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

Systematic Review of Sex and Gender Effects in Traumatic Brain Injury: Equity in Clinical and Functional Outcomes

Background: Although traumatic brain injury (TBI) is a leading cause of death and disability in male and female patients worldwide, little is known about the effect of sex and gender on TBI outcomes.

Objectives: This systematic review summarizes the evidence on the effect of sex and gender on core TBI outcomes.

Methods: All English-language studies from six literature databases that addressed core outcomes in adults with TBI and included sex or gender, TBI severity, and age in their analyses were considered eligible. Two reviewers extracted data, and two reviewers assessed study quality using tools recommended by the National Institutes of Health. The results were sorted according to time post-injury, injury severity, gender equity ranking of the study's country of origin, and outcomes studied. The results from the included studies were grouped based on the approach taken in reporting their respective findings.

Results and Limitations: Of 172 articles assessed, 58 studies were selected, comprising 1, 265, 955 participants with TBI (67% male across all studies) of all injury severities. All studies were conducted in countries with a very high or high human development index, while the Gender Inequality Index (GII) varied. While the heterogeneity across studies limited any meaningful conclusions with respect to the role of sex and gender, we did observe that as gender equality ranking improved, differences between male and female participants in outcomes would diminish. Inclusion of social equity parameters in the studies was limited.

Conclusions and Implications: The non-uniform findings observed bring forth the need to develop and use a comprehensive and consistent methodology in the study of sex and gender post-TBI, incorporating social equity parameters to uncover the potential social underpinnings of gender effects on health and functional outcomes.

Systematic Review Registration: CRD42018098697.

Genetic Modulators of Traumatic Brain Injury in Animal Models and the Impact of Sex-Dependent Effects

Traumatic brain injury (TBI) is a major health problem causing disability and death worldwide. There is no effective treatment, due in part to the complexity of the injury pathology and factors affecting its outcome. The extent of brain injury depends on the type of insult, age, sex, lifestyle, genetic risk factors, socioeconomic status, other co-injuries, and underlying health problems. This review discusses the genes that have been directly tested in TBI models, and whether their effects are known to be sex-dependent. Sex differences can affect the incidence, symptom onset, pathology, and clinical outcomes following injury. Adult males are more susceptible at the acute phase and females show greater injury in the chronic phase. TBI is not restricted to a single sex; despite variations in the degree of symptom onset and severity, it is important to consider both female and male animals in TBI pre-clinical research studies.

Chinese Head Trauma Data Bank: Effect of Gender on the Outcome of Patients With Acute Traumatic Brain Injury

Gender may be related with the outcome of patients with acute traumatic brain injury (TBI). We explored the effect of gender on the outcome of 7145 patients with acute TBI. There was no statistical difference between male and female sex in the causes of trauma, age, Glasgow Coma Scale score, computed tomgraphy findings, and surgical management. The mortality of 7145 patients with acute TBI in males and females was 7.48% and 7.22%, respectively, with the corresponding unfavorable outcomes of 16.05% and 17.23%, respectively (p > 0.05 in both cases). The mortality of 1626 patients with severe TBI in males and females was 19.68% and 20.72%, respectively, with the corresponding unfavorable outcomes of 46.96% and 48.85%, respectively (p > 0.05 in both cases). Our data suggest that sex does not play a role in the outcome of patients with acute TBI.

Comorbidity in traumatic brain injury and functional outcomes: a systematic review

INTRODUCTION

Comorbidities in people with traumatic brain injury (TBI) may negatively impact injury recovery course and result in long-term disability. Despite the high prevalence of several categories of comorbidities in TBI, little is known about their association with patients' functional outcomes. We aimed to systematically review the current evidence to identify comorbidities that affect functional outcomes in adults with TBI.

EVIDENCE ACQUISITION

A systematic search of Medline, Cochrane Central Register of Controlled Trials, Embase and PsycINFO was conducted from 1997 to 2020 for prospective and retrospective longitudinal studies published in English. Three researchers independently screened and assessed articles for fulfillment of the inclusion criteria. Quality assessment followed the Quality in Prognosis Studies tool and the Scottish Intercollegiate Guidelines Network methodology recommendations.

EVIDENCE SYNTHESIS

Twenty-two studies of moderate quality discussed effects of comorbidities on functional outcomes of patients with TBI. Cognitive and physical functioning were negatively affected by comorbidities, although the strength of association, even within the same categories of comorbidity and functional outcome, differed from study to study. Severity of TBI, sex/gender, and age were important factors in the relationship. Due to methodological heterogeneity between studies, meta-analyses were not performed.

CONCLUSIONS

Emerging evidence highlights the adverse effect of comorbidities on functional outcome in patients with TBI, so clinical attention to this topic is timely. Future research on the topic should emphasize time of comorbidity onset in relation to the TBI event, to support prevention, treatment, and rehabilitation. PROSPERO registration (CRD 42017070033).

The Short-Term Effects of Isolated Traumatic Brain Injury on the Heart in Experimental Healthy Rats

BACKGROUND

To date, cardiac dysfunction after traumatic brain injury (TBI) has not been consistent. In this study, we hypothesized that TBI may play a role in the development of new-onset cardiac dysfunction in healthy experimental rats.

MATERIALS AND METHODS

Anesthetized healthy male Sprague-Dawley rats were divided into two groups: a sham-operated control group and a TBI group. The brain was injured with 2.4 atm percussion via a fluid percussion injury model. During the 120 min after TBI, we continuously measured brain parameters, including intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and cardiac parameters, such as heart rate (HR), inter-ventricular septum dimension (IVSD), left ventricular internal dimension diastole (LVIDd), end-diastolic volume (EDV), ejection fraction (EF), fractional shortening (FS), and LV mass diastole (LVd mass) by cardiac echo. On days 1, 3, 7, and 14 after TBI, the brain damage volume was evaluated with triphenyltetrazolium chloride; the physiological parameters of the heart, including HR, IVSd, LVIDd, EDV, EF, FS, and LVd mass, were evaluated with cardiac echo; the morphology of cardiomyocytes was examined by hematoxylin and eosin (HE) and Masson trichrome staining; and the biomarkers of cardiac injury troponin I and B-type natriuretic peptide (BNP) were also examined.

RESULTS

Compared to sham-operated controls, the TBI groups had higher ICP, lower CPP, and higher brain neuronal apoptosis and infarction contusion volume. The impact of TBI on heart function showed hyperdynamic response trends in IVSd, LVIDd, EDV, EF, FS, and LVd mass within 30 min after TBI; however, EF and FS exhibited eventual decreasing trends. Simultaneously, the values of the biomarkers troponin I and BNP were within normal limits, and HE and Mass trichrome staining revealed no significant differences between the sham-operated control group and the TBI group.

CONCLUSIONS

Our results suggest that TBI due to 2.4 atm fluid percussion injury in healthy experimental rats may cause significant damage to the brain and affect the heart function as investigated by cardiac echo but not as investigated by HE and Masson trichrome stainings or troponin I and BNP evaluation.

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.

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.

Current challenges in female veterans' health

Abstract Women in the U.S. military are technically barred from serving in combat specialties, positions, or units; however, since Operation Desert Storm, women have served in forward positions in greater numbers. This increased involvement in combat zones has resulted in exposures to trauma, injury, and a myriad of environmental hazards associated with modern war. Some of these hazards present new health risks specifically relevant to women who have been deployed to or recently returned from Iraq or Afghanistan or both. To address this evolving public health concern, the Society for Women's Health Research (SWHR) convened a 1-day interdisciplinary scientific conference, with speakers and attendees from civilian, military, and veteran settings. The purpose of the conference was to reveal the state-of-the-science on the health of the female veteran and to focus attention on recent advances in biomedical research related to female veterans' health. The following topics were discussed: mental health (posttraumatic stress disorder [PTSD] and depression), urogenital health, musculoskeletal health, and traumatic brain injury (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.