Dataset Information

Red blood cell transfusion in patients with subarachnoid hemorrhage: a multidisciplinary North American survey.

ABSTRACT:

Introduction

Anemia is associated with poor outcomes in patients with aneurysmal subarachnoid hemorrhage (SAH). It remains unclear whether this association can be modified with more aggressive use of red blood cell (RBC) transfusions. The degree to which restrictive thresholds have been adopted in neurocritical care patients remains unknown.

Methods

We performed a survey of North American academic neurointensivists, vascular neurosurgeons and multidisciplinary intensivists who regularly care for patients with SAH to determine hemoglobin (Hb) concentrations which commonly trigger a decision to initiate transfusion. We also assessed minimum and maximum acceptable Hb goals in the context of a clinical trial and how decision-making is influenced by advanced neurological monitoring, clinician characteristics and patient-specific factors.

Results

The survey was sent to 531 clinicians, of whom 282 (53%) responded. In a hypothetical patient with high-grade SAH (WFNS 4), the mean Hb concentration at which clinicians administered RBCs was 8.19 g/dL (95% CI, 8.07 to 8.30 g/dL). Transfusion practices were comparatively more restrictive in patients with low-grade SAH (mean Hb 7.85 g/dL (95% CI, 7.73 to 7.97 g/dL)) (P < 0.0001) and more liberal in patients with delayed cerebral ischemia (DCI) (mean Hb 8.58 g/dL (95% CI, 8.45 to 8.72 g/dL)) (P < 0.0001). In each setting, there was a broad range of opinions. The majority of respondents expressed a willingness to study a restrictive threshold of ?8 g/dL (92%) and a liberal goal of ?10 g/dl (75%); in both cases, the preferred transfusion thresholds were significantly higher for patients with DCI (P < 0.0001). Neurosurgeons expressed higher minimum Hb goals than intensivists, especially for patients with high-grade SAH (? = 0.46, P = 0.003), and were more likely to administer two rather than one unit of RBCs (56% vs. 19%; P < 0.0001). Institutional use of transfusion protocols was associated with more restrictive practices. More senior clinicians preferred higher Hb goals in the context of a clinical trial. Respondents were more likely to transfuse patients with brain tissue oxygen tension values <15 mmHg and lactate-to-pyruvate ratios >40.

Conclusions

There is widespread variation in the use of RBC transfusions in SAH patients. Practices are heavily influenced by the specific dynamic clinical characteristics of patients and may be further modified by clinician specialty and seniority, the use of protocols and advanced neurological monitoring.

SUBMITTER: Kramer AH

PROVIDER: S-EPMC3222066 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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Publications

Red blood cell transfusion in patients with subarachnoid hemorrhage: a multidisciplinary North American survey.

Kramer Andreas H AH Diringer Michael N MN Suarez Jose I JI Naidech Andrew M AM Macdonald Loch R LR Le Roux Peter D PD

Critical care (London, England) 20110118 1

<h4>Introduction</h4>Anemia is associated with poor outcomes in patients with aneurysmal subarachnoid hemorrhage (SAH). It remains unclear whether this association can be modified with more aggressive use of red blood cell (RBC) transfusions. The degree to which restrictive thresholds have been adopted in neurocritical care patients remains unknown.<h4>Methods</h4>We performed a survey of North American academic neurointensivists, vascular neurosurgeons and multidisciplinary intensivists who reg ...[more]

PMID: 21244675

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Project description:IntroductionAnaemia is common in aneurysmal subarachnoid haemorrhage (aSAH) and is a potential critical modifiable factor affecting secondary injury. Despite physiological evidence and management guidelines that support maintaining a higher haemoglobin level in patients with aSAH, current practice is one of a more restrictive approach to transfusion. The goal of this multicentre pilot trial is to determine the feasibility of successfully conducting a red blood cell (RBC) transfusion trial in adult patients with acute aSAH and anaemia (Hb ≤100 g/L), comparing a liberal transfusion strategy (Hb ≤100 g/L) with a restrictive strategy (Hb ≤80 g/L) on the combined rate of death and severe disability at 12 months.MethodsDesign This is a multicentre open-label randomised controlled pilot trial at 5 academic tertiary care centres. Population We are targeting adult aSAH patients within 14 days of their initial bleed and with anaemia (Hb ≤110 g/L). Randomisation Central computer-generated randomisation, stratified by centre, will be undertaken from the host centre. Randomisation into 1 of the 2 treatment arms will occur when the haemoglobin levels of eligible patients fall to ≤100 g/L. Intervention Patients will be randomly assigned to either a liberal (threshold: Hb ≤100 g/L) or a restrictive transfusion strategy (threshold: Hb ≤80 g/L). Outcome Primary: Centre randomisation rate over the study period. Secondary: (1) transfusion threshold adherence; (2) study RBC transfusion protocol adherence; and (3) outcome assessment including vital status at hospital discharge, modified Rankin Score at 6 and 12 months and Functional Independence Measure and EuroQOL Quality of Life Scale scores at 12 months. Outcome measures will be reported in aggregate.Ethics and disseminationThe study protocol has been approved by the host centre (OHSN-REB 20150433-01H). This study will determine the feasibility of conducting the large pragmatic RCT comparing 2 RBC transfusion strategies examining the effect of a liberal strategy on 12-month outcome following aSAH.Trial registration numberNCT02483351; Pre-results.

Project description:BackgroundWhether a restrictive strategy for red blood cell (RBC) transfusion is applied to patients with aneurysmal subarachnoid hemorrhage (aSAH) is unclear. To inform the design and conduct of a future clinical trial, we sought to describe transfusion practices, hemoglobin (Hb) triggers, and predictors of RBC transfusion in patients with aSAH.MethodsThis is a retrospective cohort study of all consecutively admitted adult patients with aSAH at four tertiary care centers from January 1, 2012, to December 31, 2013. Patients were identified from hospital administrative discharge records and existing local aSAH databases. Data collection by trained abstractors included demographic data, aSAH characteristics, Hb and transfusion data, other major aSAH cointerventions, and outcomes using a pretested case report form with standardized procedures. Descriptive statistics were used to summarize data, and regression models were used to identify associations between anemia, transfusion, and other relevant predictors and outcome.ResultsA total of 527 patients met inclusion eligibility. Mean (±SD) age was 57 ± 13 years, and 357 patients (67.7%) were female. The median modified Fisher grade was 4 (IQR 3-4). Mean nadir Hb was 98 ± 20 g/L and occurred on median admission day 4 (IQR 2-11). RBC transfusion occurred in 100 patients (19.0%). Transfusion rates varied across centers (12.1-27.4%, p = 0.02). Patients received a median of 1 RBC unit (IQR 1-2) per transfusion episode and a median total of 2 units (IQR 1-4). Median pretransfusion Hb for first transfusion was 79 g/L (IQR 74-93) and did not vary substantially across centers (78-82 g/L, p = 0.37). Of patients with nadir Hb < 80 g/L, 66.3% received a transfusion compared with 2.0% with Hb nadir ≥ 100 g/L (p < 0.0001). Predictors of transfusion were history of oral anticoagulant use, anterior circulation aneurysm, neurosurgical clipping, and lower Hb. Controlling for numerous potential confounders, transfusion was not independently associated with poor outcome.ConclusionsWe observed that moderate anemia remains very common early in admission following SAH. Only one-fifth of patients with SAH received RBC transfusions, mostly in cases of significant anemia (Hb < 80 g/L), and this did not appear to be associated with outcome.

Project description:OBJECTIVES:Impaired oxygen delivery due to reduced cerebral blood flow is the hallmark of delayed cerebral ischemia following subarachnoid hemorrhage. Since anemia reduces arterial oxygen content, it further threatens oxygen delivery increasing the risk of cerebral infarction. Thus, subarachnoid hemorrhage may constitute an important exception to current restrictive transfusion practices, wherein raising hemoglobin could reduce the risk of ischemia in a critically hypoperfused organ. In this physiologic proof-of-principle study, we determined whether transfusion could augment cerebral oxygen delivery, particularly in vulnerable brain regions, across a broad range of hemoglobin values. DESIGN:Prospective study measuring cerebral blood flow and oxygen extraction fraction using O-PET. Vulnerable brain regions were defined as those with baseline oxygen delivery less than 4.5?mL/100?g/min. SETTING:PET facility located within the Neurology/Neurosurgery ICU. PATIENTS:Fifty-two patients at risk for delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage with hemoglobin 7-13?g/dL. INTERVENTIONS:Transfusion of one unit of RBCs over 1 hour. MEASUREMENTS AND MAIN RESULTS:Baseline hemoglobin was 9.7?g/dL (range, 6.9-12.9), and cerebral blood flow was 43?±?11?mL/100?g/min. After transfusion, hemoglobin rose from 9.6?±?1.4 to 10.8?±?1.4?g/dL (12%; p < 0.001) and oxygen delivery from 5.0 (interquartile range, 4.4-6.6) to 5.5?mL/100?g/min (interquartile range, 4.8-7.0) (10%; p = 0.001); the response was comparable across the range of hemoglobin values. In vulnerable brain regions, transfusion resulted in a greater (16%) rise in oxygen delivery associated with reduction in oxygen extraction fraction, independent of Hgb level (p = 0.002 vs normal regions). CONCLUSIONS:This study demonstrates that RBC transfusion improves cerebral oxygen delivery globally and particularly to vulnerable regions in subarachnoid hemorrhage patients at risk for delayed cerebral ischemia across a wide range of hemoglobin values and suggests that restrictive transfusion practices may not be appropriate in this population. Large prospective trials are necessary to determine if these physiologic benefits translate into clinical improvement and outweigh the risk of transfusion.

Project description:The diagnosis of cerebral vasospasm after Subarachnoid-Hemorrhage is currently very difficult, additional tools such as blood biomarkers are necessary. We tested the ability of gene expression profiles of blood cells to predict vasospasm. 32 patients suffering subarachnoid-hemorrhage were included in this prospective monocentre study. They were grouped according to have a complicated cerebral vasospasm (Vasospasm) or not (Control) and Paired according to age (+/- 10 years), sex, Fisher grade (+/- 1), location, smoking (at least 3 first parameters). Gene expression profiles of blood cells were determined using 25,000~gene microarray. Blood sample: 2.5 mL harvested in PAXgene® Blood RNA tubes (PreAnalytix) RNA extraction: PAXgene® Blood RNA kit (Qiagen). We used a Universel Reference RNA (Stratagene). RNA amplification and labelling: kit Amino Allyl MessageAmp II (Ambion). We hybridized 4 microarrays per patient using pangenomic microarrays from the "Réseau National des Génopôles" (Illkirch, France). 2 slides were hybridized with reference RNA labelled Cy3 and patient RNA labelled Cy5, and 2 slides were hybridized with reference RNA labelled Cy5 and patient RNA labelled Cy3. Hybridation : Agilent protocol with few modifications : 750 ng of each labelled RNA were hubriddized at 60°C during 17 hours in an Aglient hybridization oven. After washings, Slides were scanned with a GenePix 4000B scanner (Molecular Devices). Image intensity data were extracted with GenePix Pro 6.0 analysis software. Quantification of Cy3 and Cy5 and selection of good spots were performed using the MAIA software (Novikov E and Barillot E. Software package for automatic microarray image analysis (MAIA). The ACUITY software was then used to normalize log ratios Cy3/Cy5 with Lowess non linear normalization, to filter out genes not present in at least 3 slides out of 4, to evaluate the reproducibility of the 4 microarrays of each patient (hierarchical clustering, Self Organizing Maps). Statistical analyses to insure reproducibility was performed using Excel (correlation coefficients, ANOVA). Only slides that passed all reprocubility tests were validated.

Dataset Information

Red blood cell transfusion in patients with subarachnoid hemorrhage: a multidisciplinary North American survey.

Introduction

Methods

Results

Conclusions

Publications

Red blood cell transfusion in patients with subarachnoid hemorrhage: a multidisciplinary North American survey.

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