Transfusion of erythrocyte concentrates produces a variable increment on cerebral oxygenation in patients with severe traumatic brain injury: a preliminary study

Anemia and Optimal Transfusion Thresholds in Brain-Injured Patients: A Narrative Review of the Literature

Anemia is a highly prevalent condition that may compromise oxygen delivery to vital organs, especially among the critically ill. Although current evidence supports the adoption of a restrictive transfusion strategy and threshold among the nonbleeding critically ill patient, it remains unclear whether this practice should apply to the brain-injured patient, given the predisposition to cerebral ischemia in this patient population, in which even nonprofound anemia may exert a detrimental effect on clinical outcomes. The purpose of this review is to provide an overview of the pathophysiological changes related to impaired cerebral oxygenation in the brain-injured patient and to present the available evidence on the effect of anemia and varying transfusion thresholds on the clinical outcomes of patients with acute brain injury.

Avoiding brain hypoxia in severe traumatic brain injury in settings with limited resources - A pathophysiological guide

Cerebral oxygenation represents the balance between oxygen delivery, consumption and utilization by the brain, and therefore reflects the adequacy of cerebral perfusion. Different factors can influence the amount of oxygen to the brain including arterial blood pressure, hemoglobin levels, systemic oxygenation, and transfer of oxygen from blood to the cerebral microcirculation. A mismatch between cerebral oxygen supply and demand results in cerebral hypoxia/ischemia, and is associated with secondary brain damage and worsened outcome after acute brain injury. Therefore, monitoring and prompt treatment of cerebral oxygenation compromise is warranted in both neuro and general intensive care unit populations. Several tools have been proposed for the assessment of cerebral oxygenation, including non-invasive/invasive or indirect/direct methods, including Jugular Venous Oxygen Saturation (SjO2), Partial Brain Tissue Oxygen Tension (PtiO2), Near infrared spectroscopy (NIRS), Transcranial Doppler, electroencephalography and Computed Tomography. In this manuscript, we aim to review the pathophysiology of cerebral oxygenation, describe monitoring technics, and generate recommendations for avoiding brain hypoxia in settings with low availability of resources for direct brain oxygen monitoring.

Haemoglobin transfusion threshold in traumatic brain injury optimisation (HEMOTION): a multicentre, randomised, clinical trial protocol

INTRODUCTION

Traumatic brain injury (TBI) is the leading cause of mortality and long-term disability in young adults. Despite the high prevalence of anaemia and red blood cell transfusion in patients with TBI, the optimal haemoglobin (Hb) transfusion threshold is unknown. We undertook a randomised trial to evaluate whether a liberal transfusion strategy improves clinical outcomes compared with a restrictive strategy.

METHODS AND ANALYSIS

HEMOglobin Transfusion Threshold in Traumatic Brain Injury OptimizatiON is an international pragmatic randomised open label blinded-endpoint clinical trial. We will include 742 adult patients admitted to an intensive care unit (ICU) with an acute moderate or severe blunt TBI (Glasgow Coma Scale ≤12) and a Hb level ≤100 g/L. Patients are randomly allocated using a 1:1 ratio, stratified by site, to a liberal (triggered by Hb ≤100 g/L) or a restrictive (triggered by Hb ≤70 g/L) transfusion strategy applied from the time of randomisation to the decision to withdraw life-sustaining therapies, ICU discharge or death. Primary and secondary outcomes are assessed centrally by trained research personnel blinded to the intervention. The primary outcome is the Glasgow Outcome Scale extended at 6 months. Secondary outcomes include overall functional independence measure, overall quality of life (EuroQoL 5-Dimension 5-Level; EQ-5D-5L), TBI-specific quality of life (Quality of Life after Brain Injury; QOLIBRI), depression (Patient Health Questionnaire; PHQ-9) and mortality.

ETHICS AND DISSEMINATION

This trial is approved by the CHU de Québec-Université Laval research ethics board (MP-20-2018-3706) and ethic boards at all participating sites. Our results will be published and shared with relevant organisations and healthcare professionals.

TRIAL REGISTRATION NUMBER

NCT03260478.

Factors Associated With Brain Tissue Oxygenation Changes After RBC Transfusion in Acute Brain Injury Patients

OBJECTIVES

Anemia is common after acute brain injury and can be associated with brain tissue hypoxia. RBC transfusion (RBCT) can improve brain oxygenation; however, predictors of such improvement remain unknown. We aimed to identify the factors associated with PbtO2 increase (greater than 20% from baseline value) after RBCT, using a generalized mixed model.

DESIGN

This is a multicentric retrospective cohort study (2012-2020).

SETTING

This study was conducted in three European ICUs of University Hospitals located in Belgium, Switzerland, and Austria.

PATIENTS

All patients with acute brain injury who were monitored with brain tissue oxygenation (PbtO2) catheters and received at least one RBCT.

INTERVENTION

Patients received at least one RBCT. PbtO2 was recorded before, 1 hour, and 2 hours after RBCT.

MEASUREMENTS AND MAIN RESULTS

We included 69 patients receiving a total of 109 RBCTs after a median of 9 days (5-13 d) after injury. Baseline hemoglobin (Hb) and PbtO2 were 7.9 g/dL [7.3-8.7 g/dL] and 21 mm Hg (16-26 mm Hg), respectively; 2 hours after RBCT, the median absolute Hb and PbtO2 increases from baseline were 1.2 g/dL [0.8-1.8 g/dL] (p = 0.001) and 3 mm Hg (0-6 mm Hg) (p = 0.001). A 20% increase in PbtO2 after RBCT was observed in 45 transfusions (41%). High heart rate (HR) and low PbtO2 at baseline were independently associated with a 20% increase in PbtO2 after RBCT. Baseline PbtO2 had an area under receiver operator characteristic of 0.73 (95% CI, 0.64-0.83) to predict PbtO2 increase; a PbtO2 of 20 mm Hg had a sensitivity of 58% and a specificity of 73% to predict PbtO2 increase after RBCT.

CONCLUSIONS

Lower PbtO2 values and high HR at baseline could predict a significant increase in brain oxygenation after RBCT.

Pioglitazone Therapy and Fractures: Systematic Review and Meta- Analysis

INTRODUCTION

Thiazolidinediones are a group of synthetic medications used in type 2 diabetes treatment. Among available thiazolidinediones, pioglitazone is gaining increased attention due to its lower cardiovascular risk in type 2 diabetes mellitus sufferers and seems a promising future therapy. Accumulating evidence suggests that diabetic patients may exert bone fractures due to such treatments. Simultaneously, the female population is thought to be at greater risk. Still, the safety outcomes of pioglitazone treatment especially in terms of fractures are questionable and need to be clarified.

METHODS

We searched MEDLINE, Scopus, PsyInfo, eLIBRARY.ru electronic databases and clinical trial registries for studies reporting an association between pioglitazone and bone fractures in type 2 diabetes mellitus patients published before Feb 15, 2016. Among 1536 sources that were initially identified, six studies including 3172 patients proved relevant for further analysis.

RESULT

Pooled analysis of the included studies demonstrated that after treatment with pioglitazone patients with type 2 diabetes mellitus had no significant increase in fracture risk [odds ratio (OR): 1.18, 95% confidence interval (CI): 0.82 to 1.71, p=0.38] compared to other antidiabetic drugs or placebo. Additionally, no association was found between the risk of fractures and pioglitazone therapy duration. The gender of the patients involved was not relevant to the risk of fractures, too.

CONCLUSION

Pioglitazone treatment in diabetic patients does not increase the incidence of bone fractures. Moreover, there is no significant association between patients' fractures, their gender and the period of exposure to pioglitazone. Additional longitudinal studies need to be undertaken to obtain more detailed information on bone fragility and pioglitazone therapy.

Red blood cell transfusion in acute brain injury subtypes: An observational cohort study

PURPOSE

Optimal red blood cell (RBC) transfusion thresholds in acute brain injury (ABI) are poorly defined.

MATERIALS AND METHODS

We conducted a retrospective cohort study of adult patients with ABI and moderate anemia (Hb 7-10 g/dL) in a neurological intensive care unit (ICU) at an academic medical center between 2008 and 2015. Transfused and non-transfused patients were matched based on age, ABI subtype, pre-transfusion hemoglobin, and ICU length of stay (LOS) at the time of RBC transfusion. Multivariable regression analyses were performed to assess the relationship between RBC transfusion and hospital LOS, hospital mortality, ICU LOS, ICU mortality, and 24 h change in sequential organ failure assessment (SOFA) scores.

RESULTS

2638 patients met inclusion criteria, with 225 (8.5%) receiving RBC transfusion. Acute ischemic stroke was the most prevalent ABI diagnosis (43.3%) then intracranial hemorrhage (25.6%), subarachnoid hemorrhage (16.5%), and traumatic brain injury (TBI) (14.6%). In multivariable analyses, RBC transfusion was associated with longer hospital and ICU LOS, and higher SOFA scores. Each ABI subtype had similar results, except for TBI which showed no difference in hospital LOS. Mortality was not significantly different.

CONCLUSIONS

In moderately anemic patients with ABI, RBC transfusion was associated with longer hospital and ICU LOS. Prospective investigations are necessary to further assess these relationships.

Acute respiratory distress syndrome in traumatic brain injury: how do we manage it?

Traumatic brain injury (TBI) is an important cause of morbidity and mortality worldwide. TBI patients frequently suffer from lung complications and acute respiratory distress syndrome (ARDS), which is associated with poor clinical outcomes. Moreover, the association between TBI and ARDS in trauma patients is well recognized. Mechanical ventilation of patients with a concomitance of acute brain injury and lung injury can present significant challenges. Frequently, guidelines recommending management strategies for patients with traumatic brain injuries come into conflict with what is now considered best ventilator practice. In this review, we will explore the strategies of the best practice in the ventilatory management of patients with ARDS and TBI, concentrating on those areas in which a conflict exists. We will discuss the use of ventilator strategies such as protective ventilation, high positive end expiratory pressure (PEEP), prone position, recruitment maneuvers (RMs), as well as techniques which at present are used for 'rescue' in ARDS (including extracorporeal membrane oxygenation) in patients with TBI. Furthermore, general principles of fluid, haemodynamic and hemoglobin management will be discussed. Currently, there are inadequate data addressing the safety or efficacy of ventilator strategies used in ARDS in adult patients with TBI. At present, choice of ventilator rescue strategies is best decided on a case-by-case basis in conjunction with local expertise.

Cerebral Microdialysis Monitoring to Improve Individualized Neurointensive Care Therapy: An Update of Recent Clinical Data

Cerebral microdialysis (CMD) allows bedside semicontinuous monitoring of patient brain extracellular fluid. Clinical indications of CMD monitoring are focused on the management of secondary cerebral and systemic insults in acute brain injury (ABI) patients [mainly, traumatic brain injury (TBI), subarachnoid hemorrhage, and intracerebral hemorrhage (ICH)], specifically to tailor several routine interventions—such as optimization of cerebral perfusion pressure, blood transfusion, glycemic control and oxygen therapy—in the individual patient. Using CMD as clinical research tool has greatly contributed to identify and better understand important post-injury mechanisms—such as energy dysfunction, posttraumatic glycolysis, post-aneurysmal early brain injury, cortical spreading depressions, and subclinical seizures. Main CMD metabolites (namely, lactate/pyruvate ratio, and glucose) can be used to monitor the brain response to specific interventions, to assess the extent of injury, and to inform about prognosis. Recent consensus statements have provided guidelines and recommendations for CMD monitoring in neurocritical care. Here, we summarize recent clinical investigation conducted in ABI patients, specifically focusing on the role of CMD to guide individualized intensive care therapy and to improve our understanding of the complex disease mechanisms occurring in the immediate phase following ABI. Promising brain biomarkers will also be described.

The Impact of Red Blood Cell Transfusion on Cerebral Tissue Oxygen Saturation in Severe Traumatic Brain Injury

BACKGROUND

There are a range of opinions on the benefits and thresholds for the transfusion of red blood cells in critically ill patients with traumatic brain injury (TBI) and an urgent need to understand the neurophysiologic effects. The aim of this study was to examine the influence of red blood cell transfusions on cerebral tissue oxygenation (SctO₂) in critically ill TBI patients.

METHODS

This prospective observational study enrolled consecutive TBI patients with anemia requiring transfusion. Cerebral tissue oxygen saturation (SctO₂) was measured noninvasively with bilateral frontal scalp probes using near-infrared spectroscopy (NIRS) technology. Data were collected at baseline and for 24 h after transfusion. The primary outcome was the applicability of a four-wavelength near-infrared spectrometer to monitor SctO₂ changes during a transfusion. Secondary outcomes included the correlation of SctO₂ with other relevant physiological variables, the dependence of SctO₂ on baseline hemoglobin and transfusion, and the effect of red blood cell transfusion on fractional tissue oxygen extraction.

RESULTS

We enrolled 24 patients with severe TBI, of which five patients (21 %) were excluded due to poor SctO₂ signal quality from large subdural hematomas and bifrontal decompressive craniectomies. Twenty transfusions were monitored in 19 patients. The mean pre- and post-transfusion hemoglobin concentrations were significantly different [74 g/L (SD 8 g/L) and 84 g/L (SD 9 g/L), respectively; p value <0.0001]. Post-transfusion SctO₂ was not significantly greater than pre-transfusion SctO₂ [left-side pre-transfusion 69 % (SD 7) vs. post-transfusion 70 % (SD 10); p = 0.68, and right-side pre-transfusion 69 % (SD 5) vs. post-transfusion 71 % (SD 7); p = 0.11]. In a multivariable mixed linear analysis, mean arterial pressure was the only variable significantly associated with a change in SctO₂.

CONCLUSIONS

The bifrontal method of recording changes in NIRS signal was not able to detect a measurable impact on SctO₂ in this sample of patients receiving red blood cell transfusion therapy in a narrow but conventionally relevant, range of anemia.

Effects of Red Blood Cell Transfusion on Long-Term Disability of Patients with Traumatic Brain Injury

BACKGROUND

This 3-year prospective study examined the association between red blood cell transfusion (RBCT) and 1-year neurocognitive and disability levels in 309 patients with traumatic brain injury (TBI) admitted to the neurological intensive care unit (NICU).

METHODS

Using a telephone interview-based survey, functional outcomes were assessed by the Glasgow Outcome Scale (GOS), Rancho Los Amigos Levels of Cognitive Functioning Scale (RLCFS), and Disability Rating Scale (DRS) and dichotomized as favorable and unfavorable (dependent variable). The adjusted influence of RBCT on unfavorable results was assessed by conventional logistic regression, controlling for illness severity and propensity score (introduced as a continuous variable and by propensity score-matched patients).

RESULTS

Overall, 164 (53 %) patients received ≥1 unit of RBCT during their NICU stay. One year postinjury, transfused patients exhibited significantly higher unfavorable GOS (46.0 vs. 22.0 %), RLCFS (37.4 vs. 15.4 %), and DRS (39.6 vs. 18.7 %) scores than nontransfused patients. Although transfused patients were more severely ill upon admission, their adjusted odds ratios (95 % confidence intervals) for unfavorable GOS, RLCFS, and DRS scores were 2.5 (1.2-5.1), 3.0 (1.4-6.3), and 2.3 (1.1-4.8), respectively. These odds ratios remained largely unmodified when the calculated propensity score was incorporated as an independent continuous variable into the multivariate analysis. Furthermore, in 76 pairs of propensity score-matched patients, the rate of an unfavorable RLCFS score at the 1-year (but not 6-month) follow-up was significantly higher in transfused than nontransfused patients [3.0 (1.1-8.2)].

CONCLUSION

Our results strongly suggest an independent association between RBCT and unfavorable long-term functional outcomes of patients with TBI.

Transfusion Decision Making in Pediatric Critical Illness

Transfusion decision making (TDM) in the critically ill requires consideration of: (1) anemia tolerance, which is linked to active pathology and to physiologic reserve, (2) differences in donor RBC physiology from that of native RBCs, and (3) relative risk from anemia-attributable oxygen delivery failure vs hazards of transfusion, itself. Current approaches to TDM (e.g. hemoglobin thresholds) do not: (1) differentiate between patients with similar anemia, but dissimilar pathology/physiology, and (2) guide transfusion timing and amount to efficacy-based goals (other than resolution of hemoglobin thresholds). Here, we explore approaches to TDM that address the above gaps.

RBC Transfusion Improves Cerebral Oxygen Delivery in Subarachnoid Hemorrhage

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.

Blood transfusion indications in neurosurgical patients: A systematic review

Neurosurgical procedures can be complicated by significant blood losses that have the potential to decrease tissue perfusion to critical brain tissue. Red blood cell transfusion is used in a variety of capacities both inside, and outside, of the operating room to prevent untoward neurologic damage. However, evidence-based guidelines concerning thresholds and indications for transfusion in neurosurgery remain limited. Consequently, transfusion practices in neurosurgical patients are highly variable and based on institutional experiences. Recently, a paradigm shift has occurred in neurocritical intensive care units, whereby restrictive transfusion is increasingly favored over liberal transfusion but the ideal strategy remains in clinical equipoise. The authors of this study perform a systematic review of the literature with the objective of capturing the changing landscape of blood transfusion indications in neurosurgical patients.

The Effect of Red Blood Cell Transfusion on Cerebral Autoregulation in Patients with Severe Traumatic Brain Injury

BACKGROUND

Red blood cell (RBC) transfusion is associated with inconsistent changes in brain tissue oxygenation (PbO2). Previous studies have failed to consider alterations in cerebral autoregulation. Our objective was to investigate the effect of RBC transfusion on cerebral autoregulation, as measured by pressure reactivity index (PRx).

METHODS

Retrospective analysis of 28 severe traumatic brain injury (TBI) patients from a prospective registry between 2007 and 2014. We recorded hemoglobin (Hb) concentration, intracranial pressure, PbO2, cerebral perfusion pressure, PRx, and cerebral lactate/pyruvate ratio for 6 h before and after RBC transfusion. We also recorded body temperature, PaO2, PCO2, pH, and fraction of inspired oxygen. Subgroups of normoxia (PbO2 >20 mmHg) and hypoxia (PbO2 <20 mmHg) prior to transfusion were defined a priori.

RESULTS

The median age was 36 years [interquartile range (IQR) 27-49], 32% were female. The median admission Glasgow Coma score was 5 (IQR 4-9) and injury severity score was 16 (IQR 9-21). Overall, mean Hb concentration [80 g/L (SD 7) to 89 g/L (SD 8), p < 0.001] and PbO2 increased [23.5 mmHg (SD 8) to 25.0 mmHg (SD 9), p = 0.033] following transfusion. PRx increased post-transfusion [0.028 (SD 0.29) to 0.11 (SD 0.24), p = 0.034], indicating worsening cerebrovascular pressure reactivity. In patients with mean PbO2 >20 mmHg pre-transfusion (n = 20), the PRx increased significantly [-0.052 (SD 0.24) to 0.079 (SD 0.22), p = 0.007] but did not change in patients with PbO2 <20 mmHg: PRx [0.22 (SD 0.34) to 0.18 (SD 0.30), p = 0.36].

CONCLUSION

RBC transfusion in severe TBI patients results in worsening PRx, indicating impaired cerebral autoregulation.

Anemia and Blood Transfusion in Patients with Isolated Traumatic Brain Injury

Rationale. By reducing cerebral oxygen delivery, anemia may aggravate traumatic brain injury (TBI) secondary insult. This study evaluated the impact of anemia and blood transfusion on TBI outcomes. Methods. This was a retrospective cohort study of adult patients with isolated TBI at a tertiary-care intensive care unit from 1/1/2000 to 31/12/2011. Daily hemoglobin level and packed red blood cell (PRBC) transfusion were recorded. Patients with hemoglobin < 10 g/dL during ICU stay (anemic group) were compared with other patients. Results. Anemia was present on admission in two (2%) patients and developed in 48% during the first week with hemoglobin < 7 g/dL occurring in 3.0%. Anemic patients had higher admission Injury Severity Score and underwent more craniotomy (50% versus 13%, p < 0.001). Forty percent of them received PRBC transfusion (2.8 ± 1.5 units per patient, median pretransfusion hemoglobin = 8.8 g/dL). Higher hospital mortality was associated with anemia (25% versus 6% for nonanemic patients, p = 0.01) and PRBC transfusion (38% versus 9% for nontransfused patients, p = 0.003). On multivariate analysis, only PRBC transfusion independently predicted hospital mortality (odds ratio: 6.8; 95% confidence interval: 1.1–42.3). Conclusions. Anemia occurred frequently after isolated TBI, but only PRBC transfusion independently predicted mortality.

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.

Monitoring of brain and systemic oxygenation in neurocritical care patients

Maintenance of adequate oxygenation is a mainstay of intensive care, however, recommendations on the safety, accuracy, and the potential clinical utility of invasive and non-invasive tools to monitor brain and systemic oxygenation in neurocritical care are lacking. A literature search was conducted for English language articles describing bedside brain and systemic oxygen monitoring in neurocritical care patients from 1980 to August 2013. Imaging techniques e.g., PET are not considered. A total of 281 studies were included, the majority described patients with traumatic brain injury (TBI). All tools for oxygen monitoring are safe. Parenchymal brain oxygen (PbtO2) monitoring is accurate to detect brain hypoxia, and it is recommended to titrate individual targets of cerebral perfusion pressure (CPP), ventilator parameters (PaCO2, PaO2), and transfusion, and to manage intracranial hypertension, in combination with ICP monitoring. SjvO2 is less accurate than PbtO2. Given limited data, NIRS is not recommended at present for adult patients who require neurocritical care. Systemic monitoring of oxygen (PaO2, SaO2, SpO2) and CO2 (PaCO2, end-tidal CO2) is recommended in patients who require neurocritical care.

Red Blood Cell Transfusion in Patients With Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Our objectives were to evaluate the frequency of red blood cell (RBC) transfusion in patients with traumatic brain injury (TBI) as well as potential determinants and outcomes associated with RBC transfusion in this population. We conducted a systematic review of cohort studies and randomized trials of patients with TBI. We searched Medline, Embase, the Cochrane Library, and BIOSIS databases from their inception up to April 2015. We selected studies of adult patients with acute TBI reporting data on RBC transfusions. Cumulative incidences of transfusion were pooled using random-effect models with a DerSimonian approach. To evaluate the association between RBC transfusion and potential determinants or clinical outcomes, we pooled risk ratios or mean differences with random-effect models and the Mantel-Haenszel method. We identified 24 eligible studies (17414 patients). After pooling data from 23 studies (7524 patients), approximately 36% (95% confidence interval [CI], 28-44; I(2) = 98%) of patients received RBC transfusion at some point during their hospital stay. Hemoglobin thresholds for transfusion were rarely available (reported in 9 studies) and varied from 6 to 10 g/dL. Glasgow Coma Scale scores at admission were lower in patients who were transfused than those who were not (3 cohort studies; 1371 patients; mean difference of 1.38 points [95% CI, 0.86-1.89]; I(2) = 12%). Mortality was not significantly different among transfused and nontransfused patients in univariate and multivariate meta-analyses. Hospital length of stay was longer among patients receiving RBC transfusion compared to those who did not (3 studies; n = 455; mean difference, 9.58 days [95% CI, 3.94-15.22]; I(2) = 74%). Results should be considered cautiously due to the high heterogeneity and high risk of confounding from the observational nature of included studies. Red blood cell transfusion is frequent in patients with TBI, and transfusion practices varied widely between studies. Current published data highlight the lack of clinical evidence guiding transfusion strategies in TBI.

Blood transfusion practices in neuroanaesthesia

Neuroanaesthesia practice is associated with risk of significant blood loss resulting in anaemia in the intraoperative and postoperative period. The transfusion triggers in a neurologically injured brain are not clearly defined. Both a low haematocrit and a high haematocrit have not shown any improvement in the outcome. Transfusion of red blood cells may improve the cerebral oxygenation on neurophysiological monitors. However, these benefits have not been translated into clinical practice. Transfusion in subarachnoid haemorrhage leads to increased incidence of vasospasm and a poor outcome. Restrictive transfusion strategy is seen to have a lower incidence of pneumonia, urinary tract infection, bacteremia and septic shock in severe head injury. Current evidence suggests that a haemoglobin (Hb) level of <7 g/dl may be deleterious to the neurosurgical population. Target Hb of 8-9 g/dl may be desirable intraoperatively. Different transfusion triggers may hold true for different neurosurgical pathologies.

Strategies for the management of haemorrhage following pelvic fractures and associated trauma-induced coagulopathy

Exsanguination is the second most common cause of death in patients who suffer severe trauma. The management of haemodynamically unstable high-energy pelvic injuries remains controversial, as there are no universally accepted guidelines to direct surgeons on the ideal use of pelvic packing or early angio-embolisation. Additionally, the optimal resuscitation strategy, which prevents or halts the progression of the trauma-induced coagulopathy, remains unknown. Although early and aggressive use of blood products in these patients appears to improve survival, over-enthusiastic resuscitative measures may not be the safest strategy. This paper provides an overview of the classification of pelvic injuries and the current evidence on best-practice management of high-energy pelvic fractures, including resuscitation, transfusion of blood components, monitoring of coagulopathy, and procedural interventions including pre-peritoneal pelvic packing, external fixation and angiographic embolisation.

The impact of low hemoglobin levels and transfusion on critical care patients with severe ischemic stroke: STroke: RelevAnt Impact of HemoGlobin, Hematocrit and Transfusion (STRAIGHT)--an observational study

PURPOSE

Optimal management of hemoglobin (Hb) and red blood cell transfusion (RBCT) in neurologic intensive care unit (NICU) patients has not been determined yet. Here we aimed to investigate the impact of anemia and transfusion activity in patients who had acute ischemic stroke.

MATERIALS AND METHODS

A retrospective analysis of clinical, laboratory, and outcome data of patients with severe acute ischemic stroke treated on our NICU between 2004 and 2011 was performed.

RESULTS

Of 109 patients, 97.2% developed anemia and 33% received RBCT. Significant correlations were found between NICU length of stay (NICU LOS) and lowest (nadir) Hb (correlation coefficient, -0.42, P < .001), Hb decrease (0.52, P < .001), nadir hematocrit (Hct; -0.43, P < .001), and Hct decrease (0.51, P < .001). Duration of mechanical ventilation (MV) was strongly associated with both nadir Hb (-0.41, P < .001) and decrease (0.42, P < .001) and nadir Hct (-0.43, P < .001) and decrease (0.40, P < .001). Red blood cell transfusion correlated with NICU LOS (0.33, P < .001) and with duration of MV (0.40, P < .001). None of these hematologic parameters correlated with in-hospital mortality or 90-day outcome. The linear regression model showed number of RBCT (0.29, P = .008), nadir Hb (-0.18, P = .049), Hb decrease (0.33, P < .001), nadir Hct (-0.18, P = .03), and Hct decrease (0.29, P < .001) to be independent predictors of NICU LOS. Duration of MV was also independently predicted by number of RBC transfusions (0.29, P < .001), nadir Hb (-0.20, P = .02), Hb decrease (0.25, P = .002), nadir Hct (-0.21, P = .015), and Hct decrease (0.26, P < .001).

CONCLUSIONS

Low and further decreasing Hb and Hct levels as well as RBCT activity are associated with prolonged NICU stay and duration of MV but not with mortality or long-term outcome. Our findings do not justify using a more aggressive transfusion practice at present.

Haemoglobin management in acute brain injury

PURPOSE OF REVIEW

Anaemia is common among patients in the neurocritical care unit (NCCU) and is thought to exacerbate brain injury. However, the optimal haemoglobin (Hgb) level still remains to be elucidated for traumatic brain injury (TBI), subarachnoid haemorrhage (SAH) and acute ischaemic stroke (AIS). This review outlines recent studies about anaemia and the effects of red blood cell transfusion (RBCT) on outcome in TBI, SAH and AIS patients admitted to the NCCU.

RECENT FINDINGS

Patients with severe SAH, AIS and TBI often develop anaemia and require RBCT. In general critical care, a restrictive RBCT strategy (Hgb ~7 g/dl) is preferable in patients without serious cardiac disease. In severe TBI, AIS and SAH, both anaemia and RBCT may negatively influence clinical outcome. However, the appropriate RBCT trigger remains unclear and there is great variance in how these patients are transfused. There is evidence from PET and microdialysis studies in humans that RBCT can favourably influence brain metabolism and oxygenation. This correction of hypoxia or altered metabolism rather than anaemia may be of greater importance.

SUMMARY

Results from general critical care should not be extrapolated to all patients with acute brain injury. Transfusion is not risk free, but RBCT use needs to be considered also in terms of potential benefit.

Perioperative management of traumatic brain injury

Traumatic brain injury (TBI) is a major public health problem and the leading cause of death and disability worldwide. Despite the modern diagnosis and treatment, the prognosis for patients with TBI remains poor. While severity of primary injury is the major factor determining the outcomes, the secondary injury caused by physiological insults such as hypotension, hypoxemia, hypercarbia, hypocarbia, hyperglycemia and hypoglycemia, etc. that develop over time after the onset of the initial injury, causes further damage to brain tissue, worsening the outcome in TBI. Perioperative period may be particularly important in the course of TBI management. While surgery and anesthesia may predispose the patients to new onset secondary injuries which may contribute adversely to outcomes, the perioperative period is also an opportunity to detect and correct the undiagnosed pre-existing secondary insults, to prevent against new secondary insults and is a potential window to initiate interventions that may improve outcome of TBI. For this review, extensive Pubmed and Medline search on various aspects of perioperative management of TBI was performed, followed by review of research focusing on intraoperative and perioperative period. While the research focusing specifically on the intraoperative and immediate perioperative TBI management is limited, clinical management continues to be based largely on physiological optimization and recommendations of Brain Trauma Foundation guidelines. This review is focused on the perioperative management of TBI, with particular emphasis on recent developments.

Physiopathology of anemia and transfusion thresholds in isolated head injury

BACKGROUND

Blood transfusion strategies among patients with critical illness use a restrictive hemoglobin threshold. However, among patients with head injury, no outcome differences have been shown between either liberal or restrictive strategies. Several studies and literature reviews suggest that anemia is associated with markers of tissue ischemia. The paucity of prospective data confuses the association between surrogates of tissue ischemia and neurological outcome.

METHODS

A narrative review of transfusion practices among patients in the acute phase of head injury was performed using PubMed, MEDLINE, EMBASE, Cochrane, and WEB of Science databases. A total of 104 articles were reviewed.

RESULTS

There are few data to guide clinical practice. Clinicians use blood hemoglobin concentrations to trigger transfusion. Markers of potential cerebral injury are not in regular use despite experimental and observational data rising from histologic examination, microdialysis, oximetry, and flow-based multimonitoring systems recommending their use to titrate blood transfusion in neurotrauma.

CONCLUSION

The generalization of transfusion triggers is common practice. Evidence-based approaches to transfusions strategies in head injury are lacking and not based on an understanding of cerebral physiopathology.

Hemoglobin levels and transfusions in neurocritically ill patients: a systematic review of comparative studies

Introduction

Accumulating evidence suggests that, in critically ill patients, a lower hemoglobin transfusion threshold is safe. However, the optimal hemoglobin level and associated transfusion threshold remain unknown in neurocritically ill patients.

Methods

We conducted a systematic review of comparative studies (randomized and nonrandomized) to evaluate the effect of hemoglobin levels on mortality, neurologic function, intensive care unit (ICU) and hospital length of stay, duration of mechanical ventilation, and multiple organ failure in adult and pediatric neurocritically ill patients. We searched MEDLINE, The Cochrane Central Register of Controlled Trials, Embase, Web of Knowledge, and Google Scholar. Studies focusing on any neurocritical care conditions were included. Data are presented by using odds ratios for dichotomous outcomes and mean differences for continuous outcomes.

Results

Among 4,310 retrieved records, six studies met inclusion criteria (n = 537). Four studies were conducted in traumatic brain injury (TBI), one in subarachnoid hemorrhage (SAH), and one in a mixed population of neurocritically ill patients. The minimal hemoglobin levels or transfusion thresholds ranged from 7 to 10 g/dl in the lower-Hb groups and from 9.3 to 11.5 g/dl in the higher-Hb groups. Three studies had a low risk of bias, and three had a high risk of bias. No effect was observed on mortality, duration of mechanical ventilation, or multiple organ failure. In studies reporting on length of stay (n = 4), one reported a significant shorter ICU stay (mean, -11.4 days (95% confidence interval, -16.1 to -6.7)), and one, a shorter hospital stay (mean, -5.7 days (-10.3 to -1.1)) in the lower-Hb groups, whereas the other two found no significant association.

Conclusions

We found insufficient evidence to confirm or refute a difference in effect between lower- and higher-Hb groups in neurocritically ill patients. Considering the lack of evidence regarding long-term neurologic functional outcomes and the high risk of bias of half the studies, no recommendation can be made regarding which hemoglobin level to target and which associated transfusion strategy (restrictive or liberal) to favor in neurocritically ill patients.

Red blood cell transfusion in neurosurgery

BACKGROUND

The necessity of red blood cell (RBC) transfusions in neurosurgical procedures is under debate. Although detailed recommendations exist for many other surgical disciplines, there are very limited data on the probability of transfusions during neurosurgical procedures.

METHODS

Three-thousand and twenty-six consecutive adult patients undergoing neurosurgical procedures at Saarland University Hospital from December 2006 to June 2008 were retrospectively analyzed for administration of RBCs. The patients were grouped into 11 main diagnostic categories for analysis. The transfusion probability and cross-match to transfusion ratio (C/T ratio) were calculated.

RESULTS

Overall, the transfusion probability for neurosurgical procedures was 1.7 % (52/3,026). The probability was 6.5 % for acute subdural hematoma (7/108), 6.2 % for spinal tumors (5/80), 4.6 % for intracerebral hemorrhage (ICH, 4/98), 2.8 % for abscess (3/108), 2.4 % for traumatic brain injury (4/162), 2.3 % for cerebral ischemia (1/44), 1.9 % for subarachnoid hemorrhage (SAH) /aneurysms (4/206), 1.4 % for brain tumors (10/718), 0.8 % for hydrocephalus (2/196), 0.4 % for degenerative diseases of the spine (5/1290), including 3.6 % (3/82) for posterior lumbar interbody fusion (PLIF) and 0 % for epidural hematoma (0/15). The transfusion probabilities for clipping and coiling of SAH were 2.9 % (2/68) and 1.7 % (2/120) respectively.

CONCLUSIONS

The probability of blood transfusion during neurosurgical procedures is well below the 10 % level which is generally defined as the limit for preoperative appropriation of RBCs. Patients with spinal tumors, acute subdural hematomas or ICH, i.e., patients undergoing large decompressive procedures of bone or soft tissue, had a higher probability of transfusion.

Controversies in neurosciences critical care

Neurocritical care is an evolving subspecialty with many controversial topics. The focus of this review is (1) transfusion thresholds in patients with acute intracranial bleeding, including packed red blood cell transfusion, platelet transfusion, and reversal of coagulopathy; (2) indications for seizure prophylaxis and choice of antiepileptic agent; and (3) the role of specialized neurocritical care units and specialists in the care of critically ill neurology and neurosurgery patients.

Perioperative management of adult traumatic brain injury

This article presents an overview of the management of traumatic brain injury (TBI) as relevant to the practicing anesthesiologist. Key concepts surrounding the pathophysiology and anesthetic principles are used to describe potential ways to reduce secondary insults and improve outcomes after TBI.

Red Blood Cell Transfusion and Transfusion Alternatives in Traumatic Brain Injury

OPINION STATEMENT: Anemia develops in about 50% of patients hospitalized with traumatic brain injury (TBI) and is recognized as a cause of secondary brain injury. This review examines the effects of anemia and transfusion on TBI patients through a literature search to identify original research on anemia and transfusion in TBI, the effects of transfusion on brain physiology, and the role of erythropoietin or hemoglobin-based blood substitutes (HBBSs). However, the amount of high-quality, prospective data available to help make decisions about when TBI patients should be transfused is very small. Randomized transfusion trials have involved far too few TBI patients to reach definitive conclusions. Thus, it is hardly surprising that there is widespread practice variation. In our opinion, a hemoglobin transfusion threshold of 7 g/dL cannot yet be considered safe for TBI patients admitted to hospital, and in particular to the ICU, as it is for other critically ill patients. Red blood cell transfusions often have immediate, seemingly beneficial effects on cerebral physiology, but the magnitude of this effect may depend in part upon how long the cells have been stored before administration. In light of existing physiological data, we generally aim to keep hemoglobin concentrations greater than 9 g/dL during the first several days after TBI. In part, the decision is based on the patient's risk of or development of secondary ischemia or brain injury. An increasing number of centers use multimodal neurologic monitoring, which may help to individualize transfusion goals based on the degree of cerebral hypoxia or metabolic distress. When available, brain tissue oxygen tension values less than 15-20 mm Hg or a lactate:pyruvate ratio greater than 30-40 would influence us to use more aggressive hemoglobin correction (e.g., a transfusion threshold of 10 g/dL). Clinicians can attempt to reduce transfusion requirements by limiting phlebotomy, minimizing hemodilution, and providing appropriate prophylaxis against gastrointestinal hemorrhage. Administration of exogenous erythropoietin may have a small impact in further reducing the need for transfusion, but it also may increase complications, most notably deep venous thrombosis. Erythropoietin is currently of great interest as a potential neuroprotective agent, but until it is adequately evaluated in randomized controlled trials, it should not be used routinely for this purpose. HBBSs are also of interest, but existing preparations have not been shown to be beneficial-or even safe-in the context of TBI.

Contemporary view on neuromonitoring following severe traumatic brain injury

Evolving brain damage following traumatic brain injury (TBI) is strongly influenced by complex pathophysiologic cascades including local as well as systemic influences. To successfully prevent secondary progression of the primary damage we must actively search and identify secondary insults e.g. hypoxia, hypotension, uncontrolled hyperventilation, anemia, and hypoglycemia, which are known to aggravate existing brain damage. For this, we must rely on specific cerebral monitoring. Only then can we unmask changes which otherwise would remain hidden, and prevent adequate intensive care treatment. Apart from intracranial pressure (ICP) and calculated cerebral perfusion pressure (CPP), extended neuromonitoring (SjvO₂, ptiO₂, microdialysis, transcranial Doppler sonography, electrocorticography) also allows us to define individual pathologic ICP and CPP levels. This, in turn, will support our therapeutic decision-making and also allow a more individualized and flexible treatment concept for each patient. For this, however, we need to learn to integrate several dimensions with their own possible treatment options into a complete picture. The present review summarizes the current understanding of extended neuromonitoring to guide therapeutic interventions with the aim of improving intensive care treatment following severe TBI, which is the basis for ameliorated outcome.

Anemia and transfusion after subarachnoid hemorrhage

Delayed cerebral ischemia after subarachnoid hemorrhage (SAH) may be affected by a number of factors, including cerebral blood flow and oxygen delivery. Anemia affects about half of patients with SAH and is associated with worse outcome. Anemia also may contribute to the development of or exacerbate delayed cerebral ischemia. This review was designed to examine the prevalence and impact of anemia in patients with SAH and to evaluate the effects of transfusion. A literature search was made to identify original research on anemia and transfusion in SAH patients. A total of 27 articles were identified that addressed the effects of red blood cell transfusion (RBCT) on brain physiology, anemia in SAH, and clinical management with RBCT or erythropoietin. Most studies provided retrospectively analyzed data of very low-quality according to the GRADE criteria. While RBCT can have beneficial effects on brain physiology, RBCT may be associated with medical complications, infection, vasospasm, and poor outcome after SAH. The effects may vary with disease severity or the presence of vasospasm, but it remains unclear whether RBCTs are a marker of disease severity or a cause of worse outcome. Erythropoietin data are limited. The literature review further suggests that the results of the Transfusion Requirements in Critical Care Trial and subsequent observational studies on RBCT in general critical care do not apply to SAH patients and that randomized trials to address the role of RBCT in SAH are required.

Red blood cell transfusion in the neurological ICU

Red blood cell transfusion (RBCT) is a common therapy used in the intensive care unit to treat anemia. However, due to deleterious side effects and questionable efficacy, the clinical benefit of RBCT in patients who are not actively bleeding is unclear. The results of randomized controlled trials suggest there is no benefit to a liberal transfusion practice in general critical care populations. Whether the results of these trials are applicable to brain injured patients is unknown, as patients with primary neurological injury were excluded. This article reviews the efficacy and complications of RBCT, as well as the relationship between RBCT and its outcome in both the general intensive care unit and neurologically critically ill populations.

[Treatment of massive bleeding: summary of the updated European guidelines]

Despite improved strategies in the treatment of polytraumatized patients the mortality rate of severely injured patients remains high. Thus, worldwide 5 million patients die due to trauma or trauma-related complications each year. As the majority of early trauma-related deaths are attributed to or caused by exsanguination the prevention and treatment of coagulopathy is of paramount significance. With the aim of developing guidelines and improve strategies to treat polytraumatized patients the multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2005. Under consideration of new clinical studies, an updated version of the original publication from 2007 has recently been published. Based on a systematic review of published literature the recommendations were formed according to "Grading of Recommendations Assessment, Development and Evaluation" (GRADE). This publication summarizes the main recommendations with a special emphasis on revisions and new aspects.

Gender influences cerebral oxygenation after red blood cell transfusion in patients with severe traumatic brain injury

BACKGROUND

Important differences with respect to gender exist in the prognosis and mortality of traumatic brain injury (TBI) patients. The objective of this study was to assess the role of gender as an independent factor in cerebral oxygenation variations following red blood cell transfusion (RBCT).

METHODS

This retrospective analysis of a prospective study was conducted on patients with severe TBI. Hemoglobin levels were measured at baseline and 6 h after transfusion. Brain tissue oxygen pressure (PbrO(2)), cerebral perfusion pressure (CPP), intracranial pressure (ICP), and mean arterial pressure (MAP) were measured at baseline, at the end of RBCT and at 1, 2, 3, 4, 5, and 6 h after transfusion. After the patients were stratified into two groups according to gender, the effect of RBCT on PbrO(2) (cerebral oxygenation) was analyzed using a multivariate analysis of variance with repeated measures (MANOVA). The MANOVA was repeated after adjusting for all covariables with baseline differences between groups.

RESULTS

At baseline, we found differences in age (P = 0.01), weight (P = 0.03), MAP (P = 0.01), ISS (P = 0.05), and CCP (P = 0.01) between the groups. After adjusting for these co-variables, we observed that gender and age were related to the increase in PbrO(2) (P = 0.05 and P = 0.04, respectively).

CONCLUSIONS

Our results suggest that the effect of RBCT on cerebral oxygenation, as measured by PbrO(2), is greater in women than in men.

Anemia and transfusion therapy: an update

Anemia is one of the most prevalent diseases in the general population and is a very frequently found condition in medical and surgical patients in all medical specialties. A good evaluation of its clinical impact and its therapeutic possibilities is essential. Allogenic blood transfusion is a useful procedure in anemia management, although it has important adverse effects. It is the responsibility of the clinician to know and to take into account all the available alternatives for the treatment of anemia. Blood transfusions, erythropoiesis-stimulating agents, iron therapy (oral and endovenous) and other therapeutic alternatives must be rationally used, in accordance with the currently available clinical evidence. This review article summarizes some epidemiological characteristics of anemia, its clinical evaluation and the main therapeutic possibilities based on the present knowledge, placing special emphasis on the critically ill patient.

Anemia is associated with metabolic distress and brain tissue hypoxia after subarachnoid hemorrhage

BACKGROUND

Anemia is frequently encountered in critically ill patients and adversely affects cerebral oxygen delivery and brain tissue oxygen (PbtO2). The objective of this study is to assess whether there is an association between anemia and metabolic distress or brain tissue hypoxia in patients with subarachnoid hemorrhage.

METHODS

Retrospective study was conducted in a neurological intensive care unit in a university hospital. Patients with subarachnoid hemorrhage that underwent multimodality monitoring with intracranial pressure, PbtO2 and microdialysis were analyzed. The relationships between hemoglobin (Hb) concentrations and brain tissue hypoxia (PbtO2 < or = 15 mmHg) and metabolic distress (lactate/pyruvate ratio > or =40) were analyzed with general linear models of logistic function for dichotomized outcomes utilizing generalized estimating equations.

RESULTS

A total of 359 matched neuromonitoring hours and Hb measurements were analyzed from 34 consecutive patients. The median hemoglobin was 9.7 g/dl (interquartile range 8.8-10.5). After adjusting for significant covariates, reduced hemoglobin concentration was associated with a progressively increased risk of brain tissue hypoxia (adjusted OR 1.7 [1.1-2.4]; P = 0.01 for every unit decrease). Also after adjusting for significant covariates, hemoglobin concentrations below 9 g/dl and between 9.1 and 10 g/dl were associated with an increased risk of metabolic distress as compared to concentrations between 10.1 and 11 g/dl (adjusted OR 3.7 [1.5-9.4]; P = 0.004 for Hb < or = 9 g/dl and adjusted OR 1.9 [1.1-3.3]; P = 0.03 for Hb 9.1-10 g/dl).

CONCLUSIONS

Anemia is associated with a progressively increased risk of cerebral metabolic distress and brain tissue hypoxia after subarachnoid hemorrhage.

Invasive and noninvasive assessment of cerebral oxygenation in patients with severe traumatic brain injury

PURPOSE

The aim of this study is to investigate the relationship between invasive brain tissue oxygen pressure (PbrO(2)) and noninvasive regional transcranial oxygen saturation (rSO(2)) in 22 stable patients with severe traumatic brain injury (TBI) during a 16 h period.

METHODS

This was a prospective, observational study carried out in the Neurocritical Care Unit of a level 1 trauma center in a teaching hospital. A total of 41,809 paired records for neuromonitoring variables were analyzed and compared.

RESULTS

A direct and independent correlation between rSO(2) and PbrO(2) was confirmed through adjusted [beta coefficient and (95% confidence interval, CI) = 0.36 (0.35-0.37)] and logistic [PbrO(2) >or=15 mmHg, as a dependent variable; adjusted odds ratio (AOR) and (95% CI) = 1.11 (1.10-1.12)] regression analyses. A receiver-operating characteristic (ROC) curve demonstrated that rSO(2) had low accuracy for detecting moderate (PbrO(2) <or=15 mmHg) intracerebral hypoxia [area under curve (AUC) = 0.62], with the likelihood ratio for a positive test (LR+) = 1.2 for an optimal cutoff of rSO(2) <or=70%. In contrast, the ROC analysis showed that rSO(2) was moderately accurate for detecting severe (PbrO(2) <or=12 mmHg) intracerebral hypoxemia (AUC = 0.82; LR+ = 5.3) for an optimal cutoff of rSO(2) <or=60%.

CONCLUSIONS

In patients with severe TBI, PbrO(2) and rSO(2) were directly and significantly related. Severe intracerebral hypoxia was better detected by rSO(2) than was moderate intracerebral hypoxia. However, the diagnostic accuracy of rSO(2) was limited, and this measure should not be considered a substitute for routine PbrO(2) monitoring.

[Anemia and transfusion therapy: an update]

Anemia is one of the most prevalent diseases in the general population and is a very frequently found condition in medical and surgical patients in all medical specialties. A good evaluation of its clinical impact and its therapeutic possibilities is essential. Allogenic blood transfusion is a useful procedure in anemia management, although it has important adverse effects. It is the responsibility of the clinician to know and to take into account all the available alternatives for the treatment of anemia. Blood transfusions, erythropoiesis-stimulating agents, iron therapy (oral and endovenous) and other therapeutic alternatives must be rationally used, in accordance with the currently available clinical evidence. This review article summarizes some epidemiological characteristics of anemia, its clinical evaluation and the main therapeutic possibilities based on the present knowledge, placing special emphasis on the critically ill patient.

The effect of blood transfusion on brain oxygenation in children with severe traumatic brain injury

OBJECTIVE

The indications for blood transfusion in traumatic brain injury are controversial. In particular, little is known about the effect of blood transfusion in childhood traumatic brain injury. This study aimed to examine the influence of blood transfusion on brain tissue oxygen tension in children with severe traumatic brain injury.

DESIGN

A retrospective analysis of a prospective observational database of children with severe traumatic brain injury who received brain tissue oxygen tension monitoring and a blood transfusion.

SETTING

University-affiliated pediatric hospital.

PATIENTS

Children with severe traumatic brain injury and blood transfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Brain tissue oxygen tension was measured in normal-appearing white matter with a commercially available polarographic Clarke-type electrode. Brain tissue oxygen tension values after blood transfusion were compared with pre-transfusion values in hemodynamically stable patients. Limited interventions were allowed during the studied period. Brain tissue oxygen tension values were examined for early (1-4 hrs) and late (24 hrs) changes after blood transfusion, controlling for multiple clinical and physiologic variables with regression techniques. Further comparison was made with matched non-transfused controls to examine the influence of time after injury. Nineteen blood transfusions in 17 patients were evaluated. Brain tissue oxygen tension increased significantly in the early period after blood transfusion (p = .0018; 79% increased, 21% decreased) in comparison with baseline values and matched controls, but the overall changes were small and, in part, influenced by accompanying cerebral perfusion pressure changes. Also, this effect was limited to the early period after blood transfusion and was not significant after 24 hrs. In general, the brain tissue oxygen tension increase was larger in patients with higher baseline brain tissue oxygen tension and lower initial hemoglobin; however, no factors associated with the magnitude of the brain tissue oxygen tension change were significant in multivariate analysis. Increased age of blood did not appear to impair brain tissue oxygen tension changes, but most blood transfusion were <14 days old.

CONCLUSIONS

Brain tissue oxygen tension increased transiently in 79% of blood transfusion in pediatric traumatic brain injury patients, and decreased transiently in 21%. Brain tissue oxygen tension returned to baseline within 24 hrs. Reliable predictors of this brain tissue oxygen tension response to blood transfusion, however, remain elusive.