Pre-hospital transfusion of red blood cells. Part 2: A systematic review of treatment effects on outcomes

Current trends in the management of out of hospital cardiac arrest (OHCA)

Sudden cardiac arrest remains a relevant problem with a significant number of deaths worldwide. Although survival rates have more than tripled over the last 20 years (4% in 2001 vs. 14% in 2020), survival rates with good neurological outcomes remain persistently low, representing a major socioeconomic problem. Every minute of delay from patient collapse to start cardiopulmonary resuscitation (CPR) and early defibrillation reduces the chance of survival by approximately 10-12%. Therefore, the time to treatment is a crucial factor in the prognosis of patients with out-of-hospital cardiac arrest (OHCA). Research teams working in the pre-hospital setting are therefore looking for ways to improve the transmission of information from the site of an emergency event and to make it easier for emergency medical dispatch centres (EMDC) to recognise life-threatening conditions with minimal deviation. For emergency unit procedures already at the scene of the event, methods are being sought to efficiently and temporarily replace a non-functioning cardiopulmonary system. In the case of traumatic cardiac arrest (TCA), the focus is mainly on effective affecting non-compressible haemorrhage.

Assessing the one-month mortality impact of civilian-setting prehospital transfusion: A systematic review and meta-analysis

BACKGROUND

Based on convincing evidence for outcomes improvement in the military setting, the past decade has seen evaluation of prehospital transfusion (PHT) in the civilian emergency medical services (EMS) setting. Evidence synthesis has been challenging, due to study design variation with respect to both exposure (type of blood product administered) and outcome (endpoint definitions and timing). The goal of the current meta-analysis was to execute an overarching assessment of all civilian-arena randomized controlled trial (RCT) evidence focusing on administration of blood products compared to control of no blood products.

METHOD

The review structure followed the Cochrane group's Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). Using the Transfusion Evidence Library (transfusionevidencelibrary.com), the multidatabase (e.g. PubMed, EMBASE) Harvard On-Line Library Information System (HOLLIS), and GoogleScholar, we accessed many databases and gray literature sources. RCTs of PHT in the civilian setting with a comparison group receiving no blood products with 1-month mortality outcomes were identified.

RESULTS

In assessing a single patient-centered endpoint-1-month mortality-we calculated an overall risk ratio (RR) estimate. Analysis of three RCTs yielded a model with acceptable heterogeneity (I2 = 48%, Q-test p = 0.13). Pooled estimate revealed civilian PHT results in a statistically nonsignificant (p = 0.38) relative mortality reduction of 13% (RR 0.87, 95% CI 0.63-1.19).

CONCLUSIONS

Current evidence does not demonstrate 1-month mortality benefit of civilian-setting PHT. This should give pause to EMS systems considering adoption of civilian-setting PHT programs. Further studies should not only focus on which formulations of blood products might improve outcomes but also focus on which patients are most likely to benefit from any form of civilian-setting PHT.

Factors affecting physicians' decision to start prehospital blood product transfusion in blunt trauma patients: A cohort study of Helsinki Trauma Registry

BACKGROUND

Prehospital blood transfusions are increasing as a treatment for bleeding trauma patients at risk for exsanguination. Triggers for starting transfusion in the field are less studied. We analyzed the factors affecting the decision of physicians to start prehospital blood product transfusion (PHBT) in blunt adult trauma patients.

STUDY DESIGN AND METHODS

Data of all adult blunt trauma patients from the Helsinki Trauma Registry between March 2016 and July 2021 were retrospectively analyzed. Univariate analysis for the identification of predictive factors and multivariate regression analysis for their importance as predictive factors for the initiation of PHBT were applied.

RESULTS

There were 1652 patients registered in the database. A total of 556 of them were treated by a physician-level prehospital emergency care unit, of which by transfusion-capable unit in 394 patients. PHBT (red blood cells and/or plasma) was started in 19.8% of the patients. We identified three statistically highly important clinical triggers for starting PHBT: high crystalloid volume need, shock index ≥0.9, and need for prehospital pleural decompression.

DISCUSSION

PHBT in blunt adult trauma patients is initiated in ~20% of the patients in Southern Finland. High crystalloid volume need, shock index ≥0.9 and prehospital pleural decompression are associated with the initiation of PHBT, probably reflecting patients at high risk for bleeding.

Guidelines in trauma-related bleeding and coagulopathy: an update

PURPOSE OF REVIEW

The diagnosis and treatment of patients with severe traumatic bleeding and subsequent trauma-induced coagulopathy (TIC) is still inconsistent, although the implementation of standardized algorithms/treatment pathways was repeatedly linked to improved outcome. Various evidence-based guidelines for these patients now exist, three of which have recently been updated.

RECENT FINDINGS

A synopsis of the three recently updated guidelines for diagnosis and treatment of seriously bleeding trauma patients with TIC is presented: (i) AWMF S3 guideline 'Polytrauma/Seriously Injured Patient Treatment' under the auspices of the German Society for Trauma Surgery; (ii) guideline of the European Society of Anesthesiology and Intensive Care (ESAIC) on the management of perioperative bleeding; and (iii) European guideline on the management of major bleeding and coagulopathy after trauma in its 6th edition (EU-Trauma).

SUMMARY

Treatment of trauma-related bleeding begins at the scene with local compression, use of tourniquets and pelvic binders and rapid transport to a certified trauma centre. After arrival at the hospital, measures to record, monitor and support coagulation function should be initiated immediately. Surgical bleeding control is carried out according to 'damage control' principles. Modern coagulation management includes individualized treatment based on target values derived from point-of-care viscoelastic test procedures.

Characteristics of traumatic major haemorrhage in a tertiary trauma center

BACKGROUND

Major traumatic haemorrhage is potentially preventable with rapid haemorrhage control and improved resuscitation techniques. Although advances in prehospital trauma management, haemorrhage is still associated with high mortality. The aim of this study was to use a recent pragmatic transfusion-based definition of major bleeding to characterize patients at risk of major bleeding and associated outcomes in this cohort after trauma.

METHODS

This was a retrospective cohort study including all trauma patients (n = 7020) admitted to a tertiary trauma center from January 2015 to June 2020. The major bleeding cohort (n = 145) was defined as transfusion of 4 units of any blood components (red blood cells, plasma, or platelets) within 2 h of injury. Univariate and multivariable logistic regression analyses were performed to identify risk factors for 24-hour and 30-day mortality post trauma admission.

RESULTS

In the major bleeding cohort (n = 145; 145/7020, 2.1% of the trauma population), there were 77% men (n = 112) and 23% women (n = 33), median age 39 years [IQR 26-53] and median Injury Severity Score (ISS) was 22 [IQR 13-34]. Blunt trauma dominated over penetrating trauma (58% vs. 42%) where high-energy fall was the most common blunt mechanism and knife injury was the most common penetrating mechanism. The major bleeding cohort was younger (OR 0.99; 95% CI 0.98 to 0.998, P = 0.012), less female gender (OR 0.66; 95% CI 0.45 to 0.98, P = 0.04), and had more penetrating trauma (OR 4.54; 95% CI 3.24 to 6.36, P = 0.001) than the rest of the trauma cohort. A prehospital (OR 2.39; 95% CI 1.34 to 4.28; P = 0.003) and emergency department (ED) (OR 6.91; 95% CI 4.49 to 10.66, P = 0.001) systolic blood pressure < 90 mmHg was associated with the major bleeding cohort as well as ED blood gas base excess < -3 (OR 7.72; 95% CI 5.37 to 11.11; P < 0.001) and INR > 1.2 (OR 3.09; 95% CI 2.16 to 4.43; P = 0.001). Emergency damage control laparotomy was performed more frequently in the major bleeding cohort (21.4% [n = 31] vs. 1.5% [n = 106]; OR 3.90; 95% CI 2.50 to 6.08; P < 0.001). There was no difference in transportation time from alarm to hospital arrival between the major bleeding cohort and the rest of the trauma cohort (47 [IQR 38;59] vs. 49 [IQR 40;62] minutes; P = 0.17). However, the major bleeding cohort had a shorter time from ED to first emergency procedure (71.5 [IQR 10.0;129.0] vs. 109.00 [IQR 54.0; 259.0] minutes, P < 0.001). In the major bleeding cohort, patients with penetrating trauma, compared to blunt trauma, had a shorter alarm to hospital arrival time (44.0 [IQR 35.5;54.0] vs. 50.0 [IQR 41.5;61.0], P = 0.013). The 24-hour mortality in the major bleeding cohort was 6.9% (10/145). All fatalities were due to blunt trauma; 40% (4/10) high energy fall, 20% (2/10) motor vehicle accident, 10% (1/10) motorcycle accident, 10% (1/10) traffic pedestrian, 10% (1/10) traffic other, and 10% (1/10) struck/hit by blunt object. In the logistic regression model, prehospital cardiac arrest (OR 83.4; 95% CI 3.37 to 2063; P = 0.007) and transportation time (OR 0.95, 95% CI 0.91 to 0.99, P = 0.02) were associated with 24-hour mortality.

RESULTS

Early identification of patients at high risk of major bleeding is challenging but essential for rapid definitive haemorrhage control. The major bleeding trauma cohort is a small part of the entire trauma population, and is characterized of being younger, male gender, higher ISS, and exposed to more penetrating trauma. Early identification of patients at high risk of major bleeding is challenging but essential for rapid definitive haemorrhage control.

Unmanned aerial vehicles and pre-hospital emergency medicine

Unmanned aerial vehicles (UAVs) are used in many industrial and commercial roles and have an increasing number of medical applications. This article reviews the characteristics of UAVs and their current applications in pre-hospital emergency medicine. The key roles are transport of equipment and medications and potentially passengers to or from a scene and the use of cameras to observe or communicate with remote scenes. The potential hazards of UAVs both deliberate or accidental are also discussed.

The Golden Hour of Casualty Care: Rapid Handoff to Surgical Team is Associated With Improved Survival in War-injured US Service Members

OBJECTIVE

To examine time from injury to initiation of surgical care and association with survival in US military casualties.

BACKGROUND

Although the advantage of trauma care within the "golden hour" after an injury is generally accepted, evidence is scarce.

METHODS

This retrospective, population-based cohort study included US military casualties injured in Afghanistan and Iraq, January 2007 to December 2015, alive at initial request for evacuation with maximum abbreviated injury scale scores ≥2 and documented 30-day survival status after injury. Interventions: (1) handoff alive to the surgical team, and (2) initiation of first surgery were analyzed as time-dependent covariates (elapsed time from injury) using sequential Cox proportional hazards regression to assess how intervention timing might affect mortality. Covariates included age, injury year, and injury severity.

RESULTS

Among 5269 patients (median age, 24 years; 97% males; and 68% battle-injured), 728 died within 30 days of injury, 68% within 1 hour, and 90% within 4 hours. Only handoffs within 1 hour of injury and the resultant timely initiation of emergency surgery (adjusted also for prior advanced resuscitative interventions) were significantly associated with reduced 24-hour mortality compared with more delayed surgical care (adjusted hazard ratios: 0.34; 95% CI: 0.14-0.82; P = 0.02; and 0.40; 95% CI: 0.20-0.81; P = 0.01, respectively). In-hospital waits for surgery (mean: 1.1 hours; 95% CI; 1.0-1.2) scarcely contributed ( P = 0.67).

CONCLUSIONS

Rapid handoff to the surgical team within 1 hour of injury may reduce mortality by 66% in US military casualties. In the subgroup of casualties with indications for emergency surgery, rapid handoff with timely surgical intervention may reduce mortality by 60%. To inform future research and trauma system planning, findings are pivotal.

A comparative analysis of current out-of-hospital transfusion protocols to expert recommendations

Aim

This study aimed to compare current out-of-hospital transfusion (OHT) protocols in Canadian civilian critical care transport organizations (CCTO) to expert recommendations and explore the variability and potential benefits of standardizing OHT practices across Canada.

Methods

A comprehensive cross-sectional study was conducted, encompassing all seven Canadian CCTOs that provide OHT. The study assessed adherence to expert recommendations and examined specific aspects of the transfusion process, such as indications for transfusion and cessation criteria.

Results

The study found an 89% adherence to expert recommendations for OHT among Canadian CCTOs. It highlighted a strong alignment between current practices and recommendations, possibly attributed to collaborative frameworks like the CAN-PATT network. However, notable variability and ambiguity were observed in transfusion indications and cessation criteria. The study also emphasized the potential benefits of standardizing OHT practices, such as improved policy formulation, better interpretation of emerging literature, and evaluation of OHT efficacy.

Conclusion

This cross-sectional study assessed how Canadian CCTOs implement OHT practices compared to expert-recommended practices. The findings underscore the importance of structured protocols in trauma management. Given the consistency in OHT protocol adoption and the comprehensive approach across CCTOs, there's a solid foundation for managing trauma patients in prehospital and transport settings across Canada. As OHT practices continue to evolve, sustained efforts are vital to refine, adapt, and elevate patient care standards in trauma management.

Current state of technical transfusion medicine practice for out-of-hospital blood transfusion in Canada

BACKGROUND AND OBJECTIVES

Canadian out-of-hospital blood transfusion programmes (OHBTPs) are emerging, to improve outcomes of trauma patients by providing pre-hospital transfusion from the scene of injury, given prolonged transport times. Literature is lacking to guide its implementation. Thus, we sought to gather technical transfusion medicine (TM)-specific practices across Canadian OHBTPs.

MATERIALS AND METHODS

A survey was sent to TM representatives of Canadian OHBTPs from November 2021 to March 2022. Data regarding transport, packaging, blood components and inventory management were included and reported descriptively. Only practices involving Blood on Board programme components for emergency use were included.

RESULTS

OHBTPs focus on helicopter emergency medical service programmes, with some supplying fixed-wing aircraft and ground ambulances. All provide 1-3 coolers with 2 units of O RhD/Kell-negative red blood cells (RBCs) per cooler, with British Columbia trialling coolers with 2 units of pre-thawed group A plasma. Inventory exchanges are scheduled and blood components are returned to TM inventory using visual inspection and internal temperature data logger readings. Coolers are validated to storage durations ranging from 72 to 124 h. All programmes audit to manage wastage, though there is no consensus on appropriate benchmarks. All programmes have a process for documenting units issued, reconciliation after transfusion and for transfusion reaction reporting; however, training programmes vary. Common considerations included storage during extreme temperature environments, O-negative RBC stewardship, recipient notification, traceability, clinical practice guidelines co-reviewed by TM and a common audit framework.

CONCLUSION

OHBTPs have many similarities throughout Canada, where harmonization may assist in further developing standards, leveraging best practice and national coordination.

Pre-Hospital Blood Products for the Care of Bleeding Trauma Patients

BACKGROUND

Controversy surrounds the administration of blood products to severely traumatized patients before they arrive in the hospital in order to compensate for early blood loss and/or to correct coagulation disturbances that arise shortly after the traumatic event. A number of terrestrial and air rescue services have begun to provide this kind of treatment.

METHODS

This review is based on articles using the PICO framework, published from January 2001 to January 2021, that were retrieved by a selective search, with structured searching strategies and searching bundles in Medline (OVIDSP), the Cochrane Central Register of Controlled Trials (CENTRAL), and Epistemonikos. A demand analysis was carried out on the basis of data from the trauma registry of the German Society of Trauma Surgery (TR-DGU) and practical experience from program development and implementation was provided by the Bundeswehr Hospital Ulm.

RESULTS

The currently available evidence on the pre-hospital administration of blood products in the early treatment of severely injured patients is based largely on retrospective, single-center case series. Two randomized controlled trials (RCTs) concerning the early use of fresh frozen plasma concentrates have yielded partly conflicting results. Three further RCTs on the use of lyophilized plasma (lyplas), lyplas plus erythrocyte concentrate, or whole blood likewise revealed non-uniform effects on short-term and intermediate-term mortality. Our demand analysis based on data from the TR-DGU showed that 300 to 1800 patients per year in Germany could benefit from the pre-hospital administration of blood products. This might be indicated in patients who have systolic hypotension (<100 mmHg) in combination with a suspected or confirmed hemorrhage, as well as pathological shock parameters in the point-of-care diagnostic testing performed on the scene (serum base excess ≤ -2.5 mmol/L and/or serum lactate concentration >4 mmol/L).

CONCLUSION

The studies that have been published to date yield no clear evidence either for or against the early pre-hospital administration of blood products. Any treatment of this kind should be accompanied by scientific evaluation.

Development of a national out-of-hospital transfusion protocol: a modified RAND Delphi study

BACKGROUND

Early resuscitation with blood components or products is emerging as best practice in selected patients with trauma and medical patients; as a result, out-of-hospital transfusion (OHT) programs are being developed based on limited and often conflicting evidence. This study aimed to provide guidance to Canadian critical care transport organizations on the development of OHT protocols.

METHODS

The study period was July 2021 to June 2022. We used a modified RAND Delphi process to achieve consensus on statements created by the study team guiding various aspects of OHT in the context of critical care transport. Purposive sampling ensured representative distribution of participants in regard to geography and relevant clinical specialties. We conducted 2 written survey Delphi rounds, followed by a virtual panel discussion (round 3). Consensus was defined as a median score of at least 6 on a Likert scale ranging from 1 ("Definitely should not include") to 7 ("Definitely should include"). Statements that did not achieve consensus in the first 2 rounds were discussed and voted on during the panel discussion.

RESULTS

Seventeen subject experts participated in the study, all of whom completed the 3 Delphi rounds. After the study process was completed, a total of 39 statements were agreed on, covering the following domains: general oversight and clinical governance, storage and transport of blood components and products, initiation of OHT, types of blood components and products, delivery and monitoring of OHT, indications for and use of hemostatic adjuncts, and resuscitation targets of OHT.

INTERPRETATION

This expert consensus document provides guidance on OHT best practices. The consensus statements should support efficient and safe OHT in national and international critical care transport programs.

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

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Major Pelvic Ring Injuries: Fewer Transfusions Without Deaths from Bleeding During the Last Decade

BACKGROUND

Pelvic fracture-associated bleeding can be difficult to control with historically high mortality rates. The impact of resuscitation advancements for trauma patients with unstable pelvic ring injuries is unknown. We hypothesized that the time elapsed since introduction of our protocol would be associated with decreased blood transfusion requirements.

METHODS

A level 1 trauma center's prospective pelvic fracture database was reviewed from 01/01/2009-31/12/2018. All patients with unstable pelvic ring injuries initially presenting to our institution were included. Adjusted regression analysis was performed on the overall cohort and separately for patients in traumatic shock (TS). The primary outcome was 24 h packed red blood cell (PRBC) requirements. Secondary outcomes were 24 h plasma, cryoprecipitate, platelet and intravenous fluid (IVF) requirements, length of stay and mortality.

RESULTS

Patients with mechanically unstable pelvic ring injuries (n = 144, median [Q₁-Q₃] age 44 [28-55] years, 74% male) received a median (Q₁-Q₃) of 0 (0-4) units PRBC within 24 h, with TS patients (n = 47, 42 [28-60] years, 74% male) receiving 6 (4-9) units PRBC. There was no decrease in 24 h PRBC requirements for the overall cohort (years; IRR = 0.91, 95% CI 0.83-1.01; p = 0.07). TS patients had decreases in 24 h PRBC (years; IRR = 0.90, 95%CI 0.84-0.96; p = 0.002), plasma (IRR = 0.92, 95%CI 0.85-0.99; p = 0.019), cryoprecipitate (IRR = 0.88, 95%CI 0.81-0.95; p = 0.001) and IVF (IRR = 0.94, 95%CI 0.90-0.98; p = 0.004). There were 5 deaths (5/144, 3.5%) with no deaths due to acute hemorrhage.

CONCLUSIONS

Over this 10-year period, there was no hemorrhage-related mortality among patients presenting with pelvic fractures. Crystalloid and transfusion requirements decreased for patients presenting with traumatic shock.

Prediction of pre-hospital blood transfusion in trauma patients based on scoring systems

BACKGROUND

Pre-hospital blood transfusion (PHBT) is a safe and gradually expanding procedure applied to trauma patients. A proper decision to activate PHBT with the presently limited diagnostic options at the site of an incident poses a challenge for pre-hospital crews. The purpose of this study was to compare the selected scoring systems and to determine whether they can be used as valid tools in identifying patients with PHBT requirements.

METHODS

A retrospective single-center study was conducted between June 2018 and December 2020. Overall, 385 patients (aged [median; IQR]: 44; 24-60; 73% males) were included in this study. The values of five selected scoring systems were calculated in all patients. To determine the accuracy of each score for the prediction of PHBT, the Receiver Operating Characteristic (ROC) analysis was used and to measure the association, the odds ratio with 95% confidence intervals was counted (Fig. 1).

RESULTS

Regarding the proper indication of PHBT, shock index (SI) and pulse pressure (PP) revealed the highest value of AUC and sensitivity/specificity ratio (SI: AUC 0.88; 95% CI 0.82-0.93; PP: AUC 0.85 with 95% CI 0.79-0.91).

CONCLUSION

Shock index and pulse pressure are suitable tools for predicting PHBT in trauma patients.

A descriptive analysis of the Canadian prehospital and transport transfusion (CAN-PATT) network

Objective

Out-of-hospital blood transfusion (OHBT) is becoming increasingly common across the prehospital environment, yet there is significant variability in OHBT practices. The Canadian Prehospital and Transport Transfusion (CAN-PATT) network was established to collaborate, standardize, and evaluate the effectiveness of out-of-hospital blood transfusion (OHBT) across Canada. The objectives of this study are to describe the setting and organizational characteristics of CAN-PATT member organizations and to provide a cross-sectional examination of the current OHBT practices of CAN-PATT organizations.

Methods

This was a cross-sectional examination of all six critical care transport organizations that are involved in CAN-PATT network. Surveys were sent to identified leads from each organization. The survey focused on three main areas of interest: 1) critical care transport organizational service and coverage, 2) provider, and crew configurations, and 3) OHBT transfusion practices.

Results

All six surveys were completed and returned. There are a total of 30 critical care transport bases (19 rotor-wing, 20 fixed-wing and 6 land) across Canada and 11 bases have a blood-on-board program. Crew configurations very between organizations as either dual paramedic or paramedic/nurse teams. Median transport times range from 30 to 46 minutes for rotor-wing assets and 64 to 90 minutes for fixed-wing assets. Half of the CAN-PATT organizations started their out-of-hospital blood transfusion programs within the last three years. Most organizations carry at least two units of O-negative, K-negative red blood cells and some organizations also carry group A thawed plasma, fibrinogen concentrate and/or prothrombin complex concentrate. All organizations advocate for early administration of tranexamic acid for injured patients suspected of bleeding. All organizations return un-transfused blood components to their local transfusion medicine laboratory within a predefined timeframe to reduce wastage.

Conclusions

Variations in OHBT practices were identified and we have suggested considerations for standardization of transfusion practices and patient care as it relates to OHBT. This standardization will also enable a robust means of data collection to study and optimize outcomes of patients receiving OHBT. A fulsome description of the participating organizations within CAN-PATT should enhance interpretation of future OHBT studies that will be conducted by this network.

Initial experiences of prehospital blood product transfusions between 2016 and 2020 in Päijät-Häme hospital district, Finland

Background

Treating hemorrhaging patients with prehospital blood product transfusions (PHBT) narrows transfusion delays and potentially benefits the patient. We describe our initial experiences of PHBT in a ground-based emergency medical service (EMS), where the transfusion protocol covers both traumatic and nontraumatic hemorrhaging patients.

Methods

A descriptive retrospective analysis was performed on the records of all the patients receiving red blood cells, freeze-dried plasma, or both during prehospital care from September 2016 to December 2020. The delays of PHBT and the effects on patients’ vital signs were analyzed and reported as the median and interquartile range (IQR) and analyzed using a Wilcoxon Signed rank test.

Results

65 patients received prehospital blood product transfusions (PHBT), 29 (45%) were non-traumatic, and 36 (55%) traumatic. The main two reasons for PHBT were blunt trauma (n = 30, 46%) and gastrointestinal hemorrhage (n = 20, 31%). The median time from the emergency call to the start of PHBT was 54 min (IQR 38), and the transfusion began on a median of 61 min (IQR 42) before arrival at the hospital. The median systolic blood pressure improved from a median 76.5 mmHg (IQR 36.5) before transfusion to a median of 116.60 mmHg (IQR 26.5) (p < 0.001) on arrival to the hospital. No transfusion-related severe adverse events were noted.

Conclusions

Starting PHBT in ground-based EMS is a feasible and viable option. The PHBT began significantly earlier than it would have started on arrival to the hospital, and it seems to be safe and improve patients’ physiology.

Study approval

D/2603/07.01.04.05/2019.

Recovery of organ-specific tissue oxygen delivery at restrictive transfusion thresholds after fluid treatment in ovine haemorrhagic shock

Background

Fluid resuscitation is the standard treatment to restore circulating blood volume and pressure after massive haemorrhage and shock. Packed red blood cells (PRBC) are transfused to restore haemoglobin levels. Restoration of microcirculatory flow and tissue oxygen delivery is critical for organ and patient survival, but these parameters are infrequently measured. Patient Blood Management is a multidisciplinary approach to manage and conserve a patient’s own blood, directing treatment options based on broad clinical assessment beyond haemoglobin alone, for which tissue perfusion and oxygenation could be useful. Our aim was to assess utility of non-invasive tissue-specific measures to compare PRBC transfusion with novel crystalloid treatments for haemorrhagic shock.

Methods

A model of severe haemorrhagic shock was developed in an intensive care setting, with controlled haemorrhage in sheep according to pressure (mean arterial pressure 30–40 mmHg) and oxygen debt (lactate > 4 mM) targets. We compared PRBC transfusion to fluid resuscitation with either PlasmaLyte or a novel crystalloid. Efficacy was assessed according to recovery of haemodynamic parameters and non-invasive measures of sublingual microcirculatory flow, regional tissue oxygen saturation, repayment of oxygen debt (arterial lactate), and a panel of inflammatory and organ function markers. Invasive measurements of tissue perfusion, oxygen tension and lactate levels were performed in brain, kidney, liver, and skeletal muscle. Outcomes were assessed during 4 h treatment and post-mortem, and analysed by one- and two-way ANOVA.

Results

Each treatment restored haemodynamic and tissue oxygen delivery parameters equivalently (p > 0.05), despite haemodilution after crystalloid infusion to haemoglobin concentrations below 70 g/L (p < 0.001). Recovery of vital organ-specific perfusion and oxygen tension commenced shortly before non-invasive measures improved. Lactate declined in all tissues and correlated with arterial lactate levels (p < 0.0001). The novel crystalloid supported rapid peripheral vasodilation (p = 0.014) and tended to achieve tissue oxygen delivery targets earlier. PRBC supported earlier renal oxygen delivery (p = 0.012) but delayed peripheral perfusion (p = 0.034).

Conclusions

Crystalloids supported vital organ oxygen delivery after massive haemorrhage, despite haemodilution to < 70 g/L, confirming that restrictive transfusion thresholds are appropriate to support oxygen delivery. Non-invasive tissue perfusion and oximetry technologies merit further clinical appraisal to guide treatment for massive haemorrhage in the context of Patient Blood Management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00439-6.

Pro-Con Debate: Prehospital Blood Transfusion-Should It Be Adopted for Civilian Trauma?

Exsanguination is the leading cause of death in severely injured patients; nevertheless, prehospital blood transfusion (PHT) remains a controversial topic. Here, we review the pros and cons of PHT, which is now routine in treatment of military trauma patients in the civilian setting. While PHT may improve survival in those who suffer blunt injury or require prolonged transport from the site of injury, PHT for civilian trauma generally is not supported by high-quality evidence. This article was originally presented as a pro-con debate at the 2020 meeting of the European Society of Anesthesiology and Intensive Care.

Outcome measures used in clinical research evaluating prehospital blood component transfusion in traumatically injured bleeding patients: A systematic review

BACKGROUND

Trial outcomes should be relevant to all stakeholders and allow assessment of interventions' efficacy and safety at appropriate timeframes. There is no consensus regarding outcome measures in the growing field of prehospital trauma transfusion research. Harmonization of future clinical outcome reporting is key to facilitate interstudy comparisons and generate cohesive, robust evidence to guide practice. The objective of this study was to evaluate outcome measures reported in prehospital trauma transfusion trials.

METHODS

Data Sources, Eligibility Criteria, Participants, and InterventionsWe conducted a scoping systematic review to identify the type, number, and definitions of outcomes reported in randomized controlled trials, and prospective and retrospective observational cohort studies investigating prehospital blood component transfusion in adult and pediatric patients with traumatic hemorrhage. Electronic database searching of PubMed, Embase, Web of Science, Cochrane, OVID, clinical trials.gov, and the Transfusion Evidence Library was completed in accordance with Preferred Reporting Items for Meta-analyses guidelines.Study Appraisal and Synthesis MethodsTwo review authors independently extracted outcome data. Unique lists of salutogenic (patient-reported health and wellbeing outcomes) and nonsalutogenic focused outcomes were established.

RESULTS

A total of 3,471 records were identified. Thirty-four studies fulfilled the inclusion criteria: 4 military (n = 1,566 patients) and 30 civilian (n = 14,398 patients), all between 2000 and 2020. Two hundred twelve individual non-patient-reported outcomes were identified, which collapsed into 20 outcome domains with varied definitions and timings. All primary outcomes measured effectiveness, rather than safety or complications. Sixty-nine percent reported mortality, with 11 different definitions. No salutogenic outcomes were reported.

CONCLUSION

There is heterogeneity in outcome reporting and definitions, an absence of patient-reported outcome, and an emphasis on clinical effectiveness rather than safety or adverse events in prehospital trauma transfusion trials. We recommend stakeholder consultation and a Delphi process to develop a clearly defined minimum core outcome set for prehospital trauma transfusion trials.

LEVEL OF EVIDENCE

Scoping systematic review, level III.

A Service Evaluation of Prehospital Blood Transfusion by Critical Care Paramedics in British Columbia, Canada

Early administration of blood products is emerging as best practice in selected trauma and medical patients. Blood products carried by critical care transport (CCT) teams are sometimes the first available to critically ill and injured patients. The purpose of this research was to evaluate the introduction of prehospital transfusion into a paramedic-led CCT program in Canada. A retrospective review of electronic patient care records for all patients who received a prehospital transfusion of uncrossmatched group O packed red blood cells between February 10, 2019, and September 30, 2020, was conducted. Forty-eight patients received a prehospital transfusion. The median age of the patients was 44 years, 81.3% were male, and most patients were victims of blunt trauma. Packed red blood cells were associated with a significant increase in systolic blood pressure (P < .001) and mean arterial pressure (P < .001), a decrease in shock index (P < .001), and a reduction in the time to first transfusion, with minimal waste, no patient-related adverse events, and complete traceability. The results of this service evaluation demonstrate the successful introduction of prehospital transfusion into a paramedic-led CCT program. Further prospective research is needed to assess the impact of such a protocol in this patient population.

Acute traumatic coagulopathy and the relationship to prehospital care and on-scene red blood cell transfusion

OBJECTIVE

To identify the incidence of acute traumatic coagulopathy (ATC) in trauma patients presenting to the Royal Adelaide Hospital, analyse prehospital contributors, including red blood cell transfusion and assess the clinical significance of ATC.

METHODS

A retrospective database review was undertaken using conventional coagulation assays and viscoelastic testing (ROTEM) for diagnosis of ATC.

RESULTS

Baseline ATC incidence is 10% in trauma patients, increasing to over 80% among those where the prehospital team has attended and given a transfusion of red cells. ATC was significantly associated with higher severity of trauma (odds ratio [OR] 1.11, P < 0.0001), prehospital (OR 11.8, P < 0.0001) and in-hospital blood transfusions (OR 17.9, P < 0.0001), and massive transfusions (P < 0.001).

CONCLUSIONS

Prehospital blood transfusions are given to the most severely injured trauma patients and the incidence of ATC in this group is more than 80%. There is an association with prehospital blood transfusion and increased ATC in part related to patient selection and severity of trauma, with the contribution of red cell transfusions to ATC unclear. This association should allow earlier identification of patients at increased risk of ATC to ensure rapid correction of coagulopathy to decrease the morbidity and mortality of trauma.

Pre-hospital transfusion of red blood cells. Part 2: A systematic review of treatment effects on outcomes

The primary aim of this systematic review is to describe the effects of prehospital transfusion of red blood cells (PHTRBC) on patient outcomes. Damage control resuscitation attempts to prevent death through haemorrhage in trauma patients. In this context, transfusion of red blood cells is increasingly used by emergency medical services (EMS). However, evidence on the effects on outcomes is scarce. PubMed and Web of Science were searched through January 2019; 55 articles were included. No randomised controlled studies were identified. While several observational studies suggest an increased survival after PHTRBC, consistent evidence for beneficial effects of PHTRBC on survival was not found. PHTRBC appears to improve haemodynamic parameters, but there is no evidence that shock on arrival to hospital is averted, nor of an association with trauma induced coagulopathy or with length of stay in hospitals or intensive care units. In conclusion, PHTRBC is increasingly used by EMS, but there is no strong evidence for effects of PHTRBC on mortality. Further research with study designs that allow causal inferences is required for more conclusive evidence. The combination of PHTRBC with plasma, as well as the use of individualised transfusion criteria, may potentially show more benefits and should be thoroughly investigated in the future. The review was registered at Prospero (CRD42018084658).