Fever in subarachnoid hemorrhage: relationship to vasospasm and outcome

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.

Controversies in the temperature management of critically ill patients

Although body temperature is a classic primary vital sign, its value has received little attention compared with the others (blood pressure, heart rate, and respiratory rate). This may result from the fact that unlike the other primary vital signs, aging and diseases rarely affect the thermoregulatory system. Despite this, when humans are exposed to various anesthetics and analgesics and acute etiologies of non-infectious and infectious diseases in perioperative and intensive care settings, abnormalities may occur that shift body temperature up and down. A recent upsurge in clinical evidence in the perioperative and critical care field resulted in many clinical trials in temperature management. The results of these clinical trials suggest that aggressive body temperature modifications in comatose survivors after resuscitation from shockable rhythm, and permissive fever in critically ill patients, are carried out in critical care settings to improve patient outcomes; however, its efficacy remains to be elucidated. A recent, large multicenter randomized controlled trial demonstrated contradictory results, which may disrupt the trends in clinical practice. Thus, updated information concerning thermoregulatory interventions is essential for anesthesiologists and intensivists. Here, recent controversies in therapeutic hypothermia and fever management are summarized, and their relevance to the physiology of human thermoregulation is discussed.

Temperature Management in the Neurointensive Care Unit

OPINION STATEMENT

Fever in the neurocritical care unit has a high prevalence and is associated with worse outcomes in patients with severe neurologic illness. While it is well accepted that fever is associated with worse outcomes in this patient population, it is unclear if aggressive temperature management will improve outcomes. Temperature should be monitored routinely in this high-risk population, fever worked up appropriately to identify infectious etiology, and reasonable measures taken to control elevated temperature. While infection is a common source of fever in patients with significant neurologic illness, the fever may also be exacerbated by the underlying brain injury. The clinician must decide at which point to initiate fever control measures, how aggressively to manage the fever, and which temperature to target for normothermia. Several pharmacological agents are available as first-line therapy. Depending on the degree and severity of the febrile response, advanced temperature-control devices should be added to pharmacological measures. Several types of temperature-control devices are available, including invasive (intravascular catheters) and noninvasive (external cooling pads) technologies. The clinician should utilize both pharmacologic and device-based temperature therapies to minimize the amount of time spent in a febrile state and help to mitigate the secondary brain injury brought on by fever.

The critical care management of poor-grade subarachnoid haemorrhage

Aneurysmal subarachnoid haemorrhage is a neurological syndrome with complex systemic complications. The rupture of an intracranial aneurysm leads to the acute extravasation of arterial blood under high pressure into the subarachnoid space and often into the brain parenchyma and ventricles. The haemorrhage triggers a cascade of complex events, which ultimately can result in early brain injury, delayed cerebral ischaemia, and systemic complications. Although patients with poor-grade subarachnoid haemorrhage (World Federation of Neurosurgical Societies 4 and 5) are at higher risk of early brain injury, delayed cerebral ischaemia, and systemic complications, the early and aggressive treatment of this patient population has decreased overall mortality from more than 50% to 35% in the last four decades. These management strategies include (1) transfer to a high-volume centre, (2) neurological and systemic support in a dedicated neurological intensive care unit, (3) early aneurysm repair, (4) use of multimodal neuromonitoring, (5) control of intracranial pressure and the optimisation of cerebral oxygen delivery, (6) prevention and treatment of medical complications, and (7) prevention, monitoring, and aggressive treatment of delayed cerebral ischaemia. The aim of this article is to provide a summary of critical care management strategies applied to the subarachnoid haemorrhage population, especially for patients in poor neurological condition, on the basis of the modern concepts of early brain injury and delayed cerebral ischaemia.

Risk Factors for Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage: A Review of the Literature

OBJECTIVE

To examine the literature on risk factors for cerebral vasospasm (CV), one of the most serious complications following aneurysmal subarachnoid hemorrhage (SAH), with special reference to the definition of CV.

METHODS

Using standard search engines, including PubMed, the medical literature on risk factors for CV after SAH was reviewed, and the best definition representative of CV was searched.

RESULTS

Severe SAH evident on computed tomography scan was the only consistent risk factor for CV after SAH. Effects of risk factors on CV, including age, clinical grade, rebleeding, intraventricular or intracerebral hemorrhage on computed tomography scan, acute hydrocephalus, aneurysm site and size, leukocytosis, interleukin-6 level, and cardiac abnormalities, appeared to be associated with the severity of SAH rather than each having a direct effect. Cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram were associated with CV without any relationship to SAH severity. With regard to parameters representative of CV, the grade of angiographic vasospasm (i.e., the degree of arterial narrowing evident on angiography) was the most adequate. Nevertheless, few reports on the risk factors associated with angiographic vasospasm grade have been reported to date.

CONCLUSIONS

Severe SAH evident on computed tomography scan appears to be a definite risk factor for CV after SAH, followed by cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram. To understand the pathogenesis of CV, further studies on the relationships between risk factors, especially factors not related to the severity of SAH, and angiographic vasospasm grade are necessary.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN, SETTING AND PARTICIPANTS

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

RESULTS

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

CONCLUSIONS

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

Central fever in patients with spontaneous intracerebral hemorrhage: predicting factors and impact on outcome

BACKGROUND

Central fever (CF) is defined as elevated temperature with no identifiable cause. We aimed to identify risk factors for developing CF among patients with spontaneous intracerebral hemorrhage (ICH) and to evaluate the impact of CF on outcome.

METHODS

Patients included in our prospective stroke registry between 1/1/09 and 1/10/10 were studied. We identified patients with CF as those with a temperature ≥38.3°C without evidence for infection or drug fever. Patients with CF were compared to those without fever and those with infectious fever. Demographics, risk factors and imaging data as well as outcome parameters were reviewed.

RESULTS

We identified 95 patients with spontaneous ICH (median age 76, median admission NIHSS 9). CF was identified in 30 patients (32%), infectious etiology was found in 9 patients (9%) and the remaining patients did not develop fever. Baseline variables were similar between the groups except for intra-ventricular extension of the ICH (IVH) and larger ICH volumes that were more common in the CF group (OR = 4.667, 95% CI 1.658-13.135 and OR = 1.013/ml, 95% CI 1.004-1.021). Outcome analysis showed higher mortality rates (80% vs. 36%, p < 0.001) and lower rates of favorable functional outcome defined as a modified Rankin score ≤ 2 at 90 days (0% vs. 53%, p < 0.001) in the CF group.

CONCLUSIONS

The risk of CF is increased in patients with larger ICH and in those with IVH. CF negatively impacts outcome in patients with ICH.

The epidemiology of spontaneous fever and hypothermia on admission of brain injury patients to intensive care units: a multicenter cohort study

OBJECTIVES

Fever and hypothermia (dysthermia) are associated with poor outcomes in patients with brain injuries. The authors sought to study the epidemiology of dysthermia on admission to the intensive care unit (ICU) and the effect on in-hospital case fatality in a mixed cohort of patients with brain injuries.

METHODS

The authors conducted a multicenter retrospective cohort study in 94 ICUs in the United States. Critically ill patients with neurological injuries, including acute ischemic stroke (AIS), aneurysmal subarachnoid hemorrhage (aSAH), intracerebral hemorrhage (ICH), and traumatic brain injury (TBI), who were older than 17 years and consecutively admitted to the ICU from 2003 to 2008 were selected for analysis.

RESULTS

In total, 13,587 patients were included in this study; AIS was diagnosed in 2973 patients (22%), ICH in 4192 (31%), aSAH in 2346 (17%), and TBI in 4076 (30%). On admission to the ICU, fever was more common among TBI and aSAH patients, and hypothermia was more common among ICH patients. In-hospital case fatality was more common among patients with hypothermia (OR 12.7, 95% CI 8.4-19.4) than among those with fever (OR 1.9, 95% CI 1.7-2.1). Compared with patients with ICH (OR 2.0, 95% CI 1.8-2.3), TBI (OR 1.5, 95% CI 1.3-1.8), and aSAH (OR 1.4, 95% CI 1.2-1.7), patients with AIS who developed fever had the highest risk of death (OR 3.1, 95% CI 2.5-3.7). Although all hypothermic patients had an increased mortality rate, this increase was not significantly different across subgroups. In a multivariable analysis, when adjusted for all other confounders, exposure to fever (adjusted OR 1.3, 95% CI 1.1-1.5) or hypothermia (adjusted OR 7.8, 95% CI 3.9-15.4) on admission to the ICU was found to be significantly associated with in-hospital case fatality.

CONCLUSIONS

Fever is frequently encountered in the acute phase of brain injury, and a small proportion of patients with brain injuries may also develop spontaneous hypothermia. The effect of fever on mortality rates differed by neurological diagnosis. Both early spontaneous fever and hypothermia conferred a higher risk of in-hospital death after brain injury.

Inflammation, vasospasm, and brain injury after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) can lead to devastating neurological outcomes, and there are few pharmacologic treatments available for treating this condition. Both animal and human studies provide evidence of inflammation being a driving force behind the pathology of SAH, leading to both direct brain injury and vasospasm, which in turn leads to ischemic brain injury. Several inflammatory mediators that are elevated after SAH have been studied in detail. While there is promising data indicating that blocking these factors might benefit patients after SAH, there has been little success in clinical trials. One of the key factors that complicates clinical trials of SAH is the variability of the initial injury and subsequent inflammatory response. It is likely that both genetic and environmental factors contribute to the variability of patients' post-SAH inflammatory response and that this confounds trials of anti-inflammatory therapies. Additionally, systemic inflammation from other conditions that affect patients with SAH could contribute to brain injury and vasospasm after SAH. Continuing work on biomarkers of inflammation after SAH may lead to development of patient-specific anti-inflammatory therapies to improve outcome after SAH.

Acute subdural haemorrhage in the postpartum period as a rare manifestation of possible HELLP (haemolysis, elevated liver enzymes, and low-platelet count) syndrome: a case report

Background

The HELLP syndrome (haemolysis, elevated liver enzymes, and low-platelet count) occurs in about 0.5 to 0.9% of all pregnancies. With occurrence of thrombocytopaenia, it signals for several potentially lethal conditions such as complete or partial HELLP syndrome, thrombotic thrombocytopaenic purpura and acute fatty liver of pregnancy.

Case presentation

A previously healthy 27-year-old, Sinhala ethnic primigravida with pregnancy-induced hypertension was admitted at 38 weeks of gestation with lower abdominal pain and a blood pressure of 140/90 mmHg. She underwent emergency Caesarian section due to faetal distress giving birth to a healthy baby girl. Since postpartum day one, she was having intermittent fever spikes. All the routine investigations were normal in the first three weeks. Platelet count started dropping from post-partum day-20 onwards. On day-23, she had developed a seizure and computed tomography scan brain showed a subdural haemorrhage. She had a platelet count of 22,000 × 10⁹/liter and was managed conservatively. She also had elevated liver enzymes, lactate dehydrogenase and bilirubin levels. Blood picture on day-24 showed haemolytic anemia. On day- 36, patient again developed seizures and she was having intermittent fever with generalized headache and signs of meningism. Computed tomography scan revealed an acute on chronic subdural haemorrhage.

Conclusions

Hypertensive disorders in pregnancy should be managed as high-risk throughout the postpartum period. Development of thrombocytopaenia can be considered as an early warning sign for HELLP, thrombotic thrombocytopaenic purpura or acute fatty liver of pregnancy which are lethal conditions. Prompt recognition of intracranial haemorrhages and early neurosurgical intervention is lifesaving.

Incidence of delayed seizures, delayed cerebral ischemia and poor outcome with the use of levetiracetam versus phenytoin after aneurysmal subarachnoid hemorrhage

Current guidelines recommend against the use of phenytoin following aneurysmal subarachnoid hemorrhage (aSAH) but consider other anticonvulsants, such as levetiracetam, acceptable. Our objective was to evaluate the risk of poor functional outcomes, delayed cerebral ischemia (DCI) and delayed seizures in aSAH patients treated with levetiracetam versus phenytoin. Medical records of patients with aSAH admitted between 2005-2012 receiving anticonvulsant prophylaxis with phenytoin or levetiracetam for >72 hours were reviewed. The primary outcome measure was poor functional outcome, defined as modified Rankin Scale (mRS) score >3 at first recorded follow-up. Secondary outcomes measures included DCI and the incidence of delayed seizures. The association between the use of levetiracetam and phenytoin and the outcomes of interest was studied using logistic regression. Medical records of 564 aSAH patients were reviewed and 259 included in the analysis after application of inclusion/exclusion criteria. Phenytoin was used exclusively in 43 (17%), levetiracetam exclusively in 132 (51%) while 84 (32%) patients were switched from phenytoin to levetiracetam. Six (2%) patients had delayed seizures, 94 (36%) developed DCI and 63 (24%) had mRS score >3 at follow-up. On multivariate analysis, only modified Fisher grade and seizure before anticonvulsant administration were associated with DCI while age, Hunt-Hess grade and presence of intraparenchymal hematoma were associated with mRS score >3. Choice of anticonvulsant was not associated with any of the outcomes of interest. There was no difference in the rate of delayed seizures, DCI or poor functional outcome in patients receiving phenytoin versus levetiracetam after aSAH. The high rate of crossover from phenytoin suggests that levetiracetam may be better tolerated.

Brain ischemia in patients with intracranial hemorrhage: pathophysiological reasoning for aggressive diagnostic management

Patients with intracranial hemorrhage have to be managed aggressively to avoid or minimize secondary brain damage due to ischemia, which contributes to high morbidity and mortality. The risk of brain ischemia, however, is not the same in every patient. The risk of complications associated with an aggressive prophylactic therapy in patients with a low risk of brain ischemia can outweigh the benefits of therapy. Accurate and timely identification of patients at highest risk is a diagnostic challenge. Despite the availability of many diagnostic tools, stroke is common in this population, mostly because the pathogenesis of stroke is frequently multifactorial whereas diagnosticians tend to focus on one or two risk factors. The pathophysiological mechanisms of brain ischemia in patients with intracranial hemorrhage are not yet fully elucidated and there are several important areas of ongoing research. Therefore, this review describes physiological and pathophysiological aspects associated with the development of brain ischemia such as the mechanism of oxygen and carbon dioxide effects on the cerebrovascular system, neurovascular coupling and respiratory and cardiovascular factors influencing cerebral hemodynamics. Consequently, we review investigations of cerebral blood flow disturbances relevant to various hemodynamic states associated with high intracranial pressure, cerebral embolism, and cerebral vasospasm along with current treatment options.

Brain Injury as a Risk Factor for Fever Upon Admission to the Intensive Care Unit and Association With In-Hospital Case Fatality

Purpose:

To test the hypothesis that fever was more frequent in critically ill patients with brain injury when compared to nonneurological patients and to study its effect on in-hospital case fatality.

Methods:

Retrospective matched cohort study utilizing a single-center prospectively compiled registry. Critically ill neurological patients ≥18 years and consecutively admitted to the intensive care unit (ICU) with acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), and traumatic brain injury (TBI) were selected. Patients were matched by sex, age, and Acute Physiology and Chronic Health Evaluation II (APACHE-II) to a cohort of nonneurological patients. Fever was defined as any temperature ≥37.5°C within the first 24 hours upon admission to the ICU. The primary outcome measure was in-hospital case fatality.

Results:

Mean age among neurological patients was 65.6 ± 15 years, 46% were men, and median APACHE-II was 15 (interquartile range 11-20). There were 18% AIS, 27% ICH, and 6% TBI. More neurological patients experienced fever than nonneurological patients (59% vs 47%, P = .007). The mean hospital length of stay was higher for nonneurological patients (18 ± 20 vs 14 ± 15 days, P = .007), and more neurological patients were dead at hospital discharge (29% vs 20%, P < .0001). After risk factor adjustment, diagnosis (neurological vs nonneurological), and the probability of being exposed to fever (propensity score), the following variables were associated with higher in-hospital case fatality: APACHE-II, neurological diagnosis, mean arterial pressure, cardiovascular and respiratory dysfunction in ICU, and fever (odds ratio 1.9, 95% confidence interval 1.04-3.6, P = .04).

Conclusion:

These data suggest that fever is a frequent occurrence after brain injury, and that it is independently associated with in-hospital case fatality.

Elevated temperature and 6- to 7-year outcome of neonatal encephalopathy

OBJECTIVE

A study was undertaken to determine whether higher temperature after hypoxia-ischemia is associated with death or intelligence quotient (IQ)<70 at 6 to 7 years among infants treated with intensive care without hypothermia.

METHODS

Control infants (noncooled, n=106) of the National Institute of Child Health and Human Development Neonatal Research Network hypothermia trial had serial esophageal and skin temperatures over 72 hours. Each infant's temperature was ranked to derive an average of the upper and lower quartile, and median of each site. Temperatures were used in logistic regressions to determine adjusted associations with death or IQ<70 at 6 to 7 years. Secondary outcomes were death, IQ<70, and moderate/severe cerebral palsy (CP). IQ and motor function were assessed with Wechsler Scales for Children and Gross Motor Function Classification System. Results are odds ratio (OR; per degree Celsius increment within the quartile or median) and 95% confidence interval (CI).

RESULTS

Primary outcome was available for 89 infants. At 6 to 7 years, death or IQ<70 occurred in 54 infants (37 deaths, 17 survivors with IQ<70) and moderate/severe CP in 15 infants. Death or IQ<70 was associated with the upper quartile average of esophageal (OR=7.3, 95% CI=2.0-26.3) and skin temperature (OR=3.5, 95% CI=1.2-10.4). CP was associated with the upper quartile average of esophageal (OR=12.5, 95% CI=1.02-155) and skin temperature (OR=10.3, 95% CI=1.3-80.2).

INTERPRETATION

Among noncooled infants of a randomized trial, elevated temperatures during the first postnatal days are associated with increased odds of a worse outcome at 6 to 7 years.

Brain temperature: physiology and pathophysiology after brain injury

The regulation of brain temperature is largely dependent on the metabolic activity of brain tissue and remains complex. In intensive care clinical practice, the continuous monitoring of core temperature in patients with brain injury is currently highly recommended. After major brain injury, brain temperature is often higher than and can vary independently of systemic temperature. It has been shown that in cases of brain injury, the brain is extremely sensitive and vulnerable to small variations in temperature. The prevention of fever has been proposed as a therapeutic tool to limit neuronal injury. However, temperature control after traumatic brain injury, subarachnoid hemorrhage, or stroke can be challenging. Furthermore, fever may also have beneficial effects, especially in cases involving infections. While therapeutic hypothermia has shown beneficial effects in animal models, its use is still debated in clinical practice. This paper aims to describe the physiology and pathophysiology of changes in brain temperature after brain injury and to study the effects of controlling brain temperature after such injury.

Influence of Fever and hospital-acquired infection on the incidence of delayed neurological deficit and poor outcome after aneurysmal subarachnoid hemorrhage

Although fever and infection have been implicated in the causation of delayed neurological deficits (DND) and poor outcome after aneurysmal subarachnoid hemorrhage (SAH), the relationship between these two often related events has not been extensively studied. We reviewed these events through of our retrospective database of patients with SAH. Multivariate logistic regression was used to determine independent predictors of DND and poor outcome. A total of 186 patients were analyzed. DND was noted in 76 patients (45%). Fever was recorded in 102 patients (55%); infection was noted in 87 patients (47%). A patient with one infection was more likely to experience DND compared to a patient with no infections (adjusted OR 3.73, 95% CI 1.62, 8.59). For those with more than two infections the likelihood of DND was even greater (adjusted OR 4.24, 95% CI 1.55, 11.56). Patients with 1-2 days of fever were less likely to have a favorable outcome when compared to their counterparts with no fever (adjusted OR 0.19, 95% CI 0.06, 0.62). This trend worsened as the number of days febrile increased. These data suggest that the presence of infection is associated with DND, but that fever may have a stronger independent association with overall outcome.

Non-infectious hyperthermia in acute brain injury patients: relationships to mortality, blood pressure, intracranial pressure and cerebral perfusion pressure

The present study was conducted to investigate the frequency of hyperthermia during the first 72 h after acute brain injury, and to compare subjects that developed hyperthermia with those that did not with respect to blood pressure, intracranial pressure (ICP), cerebral perfusion pressure (CPP), Glasgow Coma Scale (GCS) score and mortality. This study was conducted by performing a retrospective medical record review of 126 brain injury patients admitted to the neurological intensive care unit of a university hospital located in Incheon, South Korea. Our results showed that 25.4% of the subjects had hyperthermia for at least 1 day during the first 3 days of hospitalization. Hyperthermic subjects demonstrated higher mortality and ICP, and lower CPP and GCS scores than non-hyperthermic subjects, indicating a reduced cerebral blood flow. The findings may provide a possible explanation for poor clinical outcome and offer justification for the careful monitoring of body temperature in patients with acute brain injury.

Use of hypothermia in the intensive care unit

Used for over 3600 years, hypothermia, or targeted temperature management (TTM), remains an ill defined medical therapy. Currently, the strongest evidence for TTM in adults are for out-of-hospital ventricular tachycardia/ventricular fibrillation cardiac arrest, intracerebral pressure control, and normothermia in the neurocritical care population. Even in these disease processes, a number of questions exist. Data on disease specific therapeutic markers, therapeutic depth and duration, and prognostication are limited. Despite ample experimental data, clinical evidence for stroke, refractory status epilepticus, hepatic encephalopathy, and intensive care unit is only at the safety and proof-of-concept stage. This review explores the deleterious nature of fever, the theoretical role of TTM in the critically ill, and summarizes the clinical evidence for TTM in adults.

Intensive care unit management of aneurysmal subarachnoid hemorrhage

The emergence of dedicated neurologic-neurosurgical intensive care units, advancements in endovascular therapies, and aggressive brain resuscitation and monitoring have contributed to overall improved outcomes for patients with aneurysmal subarachnoid hemorrhage (aSAH) over the past 20 to 30 years. Still, this feared neurologic emergency is associated with substantial mortality and morbidity. Emergency care for patients with aSAH focuses on stabilization, treatment of the aneurysm, controlling intracranial hypertension to optimize cerebral perfusion, and limiting secondary brain injury. This complex disorder can be associated with many neurologic complications such as acute hydrocephalus, rebleeding, global cerebral edema, seizures, vasospasm, and delayed cerebral ischemia in addition to systemic complications such as electrolyte imbalances, cardiopulmonary injury, and infections. Background routine intensive care practices such as avoidance of hyperthermia, venous thromboembolism prophylaxis, and avoidance of severe blood glucose derangements are additional important elements of care.

ICU management of aneurysmal subarachnoid hemorrhage

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (SAH) has very high morbidity and mortality rates. Optimal intensive care unit (ICU) management requires knowledge of the potential complications that occur in this patient population.

METHODS

Review of the ICU management of SAH. Level of evidence for specific recommendations is provided.

RESULTS

Grading scales utilizing clinical factors and brain imaging studies can help in determining prognosis and are reviewed. Misdiagnosis of SAH is fairly common so the clinical symptoms and signs of SAH are summarized. The ICU management of SAH is discussed beginning with a focus on avoiding aneurysm re-rupture and securing the aneurysm, followed by a review of the neurologic and medical complications that may occur after the aneurysm is secured. Detailed treatment strategies and areas of current and future research are reviewed.

CONCLUSIONS

The ICU management of the patient with SAH can be particularly challenging and requires an awareness of all potential neurologic and medical complications and their urgent treatments.

Treatment of resistant fever: new method of local cerebral cooling

BACKGROUND

Fever in neurocritical care patients is common and has a negative impact on neurological outcome. The purpose of this prospective observational study was (1) to evaluate the practicability of cooling with newly developed neck pads in the daily setting of neurointensive care unit (NICU) patients and (2) to evaluate its effectiveness as a surrogate endpoint to indicate the feasibility of neck cooling as a new method for intractable fever.

METHODS

Nine patients with ten episodes of intractable fever and aneurysmal subarachnoid hemorrhage were treated with one of two different shapes of specifically adapted cooling neck pads. Temperature values of the brain, blood, and urinary bladder were taken close meshed after application of the cooling neck pads up to hour 8.

RESULTS

The brain, blood, and urinary bladder temperatures decreased significantly from hour 0 to a minimum in hour 5 (P < 0.01). After hour 5, instead of continuous cooling in all the patients, the temperature of all the three sites remounted.

CONCLUSION

This study showed the practicability of local cooling for intractable fever using the newly developed neck pads in the daily setting of NICU patients.

Fever management in SAH

An electronic literature search through August 2010 was performed to obtain articles describing fever incidence, impact, and treatment in patients with subarachnoid hemorrhage. A total of 24 original research studies evaluating fever in SAH were identified, with studies evaluating fever and outcome, temperature control strategies, and shivering. Fever during acute hospitalization for subarachnoid hemorrhage was consistently linked with worsened outcome and increased mortality. Antipyretic medications, surface cooling, and intravascular cooling may all reduce temperatures in patients with subarachnoid hemorrhage; however, benefits from cooling may be offset by negative consequences from shivering.

Therapeutic hypothermia for acute neurological injuries

Therapeutic hypothermia (TH) is the intentional reduction of core body temperature to 32°C to 35°C, and is increasingly applied by intensivists for a variety of acute neurological injuries to achieve neuroprotection and reduction of elevated intracranial pressure. TH improves outcomes in comatose patients after a cardiac arrest with a shockable rhythm, but other off-label applications exist and are likely to increase in the future. This comprehensive review summarizes the physiology and cellular mechanism of action of TH, as well as different means of TH induction and maintenance with potential side effects. Indications of TH are critically reviewed by disease entity, as reported in the most recent literature, and evidence-based recommendations are provided.

Risk factors for posttraumatic vasospasm

OBJECT

Posttraumatic vasospasm (PTV) is an underrecognized cause of ischemic damage after severe traumatic brain injury (TBI) that independently predicts poor outcome. There are, however, no guidelines for PTV screening and management, partly due to limited understanding of its pathogenesis and risk factors.

METHODS

A database review of 46 consecutive cases of severe TBI in pediatric and adult patients was conducted to identify risk factors for the development of PTV. Univariate analysis was performed to identify potential risk factors for PTV, which were subsequently analyzed using a multivariate logistic regression model to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Fever on admission was an independent risk factor for development of PTV (OR 22.2, 95% CI 1.9-256.8), and patients with hypothermia on admission did not develop clinically significant vasospasm during their hospital stay. The presence of small parenchymal contusions was also an independent risk factor for PTV (OR 7.8, 95% CI 0.9-69.5), whereas the presence of subarachnoid hemorrhage or other patterns of intracranial injury were not. Other variables, such as age, sex, ethnicity, degree of TBI severity, or admission laboratory values, were not independent predictors for the development of clinically significant PTV.

CONCLUSIONS

Independent risk factors for PTV include parenchymal contusions and fever. These results suggest that diffuse mechanical injury and activation of inflammatory pathways may be underlying mechanisms for the development of PTV, and that a subset of patients with these risk factors may be an appropriate population for aggressive screening. Further studies are needed to determine if treatments targeting fever and inflammation may be effective in reducing the incidence of vasospasm following severe TBI.

Transcranial Doppler can predict intracranial hypertension in children with severe traumatic brain injuries

PURPOSE

The purpose of this study is to evaluate the accuracy of emergency Transcranial Doppler (TCD) to predict intracranial hypertension and abnormal cerebral perfusion pressure in children with severe traumatic brain injury (TBI).

PATIENTS AND METHODS

A descriptive and retrospective cross-sectional study was designed through data collected from medical records of children with severe TBI (Glasgow coma scale ≤ 8), admitted to a level I pediatric trauma center, between January 2000 and December 2005. Early TCD examination was performed upon admission, and TCD profiles were considered as altered using previously validated threshold values for diastolic velocity (<25 cm/s) and pulsatility index (>1.31) or when no-flow/backflow was detected. Invasive intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring were considered as the gold standard to measure intracranial hypertension (ICH). Statistical analyses compared TCD profiles to increased ICP (≥ 20 mmHg) and abnormal cerebral perfusion pressure (<50 mmHg) at admission.

RESULTS

Non-invasive TCD and ICP monitoring were performed in 117 severe head-injured children. Mean age was 7.6 ± 4.4 years, with a male prevalence (71%). Median initial Glasgow coma scale was 6. TCD had 94% of sensitivity to identify ICH at admission and a negative predict value of 95% to identify normal ICP at admission. Its sensitivity to predict abnormal cerebral perfusion pressure was 80%.

CONCLUSIONS

The high sensitivity of admission TCD to predict ICH and abnormal CPP after trauma demonstrates that TCD is an excellent first-line examination to determine those children who need urgent aggressive treatment and continuous invasive ICP monitoring.

Pharmacological treatment of delayed cerebral ischemia and vasospasm in subarachnoid hemorrhage

Subarachnoid hemorrhage after the rupture of a cerebral aneurysm is the cause of 6% to 8% of all cerebrovascular accidents involving 10 of 100,000 people each year. Despite effective treatment of the aneurysm, delayed cerebral ischemia (DCI) is observed in 30% of patients, with a peak on the tenth day, resulting in significant infirmity and mortality. Cerebral vasospasm occurs in more than half of all patients and is recognized as the main cause of delayed cerebral ischemia after subarachnoid hemorrhage. Its treatment comprises hemodynamic management and endovascular procedures. To date, the only drug shown to be efficacious on both the incidence of vasospasm and poor outcome is nimodipine. Given its modest effects, new pharmacological treatments are being developed to prevent and treat DCI. We review the different drugs currently being tested.

Temperature management in acute neurologic injury: to cool or not to cool

Therapeutic hypothermia is becoming an important intervention following acute neurologic injury despite inconclusive results concerning efficacy. This enthusiasm primarily stems from a lack of other effective interventions in this population. With the increase in the use of therapeutic hypothermia, several practical issues must be considered when initiating this intervention. Clinical pharmacists can play an important role in anticipating and addressing some complications such as shivering, slow drug metabolism, and infection. This review will discuss the available literature concerning the efficacy of therapeutic hypothermia in various neurologic injuries, as well as the most common adverse events associated with it.

Monitoring of the inflammatory response after aneurysmal subarachnoid haemorrhage in the clinical setting: review of literature and report of preliminary clinical experience

BACKGROUND

Clinical and experimental studies showed a marked inflammatory response in aneurysmal subarachnoid haemorrhage (SAH), and it has been proposed to play a key role in the development of cerebral vasospasm (CVS). Inflammatory response and occurrence of CVS may represent a common pathogenic pathway allowing point of care diagnostics of CVS. Therefore, monitoring of the inflammatory response might be useful in the daily clinical setting of an ICU. The aim of the current report is to give a summary about factors contributing to the complex pathophysiology of inflammatory response in SAH and to discuss possible monitoring modalities.

METHODS

Review and analysis of the existing literature and definition of own study protocols.

RESULTS

In cerebrospinal fluid, interleukin (IL)-6 has been found to be significantly higher in patients with CVS during the peri-vasospasm period. While systemic inflammatory response syndrome, high C-reactive protein levels and leukocyte counts has been linked with the occurrence of CVS, less has been reported about cytokines levels in the jugular bulb of the internal jugular vein and in the peripheral blood. Preliminary evaluation of own data suggests, that IL-6 values in the peripheral blood and the arterio-jugular differences of IL-6 are increased with the inflammatory response after SAH.

CONCLUSION

Monitoring of the inflammatory response, in particular IL-6, might be a useful tool for the daily clinical management of patients with SAH and CVS.

Impact of systemic inflammatory response syndrome on vasospasm, cerebral infarction, and outcome after subarachnoid hemorrhage: exploratory analysis of CONSCIOUS-1 database

BACKGROUND

Systemic inflammatory response syndrome (SIRS) may develop after aneurysmal subarachnoid hemorrhage (SAH). We investigated factors associated with SIRS after SAH, whether SIRS was associated with complications of SAH such as vasospasm, cerebral infarction, and clinical outcome, and whether SIRS could contribute to a difference in outcome between patients treated by endovascular coiling or neurosurgical clipping of the ruptured aneurysm.

METHODS

This was exploratory analysis of 413 patients in the CONSCIOUS-1 study. SIRS was diagnosed if the patient had at least 2 of 4 variables (hypothermia/fever, tachycardia, tachypnea, and leukocytosis/leukopenia) within 4 days of admission. Clinical outcome was measured on the Glasgow outcome scale 3 months after SAH. The relationship between clinical and radiologic variables and SIRS, angiographic vasospasm, delayed ischemic neurologic deficit (DIND), cerebral infarction, vasospasm-related infarction, and clinical outcome were modeled with uni- and multivariable analyses.

RESULTS

63% of patients developed SIRS. Many factors were associated with SIRS in univariate analysis, but only poor WFNS grade and pneumonia were independently associated with SIRS in multivariable analysis. SIRS burden (number of SIRS variables per day over the first 4 days) was associated with poor outcome, but not with angiographic vasospasm, DIND, or cerebral infarction. The method of aneurysm treatment was not associated with SIRS.

CONCLUSION

SIRS was associated with poor outcome but not angiographic vasospasm, DIND, or cerebral infarction after SAH in the CONSCIOUS-1 data. There was no support for the notion that neurosurgical clipping is associated with a greater risk of SIRS than endovascular coiling.

Fever increased in-hospital mortality after subarachnoid hemorrhage

OBJECTIVE

Fever is a common clinical complication in patients with subarachnoid hemorrhage (SAH), and is usually related to prognosis in early stage of diseases. In our study, we try to help improve the outcome of SAH by assessing possible risk factors for fever and investigating the influence of fever on in-hospital mortality.

METHODS

Fever was defined as axillary temperature above 38.3°C appearing at least two times (not in the same day). One hundred and fifty-five patients with SAH were divided into febrile group and afebrile group. The following data were documented: patient demographics, clinical grade on admission Glasgow Coma Scale score, Hunt-Hess grade), conscious state on admission, presence of seizure, imaging assessment, admission glucose levels and plasma electrolytes levels. Univariate analysis and multivariate logistic regression analysis were used to determine factors associated with fever or in-hospital mortality.

RESULTS

Forty-one percent of patients with SAH developed fever. As determined by univariate analysis, older age, history of hypertension, Glasgow Coma Scale score, Hunt-Hess grade, Fisher CT grade, conscious state on admission, presence of intraventricular hemorrhage (IVH), admission glucose levels and plasma electrolytes levels were factors for fever. Multivariate analysis indicated that three factors independently predicted the occurrence of fever: poor Hunt-Hess grade (OR 5.37, 95% CI 1.56-18.44), presence of IVH (OR 5.18, 95% CI 1.43-18.85) and older age (OR 1.06, 95% CI 1.02-1.09). In-hospital mortality after SAH was associated with fever (OR 17.36, 95% CI 4.47-67.35), consciousness disorders on admission (OR 5.89, 95% CI 1.16-29.89) and older age (OR 1.07, 95% CI 1.00-1.13).

CONCLUSIONS

Poor Hunt-Hess grade, presence of IVH and older age are independent predictors of fever in SAH. Fever is closely related to increased in-hospital mortality after SAH.

Temperature patterns in the early postresuscitation period after pediatric inhospital cardiac arrest

OBJECTIVE

To describe the prevalence of postarrest hyperthermia among children during the first 24 hrs after inhospital cardiac arrest and to determine the association of persistent postarrest hyperthermia with neurologic outcome and death before hospital discharge.

DESIGN

Multicenter, national registry of inhospital cardiopulmonary resuscitation.

SETTING

A total of 196 hospitals reporting to the American Heart Association's National Registry of Cardiopulmonary Resuscitation from January 1, 2005 to December 31, 2007.

PATIENTS

A total of 547 pediatric patients who suffered inhospital pulseless cardiac arrests reported to the National Registry of Cardiopulmonary Resuscitation, who survived resuscitative efforts and who had the maximum and the minimum temperature in the first 24 hrs postresuscitation reported to the National Registry of Cardiopulmonary Resuscitation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 547 children with pulseless cardiac arrests, 238 (43.5%) had at least one temperature of ≥38°C, and 30 (5.5%) had "persistent hyperthermia" (i.e., both the minimum and the maximum temperature of ≥38°C) during the first 24 hrs postarrest. After adjusting for potential confounders by multivariate logistic regression, persistent hyperthermia in the first 24 hrs postarrest was associated with unfavorable neurologic outcome (adjusted odds ratio, 2.7; 95% confidence interval, 1.1-6.7), but not with death before hospital discharge (adjusted odds ratio, 1.2; 95% confidence interval, 0.4-3.4).

CONCLUSIONS

Despite current guidelines to avoid postarrest hyperthermia, a temperature of ≥38°C occurred commonly among children in the first 24 hrs postarrest. Persistent postarrest hyperthermia was associated with unfavorable neurologic outcomes, even after controlling for potential confounding factors.

Current and future treatment considerations in the management of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a type of hemorrhagic stroke that can cause significant morbidity and mortality. Although guidelines have been published to help direct the care of these patients, there is insufficient quality literature regarding the medical and pharmacological management of patients with aSAH. Treatment is divided into 3 categories: supportive therapy, prevention of complications, and treatment of complications. There are numerous pharmacological therapies that are targeted at prevention and treatment of the neurological and medical complications that may arise. Rebleeding, hydrocephalus, cerebral vasospasm, and seizures are the most common neurological complications while the most common medical complications include hyponatremia, pulmonary edema, cardiac arrhythmias, neurogenic stunned myocardium, fever, anemia, infection, hyperglycemia, and venous thromboembolism. Risk factors, clinical presentation, diagnosis, pathophysiology, as well as initial management, prevention, and treatment of complications will be the focus of this discussion.

Inflammation and cerebral vasospasm after subarachnoid hemorrhage

Morbidity and mortality of patients with aneurysmal subarachnoid hemorrhage (aSAH) is significantly related to the development of chronic cerebral vasospasm. Despite extensive clinical and experimental research, the pathophysiology of the events that result in delayed arterial spasm is not fully understood. A review of the published literature on cerebral vasospasm that included but was not limited to all PubMed citations from 1951 to the present was performed. The findings suggest that leukocyte-endothelial cell interactions play a significant role in the pathophysiology of cerebral vasospasm and explain the clinical variability and time course of the disease. Experimental therapeutic targeting of the inflammatory response when timed correctly can prevent vasospasm, and supplementation of endothelial relaxation by nitric oxide-related therapies and other approaches could result in reversal of the arterial narrowing and improved outcomes in patients with aSAH.

Medical complications after subarachnoid hemorrhage

The prevention and management of medical complications are important for improving outcomes after subarachnoid hemorrhage (SAH). Fever, anemia requiring transfusion, hyperglycemia, hyponatremia, pneumonia, hypertension, and neurogenic cardiopulmonary dysfunction occur frequently after SAH. There is increasing evidence that acute hypoxia and extremes of blood pressure can exacerbate brain injury during the acute phase of bleeding. There are promising strategies to minimize these complications. Randomized controlled trials are needed to evaluate the risks and benefits of these and other medical management strategies after SAH.

Biomarkers and vasospasm after aneurysmal subarachnoid hemorrhage

Subarachnoid hemorrhage from the rupture of a saccular aneurysm is a devastating neurological disease that has a high morbidity and mortality not only from the initial hemorrhage, but also from the delayed complications, such as cerebral vasospasm. Cerebral vasospasm can lead to delayed ischemic injury 1 to 2 weeks after the initial hemorrhage. Although the pathophysiology of vasospasm has been described for decades, the molecular basis remains poorly understood. With the many advances in the past decade in the development of sensitive molecular biological techniques, imaging, biochemical purification, and protein identification, new insights are beginning to reveal the etiology of vasospasm. These findings will not only help to identify markers of vasospasm and prognostic outcome, but will also yield potential therapeutic targets for the treatment of this disease. This review focuses on the methods available for the identification of biological markers of vasospasm and their limitations, the current understanding as to the utility and prognostic significance of identified biomarkers, the utility of these biomarkers in predicting vasospasm and outcome, and future directions of research in this field.

Induced hypothermia for trauma: current research and practice

Induction of hypothermia with the goal of providing therapeutic benefit has been accepted for use in the clinical setting of adult cardiac arrest and neonatal hypoxic-ischemic encephalopathy (HIE). However, its potential as a treatment in trauma is not as well defined. This review discusses potential benefits and complications of induced hypothermia (IH) with emphasis on the current state of knowledge and practice in various types of trauma. There is excellent preclinical research showing that in cases of penetrating trauma with cardiac arrest, inducing hypothermia to 10 degrees C using cardiopulmonary bypass (CPB) could possibly save those otherwise likely to die without causing neurologic sequelae. A human trial of this intervention is about to get underway. Preclinical studies suggest that inducing hypothermia may be useful to delay cardiac arrest in penetrating trauma victims who are hypotensive. There is potential for IH to be used in cases of blunt trauma, but it has not been well studied. In the case of traumatic brain injury (TBI), clinical trials have shown conflicting results, despite almost uniform efficacy seen in preclinical experiments. Major studies are analyzed and ways to standardize its use and optimize future clinical trials are discussed. More preclinical and clinical research is needed to better define whether there could be a role for IH in the case of spinal cord injuries.