Controversy in Trauma Resuscitation: Do Ratios of Plasma to Red Blood Cells Matter?

The Efficacy of Low-Titer Group O Whole Blood Compared With Component Therapy in Civilian Trauma Patients: A Meta-Analysis

OBJECTIVES

To assess if transfusion with low-titer group O whole blood (LTOWB) is associated with improved early and/or late survival compared with component blood product therapy (CT) in bleeding trauma patients.

DATA SOURCES

A systematic search of PubMed, CINAHL, and Web of Science was performed from their inception through December 1, 2023. Key terms included injury, hemorrhage, bleeding, blood transfusion, and whole blood.

STUDY SELECTION

All studies comparing outcomes in injured civilian adults and children who received LTOWB versus CT were included.

DATA EXTRACTION

Data including author, publication year, sample size, total blood volumes, and clinical outcomes were extracted from each article and reported following the Meta-analysis Of Observational Studies in Epidemiology guidelines. Main outcomes were 24-hour (early) and combined 28-day, 30-day, and in-hospital (late) mortality rates between recipients of LTOWB versus CT, which were pooled using random-effects models.

DATA SYNTHESIS

Of 1297 studies reviewed, 24 were appropriate for analysis. Total subjects numbered 58,717 of whom 5,164 received LTOWB. Eleven studies included adults-only, seven included both adults and adolescents, and six only included children. The median (interquartile range) age for patients who received LTOWB and CT was 35 years (24-39) and 35.5 years (23-39), respectively. Overall, 14 studies reported early mortality and 22 studies reported late mortality. LTOWB was associated with improved 24-hour survival (risk ratios [RRs] [95% CI] = 1.07 [1.03-1.12]) and late (RR [95% CI] = 1.05 [1.01-1.09]) survival compared with component therapy. There was no evidence of small study bias and all studies were graded as a moderate level of bias.

CONCLUSIONS

These data suggest hemostatic resuscitation with LTOWB compared with CT improves early and late survival outcomes in bleeding civilian trauma patients. The majority of subjects were injured adults; multicenter randomized controlled studies in injured adults and children are underway to confirm these findings.

Massive transfusion protocol reactivation as a novel marker of physician team under-triage after injury

BACKGROUND

Large trauma centers have protocols for the assessment of injury and triaging of care with attempts to over-triage to ensure adequate care for all patients. We noted that a significant number of patients undergo a second massive transfusion protocol (MTP) activation in the first 24 h of care and conducted a retrospective cohort study of patients involved over a 3-year period.

METHODS

Transfusion service records of MTP activations 2019-2021 were linked to Trauma Registry records and divided into cohorts receiving a single versus a reactivation of the MTP. Time of activation and amounts of blood products issued were linked to demographic, injury severity, and outcome data. Categorical and continuous data were compared between cohorts with chi-squared, Fisher's, and Wilcoxan tests as appropriate, and multivariable regression models were used to seek interactions (p < .05).

RESULTS

MTP activation was recorded for 1884 acute trauma patients over our 3-year study period, 142 of whom (7.5%) had reactivation. Factors associated with reactivation included older age (46 vs. 40 years), higher injury severity score (ISS, 27 vs. 22), leg injuries, and presentation during morning shift change (5-7 a.m., 3.3% vs. 7.7%). Patients undergoing MTP reactivation used more RBCs (5 U vs. 2 U) and had more ICU days (3 vs. 2).

CONCLUSIONS

Older patients and those presenting during shift change are at risk for failure to recognize their complex injury patterns and under-triage for trauma care. The fidelity and granularity of transfusion service records can provide unique opportunities for quality assessment and improvement in trauma care.

Trends in massive transfusion practice for trauma in Japan from 2011 to 2020: a nationwide inpatient database study

BACKGROUND

Previous studies have reported conflicting results regarding fresh frozen plasma (FFP)-to-red blood cell (RBC) ratio and platelet-to-RBC ratio on outcomes for massive transfusion for trauma. Moreover, nationwide data on massive transfusion practices for trauma in the real-world clinical setting are scarce. This study aimed to examine the nationwide practice patterns and trends in massive transfusion for trauma in Japan using a national administrative, inpatient database.

METHOD

We identified patients who underwent emergency hospitalization for trauma and received massive transfusion, defined as administration of at least 20 units of RBC within the first 2 days of admission, using the nationwide inpatient database, which covers approximately 90% of all tertiary emergency hospitals in Japan, between 2011 and 2020. Trends in the incidence and practice patterns of massive transfusion were described by calendar year. The association of practice patterns with mortality or adverse events was tested.

RESULTS

A total of 3,530,846 trauma hospitalizations were identified, of which 5247 (0.15%) received massive transfusion. A significant declining trend was observed in the incidence of massive transfusion in trauma hospitalizations from 0.24% in 2011 to 0.10% in 2020 (P for trend < 0.001). The FFP-to-RBC ratio rose significantly from 0.77 in 2011 to 1.08 in 2020 (P for trend < 0.001), while the platelet-to-RBC ratio remained virtually unchanged from 0.71 in 2011 to 0.78 in 2020 (P for trend 0.060). Massive transfusion with lower FFP-to-RBC (< 0.75) and platelets-to-RBC ratio (< 1.00) were associated with increased in-hospital mortality compared with those ≥ 1.00, while there were linear increases in adverse events with increasing FFP and platelets ratios.

CONCLUSIONS

This study demonstrated a declining trend in the incidence and a rise in higher FFP-to-RBC ratios in massive transfusion in association with patient outcomes for trauma from 2011 to 2020 in Japan.

Age, admission platelet count, and mortality in severe isolated traumatic brain injury: A retrospective cohort study

BACKGROUND

We asked whether patients >50 years of age with acute traumatic brain injury (TBI) present with lower platelet counts and whether lower platelet counts are independently associated with mortality.

METHODS

We combined trauma registry and laboratory data on a retrospective cohort of all patients ≥18 years of age admitted to our Level 1 US regional trauma center 2015-2021 with severe (Head Abbreviated Injury Score [AIS] ≥3), isolated (all other AIS <3) TBI who had a first platelet count within 1 h of arrival. Age and platelet count were assessed continuously and as groups (age 18-50 vs. >50, platelet normals, and at conventional transfusion thresholds). Outcomes such as mean admission platelet counts and in-hospital mortality were assessed categorically and with logistic regression.

RESULTS

Of 44,056 patients, 1298 (3%, median age: 52 [IQR 33,68], 76.1% male) met all inclusion criteria with no differences between younger and older age groups for (ISS; 18 [14,26] vs. 17 [14,26], p = .22), New ISS (NISS; 29 [19,50] vs. 28 [17,50], p = .36), or AIS-Head (4 [3,5] vs. 4 [3,5]; p = .87). Patients aged >50 had lower admission platelet counts (219,000 ± 93,000 vs. 242,000 ± 76,000/μL; p < .001) and greater in-hospital mortality (24.5% vs. 15.6%, p < .001) than those 18-50. In multivariable regression, firearms injuries (OR9.08), increasing age (OR1.004), NISS (OR1.007), and AIS-Head (OR1.05), and decreasing admission platelet counts (OR0.998) were independently associated with mortality (p < .001-.041). Platelet transfusion in the first 4 h of care was more frequent among older patients (p < .001).

CONCLUSIONS

Older patients with TBI had lower admission platelet counts, which were independently associated with greater mortality.

Pro-Con Debate: Viscoelastic Hemostatic Assays Should Replace Fixed Ratio Massive Transfusion Protocols in Trauma

Major trauma patients at risk of traumatic coagulopathy are commonly treated with early clotting factor replacement to maintain hemostasis and prevent microvascular bleeding. In the United States, trauma transfusions are often dosed by empiric, low-ratio massive transfusion protocols, which pair plasma and platelets in some ratio relative to the red cells, such as the "1:1:1" combination of 1 units of red cells, 1 unit of plasma, and 1 donor's worth of pooled platelets. Empiric transfusion increases the rate of overtransfusion when unnecessary blood products are administered based on a formula and not on at patient's hemostatic profile. Viscoelastic hemostatic assays (VHAs) are point-of-care hemostatic assays that provided detailed information about abnormal clotting pathways. VHAs are used at many centers to better target hemostatic therapies in trauma. This Pro/Con section will address whether VHA guidance should replace empiric fixed ratio protocols in major trauma.

Perioperative management of the bleeding patient

Perioperative bleeding remains a major complication during and after surgery, resulting in increased morbidity and mortality. The principal causes of non-vascular sources of haemostatic perioperative bleeding are a preexisting undetected bleeding disorder, the nature of the operation itself, or acquired coagulation abnormalities secondary to haemorrhage, haemodilution, or haemostatic factor consumption. In the bleeding patient, standard therapeutic approaches include allogeneic blood product administration, concomitant pharmacologic agents, and increasing application of purified and recombinant haemostatic factors. Multiple haemostatic changes occur perioperatively after trauma and complex surgical procedures including cardiac surgery and liver transplantation. Novel strategies for both prophylaxis and therapy of perioperative bleeding include tranexamic acid, desmopressin, fibrinogen and prothrombin complex concentrates. Point-of-care patient testing using thromboelastography, rotational thromboelastometry, and platelet function assays has allowed for more detailed assessment of specific targeted therapy for haemostasis. Strategic multimodal management is needed to improve management, reduce allogeneic blood product administration, and minimize associated risks related to transfusion.

Outcomes of patients receiving a massive transfusion for major trauma

BACKGROUND

The benefits of high transfusion ratios (plasma to red blood cells and platelets to red blood cells) on survival in injured patients who receive massive transfusions remain uncertain. This study aimed to assess the association between transfusion ratios and adverse events and survival in patients undergoing massive transfusion for major trauma.

METHODS

A retrospective observational study was conducted on patients who had major trauma using a Japanese national administrative database. The associations between transfusion ratios and outcomes (in-hospital mortality and incidence of adverse events) were analysed using a non-linear logistic generalized additive model (GAM). In a logistic generalized estimating equation model, adjusted for patient and hospital-level confounders, transfusion ratios were included as continuous or categorical variables (low, transfusion ratio 0·75 or less; intermediate, over 0·75 to 1·25; high, over 1·25).

RESULTS

Some 1777 patients were included in the analysis, of whom 602 died in hospital. GAM plots of the transfusion ratios for in-hospital mortality demonstrated a downward convex unimodal curve. In-hospital mortality was similar with increasing transfusion ratios for plasma (adjusted odds ratio (OR) 1·13, 95 per cent c.i. 0·82 to 1·55; P = 0·446) and platelets (adjusted OR 0·84, 0·66 to 1·08; P = 0·171). Both plasma to red blood cell ratio (adjusted OR 1·77, 1·32 to 2·37; P < 0·001) and platelet to red blood cell ratio (adjusted OR 1·71, 1·35 to 2·15; P < 0·001) were significantly associated with a higher incidence of adverse events. No significant differences in in-hospital mortality were observed between the three transfusion categories (low, medium and high).

CONCLUSION

In this study, transfusion strategies with high plasma to red blood cell and platelet to red blood cell ratios did not have survival benefits, but were associated with an increase in adverse events.

Investigation of the status quo of massive blood transfusion in China and a synopsis of the proposed guidelines for massive blood transfusion

The aim of this study was to provide an overview of massive transfusion in Chinese hospitals, identify the important indications for massive transfusion and corrective therapies based on clinical evidence and supporting experimental studies, and propose guidelines for the management of massive transfusion. This multiregion, multicenter retrospective study involved a Massive Blood Transfusion Coordination Group composed of 50 clinical experts specializing in blood transfusion, cardiac surgery, anesthesiology, obstetrics, general surgery, and medical statistics from 20 tertiary general hospitals across 5 regions in China. Data were collected for all patients who received ≥10 U red blood cell transfusion within 24 hours in the participating hospitals from January 1 2009 to December 31 2010, including patient demographics, pre-, peri-, and post-operative clinical characteristics, laboratory test results before, during, and after transfusion, and patient mortality at post-transfusion and discharge. We also designed an in vitro hemodilution model to investigate the changes of blood coagulation indices during massive transfusion and the correction of coagulopathy through supplement blood components under different hemodilutions. The experimental data in combination with the clinical evidence were used to determine the optimal proportion and timing for blood component supplementation during massive transfusion. Based on the findings from the present study, together with an extensive review of domestic and international transfusion-related literature and consensus feedback from the 50 experts, we drafted the guidelines on massive blood transfusion that will help Chinese hospitals to develop standardized protocols for massive blood transfusion.

The pragmatic randomized optimal platelet and plasma ratios trial: what does it mean for remote damage control resuscitation?

BACKGROUND

Implications from the pragmatic, randomize, optimal platelet and plasma ratios (PROPPR) trial are critical for remote damage control resuscitation (DCR). Utilizing DCR principals in remote settings can combat early mortality from hemorrhage. Identifying the appropriate transfusion strategy is mandatory prior to adopting prehospital hemostatic resuscitation strategies.

STUDY DESIGN AND METHODS

The PROPPR study was examined in relation to the following questions: 1) Why is it important to have blood products in the prehospital setting?; 2) Which products should be investigated for prehospital hemostatic resuscitation?; 3) What is the appropriate ratio of blood product transfusion?; and 4) What are the appropriate indications for hemostatic resuscitation?

RESULTS

PROPPR demonstrates that early and balanced blood product transfusion ratios reduced mortality in all patients at 3 hours and death from exsanguination at 24 hours (p = 0.03). The median time to death from exsanguination was 2.3 hours, highlighting the need for point-of-injury DCR capabilities. A 1:1:1 transfusion ratio of plasma:platelets:packed red blood cells increased the percentage of patients achieving anatomic hemostasis (p = 0.006). PROPPR used the assessment of blood consumption score to identify patients likely to require ongoing hemostatic resuscitation. The critical administration threshold predicted patient mortality and identified patients likely to require ongoing hemostatic resuscitation.

CONCLUSION

A balanced resuscitation strategy demonstrates an early survival benefit, decreased death from exsanguination at 24 hours and a greater likelihood of achieving hemostasis in critically injured patients receiving a 1:1:1 ratio of plasma:platelets:PRBCs. This finding highlights the need to import DCR principals to remote locations.

Research in Review: Driving Critical Care Practice Change

During the past year, studies were published that will lead to practice change, address challenges at the bedside, and introduce new care strategies. This article summarizes some of this important work and considers it in the context of previous research and practice. Examples of research-based practice changes include the performance and assessment of septic shock resuscitation, and the integration of tourniquets and massive transfusions in civilian trauma. Care challenges addressed include ethical considerations in light of the Ebola epidemic, infection prevention associated with chlorhexidine bathing, bedside alarm management, evidence to enhance moral courage, and interventions to mitigate thirst in critically ill patients. Research that portends future care includes a discussion of fecal microbiota transplant for patients with refractory infection with refractory infection with Clostridium difficile.

Blood Products

Perioperative hemorrhage, anemia, thrombocytopenia, and coagulopathy are common in the surgical intensive care unit. As a result, blood product transfusion occurs frequently. While red blood cell, plasma, and platelet transfusions have a lifesaving role in the resuscitation of patients with trauma and hemorrhagic shock, their application in other settings is under scrutiny. Current data would suggest a conservative approach be taken, thus avoiding unnecessary transfusion and associated potential adverse events. New and developmental products such as prothrombin complex concentrates offer appealing alternatives to traditional transfusion practice—potentially with fewer risks—however, further investigation into their safety and efficacy is required before practice change can take place.

The Clinical Implication of Blood Product Transfusion on Morbidity and Mortality of Ruptured Abdominal Aortic Aneurysm

BACKGROUND

Transfusion of blood products occurs frequently in ruptured abdominal aortic aneurysm surgery (rAAA). The aim of this study is to establish the impact of packed red blood cell (PRBC), fresh frozen plasma (FFP), and platelet (PLT) transfusion on the 30-day mortality and morbidity (thrombotic versus non thrombotic complications) of rAAAs.

METHODS

A retrospective study of 90 consecutive rAAAs from November 2007 to June 2015 was conducted. Multivariable regression models were produced to determine blood products associated with 30-day morbidity and mortality post-rAAA.

RESULTS

The overall mortality was 14.6%. At multivariable analyses, transfusion with FFP (>3 units) was independently associated with an increased risk of mortality (odds ratio [OR]: 11.27, 95% confidence interval [CI]: 1.13-96.72, P = .027). The overall morbidity was 26.8%, and subgroup analysis (thrombotic vs nonthrombotic complications) demonstrated transfusion of PLTs (>1 pool) to be independently associated with thrombotic events (OR: 4.3, 95% CI: 1.37-13.6, P = .012). Thrombotic events were responsible for 50% (n = 11 of 22) of all morbidities and mortalities (n = 6 of 12).

CONCLUSION

Transfusion of FFP and PLTs may be associated with an increased risk of postoperative morbidity and mortality. The use of these blood components should be considered in the context of the patient's clinical and laboratory data as opposed to a fixed ratio to PRBCs. This may result in the reduction in thrombotic complications emerging in rAAA cohort.

Coagulation defects associated with massive blood transfusion: A large multicenter study

The variations in the coagulation indices of patients receiving massive blood transfusion were investigated across 20 large-scale general hospitals in China. The data of 1,601 surgical inpatients receiving massive transfusion were retrospectively collected and the trends in the platelet counts and coagulation indices prior to and at 16 different time points during packed red blood cell (pRBC; after 2–40 units of pRBC) transfusion were evaluated by linear regression analysis. Temporal variations in the means of prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (APTT) and fibrinogen (FIB) concentration were also assessed and the theoretical estimates and actual measurements of the platelet count were compared. The results demonstrated that the platelet count decreased linearly with an increase in the number of pRBC units transfused (Y=150.460−3.041X; R² linear=0.775). Following transfusion of 18 units of pRBC (0.3 units of pRBC transfused per kilogram of body weight), the average platelet count decreased to 71×10⁹/l (<75×10⁹/l). Furthermore, variations in the means of PT, INR, APTT and FIB did not demonstrate any pronounced trends and actual platelet counts were markedly higher than the theoretical estimates. In conclusion, no variations in the means of traditional coagulation indices were identified, however, the platelet count demonstrated a significant linear decrease with an increase in the number of pRBC units transfused. Furthermore, actual platelet counts were higher than theoretical estimates, indicating the requirement for close monitoring of actual platelet counts during massive pRBC transfusion.

Making thawed universal donor plasma available rapidly for massively bleeding trauma patients: experience from the Pragmatic, Randomized Optimal Platelets and Plasma Ratios (PROPPR) trial

BACKGROUND

The Pragmatic, Randomized Optimal Platelets and Plasma Ratios (PROPPR) trial was a randomized clinical trial comparing survival after transfusion of two different blood component ratios for emergency resuscitation of traumatic massive hemorrhage. Transfusion services supporting the study were expected to provide thawed plasma, platelets, and red blood cells within 10 minutes of request.

STUDY DESIGN AND METHODS

At the 12 Level 1 trauma centers participating in PROPPR, blood components transfused and delivery times were tabulated, with a focus on universal donor (UD) plasma management. The adequacy of site plans was assessed by comparing the bedside blood availability times to study goals and the new American College of Surgeons guidelines.

RESULTS

Eleven of 12 sites were able to consistently deliver 6 units of thawed UD plasma to their trauma-receiving unit within 10 minutes and 12 units in 20 minutes. Three sites used blood group A plasma instead of AB for massive transfusion without complications. Approximately 4700 units of plasma were given to the 680 patients enrolled in the trial. No site experienced shortages of AB plasma that limited enrollment. Two of 12 sites reported wastage of thawed AB plasma approaching 25% of AB plasma prepared.

CONCLUSION

Delivering UD plasma to massively hemorrhaging patients was accomplished consistently and rapidly and without excessive wastage in high-volume trauma centers. The American College of Surgeons Trauma Quality Improvement Program guidelines for massive transfusion protocol UD plasma availability are practicable in large academic trauma centers. Use of group A plasma in trauma resuscitation needs further study.

Balanced ratio of plasma to packed red blood cells improves outcomes in massive transfusion: A large multicenter study

Resuscitation with the early administration of plasma can improve the survival of patients undergoing surgery or trauma patients who require massive transfusion. To ascertain the optimal ratio of fresh frozen plasma (FFP) to packed red blood cells (pRBCs) in massive transfusions, the records of 1,048 patients who received a massive transfusion at 20 hospitals were retrospectively reviewed. The patients were stratified into three groups according to the ratio of FFP to pRBCs. These were the low (<1:2.3), middle (1:2.3-0.75) and high (≥1:0.75) ratio groups. For 24-h treatment, the middle FFP:pRBC ratio led to a lower mortality rate (9.31%) compared with that in the low (11.83%) and high (11.44%) ratio groups (P=0.477). For 72-h treatment, the middle FFP:pRBC ratio also lead to the lowest mortality rate (7.25%), which was significantly lower than the ratios in the low (10.39%) and high (13.65%) ratio groups (P=0.007). The length of hospital stay, ICU stay, and FFP:pRBC ratio in 72 h were found to be significant associated with mortality. The optimal ratio of FFP to pRBCs of 1:2.3-0.75 in 72 h can improve the survival of patients undergoing massive transfusions.

Massive hemorrhage: a report from the anesthesia closed claims project

BACKGROUND

Hemorrhage is a potentially preventable cause of adverse outcomes in surgical and obstetric patients. New understanding of the pathophysiology of hemorrhagic shock, including development of coagulopathy, has led to evolution of recommendations for treatment. However, no recent study has examined the legal outcomes of these claims. The authors reviewed closed anesthesia malpractice claims related to hemorrhage, seeking common factors to guide future management strategies.

METHODS

The authors analyzed 3,211 closed surgical or obstetric anesthesia malpractice claims from 1995 to 2011 in the Anesthesia Closed Claims Project. Claims where patient injury was attributed to hemorrhage were compared with all other surgical and obstetric claims. Risk factors for hemorrhage and coagulopathy, clinical factors, management, and communication issues were abstracted from claim narratives to identify recurrent patterns.

RESULTS

Hemorrhage occurred in 141 (4%) claims. Obstetrics accounted for 30% of hemorrhage claims compared with 13% of nonhemorrhage claims (P < 0.001); thoracic or lumbar spine surgery was similarly overrepresented (24 vs. 6%, P < 0.001). Mortality was higher in hemorrhage than nonhemorrhage claims (77 vs. 27%, P < 0.001), and anesthesia care was more often judged to be less than appropriate (55 vs. 38%, P < 0.001). Median payments were higher in hemorrhage versus nonhemorrhage claims ($607,750 vs. $276,000, P < 0.001). Risk factors for hemorrhage and coagulopathy were common, and initiation of transfusion therapy was commonly delayed.

CONCLUSIONS

Hemorrhage is a rare, but serious, cause of anesthesia malpractice claims. Understanding which patients are at risk can aid in patient referral decisions, design of institutional systems for responding to hemorrhage, and education of surgeons, obstetricians, and anesthesiologists.

Going for gold: blood planning for the London 2012 Olympic Games

The Olympics is one of the largest sporting events in the world. Major events may be complicated by disruption of normal activity and major incidents. Health care and transfusion planners should be prepared for both. Previously, transfusion contingency planning has focused on seasonal blood shortages and pandemic influenzas. This article is the first published account of transfusion contingency planning for a major event. We describe the issues encountered and the lessons identified during transfusion planning for the London 2012 Olympics. Planning was started 18 months in advance and was led by a project team reporting to the Executive. Planning was based on three periods of Gamestime. The requirements were planned with key stakeholders using normal processes enhanced by service developments. Demand planning was based on literature review together with computer modelling. The aim was blood-stock sufficiency complimented by a high readiness donor panel to minimise waste. Plans were widely communicated and table-top exercised. Full transfusion services were maintained during both Games with all demands met. The new service improvements and high readiness donors worked well. Emergency command and control have been upgraded. Red cell concentrate (RCC) stock aged but wastage was not significantly increased. The key to success was: early planning, stakeholder engagement, service developments, integration of transfusion service planning within the wider health care community and conduct within an assurance framework.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: « Does this particular AABT reduce the transfusion rate or not?» All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

[Amniotic fluid embolism: an update]

Amniotic fluid embolism (AFE) results from the passage of fœtal and amniotic fragments into the maternal circulation, occurring mostly within minutes before or after delivery. Although maternal and fœtal mortality of AFE remains high (about 40%), AFE should no longer be considered as having an ineluctable fatal course. Diagnosis is often made upon clinical presentation but histological confirmation is difficult owing favorable outcome and because an autopsy has not been performed. Identification of squamous cells in the maternal circulation could not confirm the diagnosis because of their possible maternal origin. High plasma level of insulin-like growth factor-binding protein-1 (IGFBP-1) has recently been identified as a biomarker of amniotic fluid passage into the maternal circulation and might therefore be used to confirm the diagnosis when lung tissue histology is not available. Treatment of AFE remains supportive with a special focus on correction of the coagulopathy and search for acute core pulmonale. In this later case, physicians should consider initiating an extracorporeal life support when facing a patient with refractory shock. Finally, caution is needed with the use of recombinant factor VIIa in this context.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: "Does this particular AABT reduce the transfusion rate or not?" All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

The impact of blood component transfusion practices on patient survival after abdominal aortic aneurysm surgery

BACKGROUND

The aim of the present study was to investigate the blood transfusion practice in patients operated for abdominal aortic aneurysm (AAA) with special emphasis on massive transfusion in cases with rupture.

MATERIAL AND METHODS

From a database, 504 patients operated for AAA were stratified into 2 groups; an early transfusion period (1992-1999) and a late transfusion period (2000-2008) to evaluate the changes in transfusion practices over the course of time.

RESULTS

Patients operated for nonruptured AAA (n = 330) showed a decreased mortality rate from 4% (early transfusion period) to 1% (late transfusion period) without significant changes in the transfusion practices. In patients operated for ruptured AAA (n = 174) an unexpected low mortality rate was found compared to the 30-day mortality reported in earlier studies. The transfusion practices in ruptured AAA surgery showed a significant increase in platelet use and change of fresh frozen plasma: red blood cell ratio from 0.8 to 0.9 between the early and the late transfusion period.

CONCLUSION

The present database study shows that the operating mortality for AAA surgery has declined during the past decades. The cause of the decline in mortality in patients with ruptured AAA was interpreted as partly due to a modern blood component therapy.

[Current trends in plasma transfusion for patients with severe hemorrhage]

Recent changes in plasma transfusion practices for severe hemorrhage are largely related to the recognition of an early endogenous coagulopathy associated with traumatic injury. Observational and mostly retrospective data suggest improved survival rates with high-dose plasma therapy, up to a 1:1 ratio of fresh frozen plasma to packed red blood cells, but the quality of evidence is limited. Putting it into practice raises many issues (early identification of patients at risk of massive bleeding, extrapolation to non-trauma settings, alternative or adjunctive treatments, among others) that are discussed in this brief review.

Hemoperitoneum semiquantitative analysis on admission of blunt trauma patients improves the prediction of massive transfusion

BACKGROUND

The purpose of this study was to define whether the semiquantitative analysis of hemoperitoneum increases the accuracy of early prediction of massive transfusion (MT).

METHODS

A retrospective review of severe trauma patients consecutively admitted to our trauma intensive care unit between January 2005 and December 2009 was conducted. Patients diagnosed with blunt abdominal trauma who had a computed tomography scan on admission were included. The hemoperitoneum size was defined using the Federle score on computed tomography as large, moderate, or minimal/none. The association between MT (≥10 U of packed red blood cells in the first 24 h) and moderate and large sizes of hemoperitoneum was assessed using a multiple logistic model.

RESULTS

Of the 381 patients meeting the inclusion criteria, 270 (71%) were male; the mean age was 35.5 ± 18.2 years and mean injury severity score was 23.4 ± 17. Ninety-seven (26%) had large hemoperitoneum, 107 (28%) had moderate hemoperitoneum, and 177 (46%) had minimal/no hemoperitoneum. Eighty-three patients (22%) required MT. The positive predictive value for MT of a large hemoperitoneum was 41%, 23% for a moderate hemoperitoneum, and 10% for minimal/no hemoperitoneum (P < .001). The corresponding values for hypotensive patients were 61%, 32%, and 25%, respectively (P < .001). In the multivariate analysis model, only the large size of hemoperitoneum was significantly associated with MT (OR 6.4, 95% CI 2.9-14, P < .001, r(2) = 0.47).

CONCLUSION

The assessment of the size of hemoperitoneum on admission substantially improves the prediction of MT in trauma patients and should be used to trigger and guide initial haemostatic resuscitation.

Blood utilization: fostering an effective hospital transfusion culture

An effective hospital transfusion culture should encourage clinicians to consider the possibility of transfusion in their patients well before the need actually arises, and to plan ahead in an attempt to use blood products most efficiently. Strategies for improved blood utilization include timely and adequate preoperative assessment of risk, optimization of baseline hemoglobin, anticipation of potential transfusion problems, intraoperative techniques to minimize blood loss, blood conservation technologies, transfusion guidelines and targeted therapy, point of care testing, and massive transfusion protocols. Attention to these elements promotes a safe and cost-effective transfusion culture.

What's new in resuscitation strategies for the patient with multiple trauma?

The last decade has seen a sea change in the management of major haemorrhage following traumatic injury. Damage control resuscitation (DCR), a strategy combining the techniques of permissive hypotension, haemostatic resuscitation and damage control surgery has been widely adopted as the preferred method of resuscitation in patients with haemorrhagic shock. The over-riding goals of DCR are to mitigate metabolic acidosis, hypothermia and coagulopathy and stabilise the patient as early as possible in a critical care setting. This narrative review examines the background to these changes in resuscitation practice, discusses the central importance of traumatic coagulopathy in driving these changes particularly in relation to the use of high FFP:RBC ratio and explores methods of predicting, diagnosing and treating the coagulopathy with massive transfusion protocols as well as newer coagulation factor concentrates. We discuss other areas of trauma haemorrhage management including the role of hypertonic saline and interventional radiology. Throughout this review we specifically examine whether the available evidence supports these newer practices.

Simulation of survivorship bias in observational studies on plasma to red blood cell ratios in massive transfusion for trauma

BACKGROUND

Observational studies on injured patients requiring massive transfusion have found a survival advantage associated with use of equivalent number of units of fresh frozen plasma (FFP) and packed red blood cells (RBCs) compared with use of FFP based on conventional guidelines. However, a survivorship bias might have favoured the higher use of FFP because patients who died early never had the chance to receive sufficient FFP to match the number of RBC units transfused.

METHODS

A Markov model using trauma data from local hospitals was constructed and various FFP transfusion scenarios were applied in Monte Carlo simulations in which the relative risk of death associated with exposure to high FFP transfusion was set at 1.00, so that the FFP : RBC ratio had no influence on mortality outcome.

RESULTS

Simulation results showed that the relative risk associated with exposure to high FFP transfusion was less than 1.00 (0.33-0.56 based on programmed delays in achieving an FFP : RBC ratio of 1 : 1-2), thus demonstrating a survivorship bias in favour of FFP : RBC equal to or more than 1 : 1-2 in certain observational trauma studies. This bias was directly proportional to the delay in achieving a FFP : RBC ratio of 1 : 1-2 during resuscitation.

CONCLUSION

Some observational studies comparing low and high FFP administration in injured patients requiring massive transfusion probably involve survivorship bias that inflates or creates a survival advantage in favour of a higher FFP : RBC ratio.

Resuscitative strategies to maintain homeostasis during damage control surgery

BACKGROUND

Successful outcome from damage control surgery (DCS) depends as much on elements of resuscitation and non-operative management as on details of the procedure itself. The early management of patients in haemorrhagic shock has undergone substantial revision in the past decade and is now known as 'haemostatic resuscitation'.

METHODS

An updated literature review describing the anaesthetic and resuscitative management of patients with active, ongoing traumatic haemorrhage was distilled to present the current knowledge of the pathophysiology, recommended treatments and areas of active controversy.

RESULTS

Current practice in military and civilian trauma centres is described, along with the degree of evidence in support of clinical decisions. Resuscitation of patients with ongoing traumatic haemorrhage has changed substantially in the past two decades. Optimal management now includes deliberate hypotension to minimize blood loss, early use of blood products (especially plasma) and administration of antifibrinolytic therapy. Areas of debate include the role of clotting factor concentrates and depth of anaesthesia.

CONCLUSION

Resuscitation strategies during DCS may be as important as the anatomical repair itself. Recommendations include avoidance of hypothermia, maintenance of a lower than normal blood pressure, and early support of the coagulation system in patients likely to require massive transfusion. Controversies include the optimal ratio of plasma to red blood cells for empirical resuscitation, the ideal role of clotting factor concentrates, and the potential benefit of early, deep anaesthesia. Future research will centre on the complex interaction between the humoral elements of coagulation and the vascular endothelium that regulates perfusion, clotting and integrity of the circulation.

Postpartum hemorrhage: when uterotonics and sutures fail

Systemic bleeding at the time of postpartum hemorrhage (PPH) is usually the result of coagulopathy that has developed acutely as a result of massive hemorrhage after uterotonics and sutures have failed. Occasionally, the patient has a preexisting coagulopathy, but more often, coagulopathy arises acutely as the result of massive hemorrhage, which is usually related to obstetrical and less often surgical bleeding. Despite being able to identify risk factors for PPH in the antenatal and intrapartum period, the majority of women who ultimately develop PPH do not have any such factors and every pregnancy is at risk. The coagulopathy associated with massive PPH may be due to hemodilution, failure of liver synthetic function as occurs with acute liver failure of pregnancy, or disseminated intravascular coagulation (DIC). There are no data from clinical trials to help guide management of transfusion in PPH, although the management of blood component therapy in severe PPH is similar to that in other massive hemorrhage. Standard practice is to replace fibrinogen to maintain a level of ≥ 100 mg/dL, yet recent evidence suggests that the level of fibrinogen needed to prevent PPH is at least 400 mg/dL. Recombinant activated factor VIIa (rFVIIa) has been used in the management of severe PPH unresponsive to blood component therapy. Coagulation laboratory evaluation may be useful in guiding hemostatic management during massive PPH, but for the results to be useful, they must be rapidly available and provide information that would not be available from clinical assessment alone. The hematologist or hemostasis expert has the opportunity to make the difference between life and death for the patient experiencing massive PPH.

Transfusion medicine in trauma patients: an update

In 2008, we reviewed the practical interface between transfusion medicine and the surgery and critical care of severely injured patients. Reviewed topics ranged from epidemiology of trauma to patterns of resuscitation to the problems of transfusion reactions. In the interim, trauma specialists have adopted damage control resuscitation and become much more knowledgeable and thoughtful about the use of blood products. This new understanding and the resulting changes in clinical practice have raised new concerns. In this update, we focus on which patients need damage control resuscitation, current views on the optimal form of damage control resuscitation with blood products, the roles of newer blood products, and appropriate transfusion triggers in the postinjury setting. We will also review the role of new technology in patient assessment, therapy and monitoring.

Design and preliminary results of a pilot randomized controlled trial on a 1:1:1 transfusion strategy: the trauma formula-driven versus laboratory-guided study

BACKGROUND

Retrospective reviews have recently shown an survival benefit for adopting a resuscitation strategy that transfuses plasma and platelets at a near 1:1 ratio with red blood cells (RBCs). However, a randomized controlled trial on the topic is lacking. We report on the design and preliminary results of our ongoing randomized control pilot trial (ClinicalTrial.gov NCT00945542).

METHODS

This is a 2-year feasibility randomized control trial at a single tertiary trauma center. Bleeding trauma patients were randomized to either a laboratory-driven or a formula-driven (1 plasma:1 platelet:1 RBC) transfusion protocols. Feasibility was assessed by analyzing for ability to enroll patients, appropriate activation of transfusion protocols, time to transfusion of each type of blood product, laboratory turnaround time, ratio of blood products transfused, and wastage of blood products.

RESULTS

From July 6, 2009, to May 31, 2010, n = 18 patients were randomized and included in the study. Issues that we noted were the need to do postrandomization exclusions, the need to have rapid and accurate predictors of massive bleeding to enroll patients quickly, and the need to have waived consent for study participation. As well, we noted that the logistics of administering 1:1:1 were formidable and required rapid access to thawed plasma. Similarly, challenges in the control arm of such a study included the turnaround time for obtaining laboratory results.

CONCLUSION

Despite major challenges, our initial experience suggests that with an organized system, it is possible to prospectively randomize massively bleeding trauma patients. The accomplishment of high ratios of plasma to RBCs is challenging with current thawing methods and unavailability of thawed plasma in Canada. Longer shelf-life for plasma and faster plasma thawing microwaves should overcome some of these obstacles. For a laboratory-guided transfusion protocol, massive transfusion protocols should be in place with faster turnaround time for coagulation tests. Finally, further research on predictors of massive transfusion is needed.

Clotting factor deficiency in early trauma-associated coagulopathy

BACKGROUND

Coagulopathic bleeding is a leading cause of in-hospital death after injury. A recently proposed transfusion strategy calls for early and aggressive frozen plasma transfusion to bleeding trauma patients, thus addressing trauma-associated coagulopathy (TAC) by transfusing clotting factors (CFs). This strategy may dramatically improve survival of bleeding trauma patients. However, other studies suggest that early TAC occurs by protein C activation and is independent of CF deficiency. This study investigated whether CF deficiency is associated with early TAC.

METHODS

This is a prospective observational cohort study of severely traumatized patients (Injury Severity Score ≥ 16) admitted shortly after injury, receiving minimal fluids and no prehospital blood. Blood was assayed for CF levels, thromboelastography, and routine coagulation tests. Critical CF deficiency was defined as ≤ 30% activity of any CF.

RESULTS

Of 110 patients, 22 (20%) had critical CF deficiency: critically low factor V level was evident in all these patients. International normalized ratio, activated prothrombin time, and, thromboelastography were abnormal in 32%, 36%, and 35%, respectively, of patients with any critically low CF. Patients with critical CF deficiency suffered more severe injuries, were more acidotic, received more blood transfusions, and showed a trend toward higher mortality (32% vs. 18%, p = 0.23). Computational modeling showed coagulopathic patients had pronounced delays and quantitative deficits in generating thrombin.

CONCLUSIONS

Twenty percent of all severely injured patients had critical CF deficiency on admission, particularly of factor V. The observed factor V deficit aligns with current understanding of the mechanisms underlying early TAC. Critical deficiency of factor V impairs thrombin generation and profoundly affects hemostasis.

Animal models of trauma-induced coagulopathy

Resurgent study of trauma-induced coagulopathy (TIC) has delivered considerable improvements in survival after injury. Robust, valid and clinically relevant experimental models of TIC are essential to support the evolution of our knowledge and management of this condition. The aims of this study were to identify and analyze contemporary animal models of TIC with regard to their ability to accurately characterize known mechanisms of coagulopathy and/or to test the efficacy of therapeutic agents. A literature review was performed. Structured search of the indexed online database MEDLINE/PubMed in July 2010 identified 43 relevant articles containing 23 distinct animal models of TIC. The main aim of 26 studies was to test a therapeutic and the other 17 were conducted to investigate pathophysiology. A preponderance of porcine models was identified. Three new models demonstrating an endogenous acute traumatic coagulopathy (ATC) have offered new insights into the pathophysiology of TIC. Independent or combined effects of induced hypothermia and metabolic acidosis have been extensively evaluated. Recently, a pig model of TIC has been developed that features all major etiologies of TIC, although not in correct chronological order. This review identifies a general lack of experimental research to keep pace with clinical developments. Tissue injury and hemorrhagic shock are fundamental initiating events that prime the hemostatic system for subsequent iatrogenic insults. New animal models utilizing a variety of species that accurately simulate the natural clinical trajectory of trauma are urgently needed.

Clinical review: Canadian National Advisory Committee on Blood and Blood Products--Massive transfusion consensus conference 2011: report of the panel

In June 2011 the Canadian National Advisory Committee on Blood and Blood Products sponsored an international consensus conference on transfusion and trauma. A panel of 10 experts and two external advisors reviewed the current medical literature and information presented at the conference by invited international speakers and attendees. The Consensus Panel addressed six specific questions on the topic of blood transfusion in trauma. The questions focused on: ratio-based blood resuscitation in trauma patients; the impact of survivorship bias in current research conclusions; the value of nonplasma coagulation products; the role of protocols for delivery of urgent transfusion; the merits of traditional laboratory monitoring compared with measures of clot viscoelasticity; and opportunities for future research. Key findings include a lack of evidence to support the use of 1:1:1 blood component ratios as the standard of care, the importance of early use of tranexamic acid, the expected value of an organized response plan, and the recommendation for an integrated approach that includes antifibrinolytics, rapid release of red blood cells, and a foundation ratio of blood components adjusted by results from either traditional coagulation tests or clot viscoelasticity or both. The present report is intended to provide guidance to practitioners, hospitals, and policy-makers.

Management of major trauma haemorrhage: treatment priorities and controversies

The severely injured trauma patient often arrives in the emergency department bleeding, coagulopathic and in need of a blood transfusion. The diagnosis and management of these patients has vastly improved with a better understanding of acute traumatic coagulopathy (ATC). In the emergency setting, traditional laboratory coagulation screens are of limited use in the diagnosis and management of life-threatening bleeding. Whole blood assays, such as thrombelastography (TEG) and rotational thrombelastometry (ROTEM) provide a rapid evaluation of clot formation, strength and lysis. Rapid diagnosis of ATC and aggressive haemostatic transfusion strategies utilizing early high doses of plasma are associated with improved outcomes in trauma. At present there is no accurate guide for transfusion in trauma, therefore blood and clotting products are administered on an empiric basis. Targeted transfusion therapy for major trauma haemorrhage based on comprehensive and rapid measures of coagulation e.g. TEG/ROTEM may lead to improved outcomes while optimizing blood utilization. Evidence for the clinical application of TEG and ROTEM in trauma is emerging with a number of studies evaluating their ability to diagnose coagulopathy early and facilitate goal-directed transfusion. This review explores current controversies and best practice in the diagnosis and management of major haemorrhage in trauma.

Clinical effectiveness of fresh frozen plasma compared with fibrinogen concentrate: a systematic review

Introduction

Haemostatic therapy in surgical and/or massive trauma patients typically involves transfusion of fresh frozen plasma (FFP). Purified human fibrinogen concentrate may offer an alternative to FFP in some instances. In this systematic review, we investigated the current evidence for the use of FFP and fibrinogen concentrate in the perioperative or massive trauma setting.

Methods

Studies reporting the outcome (blood loss, transfusion requirement, length of stay, survival and plasma fibrinogen level) of FFP or fibrinogen concentrate administration to patients in a perioperative or massive trauma setting were identified in electronic databases (1995 to 2010). Studies were included regardless of type, patient age, sample size or duration of patient follow-up. Studies of patients with congenital clotting factor deficiencies or other haematological disorders were excluded. Studies were assessed for eligibility, and data were extracted and tabulated.

Results

Ninety-one eligible studies (70 FFP and 21 fibrinogen concentrate) reported outcomes of interest. Few were high-quality prospective studies. Evidence for the efficacy of FFP was inconsistent across all assessed outcomes. Overall, FFP showed a positive effect for 28% of outcomes and a negative effect for 22% of outcomes. There was limited evidence that FFP reduced mortality: 50% of outcomes associated FFP with reduced mortality (typically trauma and/or massive bleeding), and 20% were associated with increased mortality (typically surgical and/or nonmassive bleeding). Five studies reported the outcome of fibrinogen concentrate versus a comparator. The evidence was consistently positive (70% of all outcomes), with no negative effects reported (0% of all outcomes). Fibrinogen concentrate was compared directly with FFP in three high-quality studies and was found to be superior for > 50% of outcomes in terms of reducing blood loss, allogeneic transfusion requirements, length of intensive care unit and hospital stay and increasing plasma fibrinogen levels. We found no fibrinogen concentrate comparator studies in patients with haemorrhage due to massive trauma, although efficacy across all assessed outcomes was reported in a number of noncomparator trauma studies.

Conclusions

The weight of evidence does not appear to support the clinical effectiveness of FFP for surgical and/or massive trauma patients and suggests it can be detrimental. Perioperatively, fibrinogen concentrate was generally associated with improved outcome measures, although more high-quality, prospective studies are required before any definitive conclusions can be drawn.

Obstetric hemorrhage

An obstetric hemorrhage may occur before or after delivery, but more than 80% of cases occur postpartum. Worldwide, a massive obstetric hemorrhage, resulting from the failure of normal obstetrical, surgical and/or systemic hemostasis, is responsible for 25% of the estimated 358,000 maternal deaths each year. Most women will not have identifiable risk factors. Nonetheless, primary prevention of a postpartum hemorrhage (PPH) begins with an assessment of identifiable risk factors. Women identified as being at high risk of a PPH should be delivered in a center with access to adequately trained staff and an onsite blood bank. A critical feature of a massive hemorrhage in obstetrics is the development of disseminated intravascular coagulation (DIC), which, in contrast to DIC that develops with hemorrhage from surgery or trauma, is frequently an early feature. Data from clinical trials to guide management of transfusion in PPH are lacking. There are likely to be similarities in the management of transfusion in severe PPH to that of major bleeding in other clinical situations, but the pathophysiological processes that contribute to a massive PPH may necessitate different transfusion strategies such as the ratio of red blood cells to plasma components, in particular fibrinogen. Caution should be exercised when considering the appropriate place for recombinant activated factor VII (rFVIIa) in the management of a major PPH. An early hysterectomy is recommended for severe bleeding as a result of placenta accreta or uterine rupture. However, in women with uterine atony who have ongoing bleeding in spite of an adequate transfusion, it may be reasonable to consider a trial of rFVIIa before a hysterectomy.

All massive transfusion criteria are not created equal: defining the predictive value of individual transfusion triggers to better determine who benefits from blood

BACKGROUND

As familiarity with military massive transfusion (MT) triggers has increased, there is a growing interest in applying these in the civilian population to initiate MT protocols (MTP) earlier. We hypothesize that these triggers do not have equal predictability for MT and understanding the contribution of each would improve our ability to initiate the MTP earlier.

METHODS

All patients presenting to a Level I trauma center from October 2007 to September 2008 requiring immediate operation were included in this study. Emergency department records, operative logs, and blood transfusion data from arrival to procedure end were analyzed using multivariate regression techniques. Triggers included systolic blood pressure (SBP) <90 mm Hg, hemoglobin <11 g/dL, temperature <35.5°C, International normalized ratio (INR) >1.5, and base deficit ≥6.

RESULTS

One hundred seventy patients required immediate operation with an overall survival of 91%. Transfusion of packed red blood cells was noted in 45% (77 of 170) with the mean number of transfused units highest in those meeting SBP (12.9 Units) or INR (12.3 Units) triggers. The triggers do not contribute equal predictive value for the need for transfusion with INR being the most predictive (odds ratio, 16.7; 95% confidence interval, 2-137) for any transfusion and highly predictive for the need for MT (odds ratio, 11.3; 95% confidence interval, 3-47). In fact, if patients met either INR or SBP triggers alone, they were likely to receive MT (p = 0.018 and 0.003, respectively).

CONCLUSION

Triggers have differential predictive values for need for transfusion. Defining the individual utility of each criterion will help to identify those most likely to benefit from an early initiation of the MTP.

Massive transfusion protocols for patients with substantial hemorrhage

Transfusion medicine for the resuscitation of patients with massive hemorrhage has recently advanced from reactive, supportive treatment with crystalloid and red blood cell therapy to use of standardized massive transfusion protocols (MTPs). Through MTPs, medical facilities are able to standardize the most effective posthemorrhage treatments and execute them rapidly while reducing potential waste of blood products. Damage control resuscitation is an example of an MTP, where patients are (1) allowed more permissive hypotension, (2) spared large volumes of crystalloid/colloid therapy (through low volume resuscitation), and (3) transfused with blood products preemptively using a balanced ratio of plasma and platelets to red blood cells. This focused approach improves the timely availability of blood components during resuscitation. However, the use of MTPs remains controversial. This review describes published experiences with MTPs and illustrates the potential value of several MTPs currently utilized by academic transfusion services.

Fixed volume or fixed pressure: a murine model of hemorrhagic shock

It is common knowledge that severe blood loss and traumatic injury can lead to a cascade of detrimental signaling events often resulting in mortality. ^{1, 2, 3, 4, 5} These signaling events can also lead to sepsis and/or multiple organ dysfunction (MOD). ^{6, 7, 8, 9} It is critical then to investigate the causes of suppressed immune function and detrimental signaling cascades in order to develop more effective ways to help patients who suffer from traumatic injuries. ¹⁰ This fixed pressure Hemorrhagic Shock (HS) procedure, although technically challenging, is an excellent resource for investigation of these pathophysiologic conditions. ^{11, 12, 13} Advances in the assessment of biological systems, i.e. Systems Biology have enabled the scientific community to further understand complex physiologic networks and cellular communication patterns. ¹⁴ Hemorrhagic Shock has proven to be a vital tool for unveiling these cellular communication patterns as they relate to immune function. ^{15, 16, 17, 18} This procedure can be mastered! This procedure can also be used as either a fixed volume or fixed pressure approach. We adapted this technique in the murine model to enhance research in innate and adaptive immune function. ^{19, 20, 21} Due to their small size HS in mice presents unique challenges. However due to the many available mouse strains, this species represents an unparalleled resource for the study of the biologic responses. The HS model is an important model for studying cellular communication patterns and the responses of systems such as hormonal and inflammatory mediator systems, and danger signals, i.e. DAMP and PAMP upregulation as it elicits distinct responses that differ from other forms of shock. ^{22, 23, 24, 25} The development of transgenic murine strains and the induction of biologic agents to inhibit specific signaling have presented valuable opportunities to further elucidate our understanding of the up and down regulation of signal transduction after severe blood loss, i.e. HS and trauma ^{26, 27, 28, 29, 30}.

There are numerous resuscitation methods (R) in association with HS and trauma. ^{31, 32, 33, 34} A fixed volume resuscitation method of solely lactated ringer solution (LR), equal to three times the shed blood volume, is used in this model to study endogenous mechanisms such as remote organ injury and systemic inflammation. ^{35, 36, 38} This method of resuscitation is proven to be effective in evaluating the effects of HS and trauma ^{38, 39}.

Defects in coagulation encountered in small animal critical care

Critically ill small animals are at risk for developing coagulation abnormalities. The processes of inflammation and coagulation are intertwined, and severe inflammation can lead to disturbances of coagulation. Severe coagulation dysfunction is associated with increased morbidity and mortality. Pathophysiology, diagnosis, and treatment of coagulation dysfunction are discussed. Defects in coagulation in small animal patients are complex and a consensus on diagnosis and treatment has yet to be reached.

A national study of plasma use in critical care: clinical indications, dose and effect on prothrombin time

INTRODUCTION

Fresh frozen plasma (FFP) is widely used, but few studies have described patterns of plasma use in critical care. We carried out a multicentre study of coagulopathy in intensive care units (ICUs) and here describe overall FFP utilisation in adult critical care, the indications for transfusions, factors indicating the doses used and the effects of FFP use on coagulation.

METHODS

We conducted a prospective, multicentre, observational study of all patients sequentially admitted to 29 adult UK general ICUs over 8 weeks. Daily data throughout ICU admission were collected concerning coagulation, relevant clinical outcomes (including bleeding), coagulopathy (defined as international normalised ratio (INR) >1.5, or equivalent prothrombin time (PT)), FFP and cryoprecipitate use and indications for transfusion.

RESULTS

Of 1,923 admissions, 12.7% received FFP in the ICU during 404 FFP treatment episodes (1,212 FFP units). Overall, 0.63 FFP units/ICU admission were transfused (0.11 units/ICU day). Reasons for FFP transfusion were bleeding (48%), preprocedural prophylaxis (15%) and prophylaxis without planned procedure (36%). Overall, the median FFP dose was 10.8 ml kg⁻¹, but doses varied widely (first to third quartile, 7.2 to 14.4 ml kg⁻¹). Thirty-one percent of FFP treatments were to patients without PT prolongation, and 41% were to patients without recorded bleeding and only mildly deranged INR (<2.5). Higher volumes of FFP were administered when the indication was bleeding (median doses: bleeding 11.1 ml kg⁻¹, preprocedural prophylaxis 9.8 ml kg⁻¹, prophylaxis without procedure 8.9 ml kg⁻¹; P = 0.009 across groups) and when the pretransfusion INR was higher (ranging from median dose 8.9 ml kg⁻¹ at INR ≤ 1.5 to 15.7 ml kg⁻¹ at INR >3; P < 0.001 across ranges). Regression analyses suggested bleeding was the strongest predictor of higher FFP dose. Pretransfusion INR was more frequently normal when the transfusion indication was bleeding. Overall, posttransfusion corrections of INR were consistently small unless the pretransfusion INR was >2.5, but administration during bleeding was associated with greater INR corrections.

CONCLUSIONS

There is wide variation in FFP use by ICU clinicians, and a high proportion of current FFP transfusions are of unproven clinical benefit. Better evidence from clinical trials could significantly alter patterns of use and modify current treatment costs.