Custom-tailored hemodilution with albumin and crystalloids in acute ischemic stroke

Albumin Levels and Risk of Early Cardiovascular Complications After Ischemic Stroke: A Propensity-Matched Analysis of a Global Federated Health Network

BACKGROUND

No studies have investigated the association between albumin levels and the risk of early cardiovascular complications in patients with ischemic stroke.

METHODS

Retrospective analysis with a federated research network (TriNetX) based on electronic medical records (International Classification of Diseases-Tenth Revision-Clinical Modification and logical observation identifiers names and codes) mainly reported between 2000 and 2023, from 80 health care organizations in the United States. Based on albumin levels measured at admission to the hospital, patients with ischemic stroke were categorized into 2 groups: (1) reduced (≤3.4 g/dL) and (2) normal (≥3.5 g/dL) albumin levels. The primary outcome was a composite of all-cause death, heart failure, atrial fibrillation, ventricular arrhythmias, myocardial infarction, and Takotsubo cardiomyopathy 30 days from the stroke. Secondary outcomes were the risk for each component of the primary outcome. Cox regression analyses were used to calculate hazard ratios (HRs) and 95% CIs following propensity score matching.

RESULTS

Overall, 320 111 patients with stroke had normal albumin levels (70.9±14.7 years; 48.9% females) and 183 729 (57.4%) had reduced albumin levels (72.9±14.3 years; 50.3% females). After propensity score matching, the primary outcomes occurred in 36.0% of patients with reduced and 26.1% with normal albumin levels (HR, 1.48 [95% CI, 1.46-1.50]). The higher risk in patients with reduced albumin levels was consistent also for all-cause death (HR, 2.77 [95% CI, 2.70-2.84]), heart failure (HR, 1.31 [95% CI, 1.29-1.34]), atrial fibrillation (HR, 1.11 [95% CI, 1.09-1.13]), ventricular arrhythmias (HR, 1.38 [95% CI, 1.30-1.46]), myocardial infarction (HR, 1.60 [95% CI, 1.54-1.65]), and Takotsubo cardiomyopathy (HR, 1.51 [95% CI, 1.26-1.82]). The association between albumin levels and the risk of cardiovascular events was independent of advanced age, sex, multimorbidity, and other causes of hypoalbuminemia. A progressively increased risk of adverse events was found in patients with mild and severe reduced compared to normal albumin levels.

CONCLUSIONS

Albumin levels are associated with the risk of early cardiovascular events and death in patients with ischemic stroke. The potential pathophysiological or therapeutic roles of albumin in patients with stroke warrant further investigation.

Adjunctive cytoprotective therapies in acute ischemic stroke: a systematic review

With the introduction of endovascular thrombectomy (EVT), a new era for treatment of acute ischemic stroke (AIS) has arrived. However, despite the much larger recanalization rate as compared to thrombolysis alone, final outcome remains far from ideal. This raises the question if some of the previously tested neuroprotective drugs warrant re-evaluation, since these compounds were all tested in studies where large-vessel recanalization was rarely achieved in the acute phase. This review provides an overview of compounds tested in clinical AIS trials and gives insight into which of these drugs warrant a re-evaluation as an add-on therapy for AIS in the era of EVT. A literature search was performed using the search terms "ischemic stroke brain" in title/abstract, and additional filters. After exclusion of papers using pre-defined selection criteria, a total of 89 trials were eligible for review which reported on 56 unique compounds. Trial compounds were divided into 6 categories based on their perceived mode of action: systemic haemodynamics, excitotoxicity, neuro-inflammation, blood-brain barrier and vasogenic edema, oxidative and nitrosative stress, neurogenesis/-regeneration and -recovery. Main trial outcomes and safety issues are summarized and promising compounds for re-evaluation are highlighted. Looking at group effect, drugs intervening with oxidative and nitrosative stress and neurogenesis/-regeneration and -recovery appear to have a favourable safety profile and show the most promising results regarding efficacy. Finally, possible theories behind individual and group effects are discussed and recommendation for promising treatment strategies are described.

Albumin therapy for acute ischemic stroke: a meta-analysis

Human serum albumin has shown remarkable efficacy in rodent models of ischemic stroke, while results from relevant clinical research on albumin therapy remain controversial. We conducted a meta-analysis of published studies to quantitatively analyze the neurofunctional outcomes of patients with ischemic stroke treated with albumin. PubMed, Embase, and Cochrane Library were searched in July 2020. A total of four studies and 1611 patients were included. The aggregated results indicated that there were 635 patients with good neurological outcomes, among which 321 patients were in the albumin group (39.8%) and 314 patients in the control group (39.1%), showing no statistically significant difference between the albumin and control groups (OR = 1.04, 95% CI 0.85-1.27). The results suggest that albumin therapy at the acute stage of ischemic stroke has no beneficial effect on the long-term neurological function of patients with ischemic stroke. Considering pulmonary edema and other complications are more likely to occur in such patients after albumin infusion, the administration of albumin therapy for acute ischemic stroke should be done with utmost caution.

Volume of Plasma Expansion and Functional Outcomes in Stroke

BACKGROUND

Plasma expansion in acute ischemic stroke has potential to improve cerebral perfusion, but the long-term effects on functional outcome are mixed in prior trials. The goal of this study was to evaluate how the magnitude of plasma expansion affects neurological recovery in acute stroke.

METHODS

This was a secondary analysis of data from the Albumin in Acute Stroke Part 2 trial investigating the relationship between the magnitude of overall intravenous volume infusion (crystalloid and colloid) to clinical outcome. The data were inclusive of 841 patients with a mean age of 64 years and a median National Institutes of Health Stroke Scale (NIHSS) of 11. In a multivariable-adjusted logistic regression model, this analysis tested the volume of plasma expansion over the first 48 h of hospitalization as a predictor of favorable outcome, defined as either a modified Rankin Scale score of 0 or 1 or a NIHSS score of 0 or 1 at 90 days. This model included all study patients, irrespective of albumin or isotonic saline treatment.

RESULTS

Patients that received higher volumes of plasma expansion more frequently had large vessel ischemic stroke and higher NIHSS scores. The multivariable-adjusted model revealed that there was decreased odds of a favorable outcome for every 250 ml additional volume plasma expansion over the first 48 h (OR 0.91, 95 % CI, 0.88-0.94).

CONCLUSIONS

The present study demonstrates an association between greater volume of plasma expansion and worse neurological recovery.

Repeated Oral Administration of Human Serum Albumin Protects from the Cerebral Ischemia in Rat Brain Following MCAO

Albumin is known to have neuroprotective effects. The protein has a long half-life circulation, and its effects can therefore persist for a long time to aid in the recovery of brain ischemia. In the present study, we investigated the neuroprotective effects of human serum albumin (HSA) on brain hemodynamics. Albumin is administrated using repeated oral gavage to the rodents. Sprague-Dawley rats underwent middle cerebral artery occlusion procedures and served as a stroke model. Afterwards, 25% human serum albumin (1.25 g/kg) or saline (5 ml/kg) was orally administrated for 2 weeks in alternating days. After 2 weeks, the rodents were assessed for levels of brain ischemia. Our testing battery consists of behavioral tests and in vivo optical imaging sessions. Modified neurological severity scores (mNSS) were obtained to assess the levels of ischemia and the effects of HSA oral administration. We found that the experimental group demonstrated larger hemodynamic responses following sensory stimulation than controls that were administered with saline. HSA administration resulted in more significant changes in cerebral blood volume following direct cortical electric stimulation. In addition, the mNSS of the treatment group was lower than the control group. In particular, brain tissue staining revealed that the infarct size was also much smaller with HSA administration. This study provides support for the efficacy of HSA, and that long-term oral administration of HSA may induce neuroprotective effects against brain ischemia.

Neuroprotective strategies and the underlying molecular basis of cerebrovascular stroke

Stroke is a leading cause of disability in the US. Although there has been significant progress in the area of medical and surgical thrombolytic technologies, neuroprotective agents to prevent secondary cerebral injury and to minimize disability remain limited. Only limited success has been reported in preclinical and clinical trials evaluating a variety of compounds. In this review, the authors discuss the most up-to-date information regarding the underlying molecular biology of stroke as well as strategies that aim to mitigate this complex signaling cascade. Results of historical research trials involving N-methyl-d-aspartate and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonists, clomethiazole, antioxidants, citicoline, nitric oxide, and immune regulators have laid the groundwork for current progress. In addition, more recent studies involving therapeutic hypothermia, magnesium, albumin, glyburide, uric acid, and a variety of other treatments have provided more options. The use of neuroprotective agents in combination or with existing thrombolytic treatments may be one of many exciting areas of further development. Although past trials of neuroprotective agents in ischemic stroke have been limited, significant insights into mechanisms of stroke, animal models, and trial design have incrementally improved approaches for future therapies.

Monitoring of hematological and hemostatic parameters in neurocritical care patients

Anemia and bleeding are paramount concerns in neurocritical care and often relate to the severity of intracranial hemorrhage. Anemia is generally associated with worse outcomes, and efforts to minimize anemia through reduced volume of blood sampled are encouraged. Point-of-care-testing reliably detects the use of non-steroidal anti-inflammatory drugs that may worsen bleeding and reduce platelet activity, particularly in patients with intracerebral hemorrhage. How best to monitor the effect of platelet transfusion or platelet-activating therapy is not well studied. For patients known to take novel oral anticoagulants, drug-specific coagulation tests before neurosurgical intervention are prudent.

Parenteral fluid regimens for improving functional outcome in people with acute stroke

BACKGROUND

Parenteral fluids are commonly used in people with acute stroke with poor oral fluid intake. However, the balance between benefit and harm for different fluid regimens is unclear.

OBJECTIVES

To assess whether different parenteral fluid regimens lead to differences in death, or death or dependence, after stroke based on fluid type, fluid volume, duration of fluid administration, and mode of delivery.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effects (DARE) (Cochrane Library 2015, Issue 5), MEDLINE (2008 to May 2015), EMBASE (2008 to May 2015), and CINAHL (1982 to May 2015). We also searched ongoing trials registers (May 2015) and reference lists, performed cited reference searches, and contacted authors.

SELECTION CRITERIA

Randomised trials of parenteral fluid regimens in adults with ischaemic or haemorrhagic stroke within seven days of stroke onset that reported death or dependence.

DATA COLLECTION AND ANALYSIS

One review author screened titles and abstracts. We obtained the full-text articles of relevant studies, and two review authors independently selected trials for inclusion and extracted data. We used Cochrane's tool for bias assessment.

MAIN RESULTS

We included 12 studies (2351 participants: range 27 to 841).Characteristics: The 12 included studies compared hypertonic (colloids) with isotonic fluids (crystalloids); of these, five studies (1420 participants) also compared 0.9% saline with another fluid. No data were available to make other comparisons. Delay from stroke to recruitment varied from less than 24 hours to 72 hours. Duration of fluid delivery was between two hours and 10 days.Bias assessment: Investigators and participants in eight of the 12 included studies were blind to treatment allocation, seven of the 12 included studies gave details of randomisation, and eight of the 12 included studies reported all outcomes measured.

RESULTS

There were no relevant completed trials that addressed the effect of volume, duration, or mode of fluid delivery on death or dependence in people with stroke.The odds of death or dependence were similar in participants allocated to colloids or crystalloid fluid regimens (odds ratio (OR) 0.97, 95% confidence interval (CI) 0.79 to 1.21, five studies, I² = 58%, low-quality evidence), and between 0.9% saline or other fluid regimens (OR 1.04, 95% CI 0.82 to 1.32, three studies, I² = 71%, low-quality evidence). There was substantial heterogeneity in these estimates.The odds of death were similar between colloids and crystalloids (OR 1.02, 95% CI 0.82 to 1.27, 12 studies, I² = 24%, moderate-quality evidence), and 0.9% saline and other fluids (OR 0.87, 95% CI 0.67 to 1.12, five studies, I² = 53%, low-quality evidence). The odds of pulmonary oedema were higher in participants allocated to colloids (OR 2.34, 95% CI 1.28 to 4.29, I² = 0%). Although the studies observed a higher risk of cerebral oedema (OR 0.20, 95% CI 0.02 to 1.74) and pneumonia (OR 0.58, 95% CI 0.17 to 2.01) with crystalloids, we could not exclude clinically important benefits or harms.

AUTHORS' CONCLUSIONS

We found no evidence that colloids were associated with lower odds of death or dependence in the medium term after stroke compared with crystalloids, though colloids were associated with greater odds of pulmonary oedema. We found no evidence to guide the best volume, duration, or mode of parenteral fluid delivery for people with acute stroke.

Haemodilution for acute ischaemic stroke

BACKGROUND

Ischaemic stroke interrupts the flow of blood to part of the brain. Haemodilution is thought to improve the flow of blood to the affected areas of the brain and thus reduce infarct size.

OBJECTIVES

To assess the effects of haemodilution in acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (February 2014), the Cochrane Central Register of Controlled Trials (Issue 1, 2014), MEDLINE (January 2008 to October 2013) and EMBASE (January 2008 to October 2013). We also searched trials registers, scanned reference lists and contacted authors. For the previous version of the review, the authors contacted manufacturers and investigators in the field.

SELECTION CRITERIA

Randomised trials of haemodilution treatment in people with acute ischaemic stroke. We included only trials in which treatment was started within 72 hours of stroke onset.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and one review author extracted the data.

MAIN RESULTS

We included 21 trials involving 4174 participants. Nine trials used a combination of venesection and plasma volume expander. Twelve trials used plasma volume expander alone. The plasma volume expander was plasma alone in one trial, dextran 40 in 12 trials, hydroxyethyl starch (HES) in five trials and albumin in three trials. Two trials tested haemodilution in combination with another therapy. Evaluation was blinded in 14 trials. Five trials probably included some participants with intracerebral haemorrhage. Haemodilution did not significantly reduce deaths within the first four weeks (risk ratio (RR) 1.10; 95% confidence interval (CI) 0.90 to 1.34). Similarly, haemodilution did not influence deaths within three to six months (RR 1.05; 95% CI 0.93 to 1.20), or death and dependency or institutionalisation (RR 0.96; 95% CI 0.85 to 1.07). The results were similar in confounded and unconfounded trials, and in trials of isovolaemic and hypervolaemic haemodilution. No statistically significant benefits were documented for any particular type of haemodiluting agents, but the statistical power to detect effects of HES was weak. Six trials reported venous thromboembolic events. There was a tendency towards reduction in deep venous thrombosis or pulmonary embolism or both at three to six months' follow-up (RR 0.68; 95% CI 0.37 to 1.24). There was no statistically significant increased risk of serious cardiac events among haemodiluted participants.

AUTHORS' CONCLUSIONS

The overall results of this review showed no clear evidence of benefit of haemodilution therapy for acute ischaemic stroke.These results are compatible with no persuasive beneficial evidence of haemodilution therapy for acute ischaemic stroke. This therapy has not been proven to improve survival or functional outcome.

High-dose albumin treatment for acute ischaemic stroke (ALIAS) Part 2: a randomised, double-blind, phase 3, placebo-controlled trial

BACKGROUND

In animal models of ischaemic stroke, 25% albumin reduced brain infarction and improved neurobehavioural outcome. In a pilot clinical trial, albumin doses as high as 2 g/kg were safely tolerated. We aimed to assess whether albumin given within 5 h of the onset of acute ischaemic stroke increased the proportion of patients with a favourable outcome.

METHODS

We did a randomised, double-blind, parallel-group, phase 3, placebo-controlled trial between Feb 27, 2009, and Sept 10, 2012, at 69 sites in the USA, 13 sites in Canada, two sites in Finland, and five sites in Israel. Patients aged 18-83 years with ischaemic (ie, non-haemorrhagic) stroke with a baseline National Institutes of Health stroke scale (NIHSS) score of 6 or more who could be treated within 5 h of onset were randomly assigned (1:1), via a central web-based randomisation process with a biased coin minimisation approach, to receive 25% albumin (2 g [8 mL] per kg; maximum dose 750 mL) or the equivalent volume of isotonic saline. All study personnel and participants were masked to the identity of the study drug. The primary endpoint was favourable outcome, defined as either a modified Rankin scale score of 0 or 1, or an NIHSS score of 0 or 1, or both, at 90 days. Analysis was by intention to treat. Thrombolytic therapies were permitted. This trial is registered with ClinicalTrials.gov, number NCT00235495.

FINDINGS

422 participants were randomly assigned to receive albumin and 419 to receive saline. On Sept 12, 2012, the trial was stopped early for futility (n=841). The primary outcome did not differ between patients in the albumin group and those in the saline group (186 [44%] vs 185 [44%]; risk ratio 0·96, 95% CI 0·84-1·10, adjusted for baseline NIHSS score and thrombolysis stratum). Mild-to-moderate pulmonary oedema was more common in patients given albumin than in those given saline (54 [13%] of 412 vs 5 [1%] of 412 patients); symptomatic intracranial haemorrhage within 24 h was also more common in patients in the albumin group than in the placebo group (17 [4%] of 415 vs 7 [2%] of 414 patients). Although the rate of favourable outcome in patients given albumin remained consistent at 44-45% over the course of the trial, the cumulative rate of favourable outcome in patients given saline rose steadily from 31% to 44%.

INTERPRETATION

Our findings show no clinical benefit of 25% albumin in patients with ischaemic stroke; however, they should not discourage further efforts to identify effective strategies to protect the ischaemic brain, especially because of preclinical literature showing convincing proof-of-principle for the possibility of this outcome.

FUNDING

National Institute of Neurological Disorders and Stroke, US National Institutes of Health; and Baxter Healthcare Corporation.

Intraventricular albumin: an optional agent in experimental post-traumatic brain edema

HYPOTHESIS

Human albumin may be effective in the treatment of posttraumatic brain edema due to its hyperoncotic features. Therefore, the aim of the experimental study presented in this paper has two points: the first is to evaluate the efficacy of intraventricular hyperoncotic human albumin on post-traumatic brain edema and the second is to try to show the appropriate posttraumatic time window for albumin administration.

METHOD

Traumatic brain injury and subsequent edema was formed by a model of impact acceleration injury in rats. Human albumin was administered via intraventricular route by using a stereotactic head holder. All animals in each group were decapitated 24 hours after the procedure and the effect of albumin was evaluated by measurement of tissue specific gravity.

RESULTS

Tissue specific gravity decreased in edematous tissue (trauma indicator), increased after albumin administration at the 12th (p < 0.001), and both at the 1st and 12th hour of the trauma (edema treatment; p < 0.001). On the other hand, albumin administered at the 12th, and at both the 1st and 12th hours in the rats without trauma has caused the formation of the brain edema.

CONCLUSION

We conclude that human albumin is effective in cytotoxic, but not in vasogenic edema and exerts its best anti-edematous effect at the 12th hour of severe head trauma and this study may help future studies that will try to show the effects of albumin with different time modalities after severe head injury.

Strategies to improve recovery in acute ischemic stroke patients: Iberoamerican Stroke Group Consensus

Stroke is not only a leading cause of death worldwide but also a main cause of disability. In developing countries, its burden is increasing as a consequence of a higher life expectancy. Whereas stroke mortality has decreased in developed countries, in Latin America, stroke mortality rates continue to rise as well as its socioeconomic dramatic consequences. Therefore, it is necessary to implement stroke care and surveillance programs to better describe the epidemiology of stroke in these countries in order to improve therapeutic strategies. Advances in the understanding of the pathogenic processes of brain ischemia have resulted in development of effective therapies during the acute phase. These include reperfusion therapies (both intravenous thrombolysis and interventional endovascular approaches) and treatment in stroke units that, through application of management protocols directed to maintain homeostasis and avoid complications, helps to exert effective brain protection that decreases further cerebral damage. Some drugs may enhance protection, and besides, there is increasing knowledge about brain plasticity and repair mechanisms that take place for longer periods beyond the acute phase. These mechanisms are responsible for recovery in certain patients and are the focus of basic and clinical research at present. This paper discusses recovery strategies that have demonstrated clinical effect, or that are promising and need further study. This rapidly evolving field needs to be carefully and critically evaluated so that investment in patient care is grounded on well-proven strategies.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid, and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register (17 October 2012), the Cochrane Central Register of Controlled Trials (The Cochrane Library) (Issue 10, 2012), MEDLINE (Ovid) 1946 to October 2012, EMBASE (Ovid) 1980 to October 2012, ISI Web of Science: Science Citation Index Expanded (1970 to October 2012), ISI Web of Science: Conference Proceedings Citation Index-Science (1990 to October 2012), PubMed (October 2012), www.clinical trials.gov and www.controlled-trials.com. We also searched the bibliographies of relevant studies and review articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross-over trials and trials involving pregnant women and neonates.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 78 eligible trials; 70 of these presented mortality data.COLLOIDS COMPARED TO CRYSTALLOIDS: Albumin or plasma protein fraction - 24 trials reported data on mortality, including a total of 9920 patients. The pooled risk ratio (RR) from these trials was 1.01 (95% confidence interval (CI) 0.93 to 1.10). When we excluded the trial with poor-quality allocation concealment, pooled RR was 1.00 (95% CI 0.92 to 1.09). Hydroxyethyl starch - 25 trials compared hydroxyethyl starch with crystalloids and included 9147 patients. The pooled RR was 1.10 (95% CI 1.02 to 1.19). Modified gelatin - 11 trials compared modified gelatin with crystalloid and included 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). (When the trials by Boldt et al were removed from the three preceding analyses, the results were unchanged.) Dextran - nine trials compared dextran with a crystalloid and included 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65). COLLOIDS IN HYPERTONIC CRYSTALLOID COMPARED TO ISOTONIC CRYSTALLOID: Nine trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1985 randomised participants. Pooled RR for mortality was 0.91 (95% CI 0.71 to 1.06).

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. Furthermore, the use of hydroxyethyl starch might increase mortality. As colloids are not associated with an improvement in survival and are considerably more expensive than crystalloids, it is hard to see how their continued use in clinical practice can be justified.

On-line blood viscosity monitoring in vivo with a central venous catheter, using electrical impedance technique

Blood viscosity is an important determinant of microvascular hemodynamics and also reflects systemic inflammation. Viscosity of blood strongly depends on the shear rate and can be characterized by a two parameter power-law model. Other major determinants of blood viscosity are hematocrit, level of inflammatory proteins and temperature. In-vitro studies have shown that these major parameters are related to the electrical impedance of blood. A special central venous catheter was developed to measure electrical impedance of blood in-vivo in the right atrium. Considering that blood viscosity plays an important role in cerebral blood flow, we investigated the feasibility to monitor blood viscosity by electrical bioimpedance in 10 patients during the first 3 days after successful resuscitation from a cardiac arrest. The blood viscosity-shear rate relationship was obtained from arterial blood samples analyzed using a standard viscosity meter. Non-linear regression analysis resulted in the following equation to estimate in-vivo blood viscosity (Viscosity(imp)) from plasma resistance (R(p)), intracellular resistance (R(i)) and blood temperature (T) as obtained from right atrium impedance measurements: Viscosity(imp)=(-15.574+15.576R(p)T)SR ((-.138RpT-.290Ri)). This model explains 89.2% (R(2)=.892) of the blood viscosity-shear rate relationship. The explained variance was similar for the non-linear regression model estimating blood viscosity from its major determinants hematocrit and the level of fibrinogen and C-reactive protein (R(2)=.884). Bland-Altman analysis showed a bias between the in-vitro viscosity measurement and the in-vivo impedance model of .04 mPa s at a shear rate of 5.5s(-1) with limits of agreement between -1.69 mPa s and 1.78 mPa s. In conclusion, this study demonstrates the proof of principle to monitor blood viscosity continuously in the human right atrium by a dedicated central venous catheter equipped with an impedance measuring device. No safety problems occurred and there was good agreement with in-vitro measurements of blood viscosity.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register (searched 16 March 2012), Cochrane Central Register of Controlled Trials 2011, issue 3 (The Cochrane Library), MEDLINE (Ovid) 1946 to March 2012, Embase (Ovid) 1980 to March 2012, ISI Web of Science: Science Citation Index Expanded (1970 to March 2012), ISI Web of Science: Conference Proceedings Citation Index-Science (1990 to March 2012), PubMed (searched 16 March 2012), www.clinical trials.gov and www.controlled-trials.com. We also searched the bibliographies of relevant studies and review articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross-over trials and trials in pregnant women and neonates.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 74 eligible trials; 66 of these presented mortality data.Colloids compared to crystalloids Albumin or plasma protein fraction - 24 trials reported data on mortality, including a total of 9920 patients. The pooled relative risk (RR) from these trials was 1.01 (95% confidence interval (CI) 0.93 to 1.10). When we excluded the trial with poor quality allocation concealment, pooled RR was 1.00 (95% CI 0.92 to 1.09). Hydroxyethyl starch - 21 trials compared hydroxyethyl starch with crystalloids, n = 1385 patients. The pooled RR was 1.10 (95% CI 0.91 to 1.32). Modified gelatin - 11 trials compared modified gelatin with crystalloid, n = 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). (When the trials by Boldt et al were removed from the three preceding analyses, the results were unchanged.) Dextran - nine trials compared dextran with a crystalloid, n = 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65).Colloids in hypertonic crystalloid compared to isotonic crystalloid Nine trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1985 randomised participants. Pooled RR was 0.91 (95% CI 0.71 to 1.06).

AUTHORS' CONCLUSIONS

There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of RCTs.

Guidelines for the treatment of acute ischaemic stroke

INTRODUCTION

Update of Acute Ischaemic Stroke Treatment Guidelines of the Spanish Neurological Society based on a critical review of the literature. Recommendations are made based on levels of evidence from published data and studies.

DEVELOPMENT

Organized systems of care should be implemented to ensure access to the optimal management of all acute stroke patients in stroke units. Standard of care should include treatment of blood pressure (should only be treated if values are over 185/105 mmHg), treatment of hyperglycaemia over 155 mg/dl, and treatment of body temperature with antipyretic drugs if it rises above 37.5 °C. Neurological and systemic complications must be prevented and promptly treated. Decompressive hemicraniectomy should be considered in cases of malignant cerebral oedema. Intravenous thrombolysis with rtPA should be administered within 4.5 hours from symptom onset, except when there are contraindications. Intra-arterial pharmacological thrombolysis can be considered within 6 hours, and mechanical thrombectomy within 8 hours from onset, for anterior circulation strokes, while a wider window of opportunity up to 12-24 hours is feasible for posterior strokes. There is not enough evidence to recommend routine use of the so called neuroprotective drugs. Anticoagulation should be administered to patients with cerebral vein thrombosis. Rehabilitation should be started as early as possible.

CONCLUSION

Treatment of acute ischaemic stroke includes management of patients in stroke units. Systemic thrombolysis should be considered within 4.5 hours from symptom onset. Intra-arterial approaches with a wider window of opportunity can be an option in certain cases. Protective and restorative therapies are being investigated.

Human albumin solution for resuscitation and volume expansion in critically ill patients

BACKGROUND

Human albumin solutions are used for a range of medical and surgical problems. Licensed indications are the emergency treatment of shock and other conditions where restoration of blood volume is urgent, such as in burns and hypoproteinaemia. Human albumin solutions are more expensive than other colloids and crystalloids.

OBJECTIVES

To quantify the effect on mortality of human albumin and plasma protein fraction (PPF) administration in the management of critically ill patients.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register (searched 31 May 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), MEDLINE (Ovid) (1948 to week 3 May 2011), EMBASE (Ovid) (1980 to Week 21 2011), CINAHL (EBSCO) (1982 to May 2011), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to May 2011), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to May 2011), PubMed (www.ncbi.nlm.nih.gov/sites/entrez/) (searched 10 June 2011, limit: last 60 days). Reference lists of trials and review articles were checked, and authors of identified trials were contacted.

SELECTION CRITERIA

Randomised controlled trials comparing albumin or PPF with no albumin or PPF or with a crystalloid solution in critically ill patients with hypovolaemia, burns or hypoalbuminaemia.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, albumin solution used, mortality at the end of follow up, and quality of allocation concealment. Analysis was stratified according to patient type.

MAIN RESULTS

We found 38 trials meeting the inclusion criteria and reporting death as an outcome. There were 1,958 deaths among 10,842 trial participants.For hypovolaemia, the relative risk of death following albumin administration was 1.02 (95% confidence interval (CI) 0.92 to 1.13). This estimate was heavily influenced by the results of the SAFE trial, which contributed 75.2% of the information (based on the weights in the meta-analysis). For burns, the relative risk was 2.93 (95% CI 1.28 to 6.72) and for hypoalbuminaemia the relative risk was 1.26 (95% CI 0.84 to 1.88). There was no substantial heterogeneity between the trials in the various categories (Chi(2) = 26.66, df = 31, P = 0.69). The pooled relative risk of death with albumin administration was 1.05 (95% CI 0.95 to 1.16).

AUTHORS' CONCLUSIONS

For patients with hypovolaemia, there is no evidence that albumin reduces mortality when compared with cheaper alternatives such as saline. There is no evidence that albumin reduces mortality in critically ill patients with burns and hypoalbuminaemia. The possibility that there may be highly selected populations of critically ill patients in which albumin may be indicated remains open to question. However, in view of the absence of evidence of a mortality benefit from albumin and the increased cost of albumin compared to alternatives such as saline, it would seem reasonable that albumin should only be used within the context of well concealed and adequately powered randomised controlled trials.

Human albumin solution for resuscitation and volume expansion in critically ill patients

BACKGROUND

Human albumin solutions are used for a range of medical and surgical problems. Licensed indications are the emergency treatment of shock and other conditions where restoration of blood volume is urgent, such as in burns and hypoproteinaemia. Human albumin solutions are more expensive than other colloids and crystalloids.

OBJECTIVES

To quantify the effect on mortality of human albumin and plasma protein fraction (PPF) administration in the management of critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register (searched 31 May 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), MEDLINE (Ovid) (1948 to week 3 May 2011), EMBASE (Ovid) (1980 to Week 21 2011), CINAHL (EBSCO) (1982 to May 2011), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to May 2011), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to May 2011), PubMed (www.ncbi.nlm.nih.gov/sites/entrez/) (searched 10 June 2011, limit: last 60 days). Reference lists of trials and review articles were checked, and authors of identified trials were contacted.

SELECTION CRITERIA

Randomised controlled trials comparing albumin or PPF with no albumin or PPF or with a crystalloid solution in critically ill patients with hypovolaemia, burns or hypoalbuminaemia.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, albumin solution used, mortality at the end of follow up, and quality of allocation concealment. Analysis was stratified according to patient type.

MAIN RESULTS

We found 38 trials meeting the inclusion criteria and reporting death as an outcome. There were 1,958 deaths among 10,842 trial participants.For hypovolaemia, the relative risk of death following albumin administration was 1.02 (95% confidence interval (CI) 0.92 to 1.13). This estimate was heavily influenced by the results of the SAFE trial, which contributed 75.2% of the information (based on the weights in the meta-analysis). For burns, the relative risk was 2.93 (95% CI 1.28 to 6.72) and for hypoalbuminaemia the relative risk was 1.26 (95% CI 0.84 to 1.88). There was no substantial heterogeneity between the trials in the various categories (Chi(2) = 26.66, df = 31, P = 0.69). The pooled relative risk of death with albumin administration was 1.05 (95% CI 0.95 to 1.16).

AUTHORS' CONCLUSIONS

For patients with hypovolaemia, there is no evidence that albumin reduces mortality when compared with cheaper alternatives such as saline. There is no evidence that albumin reduces mortality in critically ill patients with burns and hypoalbuminaemia. The possibility that there may be highly selected populations of critically ill patients in which albumin may be indicated remains open to question. However, in view of the absence of evidence of a mortality benefit from albumin and the increased cost of albumin compared to alternatives such as saline, it would seem reasonable that albumin should only be used within the context of well concealed and adequately powered randomised controlled trials.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library 2008, Issue 3), MEDLINE, EMBASE, ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S), and The Controlled Trials metaRegister (www.controlled-trials.com). Reference lists of relevant studies and review articles were searched for further trials. The searches were last updated in September 2008.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross-over trials and trials in pregnant women and neonates.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 65 eligible trials; 56 of these presented mortality data.Colloids compared to crystalloidsAlbumin or plasma protein fraction - 23 trials reported data on mortality, including a total of 7754 patients. The pooled relative risk (RR) from these trials was 1.01 (95% confidence interval (95% CI) 0.92 to 1.10). When we excluded the trial with poor quality allocation concealment, pooled RR was 1.00 (95% CI 0.91 to 1.09). Hydroxyethyl starch - 17 trials compared hydroxyethyl starch with crystalloids, n = 1172 patients. The pooled RR was 1.18 (95% CI 0.96 to 1.44). Modified gelatin - 11 trials compared modified gelatin with crystalloid, n = 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). (When the trials by Boldt et al were removed from the three preceding analyses, the results were unchanged.) Dextran - nine trials compared dextran with a crystalloid, n = 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65).Colloids in hypertonic crystalloid compared to isotonic crystalloidEight trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1283 randomised participants. Pooled RR was 0.88 (95% CI 0.74 to 1.05).

AUTHORS' CONCLUSIONS

There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of RCTs.

Albumin level and stroke. Potential association between lower albumin level and cardioembolic aetiology

BACKGROUND

Lower level of albumin was related to worse prognosis of stroke and clinical trials showed that albumin therapy reduced mortality. However, stroke is heterogeneous and differences in the baseline concentration of albumin among subtypes of stroke were not assessed. The aim was to assess albumin level in patients with ischemic stroke classified by mechanism.

METHODS

Prospective controlled clinical study, including 200 patients with ischemic stroke and 50 controls. Patients were classified following Trial of ORG 10172 in Acute Stroke Treatment criteria. Plasma levels of albumin, fibrinogen, D-dimer, and C-reactive protein were assessed during 48 hr after admission. The National Institutes of Health Stroke Scale (NIHSS) on admission, in-hospital mortality, and Rankin score on discharge were recorded. Dependence was defined as mRS > 2.

RESULTS

Patients with cardioembolic stroke showed significantly higher D-dimer and lower albumin. Mortality was related to higher NIHSS, higher D-dimer, lower albumin, and cardioembolic aetiology. Dependence was strongly related to lower albumin and higher NIHSS. LOGISTIC REGRESSION: The cardioembolic aetiology (OR 0.101, 95% CI 0.010-1.007, p = .051) and the higher NIHSS score (OR 0.871, 95% CI 0.758-1.002, p = .053) were related to mortality; NIHSS (OR 1.560, 95% CI 1.323-1.838, p < .0001) and older age (OR 1.052, 95% CI 1.012-1.093, p = .010) were independently related to dependence.

DISCUSSION

Patients with cardioembolic stroke showed lower albumin and higher risk of mortality than non-cardioembolic ones. Lower mean level of albumin was related to mortality and dependence in all patients. Reduced albumin may be a marker of chronic systemic inflammation, which may be the mechanism for cardiopathy and bad outcome of stroke. In addition, direct effects on ischemic tissue were suggested in experimental models.

Anemia and red blood cell transfusion in neurocritical care

INTRODUCTION

Anemia is one of the most common medical complications to be encountered in critically ill patients. Based on the results of clinical trials, transfusion practices across the world have generally become more restrictive. However, because reduced oxygen delivery contributes to 'secondary' cerebral injury, anemia may not be as well tolerated among neurocritical care patients.

METHODS

The first portion of this paper is a narrative review of the physiologic implications of anemia, hemodilution, and transfusion in the setting of brain-injury and stroke. The second portion is a systematic review to identify studies assessing the association between anemia or the use of red blood cell transfusions and relevant clinical outcomes in various neurocritical care populations.

RESULTS

There have been no randomized controlled trials that have adequately assessed optimal transfusion thresholds specifically among brain-injured patients. The importance of ischemia and the implications of anemia are not necessarily the same for all neurocritical care conditions. Nevertheless, there exists an extensive body of experimental work, as well as human observational and physiologic studies, which have advanced knowledge in this area and provide some guidance to clinicians. Lower hemoglobin concentrations are consistently associated with worse physiologic parameters and clinical outcomes; however, this relationship may not be altered by more aggressive use of red blood cell transfusions.

CONCLUSIONS

Although hemoglobin concentrations as low as 7 g/dl are well tolerated in most critical care patients, such a severe degree of anemia could be harmful in brain-injured patients. Randomized controlled trials of different transfusion thresholds, specifically in neurocritical care settings, are required. The impact of the duration of blood storage on the neurologic implications of transfusion also requires further investigation.

Decreased damage from transient focal cerebral ischemia by transfusion of zero-link hemoglobin polymers in mouse

BACKGROUND AND PURPOSE

Transfusion of large polymers of hemoglobin avoids the peripheral extravasation and hypertension associated with crosslinked tetrameric hemoglobin transfusion and may be more effective in rescuing brain from focal ischemia. Effects of transfusion of high-oxygen-affinity hemoglobin polymers of different weight ranges were determined.

METHODS

Hypervolemic exchange transfusion was performed during 2 hours of middle cerebral artery occlusion in mice.

RESULTS

Compared to transfusion with a 5% albumin solution or no transfusion, infarct volume was reduced 40% by transfusion of a 6% solution containing hemoglobin polymers in the nominal range 500 to 14 000 kDa. Infarct volume was not significantly reduced by transfusion of a lower concentration of 2% to 3% of this size range of polymers, 6% hemoglobin solutions without removal of polymers <500 kDa or >14000 kDa, or crosslinked hemoglobin tetramers with normal oxygen affinity. Exchange transfusion with the 6% solution of the 500 to 14 000 kDa hemoglobin polymers did not improve the distribution of cerebral blood flow during focal ischemia and, in mice without ischemia, did not affect flow to brain or other major organs.

CONCLUSIONS

An intermediate size range of polymerized bovine hemoglobin possessing high oxygen affinity appears optimal for rescuing mouse brain from transient focal cerebral ischemia. A minimum concentration of a 6% solution is required, the rescue is superior to that obtained with crosslinked tetrameric hemoglobin possessing normal oxygen affinity, and tissue salvage is not associated with increased blood flow. This polymer solution avoids the adverse effects of severe renal and splanchnic vasoconstriction seen with crosslinked tetrameric hemoglobin.

Neuroprotection for ischemic stroke: past, present and future

Neuroprotection for ischemic stroke refers to strategies, applied singly or in combination, that antagonize the injurious biochemical and molecular events that eventuate in irreversible ischemic injury. There has been a recent explosion of interest in this field, with over 1000 experimental papers and over 400 clinical articles appearing within the past 6 years. These studies, in turn, are the outgrowth of three decades of investigative work to define the multiple mechanisms and mediators of ischemic brain injury, which constitute potential targets of neuroprotection. Rigorously conducted experimental studies in animal models of brain ischemia provide incontrovertible proof-of-principle that high-grade protection of the ischemic brain is an achievable goal. Nonetheless, many agents have been brought to clinical trial without a sufficiently compelling evidence-based pre-clinical foundation. At this writing, around 160 clinical trials of neuroprotection for ischemic stroke have been initiated. Of the approximately 120 completed trials, two-thirds were smaller early-phase safety-feasibility studies. The remaining one-third were typically larger (>200 subjects) phase II or III trials, but, disappointingly, only fewer than one-half of these administered neuroprotective therapy within the 4-6h therapeutic window within which efficacious neuroprotection is considered to be achievable. This fact alone helps to account for the abundance of "failed" trials. This review presents a close survey of the most extensively evaluated neuroprotective agents and classes and considers both the strengths and weakness of the pre-clinical evidence as well as the results and shortcomings of the clinical trials themselves. Among the agent-classes considered are calcium channel blockers; glutamate antagonists; GABA agonists; antioxidants/radical scavengers; phospholipid precursor; nitric oxide signal-transduction down-regulator; leukocyte inhibitors; hemodilution; and a miscellany of other agents. Among promising ongoing efforts, therapeutic hypothermia, high-dose human albumin therapy, and hyperacute magnesium therapy are considered in detail. The potential of combination therapies is highlighted. Issues of clinical-trial funding, the need for improved translational strategies and clinical-trial design, and "thinking outside the box" are emphasized.

Small-volume resuscitation with hyperoncotic albumin: a systematic review of randomized clinical trials

Background

Small-volume resuscitation can rapidly correct hypovolemia. Hyperoncotic albumin solutions, long in clinical use, are suitable for small-volume resuscitation; however, their clinical benefits remain uncertain.

Methods

Randomized clinical trials comparing hyperoncotic albumin with a control regimen for volume expansion were sought by multiple methods, including computer searches of bibliographic databases, perusal of reference lists, and manual searching. Major findings were qualitatively summarized. In addition, a quantitative meta-analysis was performed on available survival data.

Results

In all, 25 randomized clinical trials with a total of 1,485 patients were included. In surgery, hyperoncotic albumin preserved renal function and reduced intestinal edema compared with control fluids. In trauma and sepsis, cardiac index and oxygenation were higher after administration of hydroxyethyl starch than hyperoncotic albumin. Improved treatment response and renal function, shorter hospital stay and lower costs of care were reported in patients with liver disease receiving hyperoncotic albumin. Edema and morbidity were decreased in high-risk neonates after hyperoncotic albumin administration. Disability was reduced by therapy with hyperoncotic albumin in brain injury. There was no evidence of deleterious effects attributable to hyperoncotic albumin. Survival was unaffected by hyperoncotic albumin (pooled relative risk, 0.95; 95% confidence interval 0.78 to 1.17).

Conclusion

In some clinical indications, randomized trial evidence has suggested certain benefits of hyperoncotic albumin such as reductions in morbidity, renal impairment and edema. However, further clinical trials are needed, particularly in surgery, trauma and sepsis.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group's specialised register, CENTRAL, MEDLINE, EMBASE, the National Research Register, Web of Science and MetaRegister. Bibliographies of trials and review articles retrieved were searched. The searches were last updated in December 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. Cross-over trials and trials in pregnant women and neonates were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and rated quality of allocation concealment. Trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, were analysed separately. The analysis was stratified according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 63 eligible trials, 55 of these presented mortality data. COLLOIDS COMPARED TO CRYSTALLOIDS: Albumin or plasma protein fraction - 23 trials reported data on mortality, including a total of 7,754 patients. The pooled relative risk (RR) from these trials was 1.01 (95% confidence interval [95% CI] 0.92 to 1.10). When the trial with poor quality allocation concealment was excluded, pooled RR was 1.00 (95% CI 0.91 to 1.09). Hydroxyethyl starch - 16 trials compared hydroxyethyl starch with crystalloids, n = 637 patients. The pooled RR was 1.05 (95% CI 0.63 to 1.75). Modified gelatin - 11 trials compared modified gelatin with crystalloid, n = 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). Dextran - nine trials compared dextran with a crystalloid, n = 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65). COLLOIDS IN HYPERTONIC CRYSTALLOID COMPARED TO ISOTONIC CRYSTALLOID: Eight trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1,283 randomised participants. Pooled RR was 0.88 (95% CI 0.74 to 1.05).

AUTHORS' CONCLUSIONS

There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of RCTs.

High dose human serum albumin for the treatment of acute ischemic stroke: a safety study

INTRODUCTION

In animal models of focal cerebral ischemia, albumin infusions at doses ranging from 0.6 to 2.5 g/kg are neuroprotective. It is not known whether patients with stroke, often elderly and with underlying cardiovascular disease, can safely tolerate such degrees of volume expansion. Therefore, we retrospectively reviewed the safety of high-dose albumin treatment in patients with acute ischemic stroke.

MATERIALS AND METHODS

Within 24 hours of ischemic stroke onset, patients who received at least 0.7 g/kg albumin were identified by a review of medical records. Each albumin recipient was assigned two control patients, who received standard fluid management. Controls were matched by age, number of stroke risk factors, stroke severity, and stroke subtype. Medical records were reviewed for treatment-related adverse events, defined as cardiopulmonary complications and mortality.

RESULTS

Thirty cases (mean age 62.9+/-11.4 years) and 60 controls (mean age 62.5+/-11.8 years) were identified between July 1999 and November 2001. The two groups were evenly matched. The mean dose of albumin infusion was 171 g (2.4 g/kg). Cardiopulmonary complications or death developed in 37% of cases and 18% of controls (p=0.056). Mortality was 7% in both groups. Multivariate regression analysis showed that a history of congestive heart failure and higher total albumin dose were independently associated with the occurrence of adverse events.

CONCLUSION

Albumin treatment was associated with a nonsignificant trend toward increased cardiopulmonary adverse events. However, these adverse events did not result in excess mortality.

Catheter-based impedance measurements in the right atrium for continuously monitoring hematocrit and estimating blood viscosity changes; an in vivo feasibility study in swine

Hematocrit is the most important determinant of whole blood viscosity and it affects thrombosis. As hematocrit can be measured accurately in vitro by using an electrical impedance technique, aim of the present study is to investigate the diagnostic potential of using this technique in vivo to continuously monitor hematocrit. Characteristics of a special catheter for in vivo measurement of electrical resistivity in blood in the right atrium are described. In five anesthetized swine hematocrit is monitored continuously with this catheter while different levels of hemoconcentration are induced. In addition, blood viscosity is increased by inducing 'acute phase' reaction the day before surgery, resulting in variable degree of elevated fibrinogen levels in the five swine. Good reproducibility of the resistivity measurements (S.D < 0.01) and excellent correlation between resistivity data in vivo and hematocrit levels in each swine are found (r2 = 0.95-0.99). Furthermore, stepwise regression analysis of data from all swine shows a highly significant contribution also of other important parameters of blood viscosity, such as fibrinogen, total protein and temperature (cumulative r2 = 0.97). Determining hematocrit continuously in vivo by electrical resistivity measurements with a catheter in the right atrium is feasible and these measurements correlate significantly also with other important parameters of blood viscosity.

Strategies of neuroprotection for intracranial aneurysms

Neuroprotection for patients with intracranial aneurysms encompasses the preservation of brain cells endangered by a limited blood and oxygen supply due to aneurysm rupture, clipping or coiling, as well as vasospasm. A large variety of prophylactic and therapeutic neuroprotective strategies have been proposed, but success in human disease is quite limited. Topics of this chapter are the pathophysiology and treatment options of aneurysms, as well as promising neuroprotective strategies in further developmental stages: both physiologically based (hyperoxygenation, hypothermia, avoidance of hyperthermia and hyperglycaemia, hypertension, haemodilution and hypervolaemia) and pharmacologically based (antifibrinolytic drugs, calcium antagonists, anaesthetics, magnesium, erythropoietin and others). New concepts are ischaemic preconditioning, growth factors, and gene therapy. Each strategy is rated on underlying evidence, and research agendas are mentioned.

Morbidity in hospitalized patients receiving human albumin: a meta-analysis of randomized, controlled trials

OBJECTIVE

To determine the effect of albumin administration on morbidity in acutely ill hospitalized patients.

DATA SOURCE

Computer searches of MEDLINE, EMBASE, and the Cochrane Library; hand searches of journals and Index Medicus; inquiries with investigators and fluid product suppliers; and examination of reference lists. No language or time period restrictions were adopted.

STUDY SELECTION

Randomized, controlled trials comparing the administration of albumin with that of crystalloid, no albumin, or lower-dose albumin.

DATA EXTRACTION

Two investigators independently extracted data. The primary endpoint for the meta-analysis was morbidity, defined as the incidence of complications, including death. Trial quality was evaluated by blinding, allocation concealment, presence of morbidity as a study endpoint, and individual patient crossover.

DATA SYNTHESIS

Seventy-one trials were included in the categories of surgery or trauma, burns, hypoalbuminemia, high-risk neonates, ascites, and other indications. The 3,782 randomized patients in the included trials experienced a total of 3,287 complications, including 515 deaths and 2,772 cardiovascular, gastrointestinal, hepatic, infectious, renal, respiratory, and other complications. Albumin significantly reduced overall morbidity, with a risk ratio of 0.92 (confidence interval [CI], 0.86-0.98). Control group albumin dose significantly affected the incidence of complications (p = .002). In 32 trials with no albumin administered to the control group, the risk ratio was 0.77 (CI, 0.67-0.88) compared with 0.89 (CI, 0.80-1.00) in 20 trials with control patients receiving low-dose albumin and 1.07 (CI, 0.96-1.20) in 19 trials with moderate-dose control group albumin.

CONCLUSIONS

Albumin reduces morbidity in acutely ill hospitalized patients. Concomitant administration of albumin in the control group can obscure the effects of albumin on clinical outcome in randomized trials.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects on mortality of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH STRATEGY

We searched the Injuries Group specialised register, Cochrane Controlled Trials Register, MEDLINE, EMBASE and BIDS Index to Scientific and Technical Proceedings, and checked reference lists of trials and review articles.

SELECTION CRITERIA

All randomised and quasi-randomised trials of colloids compared to crystalloids, in patients requiring volume replacement. Cross-over trials and trials in pregnant women and neonates were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and rated quality of allocation concealment. Trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, were analysed separately. The analysis was stratified according to colloid type and quality of allocation concealment.

MAIN RESULTS

Colloids compared to crystalloidsAlbumin or plasma protein fraction. Nineteen trials reported data on mortality, including a total of 7576 patients. The pooled relative risk (RR) from these trials was 1.02 (95% confidence interval [95% CI] 0.93 to 1.11). When the trial with poor quality allocation concealment was excluded, pooled RR was 1.01 (95% CI 0.92 to 1.10). Hydroxyethyl starch. Ten trials compared hydroxyethyl starch with crystalloids, including a total of 374 randomised participants. The pooled RR was 1.16 (95% CI 0.68 to 1.96). Modified gelatin. Seven trials compared modified gelatin with crystalloid, including a total of 346 randomised participants. The pooled RR was 0.54 (95% CI 0.16 to 1.85). Dextran. Nine trials compared dextran with a crystalloid, including a total of 834 randomised participants. The pooled relative risk was RR 1.24 (95% CI 0.94 to 1.65). Colloids in hypertonic crystalloid compared to isotonic crystalloidEight trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1283 randomised participants. Pooled RR was 0.88 (95% CI 0.74 to 1.05).

REVIEWERS' CONCLUSIONS

There is no evidence from randomised controlled trials that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of randomised controlled trials.

Human albumin solution for resuscitation and volume expansion in critically ill patients

BACKGROUND

Human albumin solutions are used in a range of medical and surgical problems. Licensed indications are the emergency treatment of shock and other conditions where restoration of blood volume is urgent, burns, and hypoproteinaemia. Human albumin solutions are more expensive than other colloids and crystalloids.

OBJECTIVES

To quantify the effect on mortality of human albumin and plasma protein fraction (PPF) administration in the management of critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group trials register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and BIDS Index to Scientific and Technical Proceedings. Reference lists of trials and review articles were checked, and authors of identified trials were contacted. The search was last updated in August 2004.

SELECTION CRITERIA

Randomised controlled trials comparing albumin/PPF with no albumin/PPF, or with a crystalloid solution, in critically ill patients with hypovolaemia, burns or hypoalbuminaemia.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, albumin solution used, mortality at the end of follow up, and quality of allocation concealment. Analysis was stratified according to patient type.

MAIN RESULTS

We found 32 trials meeting the inclusion criteria and reporting death as an outcome. There were 1632 deaths among 8452 trial participants. For hypovolaemia, the relative risk of death following albumin administration was 1.01 (95% confidence interval 0.92, 1.10). This estimate was heavily influenced by the results of the SAFE trial which contributed 91% of the information (based on the weights in the meta-analysis). For burns, the relative risk was 2.40 (1.11, 5.19) and for hypoalbuminaemia the relative risk was 1.38 (0.94, 2.03). There was no substantial heterogeneity between the trials in the various categories (chi-square = 21.86, df = 25, p =0.64). The pooled relative risk of death with albumin administration was 1.04 (0.95, 1.13).

REVIEWERS' CONCLUSIONS

For patients with hypovolaemia there is no evidence that albumin reduces mortality when compared with cheaper alternatives such as saline. There is no evidence that albumin reduces mortality in critically ill patients with burns and hypoalbuminaemia. The possibility that there may be highly selected populations of critically ill patients in which albumin may be indicated remains open to question. However, in view of the absence of evidence of a mortality benefit from albumin and the increased cost of albumin compared to alternatives such as saline, it would seem reasonable that albumin should only be used within the context of well concealed and adequately powered randomised controlled trial.

Physiologic aspects of anemia

The most important adaptive responses from a physiological stance involved the cardiovascular system, consisting in particular of elevation of the cardiac output and its redistribution to favor the coronary and cerebral circulations, at the expense of the splanchnic vascular beds. The evidence regarding these physiological responses, especially in experimental studies that permit the control of many variables, is particularly powerful and convincing. On the other hand, there is a remarkable lack, in quality and quantity, of clinical studies addressing how normal physiological adaptive responses may be affected by a variety of diseases and conditions that often accompany and may complicate anemia, and interactions with other such compounding variables as age and different patient populations. For these reasons, it is not possible to offer guidelines on how to increase, maintain, or even to determine optimal DO2 in high-risk patients and how best transfusion strategies might be used under these conditions. From the brief review of physiological principles and the strong consensus in the literature, it is evident that cardiac function must be a central consideration in decisions regarding transfusion in anemia, because of the critical role it plays in assuring adequate oxygen supply of all vital tissues. Particular attention should be paid to the possible presence of CAD or incipient or cardiac failure, as these conditions may require careful transfusions to improve DO2 at levels that may not necessitate such interventions when cardiac disease is absent. Although the cerebral circulation also serves an obligate aerobic organ unable to tolerate significant hypoxia, there is little convincing evidence to support the notion that cerebral ischemia is aggravated by anemia and that this can be prevented by improved DO2 through rapid correction of anemia. Consequently, the arguments favoring transfusions in the presence of ischemic heart disease do not appear to apply to occlusive cerebrovascular disease. Because firm evidence is lacking on the interactions of concurrent diseases and anemia in various patient populations, understanding of the physiological consequences of anemia, and of the diseases concerned, is useful but not fully sufficient to provide firm and rational guidance to transfusion practice in specific complex clinical instances. A good deal of clinical and experimental investigation is required to support fully rational and comprehensive guidelines. In the meantime, prudent and conservative management, based on awareness of risks and sound understanding of the normal and pathological physiology, must remain the guiding principle.

Albumin administration--what is the evidence of clinical benefit? A systematic review of randomized controlled trials

BACKGROUND AND OBJECTIVE

The advantages of albumin over less costly alternative fluids continue to be debated. Meta-analyses focusing on survival have been inconclusive, and other clinically relevant end-points have not been systematically addressed. We sought to determine whether albumin confers significant clinical benefit in acute illness compared with other fluid regimens.

METHODS

Database searches (MEDLINE, EMBASE, Cochrane Library) and other methods were used to identify randomized controlled trials comparing albumin with crystalloid, artificial colloid, no albumin or lower-dose albumin. Major findings for all end-points were extracted and summarized. A quantitative meta-analysis was not attempted.

RESULTS

Seventy-nine randomized trials with a total of 4755 patients were included. No significant treatment effects were detectable in 20/79 (25%) trials. In cardiac surgery, albumin administration resulted in lower fluid requirements, higher colloid oncotic pressure, reduced pulmonary oedema with respiratory impairment and greater haemodilution compared with crystalloid and hydroxyethylstarch increased postoperative bleeding. In non-cardiac surgery, fluid requirements, and pulmonary and intestinal oedema were decreased by albumin compared with crystalloid. In hypoalbuminaemia, higher doses of albumin reduced morbidity. In ascites, albumin reduced haemodynamic derangements, morbidity and length of stay and improved survival after spontaneous bacterial peritonitis. In sepsis, albumin decreased pulmonary oedema and respiratory dysfunction compared with crystalloid, while hydroxyethylstarch induced abnormalities of haemostasis. Complications were lowered by albumin compared with crystalloid in burn patients. Albumin-containing therapeutic regimens improved outcomes after brain injury.

CONCLUSIONS

Albumin can bestow benefit in diverse clinical settings. Further trials are warranted to delineate optimal fluid regimens, in particular indications.

Relationship of initial hematocrit level to discharge destination and resource utilization after ischemic stroke: a pilot study

OBJECTIVE

To examine the association between initial hematocrit level at the time of ischemic stroke, discharge destination, and resource utilization.

DESIGN

Case series.

SETTING

University hospital.

PARTICIPANTS

A total of 1012 consecutive patients with ischemic stroke admitted to a university health system between August 3, 1995, and June 24, 1999.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Length of stay, hospital cost, and discharge disposition.

RESULTS

Of 1012 patients presenting with ischemic stroke, 58% were discharged home, 10% were discharged home with home care services, 15% were discharged to a rehabilitation hospital, 11% were discharged to a skilled or intermediate care facility, and 6% died. After adjusting for age, sex, race, and comorbidities, a significant association (P=.009) existed between discharge outcome and initial hematocrit level. The probability of achieving an equivalent or less favorable outcome increased at both high and low hematocrit levels, with a minimum probability at a hematocrit level of approximately 45%.

CONCLUSIONS

An association exists between hematocrit level at the time of ischemic stroke and discharge outcome. Midrange hematocrit levels appear to be associated with discharge to home rather than to an inpatient rehabilitation unit or to a nursing facility. Further study is indicated to examine the relationship among hematocrit level, stroke severity, and outcome.

Regional cerebral blood flow in cats with cross-linked hemoglobin transfusion during focal cerebral ischemia

The beneficial effect of hemodilution on cerebral blood flow (CBF) during focal cerebral ischemia is mitigated by reduced arterial oxygen content (CaO2). In anesthetized cats subjected to permanent middle cerebral artery occlusion, the time course of regional CBF was evaluated after isovolemic exchange transfusion with either albumin or a tetrameric hemoglobin-based oxygen carrier. The transfusion started 30 min after arterial occlusion. We tested the hypothesis that bulk oxygen transport (CBF x CaO2) to ischemic tissue is increased by hemoglobin transfusion at a hematocrit of 18% compared with albumin-transfused cats at a hematocrit of 18% or control cats at a hematocrit of 30% and equivalent arterial pressure. In the nonischemic hemisphere, CBF increased selectively after albumin transfusion, and oxygen transport was similar among groups. In the ischemic cortex, albumin transfusion increased CBF, but oxygen transport was not increased above that of the control group. Hemoglobin transfusion increased both CBF and oxygen transport in the ischemic cortex above values in the control group, but the increase was delayed until 4 h of ischemia. Consequently, acute injury volume measured at 6 h of ischemia was not significantly attenuated. In contrast to the cortex, CBF in the ischemic caudate nucleus was not substantially increased by either albumin or hemoglobin transfusion. Therefore, in a large animal model of permanent focal ischemia in which transfusion starts 30 min after ischemia, tetrameric cross-linked hemoglobin transfusion can augment oxygen transport to the ischemic cortex, but the increase can be delayed and not necessarily provide protection. Moreover, an end-artery region such as the caudate nucleus is less likely to benefit from hemodilution.

Human albumin solution for resuscitation and volume expansion in critically ill patients

BACKGROUND

Human albumin solutions are used in a range of medical and surgical problems. Licensed indications are the emergency treatment of shock and other conditions where restoration of blood volume is urgent, burns, and hypoproteinaemia. Human albumin solutions are more expensive than other colloids and crystalloids.

OBJECTIVES

To quantify the effect on mortality of human albumin and plasma protein fraction (PPF) administration in the management of critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group trials register, Cochrane Controlled Trials Register, Medline, Embase and BIDS Index to Scientific and Technical Proceedings. Reference lists of trials and review articles were checked, and authors of identified trials were contacted. The search was last updated in November 2001.

SELECTION CRITERIA

Randomised controlled trials comparing albumin/PPF with no albumin/PPF, or with a crystalloid solution, in critically ill patients with hypovolaemia, burns or hypoalbuminaemia.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, albumin solution used, mortality at the end of follow up, and quality of allocation concealment. Analysis was stratified according to patient type.

MAIN RESULTS

We found 31 trials meeting the inclusion criteria and reporting death as an outcome. There were 177 deaths among 1519 trial participants. For each patient category the risk of death in the albumin treated group was higher than in the comparison group. For hypovolaemia the relative risk of death following albumin administration was 1.46 (95% confidence interval 0.97 to 2.22), for burns the relative risk was 2.40 (1.11 to 5.19), and for hypoalbuminaemia the relative risk was 1.38 (0.94 to 2.03). The pooled relative risk of death with albumin administration was 1.52 (1.17 to 1.99). Overall, the risk of death in patients receiving albumin was 14% compared to 9% in the control groups, an increase in the risk of death of 5% (2% to 8%). These data suggest that for every 20 critically ill patients treated with albumin there is one additional death.

REVIEWER'S CONCLUSIONS

There is no evidence that albumin administration reduces the risk of death in critically ill patients with hypovolaemia, burns or hypoalbuminaemia, and a strong suggestion that it may increase the risk of death. These data suggest that the use of human albumin in critically ill patients should be urgently reviewed and that it should not be used outside the context of a rigorously conducted randomised controlled trial.

Neuroprotective effect of treatment with human albumin in permanent focal cerebral ischemia: histopathology and cortical perfusion studies

In recent experimental studies, we demonstrated a highly beneficial neuroprotective effect of moderate- to high-dose human albumin treatment of transient focal cerebral ischemia, but we did not define the effect of albumin therapy in permanent focal cerebral ischemia. In this study, anesthetized Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion by retrograde insertion of an intraluminal nylon suture coated with poly-L-lysine. Albumin was administered i.v. at 2 h after onset of middle cerebral artery occlusion, in doses of either 1.25 (n=8) or 2.5 g/kg (n=6). In a separate group of animals, albumin (2.5 g/kg) was given 1 h after middle cerebral artery occlusion (n=6). Vehicle-treated rats (n=6) received 0.9% saline in equivalent volumes. Neurological status was evaluated during and 24 h after middle cerebral artery occlusion. One day after middle cerebral artery occlusion, infarct volumes and brain edema were determined. In a separate group of animals, cortical perfusion was assessed by Laser-Doppler perfusion imaging. Albumin (1.25 g/kg; n=3) or vehicle (sodium chloride 0.9%; n=3) was administered at 2 h after onset of middle cerebral artery occlusion. Higher-dose albumin therapy (2.5 g/kg) significantly improved the neurological score compared to vehicle rats at 24 h, when administered at either 1 or 2 h after middle cerebral artery occlusion. Total infarct volume was reduced by albumin (2.5 g/kg given at 2 h) by 32% compared with vehicle-treated rats. Both albumin doses (1.25 and 2.5 g/kg) significantly reduced cortical and striatal infarct areas at several coronal levels when administered at 2 h after middle cerebral artery occlusion. Brain swelling was not affected by albumin treatment. Cortical perfusion declined during middle cerebral artery occlusion in both groups. Treatment with albumin led to 48% increases in cortical perfusion (P<0.002), but saline caused no change. These results support a beneficial effect of albumin therapy in permanent focal cerebral ischemia.

The effect of treatment with albumin, hetastarch, or hypertonic saline on neurological status and brain edema in a rat model of closed head trauma combined with uncontrolled hemorrhage and concurrent resuscitation in rats

In rats subjected to closed head trauma (CHT) plus uncontrolled hemorrhage, giving 0.3 mL of 0.9% saline per 0.1 mL of blood lost did not restore mean arterial blood pressure (MAP) or improve neurological severity score (NSS). In CHT without hemorrhage, giving 20% albumin or 10% hetastarch improved NSS. We hypothesized that these latter treatments would also improve NSS after CHT plus uncontrolled hemorrhage. Rats were randomly assigned to one of seven groups. Experimental conditions were CHT (yes or no), uncontrolled hemorrhage (yes or no), and fluid given to replace blood loss (none; 10% hetastarch, 20% albumin, or 3% saline [0.1 mL per 0.1 mL of blood lost]; or 0.9% saline [0.3 mL per 0.1 mL of blood lost]). NSS (0--25 scale, where 0 = no impairment) was determined at 1, 4, and 24 h, and brain water content was determined at 24 h after CHT. NSS (median +/- range) at 24 h was 11 +/- 6 when no fluid was given; 16 +/- 5 with 10% hetastarch; 14 +/- 5 with 20% albumin; 12 +/- 4 with 3% saline; and 13 +/- 4 with 0.9% saline given (not significant). In addition, brain water content and MAP did not differ among the groups receiving CHT with or without uncontrolled hemorrhage. In our model of CHT plus uncontrolled hemorrhage in rats, giving 10% hetastarch, 20% albumin, 3% saline, or 0.9% saline failed to improve NSS, brain water content, or MAP.

IMPLICATIONS

In previous studies of closed head trauma (CHT) without hemorrhage, giving 20% albumin or 10% hetastarch improved neurological severity scores (NSSs). We hypothesized that these treatments also might be beneficial in CHT plus uncontrolled hemorrhage. We found that giving 10% hetastarch, 20% albumin, 3% saline, or 0.9% saline failed to improve NSS, brain water content, or mean arterial blood pressure.

The effect of treatment with albumin, hetastarch, or hypertonic saline on neurological status and brain edema in a rat model of closed head trauma combined with uncontrolled hemorrhage and concurrent resuscitation in rats

In rats subjected to closed head trauma (CHT) plus uncontrolled hemorrhage, giving 0.3 mL of 0.9% saline per 0.1 mL of blood lost did not restore mean arterial blood pressure (MAP) or improve neurological severity score (NSS). In CHT without hemorrhage, giving 20% albumin or 10% hetastarch improved NSS. We hypothesized that these latter treatments would also improve NSS after CHT plus uncontrolled hemorrhage. Rats were randomly assigned to one of seven groups. Experimental conditions were CHT (yes or no), uncontrolled hemorrhage (yes or no), and fluid given to replace blood loss (none; 10% hetastarch, 20% albumin, or 3% saline [0.1 mL per 0.1 mL of blood lost]; or 0.9% saline [0.3 mL per 0.1 mL of blood lost]). NSS (0--25 scale, where 0 = no impairment) was determined at 1, 4, and 24 h, and brain water content was determined at 24 h after CHT. NSS (median +/- range) at 24 h was 11 +/- 6 when no fluid was given; 16 +/- 5 with 10% hetastarch; 14 +/- 5 with 20% albumin; 12 +/- 4 with 3% saline; and 13 +/- 4 with 0.9% saline given (not significant). In addition, brain water content and MAP did not differ among the groups receiving CHT with or without uncontrolled hemorrhage. In our model of CHT plus uncontrolled hemorrhage in rats, giving 10% hetastarch, 20% albumin, 3% saline, or 0.9% saline failed to improve NSS, brain water content, or MAP.

IMPLICATIONS

In previous studies of closed head trauma (CHT) without hemorrhage, giving 20% albumin or 10% hetastarch improved neurological severity scores (NSSs). We hypothesized that these treatments also might be beneficial in CHT plus uncontrolled hemorrhage. We found that giving 10% hetastarch, 20% albumin, 3% saline, or 0.9% saline failed to improve NSS, brain water content, or mean arterial blood pressure.

Haemodilution for acute ischaemic stroke

BACKGROUND

Ischaemic stroke interrupts the flow of blood to part of the brain. Haemodilution is thought to improve the flow of blood to the affected areas of the brain.

OBJECTIVES

The objective of this review was to assess the effects of haemodilution in acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register, Medline and conference abstracts. We contacted manufactures and investigators in the field.

SELECTION CRITERIA

Randomised trials of haemodilution treatment in people with acute ischaemic stroke. Only trials where treatment was started within 72 hours of stroke onset were included.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and independently extracted the data.

MAIN RESULTS

Sixteen trials were included. A combination of venesection and plasma volume expander was used in eight trials. Eight trials used plasma volume expander alone. The plasma volume expander was dextran 40 in 11 trials, hydroxyethyl starch in four trials and albumin in one trial. Two trials tested haemodilution in combination with another therapy. Evaluation was blinded in 11 trials. Five trials probably included some patients with intracerebral haemorrhage. Haemodilution did not significantly reduce deaths within seven to 28 days (odds ratio 1.12, 95% confidence interval 0.88 to 1.43). Similarly, haemodilution did not influence deaths within three to six months (odds ratio 1.02, 95% confidence interval 0.85 to 1.23), or death and dependency or institutionalisation (odds ratio 1.01, 95% confidence interval 0.86 to 1.19). The results were similar in confounded and unconfounded trials, in trials of isovolaemic and hypervolaemic haemodilution, and in trials using different types of hemodiluting agents. Six trials reported venous thromboembolic events. There was a tendency towards reduction in deep venous thrombosis and/or pulmonary embolism at three to six months follow-up (odds ratio 0.59, 95% confidence interval 0.33 to 1.06).

REVIEWER'S CONCLUSIONS

The overall results of this review are compatible both with a modest benefit and a moderate harm of haemodilution therapy for acute ischaemic stroke. As used in the randomised trials, this therapy has not been proven to improve survival or functional outcome.

Neuroprotection in acute ischaemic stroke. II: Clinical potential

In the 4 years since our first article, there has been considerable progress in our understanding of the pathophysiology of acute ischaemic stroke, and the results of well-conducted trials have at last begun to change everyday clinical practice. The timing of the various processes of the ischaemic cascade and the potential time windows for different interventions are better understood. Furthermore, the importance of maintaining cerebral perfusion and optimizing systemic physiological and biochemical factors in order to prevent neurological deterioration ('progressing stroke') is increasingly being realized. Numerous antithrombotic and neuroprotective drugs have been evaluated in clinical trials, and while none has shown unequivocal benefits on its own, prospects for successful intervention are still good. This will probably involve different combinations of treatments targeted on different pathophysiological stroke types, so that the management of acute stroke will offer a considerable challenge to the stroke physicians of the future.

Rheological influences on thrombosis

Blood flow plays important roles in the localization and morphology of thrombosis within the circulation. Blood flow properties (rheological variables) are associated with thrombotic risk factors and thrombotic risk; conversely their modification may reduce thrombotic risk.