Traumatic brain injury patients with platelet inhibition receiving platelet transfusion demonstrate decreased need for neurosurgical intervention and decreased mortality

[Anaesthesiological Management of Traumatic Brain Injury]

Traumatic brain injury (TBI) is the main cause of death in people < 45 years in industrial countries. Minimising secondary injury to the injured brain is the primary goal throughout the entire treatment. Anaesthesiologic procedures aim at the reconstitution of cerebral perfusion and homeostasis. Both TBI itself as well as accompanying injuries show effects on cardiac and pulmonary function. Time management plays a crucial role in ensuring a safe anaesthesiologic environment while minimizing unnecessary procedures. Furthermore, growing medical drug pre-treatment demands for further knowledge e.g., in antagonization of anticoagulation.

The Impact of ADP Inhibition on Traumatic Brain Injury Outcomes

Platelet inhibition correlates with severity of traumatic brain injury and may be associated with mortality. Adenosine diphosphate participates in platelet aggregation via the activation of the ADP receptors, P2Y1 and P2Y12. Prior work suggests this ADP pathway is significant in managing patients with head injuries. This study aimed to measure the influence of ADP inhibition on outcomes after a traumatic brain injury (TBI), as measured by thromboelastography with platelet mapping (TEG-PM). Outcomes were defined as (a) hospital length of stay; (b) ICU length of stay, (c) mortality, and (d) progression of hemorrhage on CT. The resulting cohort was split into quartiles to compare the effect of increasingly inhibited ADP values on the identified outcomes. Comparisons of 2 groups of patients were also conducted, one defined by ADP inhibition less than or equal to 60% and the other group by ADP inhibition of greater than 60%. 98 patients were included in final analysis, with 72.4% having ADP inhibition less than 60%. These patients were significantly older and had lower global injury severity scores (ISSs), although their head-specific ISS was equivalent. Compared to the group with ADP inhibition over 60%, there was no significant difference in mortality, hospital or ICU length of stay, or progression of lesion on CT. Patients with ADP less than 60% inhibited had smaller ISS and higher GCS, indicating they were less injured than those with greater ADP inhibition, consistent with prior literature. The equivalent ICU and hospital length of stay and mortality suggests that ADP inhibition plays a smaller role in outcomes. Additional study with a larger sample size and guideline-based assessments is necessary to further define the impact of ADP inhibition and to determine the role of platelet transfusion in this population.

Management of Antithrombotic Drugs in Patients with Isolated Traumatic Brain Injury: An Intersociety Consensus Document

BACKGROUND

All available recommendations about the management of antithrombotic therapies (ATs) in patients who experienced traumatic brain injury (TBI) are mainly based on expert opinion because of the lack of strength in the available evidence-based medicine. Currently, the withdrawal and the resumption of AT in these patients is empirical, widely variable, and based on the individual assessment of the attending physician. The main difficulty is to balance the thrombotic and hemorrhagic risks to improve patient outcome.

METHODS

Under the endorsement of the Neurotraumatology Section of Italian Society of Neurosurgery, the Italian Society for the Study about Haemostasis and Thrombosis, the Italian Society of Anaesthesia, Analgesia, Resuscitation, and Intensive Care, and the European Association of Neurosurgical Societies, a working group (WG) of clinicians completed two rounds of questionnaires, using the Delphi method, in a multidisciplinary setting. A table for thrombotic and bleeding risk, with a dichotomization in high risk and low risk, was established before questionnaire administration. In this table, the risk is calculated by matching different isolated TBI (iTBI) scenarios such as acute and chronic subdural hematomas, extradural hematoma, brain contusion (intracerebral hemorrhage), and traumatic subarachnoid hemorrhage with patients under active AT treatment. The registered indication could include AT primary prevention, cardiac valve prosthesis, vascular stents, venous thromboembolism, and atrial fibrillation.

RESULTS

The WG proposed a total of 28 statements encompassing the most common clinical scenarios about the withdrawal of antiplatelets, vitamin K antagonists, and direct oral anticoagulants in patients who experienced blunt iTBI. The WG voted on the grade of appropriateness of seven recommended interventions. Overall, the panel reached an agreement for 20 of 28 (71%) questions, deeming 11 of 28 (39%) as appropriate and 9 of 28 (32%) as inappropriate interventions. The appropriateness of intervention was rated as uncertain for 8 of 28 (28%) questions.

CONCLUSIONS

The initial establishment of a thrombotic and/or bleeding risk scoring system can provide a vital theoretical basis for the evaluation of effective management in individuals under AT who sustained an iTBI. The listed recommendations can be implemented into local protocols for a more homogeneous strategy. Validation using large cohorts of patients needs to be developed. This is the first part of a project to update the management of AT in patients with iTBI.

The role of platelets in the blood-brain barrier during brain pathology

Platelets play critical roles in maintaining hemostasis. The blood brain barrier (BBB), a significant physical and metabolic barrier, helps maintain physiological stability by limiting transportations between the blood and neural tissues. When the brain undergoes inflammation, tumor, trauma, or bleeding, the platelet responses to help with maintaining BBB homeostasis. In the traditional point of view, activated platelets aggregate to form thrombi which cover the gaps of the blood vessels to protect BBB. However, increasing evidences indicate that platelets may harm BBB by enhancing vascular permeability. Hereby, we reviewed recently published articles with a special focus on the platelet-mediated damage of BBB. Factors released by platelets can induce BBB permeability, which involve platelet-activating factors (PAF), P-selectin, ADP, platelet-derived growth factors (PDGF) superfamily proteins, especially PDGF-AA and PDGF-CC, etc. Platelets can also secrete Amyloid-β (Aβ), which triggers neuroinflammation and downregulates the expression of tight junction molecules such as claudin-5 to damage BBB. Additionally, platelets can form aggregates with neutrophils to release reactive oxygen species (ROS), which can destroy the DNA, proteins, and lipids of endothelial cells (ECs). Moreover, platelets participate in neuroinflammation to affect BBB. Conversely, some of the platelet released factors such as PDGF-BB, protects BBB. In summary, platelets play dual roles in BBB integrity and the related mechanisms are reviewed.

The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Platelet Aggregation, Mitochondrial Function and Morphology in Cold Storage: Impact of Resveratrol and Cytochrome c Supplementation

Donated platelets are critical components of hemostasis management. Extending platelet storage beyond the recommended guidelines (5 days, 22 °C) is of clinical significance. Platelet coagulation function can be prolonged with resveratrol (Res) or cytochrome c (Cyt c) at 4 °C. We hypothesized that storage under these conditions is associated with maintained aggregation function, decreased reactive oxygen species (ROS) production, increased mitochondrial respiratory function, and preserved morphology. Donated platelets were stored at 22 °C or 4 °C supplemented with 50 μM Res or 100 μM Cyt c and assayed on days 0 (baseline), 5, 7 and 10 for platelet aggregation, morphology, intracellular ROS, and mitochondrial function. Declining platelet function and increased intracellular ROS were maintained by Res and Cyt c. Platelet respiratory control ratio declined during storage using complex I + II (CI + CII) or CIV substrates. No temperature-dependent differences (4 °C versus 22 °C) in respiratory function were observed. Altered platelet morphology was observed after 7 days at 22 °C, effects that were blunted at 4 °C independent of exposure to Res or Cyt c. Storage of platelets at 4 °C with Res and Cyt c modulates ROS generation and platelet structural integrity.

Neurotrauma

PURPOSE OF REVIEW

This review will highlight the latest research relevant to the clinical care of traumatic brain injury (TBI) patients over the last 2 years while underscoring the implications of these advances in the understanding of diagnosis, treatment, and prognosis of TBI.

RECENT FINDINGS

Brain tissue oxygenation monitoring can identify hypoperfusion as an adjunct to intracerebral pressure monitoring. Multiple biomarker assays are now available to help clinicians screen for mild TBI and biomarker elevations correlate with the size of intracranial injury. Beta-blocker exposure following TBI has demonstrated a survival benefit in those with TBI though the mechanism for this remains unknown. The optimal timing for venous thromboembolism prophylaxis for TBI patients is still uncertain.

SUMMARY

The current characterization of TBI as mild, moderate, or severe fails to capture the complexity of the disease process and helps little with prognostication. Molecular biomarkers and invasive monitoring devices including brain tissue oxygenation and measures of cerebral autoregulation are being utilized more commonly and can help guide therapy. Extracranial complications following TBI are common and include infection, respiratory failure, coagulopathy, hypercoagulability, and paroxysmal sympathetic hyperactivity.

Platelet Transfusion for Trauma Resuscitation

Purpose of Review

To review the role of platelet transfusion in resuscitation for trauma, including normal platelet function and alterations in behavior following trauma, blood product transfusion ratios and the impact of platelet transfusion on platelet function, platelet function assays, risks of platelet transfusion and considerations for platelet storage, and potential adjunct therapies and synthetic platelets.

Recent Findings

Platelets are a critical component of clot formation and breakdown following injury, and in addition to these hemostatic properties, have a complex role in vascular homeostasis, inflammation, and immune function. Evidence supports that platelets are activated following trauma with several upregulated functions, but under conditions of severe injury and shock are found to be impaired in their hemostatic behaviors. Platelets should be transfused in balanced ratios with red blood cells and plasma during initial trauma resuscitation as this portends improved outcomes including survival. Multiple coagulation assays can be used for goal-directed resuscitation for traumatic hemorrhage; however, these assays each have drawbacks in terms of their ability to measure platelet function. While resuscitation with balanced transfusion ratios is supported by the literature, platelet transfusion carries its own risks such as bacterial infection and lung injury. Platelet supply is also limited, with resource-intensive storage requirements, making exploration of longer-term storage options and novel platelet-based therapeutics attractive. Future focus on a deeper understanding of the biology of platelets following trauma, and on optimization of novel platelet-based therapeutics to maintain hemostatic effects while improving availability should be pursued.

Summary

While platelet function is altered following trauma, platelets should be transfused in balanced ratios during initial resuscitation. Severe injury and shock can impair platelet function, which can persist for several days following the initial trauma. Assays to guide resuscitation following the initial period as well as storage techniques to extend platelet shelf life are important areas of investigation.

Mechanism of Abnormal Coagulation Induced by Tigecycline in Cancer Patients

Tigecycline is a broad-spectrum active intravenous antibiotic that is active against methicillin-resistant staphylococcus aureus. In Phase 3 and 4 clinical trials, increased all-cause mortality was observed in patients treated with tigecycline compared to patients in the control group. The reason for the increase is unclear. In this study, we found that tigecycline cause abnormal coagulation in tumor patients, especially in patients with hematological malignancies. The main manifestations were decreased fibrinogen and prolonged activated prothrombin time (APTT), thrombin time (TT), and D-dimer. In addition, through functional studies, we found that tigecycline inhibit platelet adhesion and aggregation, and the coagulation function of patients gradually recover after discontinuation. Gene sequencing results suggested that tigecycline significantly regulate the expression of genes related to platelet function pathways and increase the incidence of single nucleotide polymorphisms and the number of alternative splices in the Chinese hamster ovary (CHO) cells treated with tigecycline. An abnormal function and low numbers of platelets are common in patients with hematological malignancies. Our study can explain the mechanism of abnormal coagulation caused by tigecycline. Additionally, doctors who apply tigecycline to cure infections in tumor patients should be warned.