Transient focal increase in perihematomal glucose metabolism after acute human intracerebral hemorrhage

The persisting burden of intracerebral haemorrhage: can effective treatments be found?

Colin Josephson, Rustam Al-Shahi Salman, and colleagues discuss the effectiveness of treatments for intracerebral haemorrhage.

Intensive care management of acute stroke: surgical treatment

Controversy still exists on surgical management of acute stroke. Even if surgical therapy represents often a life-saving measure, the issue of acceptable outcome remains open. Persuasive evidence for outcome benefit is limited. For large ischaemic strokes, recent convincing data suggest that decompressive surgery significantly reduces mortality and improves outcome quality. On the other hand, despite the long tradition in surgical removal of intracranial haematomas, the recent evidence has not been sufficient to resolve the basic argument whether to operate or not. Most recently, hopeful preliminary data have emerged on new approaches in the treatment of intraventricular haemorrhage. In this article, we review the current neurosurgical options in acute ischaemic and haemorrhagic stroke.

Do current animal models of intracerebral hemorrhage mirror the human pathology?

Although intracerebral hemorrhage (ICH) has no proven treatment, well-designed studies using animal models of ICH may lead to the development of novel therapies. We briefly review current animal models of ICH. Furthermore, we discuss how these models may be utilized and targeted to facilitate translation of preclinical findings to the clinical arena.

Dynamic metabolic response to multiple spreading depolarizations in patients with acute brain injury: an online microdialysis study

Spreading depolarizations (SDs) occur spontaneously with high incidence in patients with acute brain injury. They can be detected by subdural electrocorticographic recordings. We here characterize the dynamic metabolic response to these events. A microdialysis catheter was inserted into perilesional cortical tissue adjacent to a strip for electrocorticography following craniotomy in 10 patients. The microdialysis catheter was connected to an online microdialysis assay measuring glucose and lactate concentrations every 30 to 60 secs. Spontaneously occurring SDs systematically caused a reduction in dialysate glucose by -32.0 micromol/L (range: -92.3 to -18.4 micromol/L, n=90) and increase in lactate by +23.1 micromol/L (range: +5.5 to +93.6 micromol/L, n=49). The changes were sustained at 20 mins after the SD events and highly significant using an area under the curve analysis (P<0.0001). Multiple and frequent SDs led to a progressive stepwise depletion of brain glucose. Hence, SD events cause a massive energy imbalance and their frequent occurrence leads to a local insufficiency of glucose supply. Such a failure would compromise cellular repolarization and hence tissue viability. The findings offer a new mechanism to account for otherwise unexplained instances of depletion of brain microdialysate glucose.

Autoregulation and brain metabolism in the perihematomal region of spontaneous intracerebral hemorrhage: an observational pilot study

The metabolic and hemodynamic processes in the edema surrounding spontaneous, supratentorial intracerebral hemorrhage (ICH) are poorly understood. Specifically, the local metabolic effects of autoregulatory failure have not been described previously. In the current observational pilot study, microdialysis and brain tissue oxygenation probes (P(br)O(2)) were placed in the perihemorrhagic edema using neuronavigation in five non-surgically treated patients with deep ICH. The cerebrovascular pressure reactivity index (PRx, moving correlation between mean arterial and intracranial pressure) and P(br)O(2) reactivity index (ORx, correlation between P(br)O(2) and cerebral perfusion pressure) were used to characterize cerebral autoregulation. While all five patients had ORx values indicative for severely disturbed autoregulation, assessment of PRx only in one patient was consistent with sustained failure of cerebrovascular reactivity. This patient at the same time had the worst metabolic parameters and the poorest tissue oxygenation. We conclude that multimodality monitoring in the perihemorrhagic penumbra is feasible. A study in a larger population is needed to clarify the relationship between PRx and ORx in ICH patients, the local metabolic effects of autoregulatory failure and its relation to brain edema formation and clinical outcome.

Anaemia and its treatment in neurologically critically ill patients: being reasonable is easy without prospective trials

Most healthy humans have a haemoglobin concentration of 12 to 15 g/dL and most intensivists now transfuse packed red blood cells for haemoglobin <7 g/dL. Higher haemoglobin is associated with improved intermediate and clinical outcomes after subarachnoid hemorrhage (from ruptured brain aneurysm) or neurotrauma. An observational study in a recent issue shows that higher haemoglobin was associated with better functional outcomes in patients with spontaneous intracerebral haemorrhage; few patients received a packed red blood cell transfusion, so it is not known if that treatment is better than the disease. The mechanism of anaemia's purported impact on outcome is unclear, although altered metabolism in brain tissue that is sensitive to reduced oxygen delivery is plausible. These data may intensify the differences of opinion between intensivists: whether neurologic patients are better served by higher haemoglobin and potentially by more packed red blood cell transfusion, or simply need to be studied more in prospective clinical trials, remains unclear.

Low hemoglobin is associated with poor functional outcome after non-traumatic, supratentorial intracerebral hemorrhage

Introduction

The impact of anemia on functional outcome and mortality in patients suffering from non-traumatic intracerebral hemorrhage (ICH) has not been investigated. Here, we assessed the relationship between hemoglobin (HB) levels and clinical outcome after ICH.

Methods

One hundred and ninety six patients suffering from supratentorial, non-traumatic ICH were extracted from our local stroke database (June 2004 to June 2006). Clinical and radiologic computed tomography data, HB levels on admission, mean HB values and nadir during hospital stay were recorded. Outcome was assessed at discharge and 3 months using the modified Rankin score (mRS).

Results

Forty six (23.5%) patients achieved a favorable functional outcome (mRS ≤ 3) and 150 (76.5%) had poor outcome (mRS 4 - 6) at discharge. Patients with poor functional outcome had a lower mean HB (12.3 versus 13.7 g/dl, P < 0.001) and nadir HB (11.5 versus 13.0 g/dl, P < 0.001). Ten patients (5.1%) received red blood cell (RBC) transfusions. In a multivariate logistic regression model, the mean HB was an independent predictor for poor functional outcome at three months (odds ratio (OR) 0.73, 95% confidence interval (CI) 0.58-0.92, P = 0.007), along with National Institute of Health Stroke Scale (NIHSS) at admission (OR 1.17, 95% CI 1.11 - 1.24, P < 0.001), and age (OR 1.08, 95% CI 1.04 - 1.12, P < 0.001).

Conclusions

We report an association between low HB and poor outcome in patients with non-traumatic, supratentorial ICH. While a causal relationship could not be proven, previous experimental studies and studies in brain injured patients provide evidence for detrimental effects of anemia on brain metabolism. However, the potential risk of anemia must be balanced against the risk of harm from red blood cell infusion.

PET in Cerebrovascular Disease

Investigation of the interplay between the cerebral circulation and brain cellular function is fundamental to understanding both the pathophysiology and treatment of stroke. Currently, PET is the only technique that provides accurate, quantitative in vivo regional measurements of both cerebral circulation and cellular metabolism in human subjects. We review normal human cerebral blood flow and metabolism and human PET studies of ischemic stroke, carotid artery disease, vascular dementia, intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage and discuss how these studies have added to our understanding of the pathophysiology of human cerebrovascular disease.