Abstract

BACKGROUND Complement activation after trauma promotes hemostasis but is associated with increased morbidity and mortality. However, the specific pathways and downstream mediators remain unclear. Recently the anaphylatoxin C4a has been shown to bind to thrombin receptors. While plasma-based resuscitation has been shown to modify the endotheliopathy of trauma, it may provide complement zymogens that fuel ongoing inflammatory cascades. We sought to characterize the activation of complement after injury and the effect of fresh frozen plasma (FFP) on this inflammatory response. We hypothesized that trauma induces C4 activation, which is associated with worse outcomes and influenced by FFP resuscitation. METHODS Blood was collected from injured patients at a single Level I Trauma Center enrolled in the COMBAT randomized clinical trial. Proteomic analyses were performed through targeted liquid chromatography coupled with mass spectrometry. For the present observational study, concentrations of complement proteins were analyzed at multiple time points, compared between treatment groups, and correlated with outcomes. RESULTS C4 activation occurred over the first six hours post-injury with peak activation 6-24 hours. Tissue hypoperfusion, defined as base deficit >10 mEq/L, and requirement for massive transfusion were associated with greater C4 activation. C4 activation was associated with mortality, multiple organ failure, and longer ventilator requirement. Additionally, temporal trends of C1q, factor B, and C3 by outcome groups support the prevailing theory of primary classical pathway activation with alternative pathway amplification. Resuscitation with FFP over the first six hours was associated with increased C4 activation at 12 and 24 hours. CONCLUSIONS C4 activation has an important inflammatory role post-injury, and FFP has the potential to augment this complement activation during resuscitation. EVIDENCE Level III, Prognostic/Epidemiological.

Abstract

BACKGROUND Randomized clinical trials (RCTs) support the use of prehospital plasma in traumatic hemorrhagic shock, especially in long transports. The citrate added to plasma binds with calcium, yet most prehospital trauma protocols have no guidelines for calcium replacement. We reviewed the experience of two recent prehospital plasma RCTs regarding admission ionized-calcium (i-Ca) blood levels and its impact on survival. We hypothesized that prehospital plasma is associated with hypocalcemia, which in turn is associated with lower survival. METHODS We studied patients enrolled in two institutions participating in prehospital plasma RCTs (control, standard of care; experimental, plasma), with i-Ca collected before calcium supplementation. Adults with traumatic hemorrhagic shock (systolic blood pressure ≤70 mm Hg or 71-90 mm Hg + heart rate ≥108 bpm) were eligible. We use generalized linear mixed models with random intercepts and Cox proportional hazards models with robust standard errors to account for clustered data by institution. Hypocalcemia was defined as i-Ca of 1.0 mmol/L or less. RESULTS Of 160 subjects (76% men), 48% received prehospital plasma (median age, 40 years [interquartile range, 28-53 years]) and 71% suffered blunt trauma (median Injury Severity Score [ISS], 22 [interquartile range, 17-34]). Prehospital plasma and control patients were similar regarding age, sex, ISS, blunt mechanism, and brain injury. Prehospital plasma recipients had significantly higher rates of hypocalcemia compared with controls (53% vs. 36%; adjusted relative risk, 1.48; 95% confidence interval [CI], 1.03-2.12; p = 0.03). Severe hypocalcemia was significantly associated with decreased survival (adjusted hazard ratio, 1.07; 95% CI, 1.02-1.13; p = 0.01) and massive transfusion (adjusted relative risk, 2.70; 95% CI, 1.13-6.46; p = 0.03), after adjustment for confounders (randomization group, age, ISS, and shock index). CONCLUSION Prehospital plasma in civilian trauma is associated with hypocalcemia, which in turn predicts lower survival and massive transfusion. These data underscore the need for explicit calcium supplementation guidelines in prehospital hemotherapy. LEVEL OF EVIDENCE Therapeutic, level II.

Abstract

BACKGROUND Randomized clinical trials(RCTs) support the use of pre-hospital plasma in traumatic hemorrhagic shock, especially in long transports. The citrate added to plasma binds with calcium, yet most pre-hospital trauma protocols have no guidelines for calcium replacement. We reviewed the experience of two recent pre-hospital plasma RCTs regarding admission ionized-calcium (i-Ca) blood levels and its impact on survival. We hypothesized that pre-hospital plasma is associated with hypocalcemia, which in turn is associated with lower survival. METHODS We studied patients enrolled in two institutions participating in pre-hospital plasma RCTs (Control=Standard-of-care; Experimental=Plasma), with i-Ca collected prior to calcium supplementation. Adults with traumatic hemorrhagic shock(SBP≤70 mmHg or 71-90mmHg+HR≥108bpm) were eligible. We use generalized linear mixed models with random intercepts and Cox proportional hazards models with robust standard errors to account for clustered data by institution. Hypocalcemia was defined as i-Ca<1.0mmol/L. RESULTS Of 160 subjects(76% men), 48% received pre-hospital plasma, median age 40years(IQR:28-53), 71% suffered blunt trauma, median ISS=22(IQR:17-34). Pre-hospital plasma and control patients were similar regarding age, sex, ISS, blunt mechanism, and brain injury. Pre-hospital plasma recipients had significantly higher rates of hypocalcemia compared to controls (53% vs 36%, Adjusted Relative Risk, aRR=1.48; 95%CI: 1.03-2.12, p=0.03). Severe hypocalcemia was significantly associated with decreased survival(Adjusted Hazard Ratio:1.07;95%CI:1.02-1.13, p=0.01) and massive transfusion(aRR= 2.70;95%CI:1.13-6.46, p=0.03), after adjustment for confounders(randomization group, age, ISS, and shock index). CONCLUSION Pre-hospital plasma in civilian trauma is associated with hypocalcemia, which in turn predicts lower survival and massive transfusion. These data underscore the need for explicit calcium supplementation guidelines in pre-hospital hemotherapy. LEVEL OF EVIDENCE

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 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.

Abstract

BACKGROUND The Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) study evaluated the effects of plasma and platelets on hemostasis and mortality after hemorrhage. The pulmonary consequences of resuscitation strategies that mimic whole blood, remain unknown. METHODS A secondary analysis of the PROPPR study was performed. Injured patients predicted to receive a massive transfusion were randomized to 1:1:1 vs. 1:1:2 plasma-platelet-RBC ratios at 12 Level I North American trauma centers. Patients with survival >24 hours, an ICU stay, and a recorded PaO2/FiO2 (P/F) ratio were included. ARDS was defined as a P/F ratio < 200, with bilateral pulmonary infiltrates, and adjudicated by investigators. RESULTS 454 patients were reviewed (230 received 1:1:1, 224 1:1:2). Age, sex, injury mechanism, and regional abbreviated injury scale (AIS) scores did not differ between cohorts. Tidal volume, PEEP, and lowest P/F ratio did not differ. No significant differences in ARDS rates (14.8 vs. 18.4%), ventilator-free (24 vs. 24) or ICU-free days (17.5 vs. 18), hospital length of stay (22 vs. 18 days), or 30-day mortality were found (28 vs. 28%). ARDS was associated with blunt injury (OR 3.61 [1.53-8.81] p < 0.01) and increasing chest AIS (OR 1.40 [1.15-1.71] p < 0.01). Each 500 mL of crystalloid infused during hours 0-6 was associated with a 9% increase in the rate of ARDS (OR 1.09 [1.04-1.14] p < 0.01). Blood given at 0-6 or 7-24 hours were not risk factors for lung injury. CONCLUSION Acute crystalloid exposure, but not blood products, is a potentially modifiable risk factor for the prevention of ARDS following hemorrhage.

Abstract

BACKGROUND The resuscitation of severely injured bleeding patients has evolved into a multi-modal strategy termed damage control resuscitation (DCR). This guideline evaluates several aspects of DCR including the role of massive transfusion (MT) protocols, the optimal target ratio of plasma (PLAS) and platelets (PLT) to red blood cells (RBC) during DCR, and the role of recombinant activated factor VII (rVIIa) and tranexamic acid (TXA). METHODS Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, a subcommittee of the Practice Management Guidelines (PMG) Section of EAST conducted a systematic review using MEDLINE and EMBASE. Articles in English from1985 through 2015 were considered in evaluating four PICO questions relevant to DCR. RESULT A total of 37 studies were identified for analysis, of which 31 met criteria for quantitative meta-analysis. In these studies, mortality decreased with use of an MT/DCR protocol vs. no protocol (OR 0.61, 95% CI 0.43-0.87, p = 0.006) and with a high ratio of PLASRBC and PLT:RBC (relatively more PLAS and PLT) vs. a low ratio (OR 0.60, 95% CI 0.46-0.77, p < 0.0001; OR 0.44, 95% CI 0.28-0.71, p = 0.0003). Mortality and blood product use were no different with either rVIIa vs. no rVIIa or with TXA vs. no TXA. CONCLUSION DCR can significantly improve outcomes in severely injured bleeding patients. After a review of the best available evidence, we recommend the use of a MT/DCR protocol in hospitals that manage such patients and recommend that the protocol target a high ratio of PLAS and PLT to RBC. This is best achieved by transfusing equal amounts of RBC, PLAS, and PLT during the early, empiric phase of resuscitation. We cannot recommend for or against the use of rVIIa based on the available evidence. Finally, we conditionally recommend the in-hospital use of TXA early in the management of severely injured bleeding patients.

Abstract

IMPORTANCE Severely injured patients experiencing hemorrhagic shock often require massive transfusion. Earlier transfusion with higher blood product ratios (plasma, platelets, and red blood cells), defined as damage control resuscitation, has been associated with improved outcomes; however, there have been no large multicenter clinical trials. OBJECTIVE To determine the effectiveness and safety of transfusing patients with severe trauma and major bleeding using plasma, platelets, and red blood cells in a 1:1:1 ratio compared with a 1:1:2 ratio. DESIGN, SETTING, AND PARTICIPANTS Pragmatic, phase 3, multisite, randomized clinical trial of 680 severely injured patients who arrived at 1 of 12 level I trauma centers in North America directly from the scene and were predicted to require massive transfusion between August 2012 and December 2013. INTERVENTIONS Blood product ratios of 1:1:1 (338 patients) vs 1:1:2 (342 patients) during active resuscitation in addition to all local standard-of-care interventions (uncontrolled). MAIN OUTCOMES AND MEASURES Primary outcomes were 24-hour and 30-day all-cause mortality. Prespecified ancillary outcomes included time to hemostasis, blood product volumes transfused, complications, incidence of surgical procedures, and functional status. RESULTS No significant differences were detected in mortality at 24 hours (12.7% in 1:1:1 group vs 17.0% in 1:1:2 group; difference, -4.2% [95% CI, -9.6% to 1.1%]; P=.12) or at 30 days (22.4% vs 26.1%, respectively; difference, -3.7% [95% CI, -10.2% to 2.7%]; P=.26). Exsanguination, which was the predominant cause of death within the first 24 hours, was significantly decreased in the 1:1:1 group (9.2% vs 14.6% in 1:1:2 group; difference, -5.4% [95% CI, -10.4% to -0.5%]; P=.03). More patients in the 1:1:1 group achieved hemostasis than in the 1:1:2 group (86% vs 78%, respectively; P=.006). Despite the 1:1:1 group receiving more plasma (median of 7 U vs 5 U, P<.001) and platelets (12 U vs 6 U, P<.001) and similar amounts of red blood cells (9 U) over the first 24 hours, no differences between the 2 groups were found for the 23 prespecified complications, including acute respiratory distress syndrome, multiple organ failure, venous thromboembolism, sepsis, and transfusion-related complications. CONCLUSIONS AND RELEVANCE Among patients with severe trauma and major bleeding, early administration of plasma, platelets, and red blood cells in a 1:1:1 ratio compared with a 1:1:2 ratio did not result in significant differences in mortality at 24 hours or at 30 days. However, more patients in the 1:1:1 group achieved hemostasis and fewer experienced death due to exsanguination by 24 hours. Even though there was an increased use of plasma and platelets transfused in the 1:1:1 group, no other safety differences were identified between the 2 groups. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01545232.

Abstract

OBJECTIVE The current study leveraged data from the Early Whole Blood (EWB) trial to explore the effects of modified whole blood (mWB) versus component (COMP) transfusions on coagulation parameters over time using longitudinal statistical methods. STUDY DESIGN AND METHODS The EWB study was a single-center randomized controlled trial, approved by the local IRB. Adult patients at highest-level trauma activations were randomized into mWB or COMP groups. Coagulation status was evaluated (at times 0, 3, 6, 12, and 24 h postadmission) using thrombelastography, platelet aggregometry, and calibrated automated thrombograms. Longitudinal statistical analyses with generalized estimating equations (GEE) were used to evaluate the effects of group, time, transfusion types, and their respective interactions on changes in measured coagulation markers. RESULTS A total of 59 patients were enrolled and adhered to protocol in the EWB trial, 25 in the mWB group, and 34 in the COMP group. Patients in both the mWB and COMP groups demonstrated a significant decline in their thrombelastography parameters during the first 3-6 h, specifically K-time, alpha-angle, maximum amplitude, G, and LY30. Patients receiving mWB exhibited improved thrombin potential than those receiving COMP. Platelet count and function declined over time in both mWB and COMP groups; however, platelet aggregation in response to ristocetin in the mWB group was significantly improved at 12 h compared with the COMP group. The longitudinal GEE model revealed significant group-time interactive effects on the changes in coagulation markers and significant effect of platelet transfusions on improvements in coagulation profile. CONCLUSIONS We observed significant interactive group-time effects, indicating that the types of transfusion as well as the time of transfusion significantly affect the patient's coagulation status. Our pilot data suggest that there is an improvement in platelet function with mWB, but further studies are needed. Regardless, platelet transfusions were associated with improvements in coagulation over time in both the groups.