Abstract

OBJECTIVES Determine associations between biomarkers of endotheliopathy, 24-hour fibrinolysis phenotypes and clinical outcomes after trauma. BACKGROUND The vascular endothelium is a critical regulator of hemostasis and organ function. The relationship between markers of endotheliopathy and fibrinolysis following trauma has not been evaluated. METHODS We performed a secondary analysis of prospectively collected biomarker data in the Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized controlled trial. We stratified subjects by 24-hour thromboelastography (TEG) percent clot lysis (LY30) and plasma D-dimer (DD) levels and evaluated differences in endotheliopathy biomarkers and clinical outcomes between subjects with one of four 24-hour fibrinolysis phenotypes: LY30 0.9-2.9% (LY30(norm)), LY30 >2.9% (LY30(high)), LY30 <0.9% and low DD (LY30(low)+DD(low)), and LY30 <0.9% and high DD (LY30(low)+DD(high)). RESULTS The analysis included 168 subjects with LY30(norm), 32 with LY30(high), 147 with LY30(low)+DD(low) and 124 with LY30(low)+DD(high). LY30(low)+DD(high) subjects had greater injury severity and a higher incidence of severe head injury, multiorgan failure (MOF), and mortality than the other phenotypes. All endotheliopathy biomarkers were significantly higher in the LY30(low)+DD(high) phenotype. Adjusting for injury severity, mechanism and head trauma, 24-hour angiopoietin-2 and soluble thrombomodulin were independently associated with the LY30(low)+DD(high) phenotype. Both endothelial biomarkers were discriminating for MOF. Subjects with thrombomodulin level >9.5 ng/mL and angiopoietin-2 level >3.6 ng/mL accounted for 64% of subjects who developed MOF. CONCLUSIONS In a multicenter trauma cohort, subjects with a fibrinolysis phenotype characterized by low TEG lysis and elevated DD 24 hours after injury have significantly worse endotheliopathy and clinical outcomes. Our findings support mechanistic evaluations of the role of the endothelium in fibrinolysis dysregulation that may drive late-stage organ injury.

Abstract

BACKGROUND Patients with hemorrhagic shock from trauma often require balanced blood product transfusion with red blood cells, plasma, and platelets. Resuscitation with whole blood resuscitation is becoming a common practice. We performed a systematic review and meta-analysis of studies comparing whole blood transfusion with balanced component therapy in patients suffering from traumatic hemorrhagic shock. METHODS We searched MEDLINE Ovid, EMBASE, and the Cochrane Library for human studies comparing whole blood with component blood therapy published from January 2007 to June 2019. We included studies from both civilian and military settings and that reported 24-hour, in-hospital, or 30-day mortality. We followed the Preferred Reporting Items in Systematic Reviews and Meta-Analyses (PRISMA) guidelines, assessing study quality, publication bias, and heterogeneity. We used meta-analytic models to determine the associations (odds ratio [OR] with 95% confidence interval [CI]) between whole blood transfusion and (1) 24-hour mortality, and (2) in-hospital or 30-day mortality. RESULTS A total of 1759 identified studies, 12 (reporting on n = 8431 patients) met inclusion criteria. There was heterogeneity in the design, setting, interventions, and outcomes of the studies. On meta-analysis, whole blood transfusion was not associated with 24-hour mortality (OR = 0.83; 95% CI = 0.56-1.24) or in-hospital/30-day mortality (OR = 0.79; 95% CI = 0.48-1.31). CONCLUSION In this systematic review and meta-analysis, compared with conventional component transfusion, whole blood was not associated with 24-hour or in-hospital mortality. However, there were important limitations with and heterogeneity among the primary studies. Additional study is needed to determine the effectiveness of whole blood.

Abstract

BACKGROUND Massive transfusion protocols to treat post-injury hemorrhage are based on pre-defined blood product transfusion ratios followed by goal-directed transfusion based on patient's clinical evolution. However, it remains unclear how these transfusion ratios impact patient outcomes over time from injury. METHODS The Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) is a phase 3, randomized controlled trial, across 12 level-I trauma centers in North America. From 2012 to 2013, 680 severely injured patients required massive transfusion. We used semi-parametric machine learning techniques and causal inference methods to augment the intent-to-treat analysis of PROPPR, estimating the dynamic relationship between transfusion ratios and outcomes: mortality and hemostasis at different time-points during the first 24 hours after admission. RESULTS In the intention-to-treat analysis, the 1:1:1 group tended to have decreased mortality, but with no statistical significance. For patients in whom hemostasis took longer than 2 hours, the 1:1:1 ratio was associated with a higher probability of hemostasis, statistically significant from the 4 hour on. In the per-protocol, actual-transfusion-ratios-received analysis, during four successive time intervals, no significant association was found between the actual ratios and mortality. When comparing patient groups who received both high plasma:PRBC and high platelet:PRBC ratios to the group of low ratios in both, the relative risk of achieving hemostasis was 2.49 (95% CI = 1.19-5.22) during the 3 hour after admission, suggesting a significant beneficial impact of higher transfusion ratios of plasma and platelets on hemostasis. CONCLUSIONS Our results suggest that the impact of transfusion ratios on hemostasis is dynamic. Overall, the transfusion ratios had no significant impact on mortality over time. However, receiving higher ratios of platelets and plasma relative to red blood cells hastens hemostasis in subjects who have yet to achieve hemostasis within 3 hours after hospital admission. LEVEL OF EVIDENCE Prognostic, level III.

Abstract

BACKGROUND Women are underrepresented in trauma research, and aggregated results of clinical trials may mask effects that differ by sex. It is unclear whether women respond differently to severe hemorrhage compared with men. We sought to evaluate sex-based differences in outcomes after severe trauma with hemorrhage. METHODS We performed a secondary analysis of the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Trauma patients predicted to require massive transfusion were randomized to a 1:1:1 vs 1:1:2 plasma to platelet to red blood cell transfusion ratio. Analysis was performed according to sex, controlling for clinical characteristics and transfusion arm. RESULTS A total of 134 women and 546 men were analyzed. In multivariable analysis, there was no difference in mortality at 24 hours (hazard ratio for women 0.64, 95% confidence interval 0.34-1.23, P = .18) or in time to hemostasis (hazard ratio 1.10, 95% confidence interval 0.84-1.42, P = .49) by sex. We observed no difference between sexes in volume of blood products transfused during active hemorrhage. However, after anatomic hemostasis, women received lower volumes of all products, with a 38% reduction in fresh frozen plasma (mean ratio 0.62 (95% confidence interval 0.43-0.89, P = .01), 49% reduction in platelets (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01) and 49% reduction in volume of red blood cells (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01). CONCLUSION Mortality and time to hemostasis of trauma patients with hemorrhage did not differ by sex. Although there was no difference in transfusion requirement during active hemorrhage, once hemostasis was achieved, women received fewer units of all blood products than men. Further research is required to determine whether women exhibit differences in coagulation during and after severe traumatic hemorrhage.

Abstract

BACKDROP Clinicians intuitively recognize that faster time to hemostasis is important in bleeding trauma patients, but these times are rarely reported. METHODS Prospectively collected data from the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial were analyzed. Hemostasis was predefined as no intraoperative bleeding requiring intervention in the surgical field or resolution of contrast blush on interventional radiology (IR). Patients who underwent an emergent (within 90 minutes) operating room (OR) or IR procedure were included. Mixed-effects Poisson regression with robust error variance (controlling for age, Injury Severity Score, treatment arm, injury mechanism, base excess on admission [missing values estimated by multiple imputation], and time to OR/IR as fixed effects and study site as a random effect) with modified Bonferroni corrections tested the hypothesis that decreased time to hemostasis was associated with decreased mortality and decreased incidence of acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), multiple-organ failure (MOF), sepsis, and venous thromboembolism. RESULTS Of 680 enrolled patients, 468 (69%) underwent an emergent procedure. Patients with decreased time to hemostasis were less severely injured, had less deranged base excess on admission, and lower incidence of blunt trauma (all p < 0.05). In 408 (87%) patients in whom hemostasis was achieved, every 15-minute decrease in time to hemostasis was associated with decreased 30-day mortality (RR, 0.97; 95% confidence interval [CI], 0.94-0.99), AKI (RR, 0.97; 95% CI, 0.96-0.98), ARDS (RR, 0.98; 95% CI, 0.97-0.99), MOF (RR, 0.94; 95% CI, 0.91-0.97), and sepsis (RR, 0.98; 95% CI, 0.96-0.99), but not venous thromboembolism (RR, 0.99; 95% CI, 0.96-1.03). CONCLUSION Earlier time to hemostasis was independently associated with decreased incidence of 30-day mortality, AKI, ARDS, MOF, and sepsis in bleeding trauma patients. Time to hemostasis should be considered as an endpoint in trauma studies and as a potential quality indicator. LEVEL OF EVIDENCE Therapeutic/care management, level III.

Abstract

BACKGROUND The mortality of trauma patients requiring massive transfusion to treat hemorrhagic shock approaches 17% at 24 hours and 26% at 30 days. The use of stored RBCs is limited to less than 42 days, so older RBCs are delivered first to rapidly bleeding trauma patients. Patients who receive a greater quantity of older RBCs may have a higher risk for mortality. METHODS AND MATERIALS Characterizing blood age exposure requires accounting for the age of each RBC unit and the quantity of transfused units. To address this challenge, a novel Scalar Age of Blood Index (SBI) that represents the relative distribution of RBCs received is introduced and applied to a secondary analysis of the Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized controlled trial (NCT01545232, https://clinicaltrials.gov/ct2/show/NCT01545232). The effect of the SBI is assessed on the primary PROPPR outcome, 24-hour and 30-day mortality. RESULTS The distributions of blood storage ages successfully maps to a parameter (SBI) that fully defines the blood age curve for each patient. SBI was a significant predictor of 24-hour and 30-day mortality in an adjusted model that had strong predictive ability (odds ratio, 1.15 [1.01-1.29], p = 0.029, C-statistic, 0.81; odds ratio, 1.14 [1.02-1.28], p = 0.019, C-statistic, 0.88, respectively). CONCLUSION SBI is a simple scalar metric of blood age that accounts for the relative distribution of RBCs among age categories. Transfusion of older RBCs is associated with 24-hour and 30-day mortality, after adjustment for total units and clinical covariates.

Abstract

BACKGROUND Endotheliopathy of trauma is characterized by breakdown of the endothelial glycocalyx. Elevated biomarkers of endotheliopathy, such as serum syndecan-1 (Synd-1) ≥ 40 ng/mL, have been associated with increased need for transfusions, complications, and mortality. We hypothesized that severely injured trauma patients who exhibit elevated Synd-1 levels shortly after admission have an increased likelihood of developing sepsis. STUDY DESIGN We analyzed a subset of PROPPR patients that survived at least 72 hours after hospital admission and determined elevated Synd-1 levels (≥ 40 ng/mL) 4 hours after hospital arrival. Sepsis was defined a priori as meeting systemic inflammatory response criteria and having a known or suspected infection. Univariate analysis was performed to identify variables associated with elevated Synd-1 levels and sepsis. Significant variables at a p-value <0.2 in the univariate analysis were chosen by purposeful selection and analyzed in a mixed effects multivariate logistic regression model to account for the 12 different study sites. RESULTS We included 512 patients. Of these, 402 (79%) had elevated Synd-1 levels, and 180 (35%) developed sepsis. Median Synd-1 levels at 4 hours after admission were 70 ng/dL (IQR 36 - 157 ng/dL) in patients who did not develop sepsis, and 165 ng/dL (IQR 67 - 336 ng/dL) in those who did (p < 0.001). Adjusting for treatment arm and site, multivariable analyses revealed that elevated Synd-1 status, injury severity score (ISS), and total blood transfused were significantly associated with an increased likelihood of developing sepsis. CONCLUSIONS Elevated Synd-1 levels 4 hours after admission in severely injured adult trauma patients who survived the initial 72 hours after hospital admission is associated with subsequent sepsis.

Abstract

BACKGROUND Low tissue oxygenation (StO2) is associated with poor outcomes in obese trauma patients. A novel treatment could be the transfusion of cryopreserved packed red blood cells (CPRBCs), which the in vitro biochemical profile favors red blood cell (RBC) function. We hypothesized that CPRBC transfusion improves StO2 in obese trauma patients. METHODS Two hundred forty-three trauma patients at five Level I trauma centers who required RBC transfusion were randomized to receive one to two units of liquid packed RBCs (LPRBCs) or CPRBCs. Demographics, injury severity, StO2, outcomes, and biomarkers of RBC function were compared in nonobese (body mass index [BMI] < 30) and obese (BMI ≥ 30) patients. StO2 was also compared between obese patients with BMI of 30 to 34.9 and BMI ≥ 35. StO2 was normalized and expressed as % change after RBC transfusion. A p value less than 0.05 indicated significance. RESULTS Patients with BMI less than 30 (n = 141) and BMI of 30 or greater (n = 102) had similar Injury Severity Score, Glasgow Coma Scale, and baseline StO2. Plasma levels of free hemoglobin, an index of RBC lysis, were lower in obese patients after CPRBC (125 [72-259] mug/mL) versus LPRBC transfusion (230 [178-388] mug/mL; p < 0.05). StO2 was similar in nonobese patients regardless of transfusion type, but improved in obese patients who received CPRBCs (104 +/- 1%) versus LPRPCs (99 +/- 1%, p < 0.05; 8 hours after transfusion). Subanalysis showed improved StO2 after CPRBC transfusion was specific to BMI of 35 or greater, starting 5 hours after transfusion (p < 0.05 vs. LPRBCs). CPRBCs did not improve clinical outcomes in either group. CONCLUSION CPRBC transfusion is associated with increased StO2 and lower free hemoglobin levels in obese trauma patients, but did not improve clinical outcomes. Future studies are needed to determine if CPRBC transfusion in obese patients attenuates hemolysis to improve StO2. LEVEL OF EVIDENCE Therapeutic, level IV.

Abstract

BACKGROUND To address deficiencies associated with the classic definition of massive transfusion, Critical Administration Threshold and Resuscitation Intensity were developed to better quantify the overall severity of illness and predict the need for transfusions and early mortality. We sought to evaluate these as more appropriate replacements for MT in defining mortality risk in patients undergoing major transfusions. METHODS Patients predicted to receive MT at 12 Level-1 trauma centers were randomized in the PROPPR trial. MT: ≥10U RBC in 24 hours; CAT+: ≥3U RBC in the first hour; and RI: total products in the first 30 minutes (1U RBC, 1U plasma, 1000mL crystalloid, 500mL colloid each valued at 1U). RI was evaluated as a continuous variable and dichotomized as RI4+, where RI≥4 U. Each metric was evaluated for its ability to predict mortality at 3, 6, and 24 hours, and at 30 days. RESULTS Of the 680 patients, 301 patients met MT definition, 521 were CAT+, and 445 were RI4+. Of those that died, 23% never reached MT threshold, but all were captured by CAT+ and RI4+. The 3-hr (9 vs. 9%), 6-hr (14 vs. 14%), 24-hr (17 vs. 18%), and 30-day mortality rates (28 vs. 29%) were similar between CAT+ and RI4+ patients. When RI was evaluated as a continuous variable, each unit increase was associated with a 20% increase in hemorrhage-related mortality (OR 1.20, 95% CI [1.15-1.29], p<0.05).CONCLUSIONBoth RI and CAT are valid surrogates for early mortality in patients undergoing major transfusion, capturing patients omitted by the MT definition. CAT+ showed the best sensitivity; RI4+ demonstrated better specificity and good PPV and NPV. While CAT+ may be suited for patients receiving a RBC-dominant resuscitation, RI4+ is more comprehensive. RI can also be used as a continuous variable to provide quantitative as well qualitative risk of death.LEVEL OF EVIDENCELevel III, Prognostic.

Abstract

BACKGROUND Hypothermia is associated with poor outcomes after injury. The relationship between hypothermia during contemporary large volume resuscitation and blood product consumption is unknown. We evaluated this association, and the predictive value of hypothermia on mortality. METHODS Patients predicted to receive massive transfusion at 12 Level-1 trauma centers, randomized in the PROPPR trial, were grouped into those who were hypothermic (<36 degrees Celsius) or normothermic (36-38.5 degrees Celsius) within the first 6 hours of Emergency department arrival. The impact of hypothermia or normothermia on the volume of blood product required during the first 24 hours was determined via negative binomial regression, adjusting for treatment arm, injury severity score, mechanism, demographics, pre-emergency department fluid volume, blood administered prior to becoming hypothermic, pulse and systolic blood pressure on arrival and the time exposed to hypothermic or normothermic temperatures. RESULTS Of 680 patients, 590 had a temperature measured during the first 6 hours in hospital, and 399 experienced hypothermia. The mean number of red blood cell units given to all patients in the first 24 hours of admission was 8.8 (95% CI 7.9-9.6). In multivariable analysis, every one-degree decrease in temperature below 36.0 degrees was associated with a 10% increase (incidence rate ratio [IRR] 0.90; 95% CI 0.89-0.92; p<0.00) in consumption of red blood cells during the first 24 hours of admission. There was no association between red blood cell administration and a temperature above 36 degrees. Hypothermia on arrival was an independent predictor of mortality, with an adjusted odds ratio of 2.7 (95% CI 1.7-4.5; p<0.00) for 24-hour and 1.8 (95% CI 1.3-2.4; p<0.00) for 30-day mortality. CONCLUSION Hypothermia is associated with increased in blood product consumption and mortality. These findings support the maintenance of normothermia in trauma patients, and suggests that further investigation on the impact of cooling or rewarming during massive transfusion is warranted. LEVEL OF EVIDENCE III Prognostic.