Therapeutic Hypothermia in Stroke and Traumatic Brain Injury

Therapeutic hypothermia (TH) is considered to improve survival with favorable neurological outcome in the case of global cerebral ischemia after cardiac arrest and perinatal asphyxia. The efficacy of hypothermia in acute ischemic stroke (AIS) and traumatic brain injury (TBI), however, is not well studied. Induction of TH typically requires a multimodal approach, including the use of both pharmacological agents and physical techniques. To date, clinical outcomes for patients with either AIS or TBI who received TH have yielded conflicting results; thus, no adequate therapeutic consensus has been reached. Nevertheless, it seems that by determining optimal TH parameters and also appropriate applications, cooling therapy still has the potential to become a valuable neuroprotective intervention. Among the various methods for hypothermia induction, intravascular cooling (IVC) may have the most promise in the awake patient in terms of clinical outcomes. Currently, the IVC method has the capability of more rapid target temperature attainment and more precise control of temperature. However, this technique requires expertise in endovascular surgery that can preclude its application in the field and/or in most emergency settings. It is very likely that combining neuroprotective strategies will yield better outcomes than utilizing a single approach

Spontaneous intracerebral hemorrhage: A pediatric case of undetermined etiology and review of literature

Cerebrovascular disorders, particularly intracerebral hemorrhage (ICH), rarely occur in children. The most common underlying cause for ICH in the pediatric population is arteriovenous malformation (AVM). The best approach to diagnostic evaluation of pediatric ICH is unknown due to its low incidence (2-3/100,000 children). In recent years, early discovery of underlying cause of pediatric ICH has been possible due to a more widespread use of imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI) and digital subtraction angiography (DSA). We report a case of a 5-year-old boy with a ICH of unknown etiology. He presented with left hemiparesis and left facial droop for one hour. Noncontrast CT scan demonstrated right periventricular hematoma extending to all ventricles. Follow-up MRI, CT angiography and DSA were unremarkable. Laboratory findings including liver function tests, hematologic studies were normal. Screening for hemoglobinopathies was negative. Transthoracic echocardiography was unremarkable. Surgery for ventricular drain placement and intense physical therapy were performed. During the follow ups at 1 and 6 mo of initial admission, repeat brain MRI and magnetic resonance angiography were unremarkable. The complete diagnostic evaluation in children presenting with ICH of undetermined origin is critically important, but still the etiology may not be identified in some cases. AsAVMs are the most common cause of ICH in children and may rarely regress following hemorrhage, our patient's normal follow-up imaging may be related to such a spontaneous thrombosis of an underlying AVM

Untreated hypertension as predictor of in-hospital mortality in intracerebral hemorrhage: A multi-center study

PURPOSE: Hypertension is a significant risk factor for intracerebral hemorrhage (ICH). The importance of managing blood pressure to reduce the risk of ICH has been recognized. However, few studies have focused on ICH outcomes due to untreated hypertension. MATERIALS AND METHODS: We conducted a 5-year, retrospective, multicenter study of 490 consecutive ICH patients with histories of untreated-hypertension (n=56), treated-hypertension (n=314), and normotension (n=120). Demographics, symptom onset, vital signs, laboratory tests, and CT imaging were documented alongside in-hospital treatments, complications, and length of stay. RESULTS: Untreated-hypertension subjects were found to be significantly younger than treated-hypertension. They were found to have lower rates of anticoagulant use (p\u3c0.01), antiplatelet use (p\u3c0.01), and hyperlipidemia (p\u3c0.01) than subjects with treated-hypertension. In a multivariate model, untreated-hypertension, age ≥65years, ≥3 outpatient antihypertensive medications, and hematoma volumes ≥30ml were all associated with significantly increased in-hospital mortality. In contrast, mortality was lower in patients receiving ≥3 antihypertensive medications while in-hospital. CONCLUSIONS: Subjects with untreated-hypertension were younger and had fewer comorbidities when compared with treated-hypertension and were similar when compared to normotensive individuals. Once demographic and in-hospital factors were accounted for, untreated-hypertension subjects demonstrated significantly increased in-hospital mortality following ICH when compared with normotensive individuals

Serum magnesium level and hematoma expansion in patients with intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is a devastating subtype of stroke that results in significant rates of mortality and morbidities. The initial hematoma volume, hematoma expansion (HE), blood pressure (BP), and coagulopathy are considered strong predictors of clinical outcomes and mortality. Low serum magnesium (Mg(++)) levels have been shown to be associated with larger initial hematoma and greater HE. Coagulopathy, platelet dysfunction, high BP, and increased inflammatory response might form the mechanistic link between low serum Mg(++) levels, larger hematoma size and greater HE. However, randomized clinical trials administering intravenous Mg(++) have shown no benefit over placebo in ICH patients. The confounding effect of hypocalcemia and a delay in Mg(++) trafficking across the blood-brain barrier might explain the futile results for intravenous Mg(++) therapy. In the current review, we will discuss the evidence regarding the possible role of low serum Mg(++) level on HE in acute ICH

Exploration of Multiparameter Hematoma 3D Image Analysis for Predicting Outcome After Intracerebral Hemorrhage

BACKGROUND: Rapid diagnosis and proper management of intracerebral hemorrhage (ICH) play a crucial role in the outcome. Prediction of the outcome with a high degree of accuracy based on admission data including imaging information can potentially influence clinical decision-making practice. METHODS: We conducted a retrospective multicenter study of consecutive ICH patients admitted between 2012-2017. Medical history, admission data, and initial head computed tomography (CT) scan were collected. CT scans were semiautomatically segmented for hematoma volume, hematoma density histograms, and sphericity index (SI). Discharge unfavorable outcomes were defined as death or severe disability (modified Rankin Scores 4-6). We compared (1) hematoma volume alone; (2) multiparameter imaging data including hematoma volume, location, density heterogeneity, SI, and midline shift; and (3) multiparameter imaging data with clinical information available on admission for ICH outcome prediction. Multivariate analysis and predictive modeling were used to determine the significance of hematoma characteristics on the outcome. RESULTS: We included 430 subjects in this analysis. Models using automated hematoma segmentation showed incremental predictive accuracies for in-hospital mortality using hematoma volume only: area under the curve (AUC): 0.85 [0.76-0.93], multiparameter imaging data (hematoma volume, location, CT density, SI, and midline shift): AUC: 0.91 [0.86-0.97], and multiparameter imaging data plus clinical information on admission (Glasgow Coma Scale (GCS) score and age): AUC: 0.94 [0.89-0.99]. Similarly, severe disability predictive accuracy varied from AUC: 0.84 [0.76-0.93] for volume-only model to AUC: 0.88 [0.80-0.95] for imaging data models and AUC: 0.92 [0.86-0.98] for imaging plus clinical predictors. CONCLUSIONS: Multiparameter models combining imaging and admission clinical data show high accuracy for predicting discharge unfavorable outcome after ICH

Quantitative MRI volumetry, diffusivity, cerebrovascular flow and cranial hydrodynamics during head down tilt and hypercapnia: the SPACECOT study.

To improve the pathophysiological understanding of visual changes observed in astronauts, we aimed to use quantitative MRI to measure anatomic and physiological responses during a ground-based spaceflight analog (head-down tilt, HDT) combined with increased ambient carbon dioxide (CO2). Six healthy, male subjects participated in the double-blinded, randomized crossover design study with two conditions: 26.5 h of -12 degrees HDT with ambient air and with 0.5% CO2, both followed by 2.5-h exposure to 3% CO2. Volume and mean diffusivity quantification of the lateral ventricle and phase-contrast flow sequences of the internal carotid arteries and cerebral aqueduct were acquired at 3 T. Compared with supine baseline, HDT (ambient air) resulted in an increase in lateral ventricular volume (P = 0.03). Cerebral blood flow, however, decreased with HDT in the presence of either ambient air or 0.5% CO2 (P = 0.002 and P = 0.01, respectively); this was partially reversed by acute 3% CO2 exposure. Following HDT (ambient air), exposure to 3% CO2 increased aqueductal cerebral spinal fluid velocity amplitude (P = 0.01) and lateral ventricle cerebrospinal fluid (CSF) mean diffusivity (P = 0.001). We concluded that HDT causes alterations in cranial anatomy and physiology that are associated with decreased craniospinal compliance. Brief exposure to 3% CO2 augments CSF pulsatility within the cerebral aqueduct and lateral ventricles. NEW & NOTEWORTHY Head-down tilt causes increased lateral ventricular volume and decreased cerebrovascular flow after 26.5 h. Additional short exposure to 3% ambient carbon dioxide levels causes increased cerebrovascular flow associated with increased cerebrospinal fluid pulsatility at the cerebral aqueduct. Head-down tilt with chronically elevated 0.5% ambient carbon dioxide and acutely elevated 3% ambient carbon dioxide causes increased mean diffusivity of cerebral spinal fluid within the lateral ventricles

Effects of-12 degrees head-down tilt with and without elevated levels of CO2 on cognitive performance: the SPACECOT study

Microgravity and elevated levels of CO2 are two common environmental stressors in spaceflight that may affect cognitive performance of astronauts. In this randomized, double-blind, crossover trial (SPACECOT), 6 healthy males (mean +/- SD age: 41 +/- 5 yr) were exposed to 0.04% (ambient air) and 0.5% CO2 concentrations during 26.5-h periods of -12 degrees head-down tilt (HDT) bed rest with a 1-wk washout period between exposures. Subjects performed the 10 tests of the Cognition Test Battery before and on average 0.1, 5.2, and 21.0 h after the initiation of HDT bed rest. HDT in ambient air induced a change in response strategy, with increased response speed (+0.19 SD; P = 0.0254) at the expense of accuracy (-0.19 SD; P = 0.2867), resulting in comparable cognitive efficiency. The observed effects were small and statistically significant for cognitive speed only. However, even small declines in accuracy can potentially cause errors during missioncritical tasks in spaceflight. Unexpectedly, exposure to 0.5% CO2 reversed the response strategy changes observed under HDT in ambient air. This was possibly related to hypercapnia-induced cerebrovascular reactivity that favors cortical regions in general and the frontal cortex in particular, or to the CNS arousing properties of mildly to moderately increased CO2 levels. There were no statistically significant time-in-CO2 effects for any cognitive outcome. The small sample size and the small effect sizes are major limitations of this study and its findings. The results should not be generalized beyond the group of investigated subjects until they are confirmed by adequately powered follow-up studies. NEW & NOTEWORTHY Simulating microgravity with exposure to 21 h of -12 degrees head-down tilt bed rest caused a change in response strategy on a range of cognitive tests, with a statistically significant increase in response speed at the expense of accuracy. Cognitive efficiency was not affected. The observed speed-accuracy tradeoff was small but may nevertheless be important for mission-critical task