Retrospective evaluation of anemia and transfusion in traumatic brain injury

Association of hemoglobin concentration and mortality in critically ill patients with severe traumatic brain injury

Introduction

The critical care management of traumatic brain injury focuses on preventing secondary ischemic injury. Cerebral oxygen delivery is dependent upon the cerebral perfusion pressure and the oxygen content of blood, which is principally determined by hemoglobin. Despite its importance to the cerebral oxygen delivery, the precise hemoglobin concentration to provide adequate oxygen delivery to injured neuronal tissue in TBI patients is controversial with limited evidence to provide transfusion thresholds.

Methods

We conducted a retrospective cohort study of severe TBI patients, investigating the association between mean 7-day hemoglobin concentration and hospital mortality. Demographic, physiologic, intensive care interventions, clinical outcomes and daily hemoglobin concentrations were recorded for all patients. Patients were all cared for at a tertiary, level 1 trauma center in a mixed medical and surgical intensive unit. Patients were divided into quartiles based on their mean 7-day hemoglobin concentration: < 90 g/L, 90 - 99 g/L, 100 - 109 g/L and > 110 g/L. Multivariable log-binomial regression was used to model the association between mean daily hemoglobin concentration and hospital mortality.

Results

Two hundred seventy-three patients with traumatic brain injury were identified and 169 were included in the analysis based on inclusion/exclusion criteria. Of these, 77% of the patients were male, with a mean age of 38 (SD 17) years and a median best GCS of 6 (IQR 5 - 7). One hundred fifteen patients (68%) received a red blood cell (RBC) transfusion. In RBCs administered in the ICU, the median pre-transfusion hemoglobin was 79 g/L (IQR 73 - 85). Thirty-seven patients (22%) died in hospital. Multivariable analysis revealed that mean 7-day hemoglobin concentration < 90 g/L was independently associated with an increased risk of hospital mortality (RR 3.1, 95% CI 1.5 - 6.3, p = 0.03). Other variables associated with increased mortality on multivariable regression were insertion of external ventricular drain, age and decreased GCS. Red blood cell transfusion was not associated with mortality following multivariable adjustment.

Conclusions

A mean 7-day hemoglobin concentration of < 90g/L is associated with increased hospital mortality in patients with severe traumatic brain injury.

Perioperative management of the pediatric patient with traumatic brain injury

TBI and its sequelae remain a major healthcare issue throughout the world. With an improved understanding of the pathophysiology of TBI, refinements of monitoring technology, and ongoing research to determine optimal care, the prognosis of TBI continues to improve. In 2003, the Society of Critical Care Medicine published guidelines for the acute management of severe TBI in infants, children, and adolescents. As pediatric anesthesiologists are frequently involved in the perioperative management of such patients including their stabilization in the emergency department, familiarity with these guidelines is necessary to limit preventable secondary damage related to physiologic disturbances. This manuscript reviews the current evidence-based medicine regarding the care of pediatric patients with TBI as it relates to the perioperative care of such patients. The issues reviewed include those related to initial stabilization, airway management, intra-operative mechanical ventilation, hemodynamic support, administration of blood and blood products, positioning, and choice of anesthetic technique. The literature is reviewed regarding fluid management, glucose control, hyperosmolar therapy, therapeutic hypothermia, and corticosteroids. Whenever possible, management recommendations are provided.

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.

Research priorities in neurocritical care

This summary of the last session of the First Neurocritical Care Research Conference reviews the discussions about research priorities in neurocritical care. The first presentation reviewed current projects funded by the National Institute of Neurological Disorders and Stroke at the National Institutes of Health and potential models to follow including an independent Neurocritical Care Network or the creation of such a network with the goal of collaborating with already existing ones. Experienced neurointensivists then presented their views on the most common and important research questions that need to be answered and investigated in the field. Finally, utility of clinical registries was discussed emphasizing their importance as hypothesis generators. During the group discussion, interests in comparative effectiveness research, the use of physiological endpoints from monitoring and alternate trial design were expressed.

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.

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.

[The damage control resuscitation concept]

OBJECTIVE

Damage control is a strategy of care for bleeding trauma patients, involving minimal rescue surgery associated to perioperative resuscitation. The purpose of this review is to draw up a statement on current knowledge available on damage control.

DATA SOURCES

References were obtained from recent review articles, personal files, and Medline database research of English and French publications. All categories of articles on this topic have been selected.

DATA SYNTHESIS

Historical damage control surgery, that consist of abbreviated laparotomy with second-look after resuscitation, is now included in a wider concept called "damage control resuscitation", addressing the lethal triad (coagulopathy, hypothermia and acidosis) at an early phase. Care is focused on coagulopathy prevention. Early resuscitation, or damage control ground zero, has been improved: aggressive management of hypothermia, bleeding control techniques, permissive hypotension concept and early use of vasopressors. Transfusion practices also have evolved: early platelets and coagulation factors administration, use of hemostatic agents like recombinant FVIIa, whole blood transfusion, denote the damage control hematology. Progress in surgical practices and development of arteriographic techniques lead to wider indications of damage control strategy.

Anemia in the setting of traumatic brain injury: the arguments for and against liberal transfusion

Anemia is recognized as a possible cause of secondary injury following traumatic brain injury (TBI). Cogent arguments can be made for both liberal and restrictive blood transfusion practices in this setting. In this narrative review, we summarize available knowledge regarding the risks of anemia and transfusion in patients with TBI. Laboratory studies using animal models and healthy human subjects suggest that anemia below a hemoglobin (Hb) concentration of 7 g/dL results in impaired brain function and below 10 g/dL may be detrimental to recovery from TBI. Clinical studies that have evaluated the association of anemia with clinical outcomes have not consistently demonstrated harm, but they generally have important methodological weaknesses. Alternatively, studies that have analyzed transfusion as a predictor of worse outcome have consistently identified such an association, but these studies may involve residual confounding. What little information exists from randomized trials that have included patients with TBI and evaluated liberal versus restrictive transfusion strategies is inconclusive. Since anemia in the setting of TBI is relatively common and there is considerable variation in transfusion preferences, greater study of this topic - preferably with one or more rigorous, adequately powered, non-inferiority randomized trials - is desirable.

Transfusions and long-term functional outcomes in traumatic brain injury

OBJECT

In this paper, the authors' goal was to examine the relationship between transfusion and long-term functional outcomes in moderately anemic patients (lowest hematocrit [HCT] level 21-30%) with traumatic brain injury (TBI). While evidence suggests that transfusions are associated with poor hospital outcomes, no study has examined transfusions and long-term functional outcomes in this population. The preferred transfusion threshold remains controversial.

METHODS

The authors performed a retrospective review of patients who were admitted with TBI between September 2005 and November 2007, extracting data such as HCT level, status of red blood cell transfusion, admission Glasgow Coma Scale (GCS) score, serum glucose, and length of hospital stay. Outcome measures assessed at 6 months were Glasgow Outcome Scale-Extended score, Functional Status Examination score, and patient death. A multivariate generalized linear model controlling for confounding variables was used to assess the association between transfusion and outcome.

RESULTS

During the study period, 292 patients were identified, and 139 (47.6%) met the criteria for moderate anemia. Roughly half (54.7%) underwent transfusions. Univariate analyses showed significant correlations between outcome score and patient age, admission GCS score, head Abbreviated Injury Scale score, number of days with an HCT level < 30%, highest glucose level, number of days with a glucose level > 200 mg/dl, length of hospital stay, number of patients receiving a transfusion, and transfusion volume. In multivariate analysis, admission GCS score, receiving a transfusion, and transfusion volume were the only variables associated with outcome (F = 2.458, p = 0.007; F = 11.694, p = 0.001; and F = 1.991, p = 0.020, respectively). There was no association between transfusion and death.

CONCLUSIONS

Transfusions may contribute to poor long-term functional outcomes in anemic patients with TBI. Transfusion strategies should be aimed at patients with symptomatic anemia or physiological compromise, and transfusion volume should be minimized.

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

Introduction

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

Methods

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

Results

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

Conclusions

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

Management of bleeding following major trauma: an updated European guideline

INTRODUCTION

Evidence-based recommendations are needed to guide the acute management of the bleeding trauma patient, which when implemented may improve patient outcomes.

METHODS

The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing a guideline for the management of bleeding following severe injury. This document presents an updated version of the guideline published by the group in 2007. Recommendations were formulated using a nominal group process, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence and based on a systematic review of published literature.

RESULTS

Key changes encompassed in this version of the guideline include new recommendations on coagulation support and monitoring and the appropriate use of local haemostatic measures, tourniquets, calcium and desmopressin in the bleeding trauma patient. The remaining recommendations have been reevaluated and graded based on literature published since the last edition of the guideline. Consideration was also given to changes in clinical practice that have taken place during this time period as a result of both new evidence and changes in the general availability of relevant agents and technologies.

CONCLUSIONS

This guideline provides an evidence-based multidisciplinary approach to the management of critically injured bleeding trauma patients.

Increasing hematocrit above 28% during early resuscitative phase is not associated with decreased mortality following severe traumatic brain injury

BACKGROUND

To prevent iatrogenic damage, transfusions of red blood cells should be avoided. For this, specific and reliable transfusion triggers must be defined. To date, the optimal hematocrit during the initial operating room (OR) phase is still unclear in patients with severe traumatic brain injury (TBI). We hypothesized that hematocrit values exceeding 28%, the local hematocrit target reached by the end of the initial OR phase, resulted in more complications, increased mortality, and impaired recovery compared to patients in whom hematocrit levels did not exceed 28%.

METHODS

Impact of hematocrit (independent variable) reached by the end of the OR phase on mortality and morbidity determined by the extended Glasgow outcome scale (eGOS; dependent variables) was investigated retrospectively in 139 TBI patients. In addition, multiple logistic regression analysis was performed to identify additional important variables.

FINDINGS

Following severe TBI, mortality and morbidity were neither aggravated by hematocrit above 28% reached by the end of the OR phase nor worsened by the required transfusions. Upon multiple logistic regression analysis, eGOS was significantly influenced by the highest intracranial pressure and the lowest cerebral perfusion pressure values during the initial OR phase.

CONCLUSIONS

Based on this retrospective observational analysis, increasing hematocrit above 28% during the initial OR phase following severe TBI was not associated with improved or worsened outcome. This questions the need for aggressive transfusion management. Prospective analysis is required to determine the lowest acceptable hematocrit value during the OR phase which neither increases mortality nor impairs recovery. For this, a larger caseload and early monitoring of cerebral metabolism and oxygenation are indispensable.

Therapeutic effects of erythropoietin on histological and functional outcomes following traumatic brain injury in rats are independent of hematocrit

Erythropoietin (EPO) provides neuroprotection and neurorestoration after traumatic brain injury (TBI). The EPO doses used for treatment of TBI significantly increase hematocrit, which may affect the efficacy of EPO therapy for TBI. The aim of this study was to investigate whether normalization of hematocrit would affect EPO efficacy for treatment of TBI. Young adult male Wistar rats were randomly divided into four groups: (1) Sham group (n=6); (2) TBI+ saline group (n=6); (3) TBI+ EPO group (n=6); and (4) TBI+ EPO+ hemodilution group (n=7). TBI was induced by controlled cortical impact over the left parietal cortex. EPO (5,000 U/kg) or saline was administered intraperitoneally at days 1, 2, and 3 postinjury. Neurological function was assessed using a modified neurological severity score (mNSS), footfault and the Morris water maze (MWM) tests. Animals were sacrificed 35 days after injury, and brain sections were stained for immunohistochemistry. Compared to the saline treatment, EPO treatment significantly reduced hippocampal cell loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, and significantly improved sensorimotor functional outcome (lowered mNSS and foot faults) and spatial learning (MWM test). Normovolemic hemodilution effectively normalized the hematocrit and did not significantly affect the histological and functional outcome of EPO therapy for TBI. These data for the first time demonstrate that increased hematocrit does not affect therapeutic effects of EPO on histological and long-term functional outcomes in rats after TBI and also suggest that neuroprotection and neurorestoration of EPO treatment are independent of hematocrit.

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.

The effect of red blood cell transfusion on cerebral oxygenation and metabolism after severe traumatic brain injury

OBJECTIVE

There is evidence to suggest that anemia after severe traumatic brain injury (sTBI) is detrimental. However, there is a paucity of evidence supporting the use of transfusion of packed red blood cells in patients with sTBI. To understand the acute effect of packed red blood cell transfusion on cerebral oxygenation and metabolism in patients with sTBI.

DESIGN

Prospective clinical study.

SETTING

Addenbrooke's Neurosciences Critical Care Unit, a 21-bed tertiary academic unit.

PATIENTS

Thirty patients with sTBI.

INTERVENTIONS

Patients were randomized by computer random number generator to one of three transfusion thresholds: 8, 9, or 10 g/dL. When the patients' hemoglobin concentration fell below their assigned threshold, two units of packed red blood cells were transfused over 2 hours. A 1-hour period of stabilization was observed before final data collection.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was change in brain tissue oxygen (Pbto2). Secondary outcomes included dependence of baseline hemoglobin concentration and baseline Pbto2 on the relationship of transfusion and Pbto2, and the effect of transfusion on lactate pyruvate ratio (LPR) and brain pH as markers of cerebral metabolic state. Fifty-seven percent of patients experienced an increase in Pbto2 during the course of the study, whereas in 43% of patients, Pbto2 either did not change or decreased. Multivariable generalized estimating equation analysis revealed change in hemoglobin concentration to significantly and positively associated with change in Pbto2 [0.10 kPa/(g/dL) 95% confidence interval 0.03-0.17, p = 0.003]. Improvement in Pbto2 was not associated with baseline hemoglobin concentration or low Pbto2 (<1 kPa). Fifty-six percent of patients experienced an increase in LPR. No significant relationship between change in LPR or transfusion on pHbt and change in hemoglobin could be demonstrated.

CONCLUSIONS

Transfusion of packed red blood cells acutely results in improved brain tissue oxygen without appreciable effect on cerebral metabolism.

TRIAL REGISTRATION

ISRCTN89085577.

[Transfusion in neurosurgery]

In neurosurgery, the question of the optimal transfusion "trigger" remains a controversial matter. Regarding the brain, the current data are still incomplete, justifying the continuation of experimental and clinical studies. The existing expert advices are based on these rather poor data and would probably evolve after the completion of clinical studies in progress. In spine surgery, the situation is simpler and the transfusional stakes are quite similar to those of orthopedics and traumatology. With regard to hemostasis, standardized recommendations exist depending on the laboratory test results or the anticoagulant treatments of the patient.

Transfusion practices for acute traumatic brain injury: a survey of physicians at US trauma centers

PURPOSE

To determine whether physician specialty influences transfusion threshold in patients with acute severe traumatic brain injury (TBI).

METHODS

We surveyed transfusion preferences of chiefs of trauma surgery, chairs of neurosurgery, and surgical and neurosurgical ICU directors at all 187 US Level I trauma centers using a scenario-based, multiple-choice instrument administered by mail. We evaluated the hemoglobin value used as a transfusion threshold for patients with severe acute TBI in several scenarios as well as opinions regarding the rationale for transfusion.

RESULTS

The response rate was 58% (312/534). Mean time in practice was 17 +/- 8 years and 65% were board certified in critical care. Neurosurgeons (NS) used a greater mean hemoglobin threshold for transfusion of TBI patients than trauma surgeons (TS) and non-surgeon intensivists (CC) whether the intracranial pressure was normal (8.3 +/- 1.2, 7.5 +/- 1.0, and 7.5 +/- 0.8 g/dL; NS, TS, and CC, respectively, P < 0.001) or elevated (8.9 +/- 1.1, 8.0 +/- 1.1, and 8.4 +/- 1.1 g/dL; NS, TS, and CC, respectively, P < 0.001). All three groups commonly believed that secondary ischemic injury is an important problem following TBI (74, 66, and 63%, P = 0.32), but fewer NS believed that transfusions have important immunodulatory effects (25, 91, and 83%, P < 0.001).

CONCLUSIONS

Neurosurgeons prefer more liberal transfusion of TBI patients than TS and CC, suggesting that actual practice may depend largely on which specialist is primarily managing care. The observed clinical equipoise would justify a randomized trial of liberal versus restrictive transfusion strategies in patients with TBI.

Efficacy of red blood cell transfusion in the critically ill: a systematic review of the literature

BACKGROUND

Red blood cell (RBC) transfusions are common in intensive care unit, trauma, and surgical patients. However, the hematocrit that should be maintained in any particular patient because the risks of further transfusion of RBC outweigh the benefits remains unclear.

OBJECTIVE

A systematic review of the literature to determine the association between red blood cell transfusion, and morbidity and mortality in high-risk hospitalized patients.

DATA SOURCES

MEDLINE, Embase, Cochrane Register of Controlled Trials, and citation review of relevant primary and review articles.

STUDY SELECTION

Cohort studies that assessed the independent effect of RBC transfusion on patient outcomes. From 571 articles screened, 45 met inclusion criteria and were included for data extraction.

DATA EXTRACTION

Forty-five studies including 272,596 were identified (the outcomes from one study were reported in four separate publications). The outcome measures were mortality, infections, multiorgan dysfunction syndrome, and acute respiratory distress syndrome. The overall risks vs. benefits of RBC transfusion on patient outcome in each study was classified as (i) risks outweigh benefits, (ii) neutral risk, and (iii) benefits outweigh risks. The odds ratio and 95% confidence interval for each outcome measure was recorded if available. The pooled odds ratios were determined using meta-analytic techniques.

DATA SYNTHESIS

Forty-five observational studies with a median of 687 patients/study (range, 63-78,974) were analyzed. In 42 of the 45 studies the risks of RBC transfusion outweighed the benefits; the risk was neutral in two studies with the benefits outweighing the risks in a subgroup of a single study (elderly patients with an acute myocardial infarction and a hematocrit <30%). Seventeen of 18 studies, demonstrated that RBC transfusions were an independent predictor of death; the pooled odds ratio (12 studies) was 1.7 (95% confidence interval, 1.4-1.9). Twenty-two studies examined the association between RBC transfusion and nosocomial infection; in all these studies blood transfusion was an independent risk factor for infection. The pooled odds ratio (nine studies) for developing an infectious complication was 1.8 (95% confidence interval, 1.5-2.2). RBC transfusions similarly increased the risk of developing multi-organ dysfunction syndrome (three studies) and acute respiratory distress syndrome (six studies). The pooled odds ratio for developing acute respiratory distress syndrome was 2.5 (95% confidence interval, 1.6-3.3).

CONCLUSIONS

Despite the inherent limitations in the analysis of cohort studies, our analysis suggests that in adult, intensive care unit, trauma, and surgical patients, RBC transfusions are associated with increased morbidity and mortality and therefore, current transfusion practices may require reevaluation. The risks and benefits of RBC transfusion should be assessed in every patient before transfusion.

Aggressive red blood cell transfusion: no association with improved outcomes for victims of isolated traumatic brain injury

BACKGROUND

Clinical studies have caused blood transfusion practices in critically ill patients to become more conservative in the last decade. However, few studies have focused on trauma patients, particularly those with severe isolated traumatic brain injury.

METHODS

We conducted a retrospective study to test the hypothesis that patients with severe brain injury would not benefit from aggressive red blood cell transfusion (RBCT). End points of the study were in-hospital mortality and morbidity (pneumonia, urinary tract infection, deep venous thrombosis, pulmonary embolus, decubitus ulcer, bacteremia, septic shock, myocardial infarction, and seizure). Included in our retrospective study were patients at two urban, level I trauma centers who were admitted with a diagnosis of isolated head injury and with a Glasgow Coma Scale (GCS) score of 8 or less. We recorded demographic, interventional, and outcome variables.

RESULTS

In 289 patients, 24 of 25 (96%) were transfused if their lowest recorded intensive care unit (ICU) hemoglobin level was 8.0 g/dl or less. In contrast, only 9/182 (5%) of these 289 patients were transfused if the hemoglobin levels were 10.0 g/dl or greater. In the remaining 82 patients with lowest ICU hemoglobin levels of 8.0-10.0 g/dl, 52% were transfused. These 82 patients (43 underwent RBCT and 39 did not) were included in our analysis.

DISCUSSION

The overall in-hospital mortality rate was 32%; rates were similar between the two groups (29%, non-RBCT; 35%, RBCT) (P = 0.64). Likewise, in-hospital morbidity was similar between groups. Logistic and proportional hazard regression analyses identified RBCT as one predictor of mortality.

CONCLUSIONS

Our results suggest that a restrictive transfusion practice is safe for severely head-injured patients.

Optimal hemoglobin concentration in patients with subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury

PURPOSE OF REVIEW

The review outlines recent clinical and experimental studies regarding the effects of red blood-cell transfusion on clinical outcome in neurocritical patients, including patients with subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury. Optimal hemoglobin transfusion trigger and the role of other transfusion indicators for neurocritical patients are discussed.

RECENT FINDINGS

Acute anemia (hemoglobin levels near 7 g/dl) is well tolerated by healthy subjects, but extreme anemia might negatively affect clinical outcome of neurocritical patients. Conversely, high hemoglobin levels, attained by means other than red blood-cell transfusion, improve clinical outcome, whereas red blood-cell transfusion is associated with poorer clinical outcome (mortality, length of stay and disability) in patients presenting subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury. Studies defining the optimal hemoglobin concentration in neurocritical patients are lacking, but a restrictive transfusion policy seems to be safe and is often recommended. In the near future, signals coming from the brain, such as brain tissue oxygen tension and regional cerebral oxygen saturation, might potentially be developed into transfusion triggers.

SUMMARY

Both severe anemia and red blood-cell transfusion may negatively influence clinical outcome in neurocritical patients. Acceptance of low hemoglobin concentrations may be justified by avoiding negative transfusion effects. No evidence-based transfusion trigger in neurocritical patients can be recommended.

Role of anemia in traumatic brain injury

BACKGROUND

Few studies have investigated the effects of anemia in patients with traumatic brain injury (TBI). The objective of this study was to examine the role of anemia and blood transfusion on outcomes in TBI patients.

STUDY DESIGN

We performed a retrospective review of all blunt trauma patients with TBI admitted to the ICU from July 1998 to December 2005. Admission and daily ICU blood hemoglobin (hemoglobin) levels and blood transfusions during the first week of hospitalization were measured. Anemia was defined as a hemoglobin<9 g/dL occurring on 3 consecutive blood draws. The role of anemia and blood transfusion was investigated using logistic regression adjusting for factors, with p<0.2 from the bivariate analysis.

RESULTS

During the study period, 1,150 TBI patients were admitted to the ICU. When both anemia and blood transfusion were included in the full model, blood transfusion was significantly associated with higher mortality (adjusted odds ratio [AOR], 2.19 [95% CI, 1.27, 3.75]; p=0.0044) and more complications (AOR, 3.67 [95% CI, 2.18, 6.17]; p<0.0001), but anemia was not. But when transfusion was not included in the full model, anemia was a significant risk factor for mortality (AOR, 1.59 (95% CI, 1.13, 2.24); p=0.007) and for complications (AOR, 1.95 [95% CI, 1.42, 2.70]; p<0.0001).

CONCLUSIONS

Blood transfusion is associated with significantly worse outcomes in traumatic brain injured patients. In addition, blood transfusion is a major contributing factor to worse outcomes in TBI patients who are anemic. We caution against the liberal use of blood in TBI patients.

Traumatic brain injury: an integrated clinical case presentation and literature review. Part I: assessment and initial management

Holistic nursing care of critically ill patients continues to be a challenge for all levels of critical care clinicians. Patients with multi-system dysfunction in particular, present complicated clinical challenges that demand care based on sound knowledge and understanding of physiological, psychosocial and spiritual needs. Experiential learning through exposure to a range of patient presentations enables incremental development of professional practice and excellence in nursing care. Case study learning enhances understanding through application of theory to practice in complex clinical presentations. This two-part paper outlines the assessment, interventions and outcome of a person who sustained multiple trauma including severe traumatic brain injury (TBI). Part I explores assessment and initial management from pre-hospital care through to the Emergency Department (ED) and operating theatre. Part II describes the intensive care period as an integral component of the continuum of care. Key issues in the case are presented sequentially with relevant literature integrated and applied to clinical progress, focussing on the complex physiological, psychosocial, spiritual and environmental needs of the patient and his family. The purpose of the paper is to therefore provide a comprehensive learning resource for critical care nurses, particularly for those beginning their practice.

Cerebral blood flow and autoregulation after pediatric traumatic brain injury

Traumatic brain injury is a global health concern and is the leading cause of traumatic morbidity and mortality in children. Despite a lower overall mortality than in adult traumatic brain injury, the cost to society from the sequelae of pediatric traumatic brain injury is very high. Predictors of poor outcome after traumatic brain injury include altered systemic and cerebral physiology, including altered cerebral hemodynamics. Cerebral autoregulation is often impaired after traumatic brain injury and may adversely impact the outcome. Although altered cerebrovascular hemodynamics early after traumatic brain injury may contribute to disability in children, there is little information regarding changes in cerebral blood flow and cerebral autoregulation after pediatric traumatic brain injury. This review addresses normal pediatric cerebral physiology and cerebrovascular pathophysiology after pediatric traumatic brain injury.

The effect of anemia and blood transfusions on mortality in closed head injury patients

BACKGROUND

The purpose of this study was to determine if anemia in isolated head trauma patients results in a higher mortality rate that would justify a more liberal use of blood transfusions.

METHODS

A retrospective review of isolated blunt head trauma patients was performed between January 2001 and December 2006. Comparisons were made between survivors and nonsurvivors regarding demographics, laboratory values, transfusions received, and lengths of stay.

RESULTS

There were 788 patients with 735 survivors who were significantly younger (46.3 y +/- 21.5 survivors versus 68.9 y +/- 18.8 nonsurvivors, P < 0.0001) and less injured [(ISS: 14.7 +/- 5.2 survivors versus 23.2 +/- 4.7 nonsurvivors, P < 0.0001), (head abbreviated injury severity: 3.7 +/- 0.7 survivors versus 4.7 +/- 0.5 nonsurvivors, P < 0.0001)] than those who died (n = 53). The survivors also had shorter lengths of stay (days) [(ICU: 2.4 +/- 4.2 versus 5.6 +/- 11.7, P = 0.03), (hospital: 6.3 +/- 9.8 versus 7.8 +/- 14.8, P = 0.02)]. Multivariate logistic regression showed age (OR 1.063, CI 1.042-1.084), ISS (OR 1.376, CI 1.270-1.491), minimum hemoglobin (OR 0.855, CI 0.732-1.000), and total blood products transfused (OR 1.073, CI 1.008-1.142) to be independent predictors of mortality with an ROC of 0.942. Outcome was independent of the operative procedures, hematocrit and packed red blood cells transfused at 24, 48, and 72 h. Hemoglobin levels of <8 mg/dL were more predictive of death than >8 mg/dL (P = 0.01).

CONCLUSIONS

This study supports the need to balance mild anemia with judicious blood product use in the head trauma patient. Given the risk with blood product use, each transfusion should be carefully considered and the patient re-evaluated regularly to determine the need for further intervention.

Hemodynamic manipulation in the neuro-intensive care unit: cerebral perfusion pressure therapy in head injury and hemodynamic augmentation for cerebral vasospasm

PURPOSE OF REVIEW

The intent of this manuscript is to summarize the pathophysiologic basis for hemodynamic manipulation in subarachnoid hemorrhage and traumatic brain injury, highlight the most recent literature and present expert opinion on indications and use.

RECENT FINDINGS

Hemodynamic augmentation with vasopressors and inotropes along with hypervolemia are the mainstay of treatment of vasospasm due to subarachnoid hemorrhage. Considerable variation continues to exist regarding fluid management and the use of vasopressors and inotropes. Blood pressure augmentation, volume expansion and cardiac contractility enhancement improve cerebral blood flow in ischemic areas, ameliorate vasospasm and improve clinical condition. In patients suffering from severe traumatic brain injury, while every attempt is made to control intracranial hypertension, cerebral perfusion-directed therapy with fluids and vasopressors is also used to keep cerebral perfusion pressure above 60-70 mmHg. Yet, recent observations suggest that posttraumatic mitochondrial dysfunction has been proposed as an alternative explanation for lower cerebral blood flow after acute trauma.

SUMMARY

Hemodynamic manipulation is routinely used in the management of patients with acute vasospasm following subarachnoid hemorrhage and severe head injury. The rationale is to improve blood flow to the injured brain and prevent secondary ischemia.

Management of bleeding following major trauma: a European guideline

INTRODUCTION

Evidence-based recommendations can be made with respect to many aspects of the acute management of the bleeding trauma patient, which when implemented may lead to improved patient outcomes.

METHODS

The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing guidelines for the management of bleeding following severe injury. Recommendations were formulated using a nominal group process and the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) hierarchy of evidence and were based on a systematic review of published literature.

RESULTS

Key recommendations include the following: The time elapsed between injury and operation should be minimised for patients in need of urgent surgical bleeding control, and patients presenting with haemorrhagic shock and an identified source of bleeding should undergo immediate surgical bleeding control unless initial resuscitation measures are successful. A damage control surgical approach is essential in the severely injured patient. Pelvic ring disruptions should be closed and stabilised, followed by appropriate angiographic embolisation or surgical bleeding control, including packing. Patients presenting with haemorrhagic shock and an unidentified source of bleeding should undergo immediate further assessment as appropriate using focused sonography, computed tomography, serum lactate, and/or base deficit measurements. This guideline also reviews appropriate physiological targets and suggested use and dosing of blood products, pharmacological agents, and coagulation factor replacement in the bleeding trauma patient.

CONCLUSION

A multidisciplinary approach to the management of the bleeding trauma patient will help create circumstances in which optimal care can be provided. By their very nature, these guidelines reflect the current state-of-the-art and will need to be updated and revised as important new evidence becomes available.