Fever in subarachnoid hemorrhage: relationship to vasospasm and outcome

Beyond Control: Temperature Burden in Patients with Spontaneous Subarachnoid Hemorrhage-An Observational Study

BACKGROUND

Temperature abnormalities are common after spontaneous subarachnoid hemorrhage (SAH). Here, we aimed to describe the evolution of temperature burden despite temperature control and to assess its impact on outcome parameters.

METHODS

This retrospective observational study of prospectively collected data included 375 consecutive patients with SAH admitted to the neurological intensive care unit between 2010 and 2022. Daily fever (defined as the area over the curve above 37.9 °C multiplied by hours with fever) and spontaneous hypothermia burden (< 36.0 °C) were calculated over the study period of 16 days. Generalized estimating equations were used to calculate risk factors for increased temperature burdens and the impact of temperature burden on outcome parameters after correction for predefined variables.

RESULTS

Patients had a median age of 58 years (interquartile range 49-68) and presented with a median Hunt & Hess score of 3 (interquartile range 2-5) on admission. Fever (temperature > 37.9 °C) was diagnosed in 283 of 375 (76%) patients during 14% of the monitored time. The average daily fever burden peaked between days 5 and 10 after admission. Higher Hunt & Hess score (p = 0.014), older age (p = 0.033), and pneumonia (p = 0.022) were independent factors associated with delayed fever burden between days 5 and 10. Increased fever burden was independently associated with poor 3-month functional outcome (modified Rankin Scale 3-6, p = 0.027), poor 12-month functional outcome (p = 0.020), and in-hospital mortality (p = 0.045), but not with the development of delayed cerebral ischemia (p = 0.660) or intensive care unit length of stay (p = 0.573). Spontaneous hypothermia was evident in the first three days in patients with a higher Hunt & Hess score (p < 0.001) and intraventricular hemorrhage (p = 0.047). Spontaneous hypothermia burden was not associated with poor 3-month outcome (p = 0.271).

CONCLUSIONS

Early hypothermia was followed by fever after SAH. Increased fever time burden was associated with poor functional outcome after SAH and could be considered for neuroprognostication.

Temperature Changes in Poor-Grade Aneurysmal Subarachnoid Hemorrhage: Relation to Injury Pattern, Intracranial Pressure Dynamics, Cerebral Energy Metabolism, and Clinical Outcome

BACKGROUND

The aim was to study the course of body temperature in the acute phase of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) in relation to the primary brain injury, cerebral physiology, and clinical outcome.

METHODS

In this observational study, 166 patients with aSAH treated at the neurosurgery department at Uppsala University Hospital in Sweden between 2008 and2018 with temperature, intracranial pressure (ICP), and microdialysis (MD) monitoring were included. The first 10 days were divided into the early phase (days 1-3) and the vasospasm phase (days 4-10).

RESULTS

Normothermia (temperature = 36-38 °C) was most prevalent in the early phase. A lower mean temperature at this stage was univariately associated with a worse primary brain injury, with higher Fisher grade and higher MD glycerol concentration, as well as a worse neurological recovery at 1 year. There was otherwise no association between temperature and cerebral physiological variables in the early phase. There was a transition toward an increased burden of hyperthermia (temperature > 38 °C) in the vasospasm phase. This was associated with concurrent infections but not with neurological or radiological injury severity at admission. Elevated temperature was associated with higher MD pyruvate concentration, lower rate of an MD pattern indicative of ischemia, and higher rate of poor neurological recovery at 1 year. There was otherwise no association between temperature and cerebral physiological variables in the vasospasm phase. The associations between temperature and clinical outcome did not hold true in multiple logistic regression analyses.

CONCLUSIONS

Spontaneously low temperature in the early phase reflected a worse primary brain injury and indicated a worse outcome prognosis. Hyperthermia was common in the vasospasm phase and was more related to infections than primary injury severity but also with a more favorable energy metabolic pattern with better substrate supply, possibly related to hyperemia.

Intracranial Pressure Monitoring and Management in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage is a medical condition that can lead to intracranial hypertension, negatively impacting patients' outcomes. This review article explores the underlying pathophysiology that causes increased intracranial pressure (ICP) during hospitalization. Hydrocephalus, brain swelling, and intracranial hematoma could produce an ICP rise. Although cerebrospinal fluid withdrawal via an external ventricular drain is commonly used, ICP monitoring is not always consistently practiced. Indications for ICP monitoring include neurological deterioration, hydrocephalus, brain swelling, intracranial masses, and the need for cerebrospinal fluid drainage. This review emphasizes the importance of ICP monitoring and presents findings from the Synapse-ICU study, which supports a correlation between ICP monitoring and treatment with better patient outcomes. The review also discusses various therapeutic strategies for managing increased ICP and identifies potential areas for future research.

Fine tuning of neurointensive care in aneurysmal subarachnoid hemorrhage: From one-size-fits-all towards individualized care

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe type of acute brain injury with high mortality and burden of neurological sequelae. General management aims at early aneurysm occlusion to prevent re-bleeding, cerebrospinal fluid drainage in case of increased intracranial pressure and/or acute hydrocephalus, and cerebral blood flow augmentation in case of delayed ischemic neurological deficits. In addition, the brain is vulnerable to physiological insults in the acute phase and neurointensive care (NIC) is important to optimize the cerebral physiology to avoid secondary brain injury. NIC has led to significantly better neurological recovery following aSAH, but there is still great room for further improvements. First, current aSAH NIC management protocols are to some extent extrapolated from those in traumatic brain injury, notwithstanding important disease-specific differences. Second, the same NIC management protocols are applied to all aSAH patients, despite great patient heterogeneity. Third, the main variables of interest, intracranial pressure and cerebral perfusion pressure, may be too superficial to fully detect and treat several important pathomechanisms. Fourth, there is a lack of understanding not only regarding physiological, but also cellular and molecular pathomechanisms and there is a need to better monitor and treat these processes. This narrative review aims to discuss current state-of-the-art NIC of aSAH, knowledge gaps in the field, and future directions towards a more individualized care in the future.

Targeted Temperature Management for Severe Subarachnoid Hemorrhage Using Endovascular and Surface Cooling Systems: A Nonrandomized Interventional Study Using Historical Control

BACKGROUND

Although targeted temperature management (TTM) may mitigate brain injury for severe subarachnoid hemorrhage (SAH), rebound fever correlates with poor outcomes.

OBJECTIVE

To study the effect of endovascular TTM after rewarming from initial surface cooling during a high-risk period for delayed cerebral ischemia.

METHODS

We studied patients with World Federation of Neurological Surgeons grade V SAH before and after the introduction of endovascular TTM. Both groups (36 patients each) were treated with TTM at 34 °C with conventional surface cooling immediately after SAH diagnosis, together with emergency aneurysm repair. When rewarmed to 36 °C, around 7 days later, the study group underwent TTM at 36 to 38 °C for 7 days with an endovascular cooling system. The control group was treated with antipyretics.

RESULTS

Sex, age, Glasgow Coma Scale score, modified Fisher computed tomography classification, aneurysm location, and treatment methods were not different between the study and control groups. Differences were detected in the incidence of fever >38 °C (13 vs 26 patients, P = .0021), duration of fever >38 °C (4.1 vs 18.8 hours, P = .0021), incidence of vasospasm-related cerebral infarction (17% vs 42%, P = .037), and the likelihood of excellent outcomes (0 and 1 on a modified Rankin Scale) at 6 months (42% vs 17%, P = .037). In endovascular TTM, shivering occurred more frequently in patients with better outcomes, requiring aggressive treatment to avoid fever.

CONCLUSION

Endovascular TTM at 36 to 38 °C after surface cooling was feasible and safely performed in patients with severe SAH. Combined TTM for 2 weeks was associated with a lower incidence of vasospasm-related infarction and may improve outcomes.

Spontaneous subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH) is the third most common subtype of stroke. Incidence has decreased over past decades, possibly in part related to lifestyle changes such as smoking cessation and management of hypertension. Approximately a quarter of patients with SAH die before hospital admission; overall outcomes are improved in those admitted to hospital, but with elevated risk of long-term neuropsychiatric sequelae such as depression. The disease continues to have a major public health impact as the mean age of onset is in the mid-fifties, leading to many years of reduced quality of life. The clinical presentation varies, but severe, sudden onset of headache is the most common symptom, variably associated with meningismus, transient or prolonged unconsciousness, and focal neurological deficits including cranial nerve palsies and paresis. Diagnosis is made by CT scan of the head possibly followed by lumbar puncture. Aneurysms are commonly the underlying vascular cause of spontaneous SAH and are diagnosed by angiography. Emergent therapeutic interventions are focused on decreasing the risk of rebleeding (ie, preventing hypertension and correcting coagulopathies) and, most crucially, early aneurysm treatment using coil embolisation or clipping. Management of the disease is best delivered in specialised intensive care units and high-volume centres by a multidisciplinary team. Increasingly, early brain injury presenting as global cerebral oedema is recognised as a potential treatment target but, currently, disease management is largely focused on addressing secondary complications such as hydrocephalus, delayed cerebral ischaemia related to microvascular dysfunction and large vessel vasospasm, and medical complications such as stunned myocardium and hospital acquired infections.

Cerebral Blood Flow and Oxygen Delivery in Aneurysmal Subarachnoid Hemorrhage: Relation to Neurointensive Care Targets

Background

The primary aim was to determine to what extent continuously monitored neurointensive care unit (neuro-ICU) targets predict cerebral blood flow (CBF) and delivery of oxygen (CDO₂) after aneurysmal subarachnoid hemorrhage. The secondary aim was to determine whether CBF and CDO₂ were associated with clinical outcome.

Methods

In this observational study, patients with aneurysmal subarachnoid hemorrhage treated at the neuro-ICU in Uppsala, Sweden, from 2012 to 2020 with at least one xenon-enhanced computed tomography (Xe-CT) obtained within the first 14 days post ictus were included. CBF was measured with the Xe-CT and CDO₂ was calculated based on CBF and arterial oxygen content. Regional cerebral hypoperfusion was defined as CBF < 20 mL/100 g/min, and poor CDO₂ was defined as CDO₂ < 3.8 mL O₂/100 g/min. Neuro-ICU variables including intracranial pressure (ICP), pressure reactivity index, cerebral perfusion pressure (CPP), optimal CPP, and body temperature were assessed in association with the Xe-CT. The acute phase was divided into early phase (day 1–3) and vasospasm phase (day 4–14).

Results

Of 148 patients, 27 had underwent a Xe-CT only in the early phase, 74 only in the vasospasm phase, and 47 patients in both phases. The patients exhibited cerebral hypoperfusion and poor CDO₂ for medians of 15% and 30%, respectively, of the cortical brain areas in each patient. In multiple regressions, higher body temperature was associated with higher CBF and CDO₂ in the early phase. In a similar regression for the vasospasm phase, younger age and longer pulse transit time (lower peripheral resistance) correlated with higher CBF and CDO₂, whereas lower hematocrit only correlated with higher CBF but not with CDO₂. ICP, CPP, and pressure reactivity index exhibited no independent association with CBF and CDO₂. R² of these regressions were below 0.3. Lower CBF and CDO₂ in the early phase correlated with poor outcome, but this only held true for CDO₂ in multiple regressions.

Conclusions

Systemic and cerebral physiological variables exhibited a modest association with CBF and CDO₂. Still, cerebral hypoperfusion and low CDO₂ were common and low CDO₂ was associated with poor outcome. Xe-CT imaging could be useful to help detect secondary brain injury not evident by high ICP and low CPP.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-022-01496-1.

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.

Fever management in acute brain injury

PURPOSE OF REVIEW

Fever is common after acute brain injury and is associated with poor prognosis in this setting.

RECENT FINDINGS

Achieving normothermia is feasible in patients with ischemic or hemorrhagic stroke, subarachnoid hemorrhage and traumatic brain injury. Pharmacological strategies (i.e. paracetamol or nonsteroidal anti-inflammatory drugs) are frequently ineffective and physical (i.e. cooling devices) therapies are often required. There are no good quality data supporting any benefit from therapeutic strategies aiming at normothermia in all brain injured patients when compared with standard of care, where mild-to-moderate fever is tolerated. However, recent guidelines recommended fever control in this setting.

SUMMARY

As fever is considered a clinically relevant secondary brain damage, we have provided an individualized therapeutic approach to treat it in brain injured patients, which deserved further validation in the clinical setting.

Predictive Relevance of Early Temperature Elevation on the Risk of Delayed Cerebral Ischemia Development Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Fever in aneurysmal subarachnoid hemorrhage (aSAH) has been associated with delayed cerebral ischemia (DCI), but its relevance in risk stratification has not been explored. This study investigated whether early temperature elevation following aSAH predicts impending clinical deterioration caused by DCI.

METHODS

Relevant cases were identified from a prospectively maintained database for consecutive patients with aSAH treated at our center between July 2015 and January 2020. Temperature readings obtained every 2 hours for individual patients from admission through day 14 were recorded and analyzed. Demographic, clinical, treatment, and angiographic data were extracted from the electronic medical record. The primary end point was the occurrence of DCI (clinical and radiographic vasospasm). Multivariate logistic regression analyses were performed to account for patient age, smoking status, and VASOGRADE classification.

RESULTS

The study included 175 patients (124 women) with aSAH. The median age at diagnosis was 55.4 years (range, 20.5-87.2 years). Clinical DCI occurred in 58 patients; 2 (1.1%) responded to hemodynamic augmentation, and 56 (32.0%) required intra-arterial therapy. Temperature graphs showed a marked divergence on day 4 between clinical DCI and non-DCI groups (1.12°C ± 0.15°C and 0.76°C ± 0.08°C, respectively, P = 0.007). Patients with temperature elevation ≥2.5°C on day 4 or 5 compared with their admission temperature were more likely to clinically deteriorate owing to DCI (odds ratio 4.55, 95% confidence interval 1.31-15.77, P = 0.017).

CONCLUSIONS

Temperature elevation of ≥2.5°C on day 4 or 5 compared with baseline suggests a greater risk of clinical deterioration owing to DCI.

In a model of SAH-induced neurogenic fever, BAT thermogenesis is mediated by erythrocytes and blocked by agonism of adenosine A1 receptors

Neurogenic fever (NF) after subarachnoid hemorrhage (SAH) is a major cause of morbidity that is associated with poor outcomes and prolonged stay in the neurointensive care unit (NICU). Though SAH is a much more common cause of fever than sepsis in the NICU, it is often a diagnosis of exclusion, requiring significant effort to rule out an infectious source. NF does not respond to standard anti-pyretic medications such as COX inhibitors, and lack of good medical therapy has led to the introduction of external cooling systems that have their own associated problems. In a rodent model of SAH, we measured the effects of injecting whole blood, blood plasma, or erythrocytes on the sympathetic nerve activity to brown adipose tissue and on febrile thermogenesis. We demonstrate that following SAH the acute activation of brown adipose tissue leading to NF, is not dependent on PGE₂, that subarachnoid space injection of whole blood or erythrocytes, but not plasma alone, is sufficient to trigger brown adipose tissue thermogenesis, and that activation of adenosine A1 receptors in the CNS can block the brown adipose tissue thermogenic component contributing to NF after SAH. These findings point to a distinct thermogenic mechanism for generating NF, compared to those due to infectious causes, and will hopefully lead to new therapies.

Brain temperature regulation in poor-grade subarachnoid hemorrhage patients - A multimodal neuromonitoring study

Elevated body temperature (T_core) is associated with poor outcome after subarachnoid hemorrhage (SAH). Brain temperature (T_brain) is usually higher than T_core. However, the implication of this difference (T_delta) remains unclear. We aimed to study factors associated with higher T_delta and its association with outcome. We included 46 SAH patients undergoing multimodal neuromonitoring, for a total of 7879 h of averaged data of T_core, T_brain, cerebral blood flow, cerebral perfusion pressure, intracranial pressure and cerebral metabolism (CMD). Three-months good functional outcome was defined as modified Rankin Scale ≤2. T_brain was tightly correlated with T_core (r = 0.948, p < 0.01), and was higher in 73.7% of neuromonitoring time (T_delta +0.18°C, IQR -0.01 - 0.37°C). A higher T_delta was associated with better metabolic state, indicated by lower CMD-glutamate (p = 0.003) and CMD-lactate (p < 0.001), and lower risk of mitochondrial dysfunction (MD) (OR = 0.2, p < 0.001). During MD, T_delta was significantly lower (0°C, IQR -0.2 - 0.1; p < 0.001). A higher T_delta was associated with improved outcome (OR = 7.7, p = 0.002). Our study suggests that T_brain is associated with brain metabolic activity and exceeds T_core when mitochondrial function is preserved. Further studies are needed to understand how T_delta may serve as a surrogate marker for brain function and predict clinical course and outcome after SAH.

Unfavorable Outcome After Good Grade Aneurysmal Subarachnoid Hemorrhage: Exploratory Analysis

OBJECTIVE

Patients with good-grade aneurysmal subarachnoid hemorrhage (aSAH) are thought to recover well, yet some do not. This work sought to identify predictors of unfavorable functional outcome after good-grade aSAH.

METHODS

We performed a post-hoc analysis of the CONSCIOUS-1 trial. Patients with World Federation of Neurosurgical Societies grades I or II aSAH were included. The primary outcome was unfavorable functional outcome (defined as a modified Rankin Scale score >2) at 12 weeks. Parametric and nonparametric testing were used as appropriate. Variables were classified as modifiable or nonmodifiable, depending on whether they were present at patient admission. Stepwise logistic regression models were created for modifiable and nonmodifiable predictors of outcome. Independent predictors in the respective multivariate analyses were combined into a final multivariate regression model.

RESULTS

We included 301 patients, 67 of whom (22%) had an unfavorable outcome. Of the nonmodifiable predictors, higher admission systolic blood pressure (P = 0.002) and female sex (P = 0.011) were independently associated with unfavorable outcome. Potentially modifiable independent predictors of outcome were delayed cerebral ischemia (P = 0.039), higher maximum temperature (0.036), suffering a respiratory system complication (P = 0.004), and suffering an intracranial hemorrhagic complication (P = 0.022). All variables found to be independently predictive of poor outcome in their respective models retained statistical significance in the combined multivariate analysis.

CONCLUSIONS

About 1 in 5 good-grade aSAH patients enrolled in CONSCIOUS-1 suffered an unfavorable functional outcome. Admission systolic blood pressure, female sex, hyperthermia, delayed cerebral ischemia, respiratory complications, and intracranial hemorrhagic complications may be predictive of outcome.

Bibliometric Analysis of the Top 100 Most Cited Articles on Cerebral Vasospasm

OBJECTIVE

Bibliometric analysis reflects the scientific recognition and influential performance of a published article within its field. Our aim is to identify and analyze the top 100 most-cited articles on cerebral vasospasm.

METHODS

A title-specific search was carried out using the Scopus database. The top 100 cited articles including the keywords "Cerebral Vasospasm" AND "Vasospasm" were retrieved and stratified in a descending order: title, authors, institution, publishing journal, country of origin, year of publication, and topic of each article were studied.

RESULTS

The top 100 articles have an accumulative citation count of 20,972, with 209 average citations per article. Publication dates ranged from 1968 to 2012, with the most productive years between 1998 and 2005. Clinical studies are the most frequent category, followed by pathophysiology. The list includes 7 clinical trials, which received accumulative citations of 1525. The top cited article had received 2109 citations, with 52.7 citations per year. The top 100 articles were published across 14 countries, with most originating from the United States. The lead research institution was the University of Alberta. The most used journal was Journal of Neurosurgery.

CONCLUSIONS

Bibliometric analysis has garnered major interest in recent years. It shows the publication trends, knowledge evolution, and evidence-based practice throughout the years. The collection of highly cited articles may assist physicians in gaining a better understanding of the nature of cerebral vasospasm and optimize their clinical practice.

Seizures at the onset of aneurysmal SAH: epiphenomenon or valuable predictor?

Objective

Seizures at the onset (SAO) of aneurysmal subarachnoid hemorrhage (aSAH) occur in up to one of every five cases. To date, there is no consensus on causal background and clinical value of these early bleeding-related seizures. This study aimed to analyze the predictors and the impact of SAO in aSAH.

Methods

All aSAH patients from the institutional observational cohort (01/2003–06/2016) were retrospectively reviewed. Patients’ charts and emergency protocols from first responders were screened for the occurrence of seizures in the first 24 h after aSAH. Patients’ baseline characteristics and occurrence of post-hemorrhagic complications were analyzed. Outcome endpoints included in-hospital mortality and poor outcome at 6-month follow-up (modified Rankin Scale > 3).

Results

Of 984 patients included in the final analysis, SAO occurred in 93 cases (9.5%) and were independently associated with younger age (< 51 years, p < 0.001), WFNS grade ≥ 4 (p < 0.001), aneurysm characteristics (location at the proximal branch of the anterior cerebral artery [p = 0.037] and irregular sac [p = 0.019]) and admission body temperature > 38.3 ℃ (p = 0.008). There was an association between SAO and early complications (early infarcts [p = 0.004] and primary decompressive craniectomy [p = 0.024]). Only in the subgroup analysis restricted to the younger individuals, SAO independently predicted poor outcome of aSAH (p = 0.002).

Significance

Onset seizures following aSAH are rare and most likely related to the severity of early brain injury. Particularly, younger individuals are not only at higher risk for SAO, but are also prone to poor outcome in case of aSAH accompanied with SAO.

Trial registration number

German clinical trial registry (DRKS, unique identifier: DRKS00008749, 06/09/2015)

Hematological biomarkers for predicting carotid artery vasospasm during carotid stenting

Introduction

The vasospasm of carotid arteries is important for the progression of neurological sequelae. Many mechanisms have been found to be related to this clinical phenomenon. Predicting this event by using hematological biomarkers may provide opportunities for adopting preventive measures against unfavorable neurovascular complications. The aim of this study is to determine the hematological predictors of carotid artery vasospasm during carotid stenting.

Material and methods

A total of 120 patients who underwent carotid stenting were divided into two groups: those with and without carotid artery vasospasm. Carotid artery vasospasm was angiographically defined as transient or persistent emergent stenosis or irregularity of the vessel wall without evidence of thrombosis during carotid stenting. The hematological parameters were compared between 21 patients who developed carotid artery vasospasm (17.5%) and 99 patients who did not (82.5%).

Results

The mean age of the patients with carotid artery vasospasm and without carotid artery vasospasm was 66 ±8 and 70 ±8 years, respectively. Creatinine levels within 0.5–0.9 (OR = 3.704, 95% CI: 1.245–11.019, p = 0.019), each 1000 unit increase in neutrophil count (OR = 1.567, 95% CI: 1.027–2.392, p = 0.037) and presence of diabetes (OR = 3.081, 95% CI: 1.116–8.505, p = 0.030) were the independent predictors of carotid artery vasospasm in carotid arteries during carotid stenting.

Conclusions

The prediction of carotid artery vasospasm during carotid stenting should help clinicians adopt preventive measures against the development of neurological sequelae. This study found that creatinine levels, increased neutrophil count and presence of diabetes are independent predictors of carotid artery vasospasm.

Protocolized Brain Oxygen Optimization in Subarachnoid Hemorrhage

BACKGROUND

Brain tissue hypoxia (P_btO₂ < 20 mmHg) is common after subarachnoid hemorrhage (SAH) and associated with poor outcome. Recent data suggest that brain oxygen optimization is feasible and reduces the time spent with P_btO₂ < 20 mmHg from 45 to 16% in patients with severe traumatic brain injury. Here, we intended to quantify the brain tissue hypoxia burden despite implementation of a protocolized treatment approach in poor-grade SAH patients and to identify the simultaneous occurrence of pathologic values potentially amenable to treatment.

METHODS

We present a bi-centric observational cohort study including 100 poor-grade SAH patients admitted to two tertiary care centers who underwent multimodal brain monitoring and were managed with a P_btO₂-targeted protocolized approach. P_btO₂ optimization (≥ 20 mmHg) included a stepwise neuro-intensive care approach, aiming to prevent low cerebral perfusion pressure (CPP), and blood hemoglobin, and to keep normocapnia, normoxemia, and normothermia. Based on routine blood gas analysis, hemoglobin, PaCO_2, and PaO₂ data were matched to 2-h averaged data of continuous CPP, P_btO₂, core temperature, and to hourly cerebral microdialysis (CMD) samples over the first 11 days.

RESULTS

Patients had a Glasgow Coma Scale of 3 (IQR 3-4) and were 58 years old (IQR 48-66). Overall incidence of brain tissue hypoxia was 25%, which was not different between both sites despite differences in the treatment approach. During brain tissue hypoxia, episodes of CPP < 70 mmHg (27%), PaCO₂ < 35 mmHg (19%), PaO₂ < 80 mmHg (14%), Hb < 9 g/dL (11%), metabolic crisis (CMD-lactate/pyruvate ratio > 40, and CMD-glucose < 0.7 mmol/L; 7%), and temperature > 38.3 °C (4%) were common.

CONCLUSIONS

Our results demonstrate that brain tissue hypoxia remains common despite implementation of a P_btO₂-targeted therapy in poor-grade SAH patients, suggesting room for further optimization.

Ruptured Fisher grade 3 blister aneurysms have a higher incidence of delayed cerebral ischemia than ruptured Fisher grade 3 saccular aneurysms

BACKGROUND

Blister aneurysms are a rare subclass of aneurysms, which remain challenging to treat both with open cerebrovascular and endovascular techniques, and clinicians continue to see poor outcomes in some cases despite improvements in technology. Based on our clinical observations, we hypothesized that patients with a Fisher grade 3 subarachnoid hemorrhage (SAH) from a ruptured anterior circulation blister aneurysm are significantly more likely to develop poor outcome due to delayed cerebral ischemia than patients with a Fisher grade 3 SAH from a ruptured anterior circulation saccular aneurysm.

METHODS

In this consecutive case series, we reviewed management, outcomes, and rates of delayed cerebral ischemia for all ruptured anterior circulation blister aneurysms from 2012 to 2018 at our institution and compared them to a concurrent cohort of ruptured saccular anterior circulation aneurysms. A blister aneurysm was defined as an aneurysm that arises from a nonbranching point and demonstrates hemispherical anatomy on diagnostic angiography.

RESULTS

We identified 14 consecutive ruptured anterior circulation blister aneurysms. Thirteen aneurysms were treated operatively- 5 with clip remodeling and 8 with flow diversion embolization. While clip remodeling had a high intraoperative rupture rate (80%), there was only one (12.5%) intraoperative rupture with flow diversion embolization. Outcomes were worsened by delayed cerebral ischemia from vasospasm in patients with Fisher 3 hemorrhages from blister aneurysms (86%). The rate of delayed cerebral ischemia from vasospasm was significantly higher for ruptured blister aneurysms than for a concurrent cohort of ruptured saccular aneurysms (8.6%, P = 0.0001).

CONCLUSION

Ruptured Fisher grade 3 anterior circulation blister aneurysms have a significantly higher incidence of delayed cerebral ischemia from vasospasm compared to saccular aneurysms, regardless of the treatment modality.

Systemic Hyperthermia in Traumatic Brain Injury-Relation to Intracranial Pressure Dynamics, Cerebral Energy Metabolism, and Clinical Outcome

BACKGROUND

Systemic hyperthermia is common after traumatic brain injury (TBI) and may induce secondary brain injury, although the pathophysiology is not fully understood. In this study, our aim was to determine the incidence and temporal course of hyperthermia after TBI and its relation to intracranial pressure dynamics, cerebral metabolism, and clinical outcomes.

MATERIALS AND METHODS

This retrospective study included 115 TBI patients. Data from systemic physiology (body temperature, blood pressure, and arterial glucose), intracranial pressure dynamics (intracranial pressure, cerebral perfusion pressure, compliance, and pressure reactivity), and cerebral microdialysis (glucose, pyruvate, lactate, glycerol, glutamate, and urea) were analyzed during the first 10 days after injury.

RESULTS

Overall, 6% of patients did not have hyperthermia (T>38°C) during the first 10 days after injury, whereas 20% had hyperthermia for >50% of the time. Hyperthermia increased from 21% (±27%) of monitoring time on day 1 to 36% (±29%) on days 6 to 10 after injury. In univariate analyses, higher body temperature was not associated with higher intracranial pressure nor lower cerebral perfusion pressure, but was associated with lower cerebral glucose concentration (P=0.001) and higher percentage of lactate-pyruvate ratio>25 (P=0.02) on days 6 to 10 after injury. Higher body temperature and lower arterial glucose concentration were associated with lower cerebral glucose in a multiple linear regression analysis (P=0.02 for both). There was no association between hyperthermia and worse clinical outcomes.

CONCLUSION

Hyperthermia was most common between days 6 and 10 following TBI, and associated with disturbances in cerebral energy metabolism but not worse clinical outcome.

The EMCOOLs surface cooling system for fever control in neurocritical care patients: A pilot study

OBJECTIVES

Fever occurs in up to 50% of critically-ill patients with acute neurological injury. Small temperature elevations have been correlated with increased morbidity and mortality in this patient population. We sought to evaluate a novel single-use surface cooling system for the treatment of fever in patients with acute brain injury.

PATIENTS AND METHODS

We conducted a retrospective analysis of a prospective product evaluation using the EMCOOLS Flex.Pad™ system for acute fever (≥38.3 °C) in our 16-bed neuro-ICU. Four refrigerated pads (-18 °C) were applied to the chest, back, and anterior thighs. Core temperature (bladder) was continuously recorded over 4 h, and the highest Bedside Shivering Assessment Scale (BSAS) score was recorded hourly.

RESULTS

Twelve subjects were included in the analysis. Mean age was 55 ± 9 years, 9 patients were men, and mean weight was 85 ± 12 kg. The most common primary diagnoses were subarachnoid (N = 5) and intracerebral (N = 4) hemorrhage. Application of the EMCOOLS system resulted in a linear 1.3 ± 0.6 °C drop (T_0avg = 38.9 ⁰C, T_90avg = 37.6 ⁰C, P = 0.0032) in mean temperature over 90 min, followed by a plateau with only one subject rebounding to >38 °C within 4 h. Normothermia (<38.0 ⁰C) was achieved in all but one patient (92%) in an average of 65 min. Comatose patients displayed a non-significantly higher degree of cooling at 90 min than did awake subjects (ΔT_coma = 1.74 °C vs ΔT_awake = 0.74 °C hr^-1, P = 0.067). There was no observed skin irritation upon removal of the device for any patients.

CONCLUSION

The EMCOOLs system is a well-tolerated, safe and effective short-term intervention for control of fever in neurological patients. Future studies are needed to compare efficacy of the EMCOOLs to other devices and interventions.

Cost of hospitalization for aneurysmal subarachnoid hemorrhage in the United States

OBJECTIVE

Recent large-scale studies describing hospitalization cost trends secondary to aneurysmal subarachnoid hemorrhage (aSAH) in the United States are lacking. We sought to discover the impact of aSAH-related factors upon its hospitalization cost.

PATIENTS AND METHODS

Patients with a primary diagnosis of aSAH were selected utilizing the National Inpatient Sample. Regression analyses were used to evaluate the impact of aSAH-related factors on hospitalization costs.

RESULTS

From 2002-2014, 22,831 cases of aSAH were identified. The inflation-adjusted mean cost of hospitalization was $82,514 (standard deviation ± $54,983). The proportion of males was lower (31%), but a higher cost of $3385 (± $685; p < .001) remained compared to females. Median length of hospitalization was 16 days (interquartile range 11-23) and each day increase in hospitalization was associated with a cost increase of $3228 (± $19; p < .001). There was no difference in cost between patients undergoing aneurysmal coiling or clipping. When compared to patients < 40 years old, the increase in cost for patients 40-59 years old was $3829 (± $914; p < .001), and $4573 (± $1033; p < .001) for patients 60-79 years old; however, for patients ≥ 80 years old, there was a decrease in cost of $8124 (± $1722; p < .001). Several central nervous system complications were also associated with increased cost.

CONCLUSION

aSAH is a significant financial burden on the United States healthcare system. We were able to identify many important factors associated with higher costs, and these results may help us understand resource utilization and develop future cost-reduction strategies.

Continuous infusion of low-dose unfractionated heparin after aneurysmal subarachnoid hemorrhage: a preliminary study of cognitive outcomes

OBJECTIVE

Cognitive dysfunction occurs in up to 70% of aneurysmal subarachnoid hemorrhage (aSAH) survivors. Low-dose intravenous heparin (LDIVH) infusion using the Maryland protocol was recently shown to reduce clinical vasospasm and vasospasm-related infarction. In this study, the Montreal Cognitive Assessment (MoCA) was used to evaluate cognitive changes in aSAH patients treated with the Maryland LDIVH protocol compared with controls.

METHODS

A retrospective analysis of all patients treated for aSAH between July 2009 and April 2014 was conducted. Beginning in 2012, aSAH patients were treated with LDIVH in the postprocedural period. The MoCA was administered to all aSAH survivors prospectively during routine follow-up visits, at least 3 months after aSAH, by trained staff blinded to treatment status. Mean MoCA scores were compared between groups, and regression analyses were performed for relevant factors.

RESULTS

No significant differences in baseline characteristics were observed between groups. The mean MoCA score for the LDIVH group (n = 25) was 26.4 compared with 22.7 in controls (n = 22) (p = 0.013). Serious cognitive impairment (MoCA ≤ 20) was observed in 32% of controls compared with 0% in the LDIVH group (p = 0.008). Linear regression analysis demonstrated that only LDIVH was associated with a positive influence on MoCA scores (β = 3.68, p =0.019), whereas anterior communicating artery aneurysms and fevers were negatively associated with MoCA scores. Multivariable linear regression analysis resulted in all 3 factors maintaining significance. There were no treatment complications.

CONCLUSIONS

This preliminary study suggests that the Maryland LDIVH protocol may improve cognitive outcomes in aSAH patients. A randomized controlled trial is needed to determine the safety and potential benefit of unfractionated heparin in aSAH patients.

Neuroprotective Effects of Nasopharyngeal Perfluorochemical Cooling in a Rat Model of Subarachnoid Hemorrhage

OBJECTIVE

Subarachnoid hemorrhage (SAH) frequently results in severe morbidity, even mortality. Hypothermia is known to have a neuroprotective effect in ischemic injuries. The aim of this study was to determine whether nasopharyngeal (NP) perfluorochemical (PFC) cooling could be used in a rat model of SAH model for neuroprotection.

METHODS

SAH was induced in 16 male Sprague-Dawley rats by cisterna magna injection of 0.3 mL autologous blood. Vital signs, temperatures, cerebral blood flow (CBF), and brain histology were assessed. Brain cooling was performed on the treatment group using the NP-PFC method starting from 20 minutes after SAH.

RESULTS

No SAH-related deaths were observed in either group. SAH caused an immediate decrease in mean arterial pressure (17.0% ± 4.90% below baseline values). SAH induction caused a significant and rapid decrease in CBF from baseline (approximately -65%, ranging from -32% to -85%) in both hemispheres. In the left hemisphere, cooling facilitated the return of CBF to baseline values within 20 minutes of treatment with further increase in CBF that stabilized by the 2 hours after injury time point. Quantitative immunohistochemistry showed that there were significantly more NeuN-positive cells in the cortex and significantly fewer IBA-1-positive microglia and glial fibrillary acidic protein-positive astrocytes cells in both cortex and hippocampus in the animals that received NP-PFC cooling compared with no treatment, reflecting preserved neuronal integrity and reduced inflammation.

CONCLUSIONS

The data from this study indicate that local hypothermia by NP-PFC cooling supports return of CBF and neuronal integrity and suppresses the inflammatory response in SAH, suggestive of a promising neuroprotective approach in management of SAH.

The role of inflammation and potential use of sex steroids in intracranial aneurysms and subarachnoid hemorrhage

Background

Aneurysmal subarachnoid hemorrhage (aSAH) continues to be a devastating neurological condition with a high risk of associated morbidity and mortality. Inflammation has been shown to increase the risk of complications associated with aSAH such as vasospasm and brain injury in animal models and humans. The goal of this review is to discuss the inflammatory mechanisms of aneurysm formation, rupture and vasospasm and explore the role of sex hormones in the inflammatory response to aSAH.

Methods

A literature review was performed using PubMed using the following search terms: "intracranial aneurysm," "cerebral aneurysm," "dihydroepiandrosterone sulfate" "estrogen," "hormone replacement therapy," "inflammation," "oral contraceptive," "progesterone," "sex steroids," "sex hormones" "subarachnoid hemorrhage," "testosterone." Only studies published in English language were included in the review.

Results

Studies have shown that administration of sex hormones such as progesterone and estrogen at early stages in the inflammatory cascade can lower the risk and magnitude of subsequent complications. The exact mechanism by which these hormones act on the brain, as well as their role in the inflammatory cascade is not fully understood. Moreover, conflicting results have been published on the effect of hormone replacement therapy in humans. This review will scrutinize the variations in these studies to provide a more detailed understanding of sex hormones as potential therapeutic agents for intracranial aneurysms and aSAH.

Conclusion

Inflammation may play a role in the pathogenesis of intracranial aneurysm formation and subarachnoid hemorrhage, and administration of sex hormones as anti-inflammatory agents has been associated with improved functional outcome in experimental models. Further studies are needed to determine the therapeutic role of these hormones in the intracranial aneurysms and aSAH.

The incidence of hyperthermia during craniotomy

There is evidence that even mild hyperthermia may exacerbate brain injury. There seem reasonable grounds for considering patients undergoing craniotomy as at risk for brain injury. A retrospective observational study was undertaken to measure the incidence of mild hyperthermia in craniotomy cases in which the patient was initially normothermic. Auckland City Hospital's database of electronic anaesthetic records was searched for adult patients who were normothermic (≤37°C) prior to undergoing craniotomy procedures. For each case, demographic data, intraoperative naso- or oropharyngeal temperature measurements, and paracetamol use were extracted. We identified the proportion of patients whose temperature rose to exceed normal (>37°C) and subdivided that group into the proportion in whom the temperature rose to ≥38°C. Two thousand, nine hundred and thirty-five craniotomy cases began their operations while normothermic and had adequate temperature data collected. There were 984 (33.5%) cases that had at least one temperature reading >37°C, for a mean (standard deviation [SD]) time of 66.0 (64.6) minutes, and 49 (1.7%) cases that had at least one reading ≥38°C for a mean (SD) time of 40.4 (38.1) minutes. The majority (77.8%) who became mildly hyperthermic remained so at the end of the procedure. New mild hyperthermia occurs commonly during craniotomy. In view of the compelling evidence of potential harm arising from mild hyperthermia in brain injury, these findings suggest an opportunity for practice improvement in the anaesthetic management of craniotomy patients. Reasonable steps should be taken by anaesthetists to avoid intraoperative hyperthermia of any degree.

Higher leukocyte count predicts 3-month poor outcome of ruptured cerebral aneurysms

It is not fully established whether leukocyte can predict the poor outcome for ruptured cerebral aneurysms (CA) or not. Here, we retrospectively analyzed the clinical data of 428 patients with ruptured CA between 2010 and 2015. Patients’ demographic data, including gender, age, history of smoking, alcohol, hypertension, diabetes and hypercholesterolemia, Hunt-Hess and Fisher grade, occurrence of hydrocephalus, aneurysm location, time to surgery, delayed ischemic neurological deficit (DIND) and peak leukocyte of blood test from day 1 to 3 after aneurysmal rupture were recorded and analyzed. In the multivariable analysis model, gender, Fisher grade, time to surgery and hydrocephalus were not relevant to poor outcome. However, Hunt-Hess grade, DIND and preoperative leukocyte count (>13.84 × 10⁹/L) were significantly associated with adverse outcome. The respective increased risks were 5.2- (OR 5.24, 95% CI 1.67–16.50, p = 0.005), 6.2-(OR 6.24, 95% CI 3.55–10.99, p < 0.001) and 10.9-fold (OR 10.93, 95% CI 5.98–19.97, p < 0.001). The study revealed that Hunt-Hess grade, DIND and preoperative leukocyte count (>13.84 × 10⁹/L) were independent risk factors for poor outcome of ruptured CA at 3 months. Higher leukocyte count is a convenient and useful marker to predict 3-month poor outcome for ruptured CA.

Hemoglobin metabolism by-products are associated with an inflammatory response in patients with hemorrhagic stroke

Objective

To evaluate the relationships of brain iron and heme with the inflammatory response of the systemic and central nervous systems and to investigate the role of defensive systems against the toxicity of iron and heme in the central nervous system.

Methods

We assessed a prospective cohort of patients presenting with intracerebral and subarachnoid hemorrhage. We assayed plasma and cerebrospinal fluid samples for the presence of iron, heme, hemopexin, haptoglobin, enolase, S100-β and cytokines for the first three days following hemorrhagic stroke. We also analyzed the dynamic changes in these components within both fluids and their relationship with early mortality rates.

Results

Hemopexin and haptoglobin concentrations were nearly negligible in the brain after intracerebral and subarachnoid hemorrhage. Cerebrospinal fluid iron and heme concentrations correlated with a pro-inflammatory response in the central nervous system, and plasmatic and cerebrospinal fluid inflammatory profiles on the third day after hemorrhagic stroke were related to early mortality rates. Interleukin 4 levels within the cerebrospinal fluid during the first 24 hours after hemorrhagic stroke were found to be higher in survivors than in non-survivors.

Conclusion

Iron and heme are associated with a pro-inflammatory response in the central nervous system following hemorrhagic stroke, and protections against hemoglobin and heme are lacking within the human brain. Patient inflammatory profiles were associated with a poorer prognosis, and local anti-inflammatory responses appeared to have a protective role.

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

Targeted temperature management in the ICU: Guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term "targeted temperature management" (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de réanimation de langue française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société francaise d'anesthésie réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société française de médecine d'urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe francophone de réanimation et urgences pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association nationale de neuro-anesthésie réanimation française [ANARLF]), and the French Neurovascular Society (Société française neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts' opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Risk factors for development of postoperative cerebellar mutism syndrome in children after medulloblastoma surgery

OBJECTIVE Postoperative cerebellar mutism syndrome (pCMS) occurs in 7%-50% of children after cerebellar tumor surgery. Typical features include a latent onset of 1-2 days after surgery, transient mutism, emotional lability, and a wide variety of motor and neurobehavioral abnormalities. Sequelae of this syndrome usually persist long term. The principal causal factor is bilateral surgical damage (regardless of tumor location) to any component of the proximal efferent cerebellar pathway, which leads to temporary dysfunction of cerebral cortical regions as a result of diaschisis. Tumor type, cerebellar midline location, and brainstem involvement are risk factors for pCMS that have been identified repeatedly, but they do not explain its latent onset. Ambiguous or negative results for other factors, such as hydrocephalus, postoperative meningitis, length of vermian incision, and tumor size, have been reached. The aim of this study was to identify perioperative clinical, radiological, and laboratory factors that also increase risk for the development of pCMS. The focus was on factors that might explain the delayed onset of pCMS and thus might provide a time window for taking precautionary measures to prevent pCMS or reduce its severity. The study was focused specifically on children who had undergone surgery for medulloblastoma. METHODS In this single-center retrospective cohort study, the authors included 71 children with medulloblastoma, 28 of whom developed pCMS after primary resection. Clinical and laboratory data were collected prospectively and analyzed systematically. Variables were included for univariate and multivariate analysis. RESULTS Univariate regression analysis revealed 7 variables that had a significant influence on pCMS onset, namely, tumor size, maximum tumor diameter > 5 cm, tumor infiltration or compression of the brainstem, significantly larger decreases in hemoglobin (p = 0.010) and hematocrit (p = 0.003) in the pCMS group after surgery than in the no-pCMS group, significantly more reported incidents of severe bleeding in the tumor bed during surgery in the pCMS group, preoperative hydrocephalus, and a mean body temperature rise of 0.5°C in the first 4 days after surgery in the pCMS group. Multiple regression analysis revealed that tumor size, tumor infiltration into or compression of the brainstem, and higher mean body temperature in the first 4 postoperative days were independent and highly significant predictors for pCMS. CONCLUSIONS The authors confirmed earlier findings that tumor-associated preoperative conditions, such as a maximum tumor diameter ≥ 5 cm and infiltration into or compression of the brainstem, are associated with a higher risk for the development of pCMS. Most importantly, the authors found that a 0.5°C higher mean body temperature in the first 4 postoperative days increased the odds ratio for the development of pCMS almost 5-fold. These data suggest that an important focus for the prevention of pCMS in children who have undergone medulloblastoma surgery might be rigorous maintenance of normothermia as standard care after surgery.

Targeted temperature management in the ICU: guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term “targeted temperature management” (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société Francaise d’Anesthésie Réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société Française de Médecine d’Urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe Francophone de Réanimation et Urgences Pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association Nationale de Neuro-Anesthésie Réanimation Française [ANARLF]), and the French Neurovascular Society (Société Française Neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts’ opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Acute Cholecystitis as a Cause of Fever in Aneurysmal Subarachnoid Hemorrhage

Background

Fever is a very common complication that has been related to poor outcomes after aneurysmal subarachnoid hemorrhage (aSAH). The incidence of acalculous cholecystitis is reportedly 0.5%–5% in critically ill patients, and cerebrovascular disease is a risk factor for acute cholecystitis (AC). However, abdominal evaluations are not typically performed for febrile patients who have recently undergone aSAH surgeries. In this study, we discuss our experiences with febrile aSAH patients who were eventually diagnosed with AC.

Methods

We retrospectively reviewed 192 consecutive patients who underwent aSAH from January 2009 to December 2012. We evaluated their characteristics, vital signs, laboratory findings, radiologic images, and pathological data from hospitalization. We defined fever as a body temperature of >38.3°C, according to the Society of Critical Care Medicine guidelines. We categorized the causes of fever and compared them between patients with and without AC.

Results

Of the 192 enrolled patients, two had a history of cholecystectomy, and eight (4.2%) were eventually diagnosed with AC. Among them, six patients had undergone laparoscopic cholecystectomy. In their pathological findings, two patients showed findings consistent with coexistent chronic cholecystitis, and two showed necrotic changes to the gall bladder. Patients with AC tended to have higher white blood cell counts, aspartame aminotransferase levels, and C-reactive protein levels than patients with fevers from other causes. Predictors of AC in the aSAH group were diabetes mellitus (odds ratio [OR], 8.758; P = 0.033) and the initial consecutive fasting time (OR, 1.325; P = 0.024).

Conclusions

AC may cause fever in patients with aSAH. When patients with aSAH have a fever, diabetes mellitus and a long fasting time, AC should be suspected. A high degree of suspicion and a thorough abdominal examination of febrile aSAH patients allow for prompt diagnosis and treatment of this condition. Additionally, physicians should attempt to decrease the fasting time in aSAH patients.

Paradoxical undressing associated with subarachnoid hemorrhage in a non-hypothermia case?

Paradoxical undressing is a phenomenon characterizing some fatal hypothermia cases. The victims, despite low environmental temperatures, paradoxically remove their clothes due to a sudden feeling of warmth. In this report, we describe a case of suspected paradoxical undressing in a non-hypothermia case. The victim, a 51-year-old Caucasian man, was found dead wearing only sneakers and socks. All other clothing was found in his car. Postmortem investigations allowed the hypothesis of hypothermia to be ruled out and revealed the presence of a ruptured cerebral aneurysm that caused a subarachnoid hemorrhage, the latter responsible for the death. The absence of any elements suggesting a voluntary undressing or any third party's DNA profile or involvement along with the possibility that the subarachnoid hemorrhage might have determined a hypothalamic injury, somehow rendered conceivable the hypothesis of an inappropriate feeling of warmth due to hemorrhage-induced dysregulation of the hypothalamic temperature-regulating centers.

Normothermia and Stroke

OPINION STATEMENT

In the past two decades, there has been much focus on the adverse effect of fever on neurologic outcome, the benefits of hypothermia on functional outcomes, and the interplay of associated complications. Despite decades of experience regarding randomized, safety and feasibility, case-controlled, retrospective studies, there has yet to be a large, randomized, multicenter, clinical trial with the appropriate power to address the potential benefits of targeted temperature modulation compared to hypothermia alone. What remains unanswered is the appropriate timing of initiation, duration, rewarming speed, and depth of targeted temperature management. We learn from the cardiac arrest literature that there is a neuroprotective value to hypothermia and, most recently, near normothermia (36 °C) as well. We have also established that increased depths of cooling are associated with increases in shivering, which warrant more aggressive pharmacologic management. Normothermia also has the advantage of allowing for more rapid clearance of sedating medications and less confounding of neuroprognostication. More difficult to quantify is the increased nursing and patient care complexity associated with moderate hypothermia compared to normothermia. It remains crucial, for those patients who are being considered for hypothermia/normothermia, to be cared for in an experienced ICU, driven under protocol, with aggressive shivering management and an expectation and acceptance of the complications associated with targeted temperature management. If targeted temperature management is not of consideration, then aggressive fever control should be undertaken pharmacologically and non-invasively, as they have been shown to be safe.

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.

Paracetamol in fever in critically ill patients-an update

Fever, which is arbitrary defined as an increase in body temperature above 38.3°C, can affect up to 90% of patients admitted in intensive care unit. Induction of fever is mediated by the release of pyrogenic cytokines (tumor necrosis factor α, interleukin 1, interleukin 6, and interferons). Fever is associated with increased length of stay in intensive care unit and with a worse outcome in some subgroups of patients (mainly neurocritically ill patients). Although fever can increase oxygen consumption in unstable patients, on the contrary, it can activate physiologic systems that are involved in pathogens clearance. Treatments to reduce fever include the use of antipyretics. Thus, the reduction of fever might reduce the ability to develop an efficient host response. This balance, between harms and benefits, has to be taken into account every time we decide to treat or not to treat fever in a given patient. Among the antipyretics, paracetamol is one of the most common used. Paracetamol is a synthetic, nonopioid, centrally acting analgesic, and antipyretic drug. Its antipyretic effect occurs because it inhibits cyclooxygenase-3 and the prostaglandin synthesis, within the central nervous system, resetting the hypothalamic heat-regulation center. In this clinical review, we will summarize the use of paracetamol as antipyretic in critically ill patients (sepsis, trauma, neurological, and medical).

Hematologic counts as predictors of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

PURPOSE

Aneurysmal subarachnoid hemorrhage (SAH) is associated with high morbidity and mortality, but currently no single clinical method or ancillary test can reliably predict which subset of patients will develop delayed cerebral ischemia (DCI). The aim of this study was to find hematologic derangements and clinical factors present during the first 7 days after bleeding that could help identify patients at risk for development of DCI.

MATERIALS AND METHODS

Databank analysis of patients with SAH admitted between 2010 and 2012 in a single center. Data from demographics, imaging, laboratory, and clinical factors were collected. Statistical testing was conducted to test for association to the outcome, and multivariate logistic regression was used to design a predictive model.

RESULTS

Of 55 patients, 14 developed DCI (25%). Anemia and leukocytosis on the third day after bleeding were significantly correlated with the outcome (for anemia: P<.032; confidence interval, 1.12-15.16; odds ratio, 4.12; for leukocytosis: P<.046; confidence interval, 1.03-26.13; odds ratio, 5.18). Anemia and leukocytosis were still statistically significant after adjustment for age, sex, modified Fisher scale, and Hunt-Hess scale.

CONCLUSION

The presence of leukocytosis and anemia during the third day after SAH was statistically correlated with the occurrence of DCI.

Early Predictors of Fever in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Fever is commonly observed in patients who have had aneurysmal subarachnoid hemorrhage (SAH), and it has been associated with the occurrence of delayed cerebral ischemia and worse outcomes in previous studies. Frequently, fever is not the result of bacterial infections, and distinction between infection-related fever and fever secondary to brain injury (also referred as central fever) can be challenging.

OBJECTIVES

The current study aimed to identify risk factors on admission for the development of central fever in patients with SAH.

METHODS

Databank analysis was performed using information from demographic data (age, gender), imaging (transcranial Doppler ultrasound, computed tomography, and cerebral angiogram), laboratory (white blood cell count, hemoglobin, renal function, and electrolytes), and clinical assessment (Hunt-Hess and modified Fisher scales on admission, occurrence of fever). A multivariate logistic regression model was created.

RESULTS

Of 55 patients, 32 developed fever during the first 7 days of hospital stay (58%). None of the patients had identifiable bacterial infections during their first week in the neurocritical care unit. Hunt-Hess scale >2 and leukocytosis on admission were associated to the development of central fever, even after correction in a logistic regression model.

CONCLUSION

Leukocytosis and a poor neurologic examination on admission might help predict which subset of patients with SAH are at higher risk of developing central fever early in their hospital stay.

Neurogenic Fever

Fever is a relatively common occurrence among patients in the intensive care setting. Although the most obvious and concerning etiology is sepsis, drug reactions, venous thromboembolism, and postsurgical fevers are all on the differential diagnosis. There is abundant evidence that fever is detrimental in acute neurologic injury. Worse outcomes are reported in acute stroke, subarachnoid hemorrhage, and traumatic brain injury. In addition to the various etiologies of fever in the intensive care setting, neurologic illness is a risk factor for neurogenic fevers. This primarily occurs in subarachnoid hemorrhage and traumatic brain injury, with hypothalamic injury being the proposed mechanism. Paroxysmal sympathetic hyperactivity is another source of hyperthermia commonly seen in the population with traumatic brain injury. This review focuses on the detrimental effects of fever on the neurologically injured as well as the risk factors and diagnosis of neurogenic fever.