Platelet transfusion increases risk for acute respiratory distress syndrome in non-massively transfused blunt trauma patients

How I use platelet transfusions

Platelet transfusions are commonly administered for the prevention or treatment of bleeding in patients with acquired thrombocytopenia across a range of clinical contexts. Recent data, including randomized trials, have highlighted uncertainties in the risk-benefit balance of this therapy, which is the subject of this review. Hemovigilance systems report that platelets are the most frequently implicated component in transfusion reactions. There is considerable variation in platelet count increment after platelet transfusion, and limited evidence of efficacy for clinical outcomes, including prevention of bleeding. Bleeding events commonly occur despite the different policies for platelet transfusion prophylaxis. The underlying mechanisms of harm reported in randomized trials may be related to the role of platelets beyond hemostasis, including mediating inflammation. Research supports the implementation of a restrictive platelet transfusion policy. Research is needed to better understand the impact of platelet donation characteristics on outcomes, and to determine the optimal thresholds for platelet transfusion before invasive procedures or major surgery (eg, laparotomy). Platelet transfusion policies should move toward a risk-adapted approach that does not focus solely on platelet count.

Combat Trauma-Related Acute Respiratory Distress Syndrome: A Scoping Review

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are known complications of injuries in combat casualties, but there has been no review characterizing them. This scoping review aims to map the combat trauma-related ALI/ARDS literature and characterize these conditions in the military population.

DATA SOURCES

Pubmed was searched from 1969 to April 2022.

STUDY SELECTION

Studies were included if they examined ALI/ARDS or related entities (blast lung injury [BLI], transfusion-related acute lung injury, and acute respiratory failure) in combat trauma patients in the military (U.S. or allied forces).

DATA EXTRACTION

Study years, design, location, number of patients, target outcomes as related to ALI/ARDS or related entities, and results were collected.

DATA SYNTHESIS

The initial search yielded 442 studies, with 22 ultimately included. Literature on ALI/ARDS comes mostly from retrospective data and case studies, with limited prospective studies. The incidence and prevalence of ALI/ARDS range from 3% to 33%, and mortality 12.8% to 33%. BLI, a known antecedent to ALI/ARDS, has an incidence and mortality ranging from 1.4% to 40% and 11% to 56%, respectively. Risk factors for ALI/ARDS include pulmonary injury, inhalation injury, blunt trauma, pneumonia, higher military injury severity score, higher injury severity score, higher fresh frozen plasma volumes, higher plasma and platelet volumes, the use of warm fresh whole blood, female sex, low blood pressure, and tachycardia. Literature has demonstrated the effectiveness in transportation of these patients and the utility of extracorporeal life support.

CONCLUSIONS

ALI/ARDS incidences and prevalences in modern conflict range from 3% to 33%, with mortality ranging from 12.8% to 33%. ALI/ARDS has been associated with injury severity metrics, injury type, resuscitative fluid amount and type, vital signs, and patient demographics. Studies are limited to mostly retrospective data, and more data are needed to better characterize these conditions.

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.

The Clinical Impact of Platelets on Post-Injury Serum Creatinine Concentration in Multiple Trauma Patients: A Retrospective Cohort Study

Background and objective: Platelets contribute to the immunological response after multiple trauma. To determine the clinical impact, this study analyzes the association between platelets and creatinine concentration as an indicator of kidney function in polytraumatized patients. Methods: We investigated all patients presenting an Injury Severity Score (ISS) ≥16 for a 2-year period at our trauma center. Platelet counts and creatinine concentrations were analyzed, and correlation analysis was performed within 10 days after multiple trauma. Results: 83 patients with a median ISS of 22 were included. Platelet count was decreased on day 3 (p ≤ 0.001) and increased on day 10 (p ≤ 0.001). Platelet count was elevated on day 10 in younger patients and diminished in severely injured patients (ISS ≥35) on day 1 (p = 0.012) and day 3 (p = 0.011). Creatinine concentration was decreased on day 1 (p = 0.003) and day 10 (p ≤ 0.001) in female patients. Age (p = 0.01), male sex (p = 0.004), and injury severity (p = 0.014) were identified as factors for increased creatinine concentration on day 1, whereas platelets (p = 0.046) were associated with decreased creatinine concentrations on day 5 after multiple trauma. Conclusions: Kinetics of platelet count and creatinine concentration are influenced by age, gender, and trauma severity. There was no clear correlation between platelet counts and creatinine concentration. However, platelets seem to have a modulating effect on creatinine concentrations in the vulnerable phase after trauma.

Correlation between Platelet Count and Lung Dysfunction in Multiple Trauma Patients-A Retrospective Cohort Analysis

(1) Background: Current findings emphasize the potential contribution of platelets to the immunological response after severe trauma. As clinical relevance remains unclear, this study aims to analyze the correlation between platelets and lung dysfunction in severely injured patients. (2) Methods: We retrospectively enrolled all multiple trauma patients presenting to our level 1 trauma center from 2015 to 2016 with an Injury-Severity Score (ISS) ≥ 16. Apart from demographic data, platelet counts and PaO₂/FiO₂ as an approximate indicator for lung physiology were analyzed and correlated on subsequent days after admission. (3) Results: 83 patients with a median ISS of 22 (IQR 18–36) were included. Compared to day 1, platelet counts were decreased on day 3 (p ≤ 0.001). Platelet counts were significantly lower on day 3 in patients with an ISS ≥ 35 (p = 0.011). There were no differences regarding PaO₂/FiO₂ index. Correlation analysis revealed a positive link between increased platelet counts and PaO₂/FiO₂ index on day 1 only in severely injured patients (p = 0.007). (4) Conclusions: This work supports the concept of platelets modulating the posttraumatic immune response by affecting lung dysfunction in the early phase after multiple trauma in dependence of injury severity. Our findings contribute to the understanding of the impact of platelets on systemic processes in multiple trauma patients.

Impact of platelet transfusion on outcomes in trauma patients

Background

Trauma-induced coagulopathy includes thrombocytopenia and platelet dysfunction that impact patient outcome. Nevertheless, the role of platelet transfusion remains poorly defined. The aim of the study was 1/ to evaluate the impact of early platelet transfusion on 24-h all-cause mortality and 2/ to describe platelet count at admission (PCA) and its relationship with trauma severity and outcome.

Methods

Observational study carried out on a multicentre prospective trauma registry. All adult trauma patients directly admitted in participating trauma centres between May 2011 and June 2019 were included. Severe haemorrhage was defined as ≥ 4 red blood cell units within 6 h and/or death from exsanguination. The impact of PCA and early platelet transfusion (i.e. within the first 6 h) on 24-h all-cause mortality was assessed using uni- and multivariate logistic regression.

Results

Among the 19,596 included patients, PCA (229 G/L [189,271]) was associated with coagulopathy, traumatic burden, shock and bleeding severity. In a logistic regression model, 24-h all-cause mortality increased by 37% for every 50 G/L decrease in platelet count (OR 0.63 95% CI 0.57–0.70; p < 0.001). Regarding patients with severe hemorrhage, platelets were transfused early for 36% of patients. Early platelet transfusion was associated with a decrease in 24-h all-cause mortality (versus no or late platelets): OR 0.52 (95% CI 0.34–0.79; p < 0.05).

Conclusions

PCA, although mainly in normal range, was associated with trauma severity and coagulopathy and was predictive of bleeding intensity and outcome. Early platelet transfusion within 6 h was associated with a decrease in mortality in patients with severe hemorrhage. Future studies are needed to determine which doses of platelet transfusion will improve outcomes after major trauma.

Acute Respiratory Distress Syndrome (ARDS) after trauma: Improving incidence, but increasing mortality

PURPOSE

Acute Respiratory Distress Syndrome (ARDS) is an infrequent, yet morbid inflammatory complication in injury victims. With the current project we sought to estimate trends in incidence, determine outcomes, and identify risk factors for ARDS and related mortality.

MATERIALS & METHODS

The national Trauma Quality Improvement Program dataset (2010-2014) was queried. Demographics, injury characteristics and outcomes were compared between patients who developed ARDS and those who did not. Logistic regression models were fitted for the development of ARDS and mortality respectively, adjusting for relevant confounders.

RESULTS

In the studied 808,195 TQIP patients, incidence of ARDS decreased over the study years (3-1.1%, p < 0.001), but related mortality increased (18.-21%, p = 0.001). ARDS patients spent an additional 14.7 ± 10.3 days in the hospital, 9.7 ± 7.9 in the ICU, and 6.6 ± 9.4 on mechanical ventilation (all p < 0.001). Older age, male gender, African American race increased risk for ARDS. Age, male gender, lower GCS and higher ISS also increased mortality risk among ARDS patients. Several pre-existing comorbidities including chronic alcohol use, diabetes, smoking, and respiratory disease also increased risk.

CONCLUSION

Although the incidence of ARDS after trauma appears to be declining, mortality is on the rise.

Prophylactic use of platelets in critically ill patients with thrombocytopaenia: A retrospective two-centre observational study

PURPOSE

We report the use and effect of prophylactic platelet transfusions in critically ill thrombocytopaenic patients, comparing patients with or without bone marrow failure as a cause of thrombocytopaenia.

METHODS

A retrospective observational study of admissions to three intensive care units (ICU) in the UK. We identified thrombocytopaenic patients who received a platelet transfusion and extracted the platelet count prior and subsequent to platelet transfusion. We grouped patients with or without suspected bone marrow failure, defined by a total white cell count ≤1.0 × 10⁹/L.

RESULTS

Of 11,757 admissions, 399 (3.4%) patients received a platelet transfusion for thrombocytopaenia. The median [IQR] platelet count prior to transfusion in patients without bone marrow failure was 42 [28-64] × 10⁹/L versus 14 [7-24] × 10⁹/L (p < .0001) in those with. The median [IQR] increment in platelets following transfusion was lower in patients with marrow failure (12 [-1-23] × 10⁹/L) compared to those without (18 [5-36] × 10⁹/L) (p = .006).

CONCLUSIONS

Platelet transfusions were given at a higher median platelet count than suggested by guidelines. Patients with bone marrow failure were transfused at a lower threshold and experienced a smaller increment in platelet count when compared to patients without marrow failure.

Use of a high platelet-to-RBC ratio of 2:1 is more effective in correcting trauma-induced coagulopathy than a ratio of 1:1 in a rat multiple trauma transfusion model

BACKGROUND

Platelet dysfunction importantly contributes to trauma-induced coagulopathy (TIC). Our aim was to examine the impact of transfusing platelets (PLTs) in a 2:1 PLT-to-red blood cell (RBC) ratio versus the standard 1:1 ratio on transfusion requirements, correction of TIC, and organ damage in a rat multiple trauma transfusion model.

METHODS

Mechanically ventilated male Sprague Dawley rats were traumatized by crush injury to the small intestine and liver and a fracture of the femur, followed by exsanguination until a mean arterial pressure (MAP) of 40 mmHg. Animals were randomly assigned to receive resuscitation in a high PLT dose (PLT to plasma to RBC in a ratio of 2:1:1) or a standard PLT dose (ratio of 1:1:1) until a MAP of 60 mmHg was reached (n = 8 per group). Blood samples were taken for biochemical and thromboelastometry (ROTEM) assessment. Organs were harvested for histopathology.Outcome measures were transfusion requirements needed to reach a pretargeted MAP, as well as ROTEM correction and organ failure.

RESULTS

Trauma resulted in coagulopathy as assessed by deranged ROTEM results. Mortality rate was 19%, with all deaths occurring in the standard dose group. The severity of hypovolemic shock as assessed by lactate and base excess was not different in both groups. The volume of transfusion needed to reach the MAP target was lower in the high PLT dose group compared to the standard dose, albeit not statistically significant (p = 0.054). Transfusion with a high PLT dose resulted in significant stronger clot firmness compared to the standard dose at all time points following trauma, while platelet counts were similar. Organ failure as assessed by biochemical analysis and histopathology was not different between groups, nor were there any thromboembolic events recorded.

CONCLUSIONS

Resuscitation with a high (2:1) PLT-to-RBC ratio was more effective compared to standard (1:1) PLT-to-RBC ratio in treating TIC, with a trend towards reduced transfusion volumes. Also, high PLT dose did not aggravate organ damage. Transfusion strategies using higher PLT dose regiments might be a feasible treatment option in hemorrhaging trauma patients for the correction of TIC.

[Platelet function disorder in trauma patients, an underestimated problem? Results of a single center study]

BACKGROUND

Plasmatic coagulation disorders in trauma patients are common and their management is subject to current guidelines. Less evidence exists for platelet function. Although it is known that several trauma-associated factors have a negative influence on platelet function, routine monitoring has not yet become established.

METHODS

A retrospective single center study was carried out at a German level 1 trauma center from 2010 to 2016. In all patients fulfilling the requirements for the German Trauma Society (DGU) Traumaregister® who were admitted directly from the scene of the incident, platelet function was analyzed using the Platelet Function Analyzer (PFA 100®) with adenosine diphosphate (ADP) and epinephrine as activation factors. After exclusion of patients with intake of long-term anticoagulant and antiaggregant medication, possible influencing factors of a reduced platelet function were identified.

RESULTS

The results from 310 patients (44.0 ± 14.7 years, 76% male, Injury Severity Score, ISS 28.4 ± 14.2 points) were available. A delayed platelet activation was found in 25.5% using ADP and 31% using epinephrine. Laboratory parameters indicated a greater blood loss. Prolonged closure times were associated with an increased transfusion rate of packed red blood cell concentrates and a higher mortality rate. Logistic regression revealed hemoglobin (Hb) and fibrinogen levels at admission to be independent predictors for a decreased platelet activation in the assay with ADP (p < 0.001, Cohen's f = 0.61) and with epinephrine (p < 0.001, f = 0.42).

CONCLUSION

Approximately one quarter to one third of primarily admitted trauma patients without long-term anticoagulation medication showed a delayed platelet activation in the PFA-100 test. By considering all trauma patients an even higher rate can be expected. The Hb and fibrinogen levels at admission can be helpful to estimate platelet disorders. The development of platelet assays to guide the resuscitation of individual patients seems to be absolutely necessary. The contribution of platelet disorders to trauma-induced coagulopathy is not sufficiently understood. Regarding the importance assigned to platelet transfusion or administration of desmopressin, these aspects should be the subject of further research.

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

BACKGROUND

Severe traumatic injury continues to present challenges to healthcare systems around the world, and post-traumatic bleeding remains a leading cause of potentially preventable death among injured patients. Now in its fifth edition, this document aims to provide guidance on the management of major bleeding and coagulopathy following traumatic injury and encourages adaptation of the guiding principles described here to individual institutional circumstances and resources.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004, and the current author group included representatives of six relevant European professional societies. The group applied a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were re-examined and revised based on scientific evidence that has emerged since the previous edition and observed shifts in clinical practice. New recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated.

RESULTS

Advances in our understanding of the pathophysiology of post-traumatic coagulopathy have supported improved management strategies, including evidence that early, individualised goal-directed treatment improves the outcome of severely injured patients. The overall organisation of the current guideline has been designed to reflect the clinical decision-making process along the patient pathway in an approximate temporal sequence. Recommendations are grouped behind the rationale for key decision points, which are patient- or problem-oriented rather than related to specific treatment modalities. While these recommendations provide guidance for the diagnosis and treatment of major bleeding and coagulopathy, emerging evidence supports the author group's belief that the greatest outcome improvement can be achieved through education and the establishment of and adherence to local clinical management algorithms.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. If incorporated into local practice, these clinical practice guidelines have the potential to ensure a uniform standard of care across Europe and beyond and better outcomes for the severely bleeding trauma patient.