective study included 200 patients with acute severe CO poisoning. Hyperthermia (≥ 37.5°C) developed during the first 24 h after presentation in 55 (27.5%) patients, and poor long-term neurological sequelae assessed at 23 months after acute CO poisoning developed in 19.5% of the patients. The incidence of poor long-term neurological outcomes was significantly higher in the hyperthermia group than in the normothermia group. Patients with poor long-term neurological outcomes had higher maximum temperatures than patients with good outcomes. No significant difference was found in the time of hyperthermia onset within the first day according to the neurological outcomes. Hyperthermia (adjusted odds ratio (aOR) 5.009 (95% confidence interval (CI) 1.556-16.126)) and maximum temperature (aOR 2.581 (95% CI 1.098-6.063)) within the first 24 h after presentation to the emergency department were independently associated with poor long-term neurological outcomes. Body temperature measurements, which are easily and noninvasively recorded at the bedside in any facility, help to predict the risk for poor long-term neurological outcomes. This study carefully emphasizes fastidious control of pyrexia, particularly during the early period after acute CO poisoning.

Trends in stroke outcomes in the last ten years in a European tertiary hospital

Background

Studying the impact of demographic changes and progress in the management of stroke patients is necessary in order to organize care structures for the coming years. Consequently, we analyzed the prognostic trends of patients admitted to the Stroke Unit of a tertiary hospital in the last ten years.

Methods

The University Clinical Hospital of Santiago de Compostela is the referral hospital for stroke in a catchment area that accounts for 16.5% of the population of Galicia. Data from patients admitted to the Stroke Unit were registered prospectively. A multinomial logistic regression was performed to determine the influence of new trends in demographic factors and in the management of patients with acute stroke. For the expected trend of progression, a 2008–2011 and 2012–2017 time series model was made by selecting the most appropriate model.

Results

In the last 10 years, the age of stroke onset has only increased in women (from 74.4 ± 2.2 years in 2008 to 78.8 ± 2.1 years in 2017; p = 0.037), and the same happens with the severity of neurological symptoms (ischemic stroke (IS), p < 0.0001; from 14 [10, 19] in 2008 to 19 [15, 26] in 2017), with a higher percentage of cardioembolic strokes (40.7% vs. 32.2% of cardioembolic strokes in women vs. men, p < 0.0001). In a multiple linear regression model, hospital improvement was mainly associated with the use of reperfusion treatment (B 53.11, CI 95% 49.87, 56.36, p < 0.0001). A differentiated multinomial logistic regression analysis conducted for the whole sample with ischemic strokes in the two time periods (2008–2011 and 2012–2017) showed no differences in the influence of factors associated with higher morbidity and mortality. The modeling of time series showed a distinct falling trend in mortality, with a slight increase in good outcome as well as morbidity in both ischemic and hemorrhagic stroke.

Conclusions

Our results showed that mortality decreased in the entire sample; however, although outcome at discharge improved in ischemic stroke, severe disability also increased in these patients. Importantly, this tendency towards increased morbidity seems to be confirmed for the coming years.

Factors that may contribute to poor outcome despite good reperfusion after acute endovascular stroke therapy

Endovascular therapy with mechanical thrombectomy is a formidable treatment for severe acute ischemic stroke caused by occlusion of a proximal intracranial artery. Its strong beneficial effect is explained by the high rates of very good and excellent reperfusion achieved with current endovascular techniques. However, there is a sizable proportion of patients who do not experience clinical improvement despite successful recanalization of the occluded artery and reperfusion of the ischemic territory. Factors such as baseline reserve, collateral flow, anesthesia and systemic factors have been identified as potential culprits for lack of improvement in the setting of timely and successful revascularization. Older age, baseline disability and perhaps radiological markers of chronic brain injury can affect the prognosis of patients treated with endovascular therapy. Collateral flow is a major determinant of outcome after endovascular therapy and it is manifested by the size of the core in relation to the volume of the salvageable tissue. Parenchymal and vascular imaging can help assess the quality of collateral flow, but the optimal radiological strategy for daily practice (i.e. the optimal combination of rapid availability and diagnostic precision) has not been established. A sizable body of observational evidence indicates that acute hypertension, hyperglycemia and fever are associated with worse outcomes after a stroke even after optimal reperfusion with endovascular therapy. Lastly, current randomized controlled trials in anesthesia for stroke demonstrate similar rates of good functional outcome between general anesthesia and conscious sedation suggesting equipoise exists.

Fever worsens outcomes in animal models of ischaemic stroke: A systematic review and meta-analysis

Background

Subfebrile temperatures and fever in the first days after stroke are associated with a greater risk of a poor outcome. If this relation is causal, prevention of hyperthermia may improve outcome. Causality can be tested in animal models. We therefore assessed the effects of hyperthermia on outcomes in animal models of ischaemic stroke and explored under which conditions prevention of hyperthermia could be most effective.

Methods

We performed a systematic review and meta-analysis of data from animal experiments testing the effect of spontaneous or induced hyperthermia on outcome after focal cerebral ischaemia. Our primary outcome measure was infarct size. Normalised mean differences were combined using the random effects model and stratified meta-analysis was used to explore the impact of study characteristics.

Results

We included 19 publications, reporting on 49 comparisons involving 603 animals. Overall, hyperthermia increased infarct size by 43.4% (95% confidence interval, 29.8-56.9%) and worsened neurobehavioral outcomes by 48.5% (17.2-79.8%). The increase in infarct size was larger with higher temperatures. Hyperthermia was most harmful if present for more than 2 h and when started at the time of artery occlusion rather than later.

Conclusion

Hyperthermia substantially increased infarct size in animal models of ischaemic stroke, suggesting that the relation between fever and poor outcome observed in patients is at least in part causal. These data provide support to trials testing the effect of the prevention of fever with antipyretic drugs in patients with acute stroke.

In-hospital dynamics of glucose, blood pressure and temperature predict outcome in patients with acute ischaemic stroke

INTRODUCTION

We aimed to assess alterations in glucose, blood pressure and temperature in acute ischaemic stroke and investigate their association with early all-cause mortality and functional outcome.

PATIENTS AND METHODS

We studied all consecutive acute ischaemic stroke patients admitted in 2001-2010 to the Acute Stroke Unit, at Alexandra University Hospital, in Athens. Serial measurements were performed in the first seven days post-stroke and different parameters have been estimated: mean daily values, variability, subject-specific baseline levels and rate of change in serial measurements. Cox-proportional-hazards-model analysis and logistic-regression analysis were applied to investigate the association between these parameters and all-cause mortality and functional outcome after adjustment for known confounders of stroke outcome.

RESULTS

In 1271 patients (mean age 72.3 ± 11.2 years), after adjusting for confounders, baseline glucose levels (HR: 1.005, 95%CI: 1.001-1.01; p = 0.017), variability of systolic BP (SBP) as estimated by standard deviation (HR: 1.028, 95%CI: 1.01-1.048; p = 0.005), the baseline temperature (HR: 2.758, 95%CI: 2.067-3.68; p < 0.001) and the rate of temperature change (HR: 1.841, 95%CI: 1.616-2.908; p < 0.001) were independently associated with all-cause mortality within three months. Poor functional outcome was associated with subject-specific baseline values of temperature (OR: 1.743; 95%CI: 1.076-2.825; p = 0.024), the rate of SBP (OR: 1.159; 95% CI: 1.047-1.280; p = 0.004) and temperature change (OR: 1.402; 95% CI: 1.061-1.853; p = 0.018).

DISCUSSION

The main strength of our study is that we analysed simultaneously three parameters and we used four different variables for each parameter of interest.

CONCLUSION

Baseline glucose levels, variability of SBP and baseline temperature and its rate of change are independent predictors of all-cause mortality. Baseline values of temperature and the rate of changes in SBP and temperature are independent predictors of poor functional outcome.

Clinical and Radiographic Predictors of Intracerebral Hemorrhage Outcome

BACKGROUND

Intracerebral hemorrhage (ICH) represents 10-15% of all stroke cases in the US annually. Fewer than 40% of these patients ever reach long-term functional independence, and mortality rate is roughly 40% at 1 month. Due to the high morbidity and mortality rates after ICH, early detection of high-risk patients would be beneficial in directing the management course and goals of care. This review aims to discuss relevant clinical and radiographic characteristics that can serve as predictors of poor prognosis and examine their efficacy in predicting patient outcomes after ICH.

SUMMARY

A literature review was conducted on various clinical and radiographic factors. They were examined for their predictive value in relation to ICH outcome. Studies that focused on each of these factors were included, and their results analyzed for trends with regard to incidence, patient outcome, and mortality rate.

KEY MESSAGE

In this review, we examined clinical and radiographic characteristics that have been found to be significantly associated to a varying degree with poor outcome. Clinical and radiographic predictors of poor patient outcome are invaluable when it comes to identifying high-risk patients and triaging accordingly as well as guiding decision-making.

Thermoregulation in brain injury

Different mechanisms explain thermoregulatory dysfunction following ischemic stroke, hemorrhagic stroke, and traumatic brain injury. Temperature instability following brain injury likely involves hypothalamic injury, pathologic changes in cerebral blood flow, metabolic derangement, and a neurogenic inflammatory response. Although targeted temperature management (TTM) exerts pleiotropic effects, the heterogeneity of brain injury has hindered identification of patient subsets most likely to benefit from TTM. Early optimism about TTM's role in brain injury has been tempered by the failure of successive clinical trials to show improved patient outcomes. However, given the deleterious effects of fever, aggressive fever management is still warranted in the critically ill neurologic patient.

Acute Ischaemic Stroke: Management, Recent Advances and Controversies

Acute ischaemic stroke is a major cause of death and disability. It may become an enormous burden to the patients themselves, their families as well as the health care systems. Patients at risk of airway, breathing and circulatory compromise should receive prompt resuscitation. Vital parameters and neurological status should be closely monitored. Attentions to blood pressure, temperature and sugar profile are important. The significance of early and correct diagnosis and subsequent treatment cannot be over-emphasised. There have been tremendous recent advances in different treatment modalities in acute stroke management. Various recanalisation modalities include intravenous and/or intra-arterial thrombolysis, acute defibrinogenation, anti-platelet treatment and anticoagulation. Carotid endarterectomy and endovascular strategies are recommended in selected patients. Advanced neuro-imaging techniques and neuroprotectants are being evaluated. Multidisciplinary stroke teams have been shown to improve patient survival and functional outcome. Pre-defined algorithms and protocols should be in place to expedite smooth and effective delivery of stroke service. Future directions should be aimed at exploring safer recanalisation modalities and extending the limit of the current 3-hour treatment window for thrombolysis.

Elevated body temperature in ischemic stroke associated with neurological improvement

OBJECTIVES

Some studies suggest that high body temperature within the first few hours of ischemic stroke onset is associated with improved outcome. We hypothesized an association between high body temperature on admission and detectable improvement within 6-9 hours of stroke onset.

MATERIALS AND METHODS

Consecutive ischemic stroke patients with NIHSS scores obtained within 3 hours and in the interval 6-9 hours after stroke onset were included. Body temperature was measured on admission.

RESULTS

A total of 315 patients with ischemic stroke were included. Median NIHSS score on admission was 6. Linear regression showed that NIHSS score 6-9 hours after stroke onset was inversely associated with body temperature on admission after adjusting for confounders including NIHSS score <3 hours after stroke onset (P<.001). The same result was found in patients with proximal middle cerebral occlusion on admission.

CONCLUSIONS

We found an inverse association between admission body temperature and neurological improvement within few hours after admission. This finding may be limited to patients with documented proximal middle cerebral artery occlusion on admission and suggests a beneficial effect of higher body temperature on clot lysis within the first three hours.

Should preventive antibiotics be used in patients with acute stroke? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Infection is a common complication in acute stroke. Whether or not preventive antibiotics reduce the risk of infection or even lead to a favorable outcome and reduction of mortality after a stroke still remains equivocal. This review was performed to update the current knowledge on the effect and possible benefits of prophylactic antibiotic therapy in patients with stroke.

METHODS

A systematic review and meta-analysis of preventive antibiotics`effect on the incidence of infection, favorable outcome (mRS≤2) and mortality in patients with acute stroke is performed with relevant randomized controlled trials.

RESULTS

Six studies were identified, involving 4125 participants. Compared with the control group, the treated groups were significantly less prone to suffer from early overall infections [RR = 0.52, 95%CI (0.39, 0.70), p<0.0001], early pneumonia [RR = 0.64, 95%CI (0.42, 0.96), p = 0.03] and early urinary tract infections [RR = 0.35, 95%CI (0.25, 0.48), p<0.00001]. However, there was no significant difference in overall mortality [RR = 1.07, 95%CI (0.90, 1.27), p = 0.44], early mortality [RR = 0.99, 95%CI (0.78, 1.26), p = 0.92], late mortality [RR = 1.12, 95%CI (0.94, 1.35), p = 0.21] or favorable outcome [RR = 1.00, 95%CI (0.92, 1.08), p = 0.98].

CONCLUSION

Although preventive antibiotic treatment did reduce the occurrence of early overall infections, early pneumonia and early urinary tract infection in patients with acute stroke, this advantage was not eventually translated to a favorable outcome and reduction in mortality. Future studies are warranted to identify any subgroup of stroke patients who might benefit from preventive antibiotic treatment.

Hypothermia revisited: Impact of ischaemic duration and between experiment variability

To assess the true effect of novel therapies for ischaemic stroke, a positive control that can validate the experimental model and design is vital. Hypothermia may be a good candidate for such a positive control, given the convincing body of evidence from animal models of ischaemic stroke. Taking conditions under which substantial efficacy had been seen in a meta-analysis of hypothermia for focal ischaemia in animal models, we undertook three randomised and blinded studies examining the effect of hypothermia induced immediately following the onset of middle cerebral artery occlusion on infarct volume in rats (n = 15, 23, 264). Hypothermia to a depth of 33℃ and maintained for 130 min significantly reduced infarct volume compared to normothermia treatment (by 27-63%) and depended on ischaemic duration (F(3,244) = 21.242, p < 0.05). However, the protective effect varied across experiments with differences in both the size of the infarct observed in normothermic controls and the time to reach target temperature. Our results highlight the need for sample size and power calculations to take into account variations between individual experiments requiring induction of focal ischaemia.

Central Hyperthermia Treated with Bromocriptine

Introduction. Central hyperthermia is common in patients with brain injury. It typically has a rapid onset with high temperatures and marked fluctuations and responds poorly to antibiotics and antipyretics. It is also associated with worse outcomes in the brain injured patient. Recognizing this, it is important to aggressively manage it. Case Report. We report a 34-year-old male with a right thalamic hemorrhage extending to the midbrain and into the ventricles. During his admission, he developed intractable fevers with core temperatures as high as 39.3°C. Infectious workup was unremarkable. The fever persisted despite empiric antibiotics, antipyretics, and cooling wraps. Bromocriptine was started resulting in control of the central hyperthermia. The fever spikes were reduced to minor fluctuations that significantly worsened with any attempt to wean off the bromocriptine. Conclusion. Diagnosing and managing central hyperthermia can be challenging. The use of bromocriptine can be beneficial as we have reported.

Body Temperature Modulates Infarction Growth following Endovascular Reperfusion

BACKGROUND AND PURPOSE

The neuronal substrate is highly sensitive to temperature elevation; however, its impact on the fate of the ischemic penumbra has not been established. We analyzed interactions between temperature and penumbral expansion among successfully reperfused patients with acute ischemic stroke, hypothesizing infarction growth and worse outcomes among patients with fever who achieve full reperfusion.

MATERIALS AND METHODS

Data from 129 successfully reperfused (modified TICI 2b/3) patients (mean age, 65 ± 15 years) presenting within 12 hours of onset were examined from a prospectively collected acute ischemic stroke registry. CT perfusion was analyzed to produce infarct core, hypoperfusion, and penumbral mismatch volumes. Final DWI infarction volumes were measured, and relative infarction growth was computed. Systemic temperatures were recorded throughout hospitalization. Correlational and logistic regression analyses assessed the associations between fever (>37.5°C) and both relative infarction growth and favorable clinical outcome (90-day mRS of ≤2), corrected for NIHSS score, reperfusion times, and age. An optimized model for outcome prediction was computed by using the Akaike Information Criterion.

RESULTS

The median presentation NIHSS score was 18 (interquartile range, 14-22). Median (interquartile range) CTP-derived volumes were: core = 9.6 mL (1.5-25.3 mL); hypoperfusion = 133 mL (84.2-204 mL); and final infarct volume = 9.6 mL (8.3-45.2 mL). Highly significant correlations were observed between temperature of >37.5°C and relative infarction growth (Kendall τ correlation coefficient = 0.24, P = .002). Odds ratios for favorable clinical outcome suggested a trend toward significance for fever in predicting a 90-day mRS of ≤2 (OR = 0.31, P = .05). The optimized predictive model for favorable outcomes included age, NIHSS score, procedure time to reperfusion, and fever. Likelihood ratios confirmed the superiority of fever inclusion (P < .05). Baseline temperature, range, and maximum temperature did not meet statistical significance.

CONCLUSIONS

These findings suggest that imaging and clinical outcomes may be affected by systemic temperature elevations, promoting infarction growth despite reperfusion.

Comparison of Two Surface Cooling Devices for Temperature Management in a Neurocritical Care Unit

Fever increases mortality and morbidity and length of stay in neurocritically ill patients. Various methods are used in the neuroscience intensive care unit (NSICU) to control fever. Two such methods involve the Arctic Sun hydrogel wraps and the Gaymar cooling wraps. The purpose of our study was to compare these two methods in neurocritical care patients who had temperature >37.5°C for more than three consecutive hours and that was refractory to standard treatments. Data of patients requiring cooling wraps for treatment of hyperthermia at an NSICU at an academic, tertiary referral center were retrospectively reviewed. The average temperature before cooling was 38.5°C ± 0.38°C and 38.4°C ± 0.99°C for the Gaymar and Arctic Sun groups, respectively (p = 0.89). The Gaymar group took on average 16 ± 21.9 hours to reach goal temperature, whereas the Arctic Sun group took 2.22 ± 1.39 hours (p = 0.08). The average time outside of the target temperature was 57.0 ± 58.0 hours in the Gaymar group compared with 13.7 ± 17.1 hours in the Arctic Sun group (p = 0.04). Average duration of using the cooling wraps was similar between the two groups; 81.8% of patients had rebound hyperthermia in the Gaymar group compared with 20% in the Arctic Sun group (p = 0.0089). The Arctic Sun group had a nonsignificant increased incidence of shivering compared with the Gaymar group (40% vs. 18.18%, p = 0.36). We found that Arctic Sun surface cooling device was more efficient in attaining the target temperature, had less incidence of rebound hyperthermia, and was able to maintain normothermia better than Gaymar cooling wraps. The incidence of shivering tended to be more common in the Arctic Sun group.

Temporal profile of body temperature in acute ischemic stroke: relation to infarct size and outcome

Background

High body temperatures after ischemic stroke have been associated with larger infarct size, but the temporal profile of this relation is unknown. We assess the relation between temporal profile of body temperature and infarct size and functional outcome in patients with acute ischemic stroke.

Methods

In 419 patients with acute ischemic stroke we assessed the relation between body temperature on admission and during the first 3 days with both infarct size and functional outcome. Infarct size was measured in milliliters on CT or MRI after 3 days. Poor functional outcome was defined as a modified Rankin Scale score ≥3 at 3 months.

Results

Body temperature on admission was not associated with infarct size or poor outcome in adjusted analyses. By contrast, each additional 1.0 °C in body temperature on day 1 was associated with 0.31 ml larger infarct size (95% confidence interval (CI) 0.04–0.59), on day 2 with 1.13 ml larger infarct size(95% CI, 0.83–1.43), and on day 3 with 0.80 ml larger infarct size (95% CI, 0.48–1.12), in adjusted linear regression analyses. Higher peak body temperatures on days two and three were also associated with poor outcome (adjusted relative risks per additional 1.0 °C in body temperature, 1.52 (95% CI, 1.17–1.99) and 1.47 (95% CI, 1.22–1.77), respectively).

Conclusions

Higher peak body temperatures during the first days after ischemic stroke, rather than on admission, are associated with larger infarct size and poor functional outcome. This suggests that prevention of high temperatures may improve outcome if continued for at least 3 days.

Intraventricular infusion of a low fraction of serum enhances neurogenesis and improves recovery in a rodent stroke model

Enhancing endogenous neurogenesis is a potential therapeutic strategy in stroke treatment. We have previously demonstrated that treatment with a fraction of serum with molecular weight of less than 100 kDa (100K) combined with bFGF promoted neurogenesis of cultured stem and progenitor cells (NSPCs). In this study, we further evaluated the efficacy of intraventricular administration of 100K with bFGF (100K/bFGF) in a rat model of transient middle cerebral artery occlusion (MCAO). Rats administered 100K/bFGF on post-stroke day 1 exhibited a higher number of Ki67 and Nestin immunoreactive cells at the subventricular zone (SVZ) area and in the infarcted brain, indicating promotion of NSPCs proliferation. The 100K/bFGF treatment also predominantly increased the number of MAP-2 immunoreactive cells rather than GFAP immunoreactive cells at the SVZ area and in the infarcted regions, implying that 100K/bFGF dominated NSPCs differentiating into neurons rather than astrocytes. Importantly, treatment with 100K/bFGF significantly improved the animals' motor coordination. These findings demonstrated that treatment with a low serum fraction and bFGF benefited ischemic stroke likely through promotion of the proliferation and neuronal differentiation of endogenous NSPCs.

Effects of Acute Lithium Treatment on Brain Levels of Inflammatory Mediators in Poststroke Rats

Stroke is a leading cause of mortality and morbidity worldwide. Few therapeutic options with proven efficacy are available for the treatment of this disabling disease. Lithium is the gold standard treatment for bipolar disorder. Moreover, lithium has been shown to exhibit neuroprotective effects and therapeutic efficacy as a treatment of other neurological disorders. This study was undertaken to examine the effects of lithium on brain inflammatory mediators levels, fever, and mortality in postischemic stroke rats. Ischemic stroke was induced by occlusion of the mid cerebral artery (MCAO). Pretreatment with a single dose of lithium at 2 hours before MCAO induction significantly reduced the elevation in interleukin- (IL-) 6 and prostaglandin E₂ levels in brain of post-MCAO rats, as compared to vehicle-treated animals. On the other hand, lithium did not affect the elevation in IL-1α, IL-10, IL-12, and tumor necrosis factor-α levels in brain of post-MCAO rats. Moreover, pretreatment with lithium did not alter post-MCAO fever and mortality. These results suggest that acute pretreatment with a single dose of lithium did not markedly affect post-MCAO morbidity and mortality in rats.

European Stroke Organisation (ESO) Guidelines for the Management of Temperature in Patients with Acute Ischemic Stroke

Background

Hyperthermia is a frequent complication in patients with acute ischemic stroke. On the other hand, therapeutically induced hypothermia has shown promising potential in animal models of focal cerebral ischemia. This Guideline Document presents the European Stroke Organisation guidelines for the management of temperature in patients with acute ischemic stroke.

Methods

A multidisciplinary group identified related questions and developed its recommendations based on evidence from randomized controlled trials elaborating the Grading of Recommendations Assessment, Development, and Evaluation approach. This Guideline Document was reviewed within the European Stroke Organisation and externally and was approved by the European Stroke Organisation Guidelines Committee and the European Stroke Organisation Executive Committee.

Results

We found low-quality evidence, and therefore, we cannot make any recommendation for treating hyperthermia as a means to improve functional outcome and/or survival in patients with acute ischemic stroke and hyperthermia; moderate evidence to suggest against routine prevention of hyperthermia with antipyretics as a means to improve functional outcome and/or survival in patients with acute ischemic stroke and normothermia; very low-quality evidence to suggest against routine induction of hypothermia as a means to improve functional outcome and/or survival in patients with acute ischemic stroke.

Conclusions

The currently available data about the management of temperature in patients with acute ischemic stroke are limited, and the strengths of the recommendations are therefore weak. We call for new randomized controlled trials as well as recruitment of eligible patients to ongoing randomized controlled trials to allow for better-informed recommendations in the future.

Systemic Inflammatory Response Syndrome Predicts Severity of Stroke and Outcome

BACKGROUND

This study was undertaken to evaluate the frequency of systemic inflammatory response syndrome (SIRS) at admission and its correlation with clinical and radiological severity of stroke and outcome.

METHODS

Two hundred consecutive stroke patients within 48 hours of ictus were prospectively included, and their clinical details including Glasgow Coma Scale (GCS), National Institutes of Health Stroke Scale (NIHSS), and feature of raised intracranial tension were noted. Computed tomography/magnetic resonance imaging finding included stroke type, location, size, midline shift, herniation, and intraventricular hemorrhage score. SIRS was noted on days 1, 2, 7, and 15. Death and outcome at 3 months were based on modified Rankin Scale (mRS) score.

RESULTS

Seventy-five (37.5%) had infraction and 125(62.5%) intracranial hemorrhage (ICH). SIRS was present in 120 (60%) patients: all the features in 56 (28%), 3 in 48 (24%), and 2 in 16 (8%). The presence of SIRS decreased with time: on the second day in 57%, seventh day in 43%, and 15th day in 21% of patients. Admission SIRS correlated with the GCS score (P < .001), NIHSS score (P < .001), volume of ICH (P < .001), infarction size (P < .001), hypernatremia (P = .001), and respiratory paralysis (P < .001). Thirty-one (15.5%) patients died, and 30 (97%) of them had SIRS. At 3 months, 110 (55%) patients had poor outcome (mRS >2) and of them 90 (82%) had SIRS (P < .001). On multivariate regression analysis, the number of SIRS criteria (P = .16) was not significantly related to 3-month outcome and death but independently related to NIHSS score at admission (odds ratio [OR] = 1.39; 95% confidence interval [CI] = 1.22-1.56; P < .001), GCS score (OR = 1.32; 95% CI = 1.01-1.71; P = .04), and duration of hospitalization (OR = 1.07; 95% CI = 1.01-1.15; P = .03).

CONCLUSIONS

SIRS at presentation is a useful marker for clinicoradiological severity of stroke but not an independent marker of death and disability.

Early temperature and mortality in critically ill patients with acute neurological diseases: trauma and stroke differ from infection

BACKGROUND

Fever suppression may be beneficial for patients with traumatic brain injury (TBI) and stroke, but for patients with meningitis or encephalitis [central nervous system (CNS) infection], the febrile response may be advantageous.

OBJECTIVE

To evaluate the relationship between peak temperature in the first 24 h of intensive care unit (ICU) admission and all-cause hospital mortality for acute neurological diseases.

DESIGN, SETTING AND PARTICIPANTS

Retrospective cohort design from 2005 to 2013, including 934,159 admissions to 148 ICUs in Australia and New Zealand (ANZ) and 908,775 admissions to 236 ICUs in the UK.

RESULTS

There were 53,942 (5.8 %) patients in ANZ and 56,696 (6.2 %) patients in the UK with a diagnosis of TBI, stroke or CNS infection. For both the ANZ (P = 0.02) and UK (P < 0.0001) cohorts there was a significant interaction between early peak temperature and CNS infection, indicating that the nature of the relationship between in-hospital mortality and peak temperature differed between TBI/stroke and CNS infection. For patients with CNS infection, elevated peak temperature was not associated with an increased risk of death, relative to the risk at 37-37.4 °C (normothermia). For patients with stroke and TBI, peak temperature below 37 °C and above 39 °C was associated with an increased risk of death, compared to normothermia.

CONCLUSIONS

The relationship between peak temperature in the first 24 h after ICU admission and in-hospital mortality differs for TBI/stroke compared to CNS infection. For CNS infection, increased temperature is not associated with increased risk of death.