Feasibility and Safety of Mild Therapeutic Hypothermia in Poor-Grade Subarachnoid Hemorrhage: Prospective Pilot Study

Application of artificial hibernation technology in acute brain injury

Controlling intracranial pressure, nerve cell regeneration, and microenvironment regulation are the key issues in reducing mortality and disability in acute brain injury. There is currently a lack of effective treatment methods. Hibernation has the characteristics of low temperature, low metabolism, and hibernation rhythm, as well as protective effects on the nervous, cardiovascular, and motor systems. Artificial hibernation technology is a new technology that can effectively treat acute brain injury by altering the body's metabolism, lowering the body's core temperature, and allowing the body to enter a state similar to hibernation. This review introduces artificial hibernation technology, including mild hypothermia treatment technology, central nervous system regulation technology, and artificial hibernation-inducer technology. Upon summarizing the relevant research on artificial hibernation technology in acute brain injury, the research results show that artificial hibernation technology has neuroprotective, anti-inflammatory, and oxidative stress-resistance effects, indicating that it has therapeutic significance in acute brain injury. Furthermore, artificial hibernation technology can alleviate the damage of ischemic stroke, traumatic brain injury, cerebral hemorrhage, cerebral infarction, and other diseases, providing new strategies for treating acute brain injury. However, artificial hibernation technology is currently in its infancy and has some complications, such as electrolyte imbalance and coagulation disorders, which limit its use. Further research is needed for its clinical application.

Temperature Control in Acute Brain Injury: An Update

Temperature control in severe acute brain injury (SABI) is a key component of acute management. This manuscript delves into the complex role of temperature management in SABI, encompassing conditions like traumatic brain injury (TBI), acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), aneurysmal subarachnoid hemorrhage (aSAH), and hypoxemic/ischemic brain injury following cardiac arrest. Fever is a common complication in SABI and is linked to worse neurological outcomes due to increased inflammatory responses and intracranial pressure (ICP). Temperature management, particularly hypothermic temperature control (HTC), appears to mitigate these adverse effects primarily by reducing cerebral metabolic demand and dampening inflammatory pathways. However, the effectiveness of HTC varies across different SABI conditions. In the context of post-cardiac arrest, the impact of HTC on neurological outcomes has shown inconsistent results. In cases of TBI, HTC seems promising for reducing ICP, but its influence on long-term outcomes remains uncertain. For AIS, clinical trials have yet to conclusively demonstrate the benefits of HTC, despite encouraging preclinical evidence. This variability in efficacy is also observed in ICH, aSAH, bacterial meningitis, and status epilepticus. In pediatric and neonatal populations, while HTC shows significant benefits in hypoxic-ischemic encephalopathy, its effectiveness in other brain injuries is mixed. Although the theoretical basis for employing temperature control, especially HTC, is strong, the clinical outcomes differ among various SABI subtypes. The current consensus indicates that fever prevention is beneficial across the board, but the application and effectiveness of HTC are more nuanced, underscoring the need for further research to establish optimal temperature management strategies. Here we provide an overview of the clinical evidence surrounding the use of temperature control in various types of SABI.

Factors Affecting Outcomes of Poor-Grade Subarachnoid Hemorrhage

OBJECTIVE

Poor-grade subarachnoid hemorrhage (SAH) accounts for 20% of all SAH and is associated with poor outcomes. The first step in improving outcomes is to analyze the factors that contribute to poor outcomes.

METHODS

This was a multicenter, retrospective, observational, cohort study. Data fields included demographic, clinical, radiological, and outcome data for all spontaneous patients with SAH treated at 4 hospitals in Aomori Prefecture in Japan. Patients with modified Rankin Scale score 0-2 at discharge were defined as the good outcome group, and those with modified Rankin Scale score 3-6 were defined as the poor outcome group, and comparisons were made between the 2 groups.

RESULTS

There were 329 eligible patients with poor-grade SAH, 41 with good outcome group, and 288 with poor outcome group. On multivariate analysis of the outcome, conservative treatment (P < 0.001), Fisher group 4 (P < 0.007), age ≥65 years (P = 0.011), and Hunt and Kosnik grade V on admission (P = 0.021) were significant factors contributing to a poor outcome.

CONCLUSIONS

Nonelderly patients who are not in grade V and Fisher group 4 should undergo aneurysm treatment as soon as possible because they are more likely to have a good outcome, whereas elderly patients in grade V and Fisher group 4 are unlikely to benefit from aneurysm treatment at present. The development of a treatment for early brain injury may be important to improve the outcomes of patients with poor-grade SAH.

The efficacy of therapeutic hypothermia in patients with poor-grade aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

BACKGROUND

This study evaluates the effectiveness of Therapeutic Hypothermia (TH) in treating poor-grade aneurysmal subarachnoid hemorrhage (SAH), focusing on functional outcomes, mortality, and complications such as vasospasm, delayed cerebral ischemia (DCI), and hydrocephalus.

METHODS

Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, a comprehensive literature search was conducted across multiple databases, including Medline, Embase, and Cochrane Central, up to November 2023. Nine studies involving 368 patients were selected based on eligibility criteria focusing on TH in poor-grade SAH patients. Data extraction, bias assessment, and evidence certainty were systematically performed.

RESULTS

The primary analysis of unfavorable outcomes in 271 participants showed no significant difference between the TH and standard care groups (risk ratio [RR], 0.87). However, a significant reduction in vasospasm was observed in the TH group (RR, 0.63) among 174 participants. No significant differences were found in DCI, hydrocephalus, and mortality rates in the respective participant groups.

CONCLUSIONS

TH did not significantly improve primary unfavorable outcomes in poor-grade SAH patients. However, the reduction in vasospasm rates indicates potential specific benefits. The absence of significant findings in other secondary outcomes and mortality highlights the need for further research to better understand TH's role in treating this patient population.

Targeted Temperature Management for Poor Grade Aneurysmal Subarachnoid Hemorrhage: A Pilot Study

OBJECTIVE

We assessed the effectiveness and safety of target temperature management (TTM) in treating patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH). The primary objective was to evaluate the neurological outcome at 3 months. Secondary objectives were to assess mortality, delayed cerebral ischemia, cerebral edema, hydrocephalus, midline shift, and laboratory indicators related to TTM.

METHODS

A single-blind, nonrandomized controlled trial was conducted. After admission, patients with poor-grade aSAH (Hunt-Hess scores IV ∼ V) were assigned to a TTM group or a control group in a 1:1 ratio. TTM with core temperatures ranging from 36°C to 37°C was performed immediately and maintained until microclipping or endovascular embolization. Subsequently, rapid induction to 33°C ∼ 35°C was carried out and maintained for 3 to 5 days. Then, the patients underwent slow rewarming to 36°C ∼ 37°C and maintained at that temperature for a minimum of 48 hours.

RESULTS

Sixty patients (30 treated with TTM and 30 with standard treatment) were included in the study. At 3 months, a favorable prognosis (modified Rankin scale score 0 to 3) was significantly higher in the TTM group than in the control group (n = 14, 46.7% vs. n = 6, 20.0%, P = 0.028). Adjusted multivariate logistics regression analysis indicated that TTM (odds ratio = 0.20, 95% confidence interval: 0.05-0.77, P = 0.019) reduced the number of unfavorable prognoses 3 months after admission.

CONCLUSIONS

This study demonstrated the effectiveness and safety of TTM in patients with poor-grade aSAH, and its implementation improved neurological outcomes. Multicenter randomized controlled studies with a large number of patients are needed to confirm these observations.

Clinical Outcome of Patients with Poor-Grade Aneurysmal Subarachnoid Hemorrhage with Bundled Treatments: A Propensity Score-Matched Analysis

BACKGROUND

Poor-grade aneurysmal subarachnoid hemorrhage (aSAH), defined as Hunt and Hess (HH) grades IV and V, is a challenging disease because of its high mortality and poor functional outcomes. The effectiveness of bundled treatments has been demonstrated in critical diseases. Therefore, poor-grade aSAH bundled treatments have been established. This study aims to evaluate whether bundled treatments can improve long-term outcomes and mortality in patients with poor-grade aSAH.

METHODS

This is a comparative study using historical control from 2008 to 2022. Bundled treatments were introduced in 2017. We compared the rate of favorable outcomes (modified Rankin Scale score 0-2) at 6 months and mortality before and after the introduction of the bundled treatments. To eliminate confounding bias, the propensity score matching method was used.

RESULTS

A total of 90 consecutive patients were evaluated. Forty-three patients received bundled treatments, and 47 patients received conventional care. The proportion of patients with HH grade V was higher in the bundle treatment group (41.9% vs. 27.7%). Conversely, the proportion of patients with fixed pupils on the initial examination was higher in the conventional group (30.2% vs. 38.3%). After 1:1 propensity score matching, 31 pairs were allocated to each group. The proportion of patients with 6-month favorable functional outcomes was significantly higher in the bundled treatments group (46.4% vs. 20.7%, p = 0.04). The 6-month mortality rate was 14.3% in the bundled treatments group and 27.3% in the conventional group (p = 0.01). Bundled treatments (odd ratio 14.6 [95% confidence interval 2.1-100.0], p < 0.01) and the presence of an initial pupil reflex (odd ratio 12.0 [95% confidence interval 1.4-104.6], p = 0.02) were significantly associated with a 6-month favorable functional outcome.

CONCLUSIONS

The bundled treatments improve 6-month functional outcome and mortality in patients with poor-grade aSAH.

2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage: A Guideline From the American Heart Association/American Stroke Association

AIM

The "2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage" replaces the 2012 "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage." The 2023 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with aneurysmal subarachnoid hemorrhage.

METHODS

A comprehensive search for literature published since the 2012 guideline, derived from research principally involving human subjects, published in English, and indexed in MEDLINE, PubMed, Cochrane Library, and other selected databases relevant to this guideline, was conducted between March 2022 and June 2022. In addition, the guideline writing group reviewed documents on related subject matter previously published by the American Heart Association. Newer studies published between July 2022 and November 2022 that affected recommendation content, Class of Recommendation, or Level of Evidence were included if appropriate. Structure: Aneurysmal subarachnoid hemorrhage is a significant global public health threat and a severely morbid and often deadly condition. The 2023 aneurysmal subarachnoid hemorrhage guideline provides recommendations based on current evidence for the treatment of these patients. The recommendations present an evidence-based approach to preventing, diagnosing, and managing patients with aneurysmal subarachnoid hemorrhage, with the intent to improve quality of care and align with patients' and their families' and caregivers' interests. Many recommendations from the previous aneurysmal subarachnoid hemorrhage guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

Mild hypothermia alleviates early brain injury after subarachnoid hemorrhage via suppressing pyroptosis through AMPK/NLRP3 inflammasome pathway in rats

As a subtype of stroke, subarachnoid hemorrhage (SAH) has a notoriously high rate of disability and mortality owing to the lack of effective intervention. Early brain injury (EBI) is the main factor responsible for the dismal prognosis of SAH patients. The current study intends to explore the molecular mechanism underlying the effect of MH on EBI after SAH from a novel perspective of pyroptosis, a highly specific inflammatory programmed cell death, in the SAH rat model. Sprague-Dawley (SD) rats were divided into different groups in accordance with various treatments. In the treatment group, the rats underwent mild hypothermia for 4 h after modeling; in the inhibitor group, Compound C (an inhibitor of AMPK) was administered intravenous injections (i.v.) 30 min before modeling. Neurological score, neuronal death, brain water content, inflammatory reaction, and expression levels of pyroptosis-related proteins were evaluated in the rats. Our results indicate that the MH therapy significantly increased the neurological score and assuaged brain edema, neuronal injury, and inflammatory reaction induced by SAH. Meanwhile, MH therapy upregulated the level of AMPK phosphorylation whereas downregulated the protein expressions of NLRP3, ASC, cleaved caspase-1, GSDMD, IL-1β, and IL-18. The reversed effect of MH therapy by Compound C concretely indicated that MH therapy inhibited pyroptosis through an AMPK-dependent pathway. Our study also found that MH therapy potently curbed the increasing trend of brain temperature (BT), rectal temperature (RT), and ICP after SAH. Taken together, our data indicate that the neuroprotective effects of MH therapy were manifested by inhibiting pyroptosis via the AMPK/NLRP3 inflammasome pathway, which may serve as a promising therapy for the intervention of SAH.

A nomogram for predicting the risk of poor prognosis in patients with poor-grade aneurysmal subarachnoid hemorrhage following microsurgical clipping

Objective

Aneurysmal subarachnoid hemorrhage (aSAH) is a common and potentially fatal cerebrovascular disease. Poor-grade aSAH (Hunt-Hess grades IV and V) accounts for 20-30% of patients with aSAH, with most patients having a poor prognosis. This study aimed to develop a stable nomogram model for predicting adverse outcomes at 6 months in patients with aSAH, and thus, aid in improving the prognosis.

Method

The clinical data and imaging findings of 150 patients with poor-grade aSAH treated with microsurgical clipping of intracranial aneurysms on admission from December 2015 to October 2021 were retrospectively analyzed. Least absolute shrinkage and selection operator (LASSO), logistic regression analyses, and a nomogram were used to develop the prognostic models. Receiver operating characteristic (ROC) curves and Hosmer-Lemeshow tests were used to assess discrimination and calibration. The bootstrap method (1,000 repetitions) was used for internal validation. Decision curve analysis (DCA) was performed to evaluate the clinical validity of the nomogram model.

Result

LASSO regression analysis showed that age, Hunt-Hess grade, Glasgow Coma Scale (GCS), aneurysm size, and refractory hyperpyrexia were potential predictors for poor-grade aSAH. Logistic regression analyses revealed that age (OR: 1.107, 95% CI: 1.056-1.116, P < 0.001), Hunt-Hess grade (OR: 8.832, 95% CI: 2.312-33.736, P = 0.001), aneurysm size (OR: 6.871, 95% CI: 1.907-24.754, P = 0.003) and refractory fever (OR: 3.610, 95% CI: 1.301-10.018, P < 0.001) were independent predictors of poor outcome. The area under the ROC curve (AUC) was 0.909. The calibration curve and Hosmer-Lemeshow tests showed that the nomogram had good calibration ability. Furthermore, the DCA curve showed better clinical utilization of the nomogram.

Conclusion

This study provides a reliable and valuable nomogram that can accurately predict the risk of poor prognosis in patients with poor-grade aSAH after microsurgical clipping. This tool is easy to use and can help physicians make appropriate clinical decisions to significantly improve patient prognosis.

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.

Early and Prolonged Mild Hypothermia in Patients with Poor-Grade Subarachnoid Hemorrhage: A Pilot Study

We assessed the feasibility of therapeutic early and prolonged mild hypothermia (MH) in patients with poor-grade subarachnoid hemorrhage (SAH). A retrospective pilot study was conducted for poor-grade SAH patients at two university hospitals from March 2015 to December 2018 who had received MH immediately after coil embolization and maintained a target temperature of 34-35°C for 5 days. A matched controlled design at a 1:2 ratio was used to compare MH therapy outcomes. The primary goal was to assess the two groups' severe functional outcomes at discharge defined as a modified Rankin Scale score of 4-6. The secondary aim was to assess mortality and severe vasospasm depending upon MH. A binary logistic regression analysis was performed to identify relevant risk factors for the outcomes. A total of 54 patients (18 with MH treatment and 36 without MH treatment) were included. Severe functional outcome was significantly decreased in poor-grade SAH patients with MH (n = 7, 38.9%) than those without MH (n = 25, 69.4%; p = 0.031). In patients treated with MH, mortality and severe vasospasm tended to be less common, although the difference was not statistically significant. A binary logistic regression analysis revealed that early and prolonged MH (odds ratio [OR] = 0.156, 95% confidence intervals [CI]: 0.037-0.644) and severe vasospasm (OR = 5.593, 95% CI: 1.372-22.812) were risk factors for severe functional outcomes. This study shows potential therapeutic effect of early and prolonged MH treatment in poor-grade SAH patients. A randomized controlled study with a large number of patients is warranted in the future.

Diagnosis and Treatment of Unruptured Intracranial Aneurysms and Aneurysmal Subarachnoid Hemorrhage

Unruptured intracranial aneurysms (UIAs) are commonly acquired vascular lesions that form an outpouching of the arterial wall due to wall thinning. The prevalence of UIAs in the general population is 3.2%. In contrast, an intracranial aneurysm may be manifested after rupture with classic presentation of a thunderclap headache suggesting aneurysmal subarachnoid hemorrhage (SAH). Previous consensus suggests that although small intracranial aneurysms (<7 mm) are less susceptible to rupture, aneurysms larger than 7 mm should be treated on a case-by-case basis with consideration of additional risk factors of aneurysmal growth and rupture. However, this distinction is outdated. The PHASES score, which comprises data pooled from several prospective studies, provides precise estimates by considering not only the aneurysm size but also other variables, such as the aneurysm location. The International Study of Unruptured Intracranial Aneurysms is the largest observational study on the natural history of UIAs, providing the foundation to the current guidelines for the management of UIAs. Although SAH accounts for only 3% of all stroke subtypes, it is associated with considerable burden of morbidity and mortality. The initial management is focused on stabilizing the patient in the intensive care unit with close hemodynamic and serial neurologic monitoring with endovascular or open surgical aneurysm treatment to prevent rebleeding. Since the results of the International Subarachnoid Aneurysm Trial, treatment of aneurysmal SAH has shifted from surgical clipping to endovascular coiling, which demonstrated higher odds of survival free of disability at 1 year after SAH. Nonetheless, aneurysmal SAH remains a public health hazard and is associated with high rates of disability and death.

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

Background

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

Methods

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

Discussion

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

Trial registration

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

Risk Factors for Intraprocedural Rerupture during Embolization of Ruptured Intracranial Aneurysms

BACKGROUND

Intraprocedural rupture (IPR) is a devastating complication in endovascular treatment of ruptured intracranial aneurysms, but its risk factors have not been fully assessed. This study was performed to explore the risk factors for IPR during embolization of ruptured cerebral aneurysms.

METHODS

A total of 1,494 patients with ruptured intracranial aneurysms who underwent endovascular interventional embolization were enrolled. Clinical characteristics were collected for each patient. Univariate and multivariate logistic regression analysis was employed to identify the factors independently associated with IPR. A receiver operating characteristic (ROC) curve analysis was performed to determine the cutoff values of continuous variables predicting IPR.

RESULTS

Forty-one patients suffered from IPR (2.7%). Multivariate logistic regression analysis indicated that aneurysm size (odds ratio [OR], 0.819; 95% confidence interval [CI], 0.732-0.916), aneurysms with irregular morphology (OR, 2.162; 95% CI, 1.143-4.091), time from symptom onset to intervention (OR, 1.615; 95% CI, 1.207-2.161), and vasospasm during embolization (OR, 2.021; 95% CI, 1.038-3.934) were the independent risk factors of IPR. ROC curve analysis showed that the area under the curve for aneurysm size and time from onset to intervention were 0.697 (cutoff value, 3.4 mm; sensitivity, 78.8%; and specificity, 53.7%) and 0.659 (cutoff value, 2 days; sensitivity, 78.0%; and specificity, 45.2%), respectively.

CONCLUSION

Aneurysms with irregular morphology, aneurysms ≤ 3.4 mm in diameter, time from onset to intervention > 2 days and cerebral vasospasm during embolization are independent risk factors for IPR during coil embolization of ruptured aneurysms. More attention should be paid to the factors increasing the risk of IPR in patients with ruptured aneurysms so as to minimize this complication.

[Effect of mild hypothermia on behaviors of rats with intracerebral hemorrhage and the possible mechanism]

OBJECTIVE

To explore the effect of mild hypothermia on inflammatory response and angiogenesis in brain tissues of rats with intracerebral hemorrhage (ICH) and its possible mechanism for improving behavioral deficits of the rats After ICH.

METHODS

A total of 120 healthy male SD rats were randomly divided into sham operation group, ICH group and mild hypothermia group. Rat models of ICH were established in the latter two groups by stereotactic injection of autogenous blood in the brain, and the rats in the sham operation group received injection of normal saline in the same manner. At 15 min after modeling, the rats in hypothermia group were subjected to mild hypothermia (30-32 ℃) for 8 h followed by rewarming (37-38 ℃); the body temperature was maintained at 37-38 ℃ in the other two groups. At 2, 4, 7, 14 and 21 days after the treatment, Longa scoring, balance beam scoring and Berderson scoring were used to evaluate the behavioral deficits of the rats. Immunohistochemical staining was used to detect the protein expressions of tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in the brain tissue of the rats, and the mRNA expressions of α subunit of hypoxia-inducible factor 1 (HIF1-α) and vascular endothelial growth factor (VEGF) were detected using RT- PCR.

RESULTS

At 2, 4, 7, 14 and 21 days after the treatment, the behavioral scores of the rats were significantly higher in ICH group and mild induced hypothermia group than in the sham operation group (P < 0.05 or 0.01). The protein expressions of TNF-α and NF-κB and mRNA expressions of HIF1-α and VEGF were significantly higher in ICH group and mild hypothermia group than in the sham operation group (P < 0.01). The behavioral scores were significantly lower in mild hypothermia group than in ICH group (P < 0.05), and the protein expressions of TNF-α and NF-κB were lower and the mRNA expressions of HIF1- α and VEGF were higher in mild hypothermia group than in ICH group (P < 0.05 or 0.01).

CONCLUSIONS

Mild hypothermia can improve behavioral deficits in rats with ICH possibly by antagonizing brain inflammation and promoting angiogenesis.

Targeted Temperature Management for Subarachnoid Hemorrhage: Excellent Outcome After Severe Vasospasm-A Case Series

Targeted temperature management (TTM) might improve outcome of patients with severe subarachnoid hemorrhage (SAH) in which vasospasm, delayed cerebral ischemia (DCI), and increased intracranial pressure (ICP) are frequent and severe complications. A series of patients (n = 3) with severe aneurysmatic SAH were treated by TTM if they developed ICP crisis and/or severe vasospasm diagnosed by angiography. Once these complications were detected, body core temperature (BCT) was rapidly decreased to 35°C or 33°C, if necessary. BCT induced and maintained by surface cooling remained at the desired level for at least 72 hours. Rewarming was performed by 1°C, only if the target parameters ICP and velocities in the serial Doppler sonography indicating macrovascular vasospasm improved to regular levels. In case of increase of ICP or middle cerebral arteries velocities BCT was decreased again to the last effective level. The patients developed vasospasm between days 6 and 12 after SAH. All aneurysms were treated by coiling. BCT was reduced between days 6 and 12 after SAH. Total duration of BCT <36.5°C was between 5.5 and 8 days. It remained <35°C for 4-6 days, and at 33°C for 3 days on average. ICP could be sufficiently controlled in all patients, because no ICP crisis was observed during TTM and after rewarming. Two patients developed minor DCI. Side effects of prolonged ventilation of 7-18 days included pneumonia for two patients that could be treated sufficiently. Other complications were one case of ventriculitis and two temporary deliriums. Outcome of the patients was good because no focal neurological symptoms could be detected after rehabilitation. TTM represents a promising treatment approach for severe SAH in which standard treatment is often limited and experimental. It deserves further clinical investigation in a larger cohort.

Evidence-Based Review of Clinical Trials in Neurocritical Care

Neurocritical care is a rapidly growing specialty of complex care for the critically ill patient with neurological injury. This rapid growth has led to an increase in the number of important clinical trials to guide clinical practice and evidence-based care of the critically ill patient with neurological injury. Specialty-trained critical care nurses and advanced practice providers are integral members of neurocritical care teams and must remain informed about pivotal trials shaping practice recommendations. This article presents a summary of recent trials that have affected current practice and influenced care recommendations in the neurocritical care setting.

Periprocedural management of patients with subarachnoid hemorrhage

PURPOSE OF REVIEW

Anesthesiologists and intensivists may be involved in the management of aneurysmal subarachnoid hemorrhage (aSAH) patients at various stages of care. This article will review the recent advances in the periprocedural management of aSAH patients.

RECENT FINDINGS

New scoring systems to assess gravity and prognosis of aSAH patients have been evaluated and proposed. Rebleeding still remains, with early aneurysmal treatment, a major challenge in the first hours of aSAH management. In the last decades, the treatment of the aSAH has shifted from clipping to coiling and more recently, the use of flow diversion technique has been introduced in selected patients. Although these improvements allow treatment of more complex aneurysms, they have implications for the anesthesiologist, including requiring the management of anticoagulation with its inherent risks. Even though knowledge, monitoring, and management of postprocedural phase of aSAH patients has improved, vasospasm and cerebral-delayed ischemia still remain the major and devastating complications in the postoperative course of aSAH patients.

SUMMARY

Despite recent progress in the scoring, diagnosis, and treatment of aSAH patients, the periprocedural management of these patients is still a major challenge for anesthesiologists and intensivists, who are involved from the first phase of the aneurysm rupture through the postoperative phases and vasospasm period.

Moderate hypothermia protects increased neuronal autophagy via activation of extracellular signal-regulated kinase signaling pathway in a rat model of early brain injury in subarachnoid hemorrhage

Moderate hypothermia (MH) used as treatment for neurological diseases has a protective effect; however, its mechanism remains unclear. Neuronal autophagy is a fundamental pathological process of early brain injury in subarachnoid hemorrhage (SAH). We found that moderate activation of autophagy can reduce nerve cells damage. In this study, We found that MH can moderately increase the level of autophagy in nerve cells and improve the neurological function in rats. This type of autophagy activation is dependent on extracellular signal-regulated kinase (ERK) signaling pathways. The level of neuronal autophagy was down-regulated significantly by using U0126, an ERK signaling pathway inhibitor. In summary, these results suggest that MH can moderately activate neuronal autophagy through ERK signaling pathway, reduce nerve cell death, and produce neuroprotective effects.

Aneurysmal subarachnoid hemorrhage: intensive care for improving neurological outcome

Background

Aneurysmal subarachnoid hemorrhage is a life-threatening disease requiring neurocritical care. Delayed cerebral ischemia is a well-known complication that contributes to unfavorable neurological outcomes. Cerebral vasospasm has been thought to be the main cause of delayed cerebral ischemia, and although several studies were able to decrease cerebral vasospasm, none showed improved neurological outcomes. Our target is not cerebral vasospasm but improving neurological outcomes. The purpose of this review is to discuss what intensivists should know and can do to improve clinical outcomes in subarachnoid hemorrhage patients.

Main body of the abstract

Delayed cerebral ischemia is thought to be due to not only vasospasm but also multifactorial mechanisms. Additionally, the concept of early brain injury, which occurs within the first 72 h after the hemorrhage, has become an important concern. Increasing sympathetic activity after the hemorrhage is associated with cardiopulmonary complications and poor outcomes. Serum lactate measurement may be a valuable marker reflecting the severity of sympathetic activity. The transpulmonary thermodilution method will bring about an advanced understanding of hemodynamic management. Fever is a well-recognized symptom and targeted temperature management is an anticipated intervention. To avoid hyperglycemia and hypoglycemia, performing moderate glucose control and minimizing glucose variability are important concepts in glycemic management, but the optimal target range remains unknown. Dysnatremia seems to be associated with negative outcomes. It is not clear yet that maintaining normonatremia actively improves neurological outcomes. Optimal duration of intensive care management has not been determined.

Short conclusion

Although we have an advanced understanding of the pathophysiology and clinical characteristics of subarachnoid hemorrhage, there are many controversies in the intensive care unit management of subarachnoid hemorrhage. With an awareness of not only delayed cerebral ischemia but also early brain injury, more attention should be given to various aspects to improve neurological outcomes.

Effect and Feasibility of Therapeutic Hypothermia in Patients with Hemorrhagic Stroke: A Systematic Review and Meta-Analysis

INTRODUCTION

Therapeutic hypothermia (TH) has shown good results in experimental models of hemorrhagic stroke. The clinical application of TH, however, remains controversial, since reports regarding its therapeutic effect are inconsistent.

METHODS

We conducted a systematic review based on Preferred Reporting Items for Systematic Reviews and Meta-analyses comparing TH with a control group in terms of mortality, poor outcome, delayed cerebral ischemia (DCI), and specific complications. The subgroup analyses were stratified by study type, country, mean age, hemorrhage type, cooling method, treatment duration, rewarming velocity, and follow-up time.

RESULTS

Nine studies were included, most of which were of moderate quality. The overall effect demonstrated insignificant differences in mortality (risk ratio [RR] 0.78; 95% confidence interval [CI] 0.58-1.06; P = 0.11) and poor outcome rate (RR 0.89; 95% CI 0.70-1.12; P = 0.32) between TH and the control group. However, sensitivity analyses, after we omitted 1 study, achieved a statistically significant difference in poor outcome favoring TH. Moreover, in the subgroup analyses, the results derived from randomized studies revealed that TH significantly reduced poor outcomes (RR 0.40; 95% CI 0.22-0.74; P = 0.003). In addition, TH significantly reduced DCI compared with control (RR 0.61; 95% CI 0.40-0.93; P = 0.02). The incidence of specific complications (rebleeding, pneumonia, sepsis, arrhythmia, and hydrocephalus) between the 2 groups were comparable and did not reach significant difference.

CONCLUSIONS

The overall effect showed TH did not significantly reduce mortality and poor outcomes but led to a decreased incidence of DCI. Compared with control, TH resulted in comparable incidences of specific complications.

Early Transient Mild Hypothermia Attenuates Neurologic Deficits and Brain Damage After Experimental Subarachnoid Hemorrhage in Rats

OBJECTIVE

Metabolic exhaustion in ischemic tissue is the basis for a detrimental cascade of cell damage. In the acute stage of subarachnoid hemorrhage (SAH), a sequence of global and focal ischemia occurs, threatening brain tissue to undergo ischemic damage. This study was conducted to investigate whether early therapy with moderate hypothermia can offer neuroprotection after experimental SAH.

METHODS

Twenty male Sprague-Dawley rats were subjected to SAH and treated by active cooling (34°C) or served as controls by continuous maintenance of normothermia (37.0°C). Mean arterial blood pressure, intracranial pressure, and local cerebral blood flow over both hemispheres were continuously measured. Neurologic assessment was performed 24 hours later. Hippocampal damage was assessed by hematoxylin-eosin and caspase-3 staining.

RESULTS

By a slight increase of mean arterial blood pressure in the cooling phase and a significant reduction of intracranial pressure, hypothermia improved cerebral perfusion pressure in the first 60 minutes after SAH. Accordingly, a trend to increased cerebral blood flow was observed during this period. The rate of injured neurons was significantly reduced in hypothermia-treated animals compared with normothermic controls.

CONCLUSIONS

The results of this series cannot finally answer whether this form of treatment permanently attenuates or only delays ischemic damage. In the latter case, slowing down metabolic exhaustion by hypothermia may still be a valuable treatment during this state of ischemic brain damage and prolong the therapeutic window for possible causal treatments of the acute perfusion deficit. Therefore, it may be useful as a first-tier therapy in suspected SAH.