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Orthopaedic Trauma and Anemia: Conservative versus Liberal Transfusion Strategy: A Prospective Randomized Study
Mullis, B. H., Mullis, L. S., Kempton, L. B., Virkus, W., Slaven, J. E., Bruggers, J.
Journal of orthopaedic trauma. 2024;38(1):18-24
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Editor's Choice
Abstract
OBJECTIVES To determine whether it is safe to use a conservative packed red blood cell transfusion hemoglobin (Hgb) threshold (5.5 g/dL) compared with a liberal transfusion threshold (7.0 g/dL) for asymptomatic musculoskeletal injured trauma patients who are no longer in the initial resuscitative period. METHODS Design: Prospective, randomized, multicenter trial. SETTING Three level 1 trauma centers. PATIENT SELECTION CRITERIA Patients aged 18-50 with an associated musculoskeletal injury with Hgb less than 9 g/dL or expected drop below 9 g/dL with planned surgery who were stable and no longer being actively resuscitated were randomized once their Hgb dropped below 7 g/dL to a conservative transfusion threshold of 5.5 g/dL versus a liberal threshold of 7.0 g/dL. OUTCOME MEASURES AND COMPARISONS Postoperative infection, other post-operative complications and Musculoskeletal Functional Assessment scores obtained at baseline, 6 months, and 1 year were compared for liberal and conservative transfusion thresholds. RESULTS Sixty-five patients completed 1 year follow-up. There was a significant association between a liberal transfusion strategy and higher rate of infection (P = 0.01), with no difference in functional outcomes at 6 months or 1 year. This study was adequately powered at 92% to detect a difference in superficial infection (7% for liberal group, 0% for conservative, P < 0.01) but underpowered to detect a difference for deep infection (14% for liberal group, 6% for conservative group, P = 0.2). CONCLUSIONS A conservative transfusion threshold of 5.5 g/dL in an asymptomatic young trauma patient with associated musculoskeletal injuries leads to a lower infection rate without an increase in adverse outcomes and no difference in functional outcomes at 6 months or 1 year. LEVEL OF EVIDENCE Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
PICO Summary
Population
Musculoskeletal trauma patients with planned surgery (n= 99).
Intervention
Liberal transfusion threshold of 7.0 g/dL (n= 49).
Comparison
Conservative transfusion threshold of 5.5 g/dL (n= 50).
Outcome
Overall, 46/49 (93.9%) of the liberal group had a transfusion versus 23/50 (46.0%) of the conservative group had a transfusion after resuscitation and after enrollment in this study. Following resuscitation and enrollment in the study, patients in the liberal group received a median of 1 unit of blood transfused (range 0–12) and patients in the conservative group received a median of 0 units of blood (range 0–14). Sixty-five patients completed 1- year follow-up. There was a significant association between a liberal transfusion strategy and higher rate of infection, with no difference in functional outcomes at 6 months or 1 year.
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The Restrictive Red Blood Cell Transfusion Strategy for Critically Injured Patients (RESTRIC) trial: a cluster-randomized, crossover, non-inferiority multicenter trial of restrictive transfusion in trauma
Hayakawa, M., Tagami, T., Kudo, D., Ono, K., Aoki, M., Endo, A., Yumoto, T., Matsumura, Y., Irino, S., Sekine, K., et al
Journal of intensive care. 2023;11(1):34
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Editor's Choice
Abstract
BACKGROUND The efficacies of fresh frozen plasma and coagulation factor transfusion have been widely evaluated in trauma-induced coagulopathy management during the acute post-injury phase. However, the efficacy of red blood cell transfusion has not been adequately investigated in patients with severe trauma, and the optimal hemoglobin target level during the acute post-injury and resuscitation phases remains unclear. Therefore, this study aimed to examine whether a restrictive transfusion strategy was clinically non-inferior to a liberal transfusion strategy during the acute post-injury phase. METHODS This cluster-randomized, crossover, non-inferiority multicenter trial was conducted at 22 tertiary emergency medical institutions in Japan and included adult patients with severe trauma at risk of major bleeding. The institutions were allocated a restrictive or liberal transfusion strategy (target hemoglobin levels: 7-9 or 10-12 g/dL, respectively). The strategies were applied to patients immediately after arrival at the emergency department. The primary outcome was 28-day survival after arrival at the emergency department. Secondary outcomes included transfusion volume, complication rates, and event-free days. The non-inferiority margin was set at 3%. RESULTS The 28-day survival rates of patients in the restrictive (n = 216) and liberal (n = 195) strategy groups were 92.1% and 91.3%, respectively. The adjusted odds ratio for 28-day survival in the restrictive versus liberal strategy group was 1.02 (95% confidence interval: 0.49-2.13). Significant non-inferiority was not observed. Transfusion volumes and hemoglobin levels were lower in the restrictive strategy group than in the liberal strategy group. No between-group differences were noted in complication rates or event-free days. CONCLUSIONS Although non-inferiority of the restrictive versus liberal transfusion strategy for 28-day survival was not statistically significant, the mortality and complication rates were similar between the groups. The restrictive transfusion strategy results in a lower transfusion volume. TRIAL REGISTRATION NUMBER umin.ac.jp/ctr: UMIN000034405, registration date: 8 October 2018.
PICO Summary
Population
Adult patients with severe trauma at risk of major bleeding, enrolled in the RESTRIC cluster-randomized, crossover trial at 22 tertiary emergency medical institutions in Japan (n= 422).
Intervention
Restrictive transfusion strategy (n= 222).
Comparison
Liberal transfusion strategy (n= 200).
Outcome
The restrictive and liberal red blood cell strategy groups included 216 and 195 patients in the intention-to-treat analysis, respectively. The primary outcome was 28-day survival after arrival at the emergency department. Secondary outcomes included transfusion volume, complication rates, and event-free days. The non-inferiority margin was set at 3%. The 28-day survival rates of patients in the restrictive (n= 216) and liberal (n= 195) strategy groups were 92.1% and 91.3%, respectively. The adjusted odds ratio for 28-day survival in the restrictive versus liberal strategy group was 1.02; 95% confidence interval [0.49, 2.13]. Significant non-inferiority was not observed. Transfusion volumes and haemoglobin levels were lower in the restrictive strategy group than in the liberal strategy group. No between-group differences were noted in complication rates or event-free days.
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Resuscitation with blood products in patients with trauma-related haemorrhagic shock receiving prehospital care (RePHILL): a multicentre, open-label, randomised, controlled, phase 3 trial
Crombie N, Doughty HA, Bishop JRB, Desai A, Dixon EF, Hancox JM, Herbert MJ, Leech C, Lewis SJ, Nash MR, et al
The Lancet. Haematology. 2022
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Editor's Choice
Abstract
BACKGROUND Time to treatment matters in traumatic haemorrhage but the optimal prehospital use of blood in major trauma remains uncertain. We investigated whether use of packed red blood cells (PRBC) and lyophilised plasma (LyoPlas) was superior to use of 0·9% sodium chloride for improving tissue perfusion and reducing mortality in trauma-related haemorrhagic shock. METHODS Resuscitation with pre-hospital blood products (RePHILL) is a multicentre, allocation concealed, open-label, parallel group, randomised, controlled, phase 3 trial done in four civilian prehospital critical care services in the UK. Adults (age ≥16 years) with trauma-related haemorrhagic shock and hypotension (defined as systolic blood pressure <90 mm Hg or absence of palpable radial pulse) were assessed for eligibility by prehospital critial care teams. Eligible participants were randomly assigned to receive either up to two units each of PRBC and LyoPlas or up to 1 L of 0·9% sodium chloride administered through the intravenous or intraosseous route. Sealed treatment packs which were identical in external appearance, containing PRBC-LyoPlas or 0·9% sodium chloride were prepared by blood banks and issued to participating sites according to a randomisation schedule prepared by the co-ordinating centre (1:1 ratio, stratified by site). The primary outcome was a composite of episode mortality or impaired lactate clearance, or both, measured in the intention-to-treat population. This study is completed and registered with ISRCTN.com, ISRCTN62326938. FINDINGS From Nov 29, 2016 to Jan 2, 2021, prehospital critical care teams randomly assigned 432 participants to PRBC-LyoPlas (n=209) or to 0·9% sodium chloride (n=223). Trial recruitment was stopped before it achieved the intended sample size of 490 participants due to disruption caused by the COVID-19 pandemic. The median follow-up was 9 days (IQR 1 to 34) for participants in the PRBC-LyoPlas group and 7 days (0 to 31) for people in the 0·9% sodium chloride group. Participants were mostly white (62%) and male (82%), had a median age of 38 years (IQR 26 to 58), and were mostly involved in a road traffic collision (62%) with severe injuries (median injury severity score 36, IQR 25 to 50). Before randomisation, participants had received on average 430 mL crystalloid fluids and tranexamic acid (90%). The composite primary outcome occurred in 128 (64%) of 199 participants randomly assigned to PRBC-LyoPlas and 136 (65%) of 210 randomly assigned to 0·9% sodium chloride (adjusted risk difference -0·025% [95% CI -9·0 to 9·0], p=0·996). The rates of transfusion-related complications in the first 24 h after ED arrival were similar across treatment groups (PRBC-LyoPlas 11 [7%] of 148 compared with 0·9% sodium chloride nine [7%] of 137, adjusted relative risk 1·05 [95% CI 0·46-2·42]). Serious adverse events included acute respiratory distress syndrome in nine (6%) of 142 patients in the PRBC-LyoPlas group and three (2%) of 130 in 0·9% sodium chloride group, and two other unexpected serious adverse events, one in the PRBC-LyoPlas (cerebral infarct) and one in the 0·9% sodium chloride group (abnormal liver function test). There were no treatment-related deaths. INTERPRETATION The trial did not show that prehospital PRBC-LyoPlas resuscitation was superior to 0·9% sodium chloride for adult patients with trauma related haemorrhagic shock. Further research is required to identify the characteristics of patients who might benefit from prehospital transfusion and to identify the optimal outcomes for transfusion trials in major trauma. The decision to commit to routine prehospital transfusion will require careful consideration by all stakeholders. FUNDING National Institute for Health Research Efficacy and Mechanism Evaluation.
PICO Summary
Population
Patients aged 16 years old or older with trauma-related haemorrhagic shock enrolled in the resuscitation with pre-hospital blood products (RePHILL) trial, based across four UK prehospital critical care services (n= 432).
Intervention
Packed red blood cells and lyophilised plasma (PRBC-LyoPlas, n= 209).
Comparison
Sodium chloride (n= 223).
Outcome
The primary outcome was a composite of episode mortality or impaired lactate clearance, or both, measured in the intention-to-treat population. The composite primary outcome occurred in 128 (64%) of 199 patients receiving PRBC-LyoPlas and 136 (65%) of 210 receiving sodium chloride. The rates of transfusion-related complications in the first 24 hours after emergency department arrival were similar (PRBC-LyoPlas eleven (7%) of 148 compared with sodium chloride nine (7%) of 137). Serious adverse events included acute respiratory distress syndrome in nine (6%) of 142 patients in the PRBC-LyoPlas group and three (2%) of 130 in the sodium chloride group, and two other unexpected serious adverse events, one in the PRBC-LyoPlas (cerebral infarct) and one in the sodium chloride group (abnormal liver function test). There were no treatment-related deaths.
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Hemoglobin levels as a transfusion criterion in moderate to severe traumatic brain injury: a systematic review and meta-analysis
Florez-Perdomo WA, García-Ballestas E, Martinez-Perez R, Agrawal A, Deora H, Joaquim AF, Quiñones-Ossa GA, Moscote-Salazar LR
British journal of neurosurgery. 2021;:1-7
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Editor's Choice
Abstract
BACKGROUND Several factors can influence the outcome of severe head injuries including the patient's hemoglobin levels. There has often been a dilemma regarding levels of hemoglobin at which red cell blood transfusion (RCBT) should be performed. OBJECTIVE To systematically review the literature to determine the usefulness of management protocols that have hemoglobin levels <10 g/dL vs <7 g/dL as an RCBT criterion. METHODS Following the PRISMA statement, the search was constructed using terms and descriptors of the Medical Subject Heading (MeSH), combined with Boolean operators. Full text of these articles was studied, and outcome measures at 3-6 months were considered for patients who were given a RCBT at <10 g/dL or at 7 g/dL hemoglobin levels. RESULTS A total of 4 articles were found suitable for inclusion in the meta-analysis. RCBT below 7 g/dL was not associated with an increased risk of mortality as compared to RCBT using the value of less than 10 g/dL. RCBT at lower levels of hemoglobin was also not associated with a poor neurological outcome (GOS 4-5) but rather RCBT at lower levels lead to better outcomes (GOS 1-3) and the association was significant. CONCLUSION Allogenic RCBT was associated with poorer neurological outcomes, within a wide range of reported differences in the hemoglobin threshold to decide for RCBT in TBI patients. Restrictive RCBT strategy may be useful in moderate to severe TBI cases although the risk of anemia-induced cerebral injury needs further investigation regarding the risks and complications inherent to RCBT.
PICO Summary
Population
Patients with traumatic brain injury (4 studies, n= 607).
Intervention
Liberal red cell blood transfusion (RCBT) criterion protocol of haemoglobin level <10 g/dL.
Comparison
Restrictive RCBT criterion protocol of haemoglobin level <7 g/dL.
Outcome
RCBT below 7 g/dL was not associated with an increased risk of mortality as compared to RCBT using the value of less than 10 g/dL. RCBT at lower levels of haemoglobin was also not associated with a poor neurological outcome (GOS 4-5) but rather RCBT at lower levels lead to better outcomes (GOS 1-3) and the association was significant.
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Massive Transfusion Protocols in Pediatric Trauma Population: A Systematic Review
Kinslow K, McKenney M, Boneva D, Elkbuli A
Transfus Med. 2020
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Editor's Choice
Abstract
BACKGROUND Our main objective was to review the literature to answer the following questions regarding pediatric massive transfusion (PMT) protocols: 1) How is PMT defined? 2) Which blood product ratios have been investigated and what is their effect on outcomes? 3) What evidence exists regarding PMT outcomes? METHODS The PRISMA guidelines were used. We searched PubMed, Google Scholar, Cochrane Library, EMBASE, Wiley Online Library, and Ovid. Articles were screened for inclusion based on relevance to PMT. Articles were assessed for study design, presence of established/tested PMT, PMT definition, PMT activation criteria, and Transfusion Ratios, for final determination of article inclusion. RESULTS Our search produced 3213 articles with 33 included for final review. Existing definitions of PMT are based on volume administered/kg but vary in timeframe criteria (over 4 hr vs 24 hr). Some studies have investigated "high" balanced transfusion ratios as seen in adults (1:1 FFP:pRBC) with a few showing statistically significant improvement in pediatric mortality vs lower ratios. PMT protocol implementation has not been shown to consistently reduce pediatric trauma mortality across multiple centers. However, other operational aspects such as reduced time to first transfusion are apparent benefits. CONCLUSIONS There is poor consensus over the definition of PMT. Definitions that involve early recognition have the most promise for practice and future studies. Evidence supporting an optimal blood product ratio in PMT is also lacking but trends towards supporting balanced approaches. Implementation of PMT protocols have been limited in showing significant improvement of overall pediatric trauma mortality but may reduce associated morbidity.
PICO Summary
Population
Paediatric trauma patients undergoing massive transfusions (33 studies).
Intervention
Systematic review to define paediatric massive transfusion (PMT) protocols, and to review the evidence on PMT outcomes.
Comparison
Outcome
Existing definitions of PMT are based on volume administered/kg but vary in timeframe criteria (over 4 hr vs. 24 hr). Some studies have investigated "high" balanced transfusion ratios as seen in adults (1:1 FFP:pRBC) with a few showing statistically significant improvement in paediatric mortality vs. lower ratios. PMT protocol implementation has not been shown to consistently reduce paediatric trauma mortality across multiple centers. However, other operational aspects such as reduced time to first transfusion are apparent benefits.
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The effect of massive transfusion protocol implementation on the survival of trauma patients: a systematic review and meta-analysis
Consunji R, Elseed A, El-Menyar A, Sathian B, Rizoli S, Al-Thani H, Peralta R
Blood transfusion = Trasfusione del sangue. 2020
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Editor's Choice
Abstract
BACKGROUND Massive transfusion protocol (MTP) has been widely adopted for the care of bleeding trauma patients but its actual effectiveness is unclear. An earlier meta-analysis on the implementation of MTP for injured patients from 1990 to 2013 reported that only 2 out of 8 studies showed statistical improvement in survival. This study aimed to conduct an updated systematic review and meta-analysis to evaluate the effect of implementing an MTP on the mortality of trauma patients. MATERIALS AND METHODS MEDLINE, PubMed, Cochrane Library and Google scholar databases were systematically searched for relevant studies published from 1(st) January 2008 to 30(th) September 2019 using a combination of keywords and additional manual searching of reference lists. Inclusion criteria were: original study in English, study population including trauma patients, and comparison of mortality outcomes before and after institutional implementation of an MTP. Primary outcomes were 24-hour, 30-day, and overall mortality. RESULTS Fourteen studies met inclusion criteria, analysing outcomes from 3,201 trauma patients. There was a wide range of outcomes, patient populations, and process indicators utilised by the different authors. MTP significantly reduced the overall mortality for trauma patients (OR 0.71 [0.56-0.90]). No significant reduction was seen in either the 24-hour mortality (OR 0.81 [0.57-1.14]) or the 30-day mortality (OR 0.73 [0.46-1.16]). However, when mortality timing was unspecified, mortality was statistically reduced (OR 0.69 [0.55-0.86]). DISCUSSION The present study found a significant reduction in mortality following MTP implementation and thus it should be recommended to all institutions managing acutely injured patients. To better identify which elements of an MTP contribute to this effect, we encourage the use of standard nomenclature, indicators, protocols and patient populations in all future MTP studies.
PICO Summary
Population
Trauma patients (14 studies, n= 3201).
Intervention
Implementation of a massive transfusion protocol (MTP) on the mortality of trauma patients.
Comparison
Outcome
There was a wide range of outcomes, patient populations, and process indicators utilised by the different authors. MTP significantly reduced the overall mortality for trauma patients. No significant reduction was seen in either the 24-hour mortality or the 30-day mortality. However, when mortality timing was unspecified, mortality was statistically reduced.
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Evaluation of blood product transfusion therapies in acute injury care in low- and middle-income countries: a systematic review
Yang L, Slate-Romano J, Marques CG, Uwamahoro C, Twagirumukiza FR, Naganathan S, Moretti K, Jing L, Levine AC, Stephen A, et al
Injury. 2020
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Editor's Choice
Abstract
BACKGROUND Worldwide, injuries account for approximately five million mortalities annually, with 90% occurring in low- and middle-income countries (LMICs). Although guidelines characterizing data for blood product transfusion in injury resuscitation have been established for high-income countries (HICs), no such information on use of blood products in LMICs exists. This systematic review evaluated the available literature on the use and associated outcomes of blood product transfusion therapies in LMICs for acute care of patients with injuries. METHODS A systematic search of PubMed, EMBASE, Global Health, CINAHL and Cochrane databases through November 2018 was performed by a health sciences medical librarian. Prospective and cross-sectional reports of injured patients from LMICs involving data on blood product transfusion therapies were included. Two reviewers identified eligible records (kappa=0.92); quality was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Report elements, patient characteristics, injury information, blood transfusion therapies provided and mortality outcomes were extracted and analyzed. RESULTS Of 3411 records, 150 full-text reports were reviewed and 17 met inclusion criteria. Identified reports came from the World Health Organization regions of Africa, the Eastern Mediterranean, and South-East Asia. A total of 6535 patients were studied, with the majority from exclusively inpatient hospital settings (52.9%). Data on transfusion therapies demonstrated that packed red blood cells were given to 27.0% of patients, fresh frozen plasma to 13.8%, and unspecified product types to 50.1%. Among patients with blunt and penetrating injuries, 5.8% and 15.7% were treated with blood product transfusions, respectively. Four reports provided data on comparative mortality outcomes, of which two found higher mortality in blood transfusion-treated patients than in untreated patients at 17.4% and 30.4%. The overall quality of evidence was either low (52.9%) or very low (41.2%), with one report of moderate quality by GRADE criteria. CONCLUSION There is a paucity of high-quality data to inform appropriate use of blood transfusion therapies in LMIC injury care. Studies were geographically limited and did not include sufficient data on types of therapies and specific injury patterns treated. Future research in more diverse LMIC settings with improved data collection methods is needed to inform injury care globally.
PICO Summary
Population
Patients with injuries requiring acute care in low and middle income countries (17 studies, n=6535).
Intervention
Systematic review on the use of blood product transfusion therapies.
Comparison
Outcome
Packed red blood cells were given to 27.0% of patients, fresh frozen plasma to 13.8%, and unspecified product types to 50.1%. Among patients with blunt and penetrating injuries, 5.8% and 15.7% were treated with blood product transfusions, respectively. Four reports provided data on comparative mortality outcomes, of which two found higher mortality in blood transfusion-treated patients than in untreated patients at 17.4% and 30.4%.
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Systematic reviews of scores and predictors to trigger activation of massive transfusion protocols
Shih AW, Al Khan S, Wang AY, Dawe P, Young PY, Greene A, Hudoba M, Vu E
The journal of trauma and acute care surgery. 2019;87(3):717-729
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Editor's Choice
Abstract
BACKGROUND The use of massive transfusion protocols (MTPs) in the resuscitation of hemorrhaging trauma patients ensures rapid delivery of blood products to improve outcomes, where the decision to trigger MTPs early is important. Scores and tools to predict the need for MTP activation have been developed for use to aid with clinical judgment. We performed a systematic review to assess (1) the scores and tools available to predict MTP in trauma patients, (2) their clinical value and diagnostic accuracies, and (3) additional predictors of MTP. METHODS MEDLINE, EMBASE, and CENTRAL were searched from inception to June 2017. All studies that utilized scores or predictors of MTP activation in adult (age, ≥18 years) trauma patients were included. Data collection for scores and tools included reported sensitivities and specificities and accuracy as defined by the area under the curve of the receiver operating characteristic. RESULTS Forty-five articles were eligible for analysis, with 11 validated and four unvalidated scores and tools assessed. Of four scores using clinical assessment, laboratory values, and ultrasound assessment the modified Traumatic Bleeding Severity Score had the best performance. Of those scores, the Trauma Associated Severe Hemorrhage score is most well validated and has higher area under the curve of the receiver operating characteristic than the Assessment of Blood Consumption and Prince of Wales scores. Without laboratory results, the Assessment of Blood Consumption score balances accuracy with ease of use. Without ultrasound use, the Vandromme and Schreiber scores have the highest accuracy and sensitivity respectively. The Shock Index uses clinical assessment only with fair performance. Other clinical variables, laboratory values, and use of point-of-care testing results were identified predictors of MTP activation. CONCLUSION The use of scores or tools to predict MTP need to be individualized to hospital resources and skill set to aid clinical judgment. Future studies for triggering nontrauma MTP activations are needed. LEVEL OF EVIDENCE Systematic review, level III.
PICO Summary
Population
Trauma patients requiring massive transfusion (45 studies).
Intervention
Scores and tools to predict the need for massive transfusion protocol (MTP) activation (n=11). Assessed the scores and tools available to predict massive transfusion protocols (MTPs) in trauma patients, their clinical value and diagnostic accuracies, and additional predictors of MTP.
Comparison
MTP scores and tools were compared with each other.
Outcome
Of four scores using clinical assessment, laboratory values, and ultrasound assessment the modified Traumatic Bleeding Severity Score had the best performance. Of those scores, the Trauma Associated Severe Hemorrhage score is most well validated and has higher area under the curve of the receiver operating characteristic than the Assessment of Blood Consumption and Prince of Wales scores. Without laboratory results, the Assessment of Blood Consumption score balances accuracy with ease of use. Without ultrasound use, the Vandromme and Schreiber scores have the highest accuracy and sensitivity respectively. The Shock Index uses clinical assessment only with fair performance. Other clinical variables, laboratory values, and use of point-of-care testing results were identified predictors of MTP activation.
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Does the evidence support the importance of high transfusion ratios of plasma and platelets to red blood cells in improving outcomes in severely injured patients: a systematic review and meta-analyses
da Luz LT, Shah PS, Strauss R, Mohammed AA, D'Empaire PP, Tien H, Nathens AB, Nascimento B
Transfusion. 2019
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Editor's Choice
Abstract
BACKGROUND Deaths by exsanguination in trauma are preventable with hemorrhage control and resuscitation with allogeneic blood products (ABPs). The ideal transfusion ratio is unknown. We compared efficacy and safety of high transfusion ratios of FFP:RBC and PLT:RBC with low ratios in trauma. STUDY DESIGN AND METHODS Medline, Embase, Cochrane, and Controlled Clinical Trials Register were searched. Observational and randomized data were included. Risk of bias was assessed using validated tools. Primary outcome was 24-h and 30-day mortality. Secondary outcomes were exposure to ABPs and improvement of coagulopathy. Meta-analysis was conducted using a random-effects model. Strength and evidence quality were graded using GRADE profile RESULTS 55 studies were included (2 randomized and 53 observational), with low and moderate risk of bias, respectively, and overall low evidence quality. The two RCTs showed no mortality difference (odds ratio [OR], 1.35; 95% confidence interval [CI], 0.40-4.59). Observational studies reported lower mortality in high FFP:RBCs ratio (OR, 0.38 [95% CI, 0.22-0.68] for 1:1 vs. <1:1; OR, 0.42 [95% CI, 0.22-0.81] for 1:1.5 vs. <1:1.5; and OR, 0.47 [95% CI, 0.31-0.71] for 1:2 vs. <1:2, respectively). Meta-analyses in observational studies showed no difference in exposure to ABPs. No data on coagulopathy for meta-analysis was identified. CONCLUSIONS Meta-analyses in observational studies suggest survival benefit and no difference in exposure to ABPs. No survival benefit in RCTs was identified. These conflicting results should be interpreted with caution. Studies are mostly observational, with relatively small sample sizes, nonrandom treatment allocation, and high potential for confounding. Further research is warranted.
PICO Summary
Population
Adult trauma patients (≥15 years old) with an important risk of bleeding: 2 randomized controlled trials (RCTs) (n=749 patients), and 53 observational cohort studies (n=27,228 patients).
Intervention
High fixed transfusion ratio of fresh-frozen plasma (FFP) and platelets (PLTs) to red blood cells (RBCs) or FFP or PLTs to RBCs, as defined in each study.
Comparison
The control was a low fixed transfusion ratio of FFP and PLTs to RBCs or FFP or RBCs to RBCs, also defined and compared in each study.
Outcome
The two RCTs showed no mortality difference (odds ratio [OR], 1.35). Observational studies reported lower mortality in high FFP:RBCs ratio (OR, 0.38 for 1:1 vs. <1:1; OR, 0.42 for 1:1.5 vs. <1:1.5; and OR, 0.47 for 1:2 vs. <1:2, respectively). Meta‐analyses in observational studies showed no difference in exposure to ABPs. No data on coagulopathy for meta‐analysis was identified.