Protocol guided bleeding management improves cardiac surgery patient outcomes

Trial Of Pathogen-reduced Cryoprecipitate vs. Cryoprecipitated AHF to Lower Operative Transfusions (TOP-CLOT): study protocol for a single center, prospective, cluster randomized trial

BACKGROUND

Intraoperative hemorrhage in cardiac surgery increases risk of morbidity and mortality. Low pre-operative and perioperative levels of fibrinogen, a key clotting factor, are associated with severity of hemorrhage and increased transfusion of blood components. The ability to supplement fibrinogen during hemorrhagic resuscitation is delayed 45-60 min because cryoprecipitated antihemophilic factor (cryo AHF) is stored frozen, due to a short post-thaw shelf life. Pathogen Reduced Cryoprecipitated Fibrinogen Complex (INTERCEPT Fibrinogen Complex, IFC) can be kept thawed, at room temperature, for up to 5 days, making it possible to be immediately available for hemorrhaging patients. This trial will investigate if earlier correction of acquired hypofibrinogenemia with IFC in hemorrhaging cardiac surgery patients reduces the total number of perioperatively transfused allogeneic blood products (red blood cells, plasma, and platelets) as compared to cryo AHF.

METHODS

This is a single center, prospective, cluster randomized trial with an adaptive design. Acquired hypofibrinogenemia will be assessed by rotational thromboelastometry (ROTEM) and the threshold for cryo AHF/IFC transfusion defined as FIBTEM A10 ≤ 10 mm in bleeding patients. IFC/cryo AHF will be randomized by 1-month blocks. Cardiac surgery patients will be enrolled in the study if they have an eligible procedure and at least one dose of a cryo AHF/IFC product (approximately 2 g fibrinogen) is transfused. Data from the electronic health record, including the blood bank and lab information systems, will be prospectively collected from the health system's data warehouse.

DISCUSSION

This trial aims to provide evidence of the clinical efficacy of utilizing readily available thawed IFC during acute bleeding in the cardiac surgery setting compared to traditional cryo AHF.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05711524. Feb 3, 2023.

Cardiac Surgical Bleeding, Transfusion, and Quality Metrics: Joint Consensus Statement by the Enhanced Recovery After Surgery Cardiac Society and Society for the Advancement of Patient Blood Management

BACKGROUND

Excessive perioperative bleeding is associated with major complications in cardiac surgery, resulting in increased morbidity, mortality, and cost.

METHODS

An international expert panel was convened to develop consensus statements on the control of bleeding and management of transfusion and to suggest key quality metrics for cardiac surgical bleeding. The panel reviewed relevant literature from the previous 10 years and used a modified RAND Delphi methodology to achieve consensus.

RESULTS

The panel developed 30 consensus statements in 8 categories, including prioritizing control of bleeding, prechest closure checklists, and the need for additional quality indicators beyond reexploration rate, such as time to reexploration. Consensus was also reached on the need for a universal definition of excessive bleeding, the use of antifibrinolytics, optimal cessation of antithrombotic agents, and preoperative risk scoring based on patient and procedural factors to identify those at greatest risk of excessive bleeding. Furthermore, an objective bleeding scale is needed based on the volume and rapidity of blood loss accompanied by viscoelastic management algorithms and standardized, patient-centered blood management strategies reflecting an interdisciplinary approach to quality improvement.

CONCLUSIONS

Prioritizing the timely control and management of bleeding is essential to improving patient outcomes in cardiac surgery. To this end, a cardiac surgical bleeding quality metric that is more comprehensive than reexploration rate alone is needed. Similarly, interdisciplinary quality initiatives that seek to implement enhanced quality indicators will likely lead to improved patient care and outcomes.

How do I implement pathogen reduced Cryoprecipitated fibrinogen complex in a tertiary Hospital's blood Bank

BACKGROUND

Kaiser-Permanente Los Angeles Medical Center (LAMC) is a 560 licensed bed facility that provides regional cardiovascular services, including 1200 open heart surgeries annually. In 2021, LAMC explored alternative therapies to offset the impact of pandemic-driven cryo AHF shortages, and implemented Pathogen Reduced Cryoprecipitated Fibrinogen Complex (also known as INTERCEPT Fibrinogen Complex or IFC). IFC is approved to treat and control bleeding associated with fibrinogen deficiency. Unlike cryo AHF, IFC has 5-day post-thaw shelf life with potential operational and clinical benefits. The implementation steps and the operational advantages to the LAMC Blood Bank are described.

STUDY DESIGN AND METHODS

Eighteen months post-implementation, the institution reviewed their product implementation experience and compared IFC with cryo AHF with a retrospective review of transfusion service and cardiac post-op data.

RESULTS

IFC significantly decreased product wastage rates and order-to-issue time. It did not significantly impact post-op product utilization or hospital length of stay (LOS) in cardiac surgery patients when compared with cryo AHF.

DISCUSSION

Implementation of IFC provides improved product supply stability, shorter turnaround times, and reduced wastage.

Analyzing and modeling massive transfusion strategies and the role of fibrinogen-How much is the patient actually receiving?

BACKGROUND

Hemorrhage is a leading cause of preventable death in trauma, cardiac surgery, liver transplant, and childbirth. While emphasis on protocolization and ratio of blood product transfusion improves ability to treat hemorrhage rapidly, tools to facilitate understanding of the overall content of a specific transfusion strategy are lacking. Medical modeling can provide insights into where deficits in treatment could arise and key areas for clinical study. By using a transfusion model to gain insight into the aggregate content of massive transfusion protocols (MTPs), clinicians can optimize protocols and create opportunities for future studies of precision transfusion medicine in hemorrhage treatment.

METHODS

The transfusion model describes the individual round and aggregate content provided by four rounds of MTP, illustrating that the total content of blood elements and coagulation factor changes over time, independent of the patient's condition. The configurable model calculates the aggregate hematocrit, platelet concentration, percent volume plasma, total grams and concentration of citrate, percent volume anticoagulant and additive solution, and concentration of clotting factors: fibrinogen, factor XIII, factor VIII, and von Willebrand factor, provided by the MTP strategy.

RESULTS

Transfusion strategies based on a 1:1:1 or whole blood foundation provide between 13.7 and 17.2 L of blood products over four rounds. Content of strategies varies widely across all measurements based on base strategy and addition of concentrated sources of fibrinogen and other key clotting factors.

DISCUSSION

Differences observed between modeled transfusion strategies provide key insights into potential opportunities to provide patients with precision transfusion strategy.

Patient Blood Management as an Emerging Concept in Quality: The Role of Nurses

BACKGROUND

Transfusion of blood components has long been considered lifesaving therapy. While blood transfusion may be clinically indicated as a treatment option for some patients, the benefits of transfusion in asymptomatic, hemodynamically stable patients are questionable.

PROBLEM

Blood component transfusion is routinely used as a default therapy when not clinically indicated, increasing the risk of poor patient outcomes, adverse events, pressures on blood supply and availability, and increased health care costs.

APPROACH

Nurses have the responsibility to advocate for patients and reduce/avoid unnecessary blood transfusion through the implementation of patient blood management (PBM). The PBM paradigm includes treatment of anemia, minimizing blood loss and bleeding, optimization of coagulation, and employing true patient-centered decision making.

CONCLUSIONS

PBM should become the standard of care with the goal of improving health care quality and patient outcomes while using the multidisciplinary team for its implementation. As advocates for their patients, nurses can play a major role in the development, implementation, and promotion of PBM.

Implementation of Patient Blood Management in Orthotopic Heart Transplants: A Single Centre Retrospective Observational Review

BACKGROUND

Blood transfusion in the perioperative cardiothoracic setting has accepted risks including deep sternal wound infection, increased intensive care unit length of stay, lung injury, and cost. It has an immunomodulatory effect which may cause allo-immunisation. This may influence long-term survival through immune-mediated factors. Targeting coagulation defects to reduce unnecessary or inappropriate transfusions may reduce these complications.

METHODS

In 2012, an institution-wide patient blood management evidence-based algorithmic bleeding management protocol was implemented at The Prince Charles Hospital, Brisbane, Australia. The benefit of this has been previously reported in our lung transplant and cardiac surgery (excluding transplants) cohorts. This study aimed to investigate the effect of this on our orthotopic heart transplant recipients.

RESULTS

After the implementation of the protocol, despite no difference in preoperative haemoglobin levels and higher risk patients (EuroSCORE 20 vs 26; p=0.013), the use of packed red blood cells (13.0 U vs 4.4 U; p=0.046) was significantly lower postoperatively and fresh frozen plasma was significantly lower both intra- and postoperatively (7.4 U vs 0.6 U; p<0.001, and 3.3 U vs 0.6 U; p=0.011 respectively). Concurrently, the use of prothrombin complex concentrate (33% vs 78%; p<0.001) and desmopressin (5% vs 22%; p=0.0028) was significantly higher in the post-protocol group, while there was less use of recombinant factor VIIa (15% vs 4%; p=0.058). Intraoperative units of cryoprecipitate also rose from 0.9 to 2.0 (p=0.006).

CONCLUSIONS

We have demonstrated that a targeted patient blood management protocol with point-of-care testing for heart transplant recipients is correlated with fewer blood products used postoperatively, with some increase in haemostatic products and no evidence of increased adverse events.

Thromboelastographic evaluation after cardiac surgery optimizes transfusion requirements in the intensive care unit: a single-center retrospective cohort study using an inverse probability weighting method

OBJECTIVE

There are no reports from Japan showing the effects of using the thromboelastography algorithm on transfusion requirements after Intensive Care Unit (ICU) admission, and post-implementation knowledge regarding the thromboelastography algorithm under the Japanese healthcare system is insufficient. Therefore, this study aimed to clarify the effect of the TEG6s thromboelastography algorithm on transfusion requirements for patients in the ICU after cardiac surgery.

METHODS

We retrospectively compared the requirements for blood transfusion up to 24 h after ICU admission using the thromboelastography algorithm (January 2021 to April 2022) (thromboelastography group; n = 201) and specialist consultation with surgeons and anesthesiologists (January 2018 to December 2020) (non-thromboelastography group; n = 494).

RESULTS

There were no significant between-group differences in terms of age, height, weight, body mass index, operative procedure, duration of surgery or cardiopulmonary bypass, body temperature, or urine volume during surgical intervention. Moreover, there was no significant between-group difference in the amount of drainage at 24 h after ICU admission. However, crystalloid and urine volumes were significantly higher in the thromboelastography group than in the non-thromboelastography group. Additionally, fresh-frozen plasma (FFP) transfusion volumes were significantly lower in the thromboelastography group. However, there were no significant between-group differences in red blood cell count or platelet transfusion volume. After variable adjustment, the amount of FFP used from the operating room to 24 h after ICU admission was significantly reduced in the thromboelastography group.

CONCLUSIONS

The thromboelastography algorithm optimized transfusion requirements at 24 h after admission to the ICU following cardiac surgery.

Determining sex-specific preoperative haemoglobin levels associated with intraoperative red blood cell transfusion in cardiac surgery: a retrospective cohort study

BACKGROUND

Anaemic cardiac surgery patients are at greater risk of intraoperative red blood cell transfusion. This study questions the application of the World Health Organization population-based anaemia thresholds (haemoglobin <120 g L-1 in non-pregnant females and <130 g L-1 in males) as appropriate preoperative optimisation targets for cardiac surgery.

METHODS

A retrospective cohort study was conducted on adults ≥18 yr old undergoing cardiopulmonary bypass surgery. Logistic regression was applied to define sex-specific preoperative haemoglobin concentrations with reduced probability of intraoperative red blood cell transfusion for cardiac surgery patients.

RESULTS

Data on 4384 male and 1676 female patients were analysed. Binarily stratified multivariable logistic regression odds of receiving intraoperative red blood cell transfusion increased in cardiac surgery patients >45 yr old (odds ratio [OR] 1.84; 95% confidence interval [CI] 1.33-2.55), surgery urgency <30 days (OR 2.03; 95% CI 1.66-2.48), combined coronary artery bypass grafting and valve surgery, or other surgery types (OR 2.24; 95% CI 1.87-2.67), and female sex (OR 1.92; 95% CI 1.62-2.28). The odds decreased by 8.4% with each 1 g L-1 increase in preoperative haemoglobin (OR 0.92; 95% CI 0.91-0.92). Logistic regression predicted females required a preoperative haemoglobin concentration of 133 g L-1 and males 127 g L-1 to have a 15% probability of intraoperative transfusion.

CONCLUSIONS

The World Health Organization female anaemia threshold of haemoglobin <120 g L-1 disproportionately disadvantages female cardiac surgery patients. A preoperative haemoglobin concentration ≥130 g L-1 in adult cardiac surgery patients would minimise their overall probability of intraoperative red blood cell transfusion to <15%.

Retrospective study assessing outcomes in cardiac surgery after implementation of Quantra

BACKGROUND

The Quantra QPlus System is a cartridge-based device with a unique ultrasound technology that can measure the viscoelastic properties of whole blood during coagulation. These viscoelastic properties correlate directly with hemostatic function. The primary objective of this study was to assess blood product utilization in cardiac surgery patients before and after the implementation of the Quantra QPlus System.

METHODS

Yavapai Regional Medical Center implemented the Quantra QPlus System to aid in their efforts to reduce the transfusion of allogenic blood products and improve outcomes in patients undergoing cardiac surgery. A total of 64 patients were enrolled prior to the utilization of the Quantra (pre-Quantra cohort), and 64 patients were enrolled after (post-Quantra cohort). The pre-Quantra cohort had been managed via standard laboratory assays along with physician discretion for transfusion decisions. The utilization of blood products and frequency of transfusions were compared and analyzed between the two cohorts. (using the Student's t-test) RESULTS: The implementation of the Quantra resulted in a change in the pattern of blood product utilization leading to a demonstrated decrease in the amount of blood products transfused and the associated costs. The amount of FFP transfused was significantly decreased by 97% (P = 0.0004), whereas cryoprecipitate decreased by 67% (P = 0.3134), platelets decreased by 26% (P = 0.4879), and packed red blood cells decreased by 10% (P = 0.8027) however these trends did not reach statistical significance. The acquisition cost of blood products decreased by 41% for total savings of roughly $40,682.

CONCLUSIONS

Use of the Quantra QPlus System has the potential to improve patient blood management and decrease costs. STUDY REGISTERED AT CLINICALTRIALS.GOV: NCT05501730.

Improving Patient Blood Management Programs: An Implementation Science Approach

Organized patient blood management (PBM) programs function in numerous hospitals and health systems around the world contributing to improved patient outcomes as well as increased patient engagement, decreased resource use, and reductions in health care costs. PBM "programming" ranges from the implementation of single strategies/initiatives to comprehensive programs led by dedicated clinicians and PBM committees, employing the use of multiple PBM strategies. Frontline health care professionals play an important role in leading, implementing, operationalizing, measuring, and sustaining successful PBM programs. In this article, we provide practical implementation guidance to support key clinical, administrative, leadership, and structural elements required for the safe and comprehensive delivery of care in PBM programs at the local level.

Fibrinogen, Coagulation, and Ageing

The World Health Organization estimates that the world's population over 60 years of age will nearly double in the next 30 years. This change imposes increasing demands on health and social services with increased disease burden in older people, hereafter defined as people aged 60 years or more. An older population will have a greater incidence of cardiovascular disease partly due to higher levels of blood fibrinogen, increased levels of some coagulation factors, and increased platelet activity. These factors lead to a hypercoagulable state which can alter haemostasis, causing an imbalance in appropriate coagulation, which plays a crucial role in the development of cardiovascular diseases. These changes in haemostasis are not only affected by age but also by gender and the effects of hormones, or lack thereof in menopause for older females, ethnicity, other comorbidities, medication interactions, and overall health as we age. Another confounding factor is how we measure fibrinogen and coagulation through laboratory and point-of-care testing and how our decision-making on disease and treatment (including anticoagulation) is managed. It is known throughout life that in normal healthy individuals the levels of fibrinogen and coagulation factors change, however, reference intervals to guide diagnosis and management are based on only two life stages, paediatric, and adult ranges. There are no specific diagnostic guidelines based on reference intervals for an older population. How ageing relates to alterations in haemostasis and the impact of the disease will be discussed in this chapter. Along with the effect of anticoagulation, laboratory testing of fibrinogen and coagulation, future directions, and implications will be presented.

Patients' Choice, Consent, and Ethics in Patient Blood Management

The goal of patient blood management (PBM) is to optimize clinical outcomes for individual patients by managing their blood as a precious and unique resource to be safeguarded and managed judiciously. A corollary to successful PBM is the minimization or avoidance of blood transfusion and stewardship of donated blood. The first is achieved by a multidisciplinary approach with personalized management plans shared and decided on with the patient or their substitute. It follows that the physician-patient relationship is an integral component of medical practice and the fundamental link between patient and doctor based on trust and honest communication. Central to PBM is accurate and timely diagnosis based on sound physiology and pathophysiology as the bedrock on which scientifically based medicine is founded. PBM in all disease contexts starts with the questions, "What is the status of the patient's blood?" "If there are specific abnormalities in the blood, how should they be managed?" and "If allogeneic blood transfusion is considered, is there no reasonable alternative therapy?" There are compelling scientific reasons to implement a nontransfusion default position when there is clinical uncertainty and questionable evidence of clinical efficacy for allogeneic blood transfusion due to known potential hazards. Patients must be informed of their diagnosis, the nature, severity and prognosis of the disease, and treatment options along with risks and benefits. They should be involved in decision-making regarding their management. However, as part of this process, there are multifaceted medical, legal, ethical, and economic issues, encompassing shared decision-making, patient choice, and informed consent. Furthermore, variability in patient circumstances and preferences, the complexity of medical science, and the workings of health care systems in which consent takes place can be bewildering, not only for the patient but also for clinicians obtaining consent. Adding "patient" to the concept of blood management differentiates it from "donor" blood management to avoid confusion and the perception that PBM is a specific medical intervention. Personalized PBM is tailoring the PBM to the specific characteristics of each patient. With this approach, there should be no difficulty addressing the informed consent and ethical aspects of PBM. Patients can usually be reassured that there is nothing out of order with their blood, in which case the focus of PBM is to keep it that way. In some circumstances, a hematologist may be involved as a patient's blood advocate when abnormalities require expert involvement while the primary disease is being managed.

Patient Blood Management: Improving Outcomes for Millions While Saving Billions. What Is Holding It Up?

Patient blood management (PBM) offers significantly improved outcomes for almost all medical and surgical patient populations, pregnant women, and individuals with micronutrient deficiencies, anemia, or bleeding. It holds enormous financial benefits for hospitals and payers, improves performance of health care providers, and supports public authorities to improve population health. Despite this extraordinary combination of benefits, PBM has hardly been noticed in the world of health care. In response, the World Health Organization (WHO) called for its 194 member states, in its recent Policy Brief, to act quickly and decidedly to adopt national PBM policies. To further support the WHO's call to action, this article addresses 3 aspects in more detail. The first is the urgency from a health economic perspective. For many years, growth in health care spending has outpaced overall economic growth, particularly in aging societies. Due to competing economic needs, the continuation of disproportionate growth in health care spending is unsustainable. Therefore, the imperative for health care leaders and policy makers is not only to curb the current spending rate relative to the gross domestic product (GDP) but also to simultaneously improve productivity, quality, safety of patient care, and the health status of populations. Second, while PBM meets these requirements on an exceptional scale, uptake remains slow. Thus, it is vital to identify and understand the impediments to broad implementation. This includes systemic challenges such as the so-called "waste domains" of failure of care delivery caused by malfunctions of health care systems, failure of care coordination, overtreatment, and low-value care. Other impediments more specific to PBM are the misperception of PBM and deeply rooted cultural patterns. Third, understanding how the 3Es-evidence, economics, and ethics-can effectively be used to motivate relevant stakeholders to take on their respective roles and responsibilities and follow the urgent call to implement PBM as a standard of care.

Development of a management protocol for internal carotid artery injury during endoscopic surgery: a modified Delphi method and single-center multidisciplinary working group

BACKGROUND

Intra-operative internal carotid artery (ICA) injury during transnasal endoscopic surgery is a potentially catastrophic event. Such an injury is life-threatening in the immediate setting, with a reported peri-operative mortality rate of 10%. Nasal packing, muscle patches, direct vessel closure, and endovascular techniques have been described as useful strategies for managing ICA bleeds. The objective of this study was to develop a formalized management protocol for intra-operative ICA injury through engagement with a multi-disciplinary panel.

METHODS

A modified Delphi method including literature review, iterative rounds of stakeholder feedback, and expert panel discussions was used to develop a management protocol for ICA injury during transnasal endoscopic surgery. The 10-person multi-disciplinary panel included otolaryngologists, neurosurgeons, interventional neuroradiologists, anesthesiologists, and operating room nursing staff.

RESULTS

After three rounds of stakeholder engagement with the expert panel, consensus was reached on important elements to include within the protocol. The protocol was divided in three categories: Alert, Control, and Transfer. 'Alert' focusses on early communication with anesthesia and nursing staff. 'Control' focusses on techniques to expose the injury and obtain hemostasis or adequate tamponade. Lastly, 'Transfer' describes the process of contacting neuro-interventional radiology and safely transferring the patient. A one-page handout of the protocol was developed for placement in operating theatres.

CONCLUSION

Due to the life-threatening nature of ICA injury, it is imperative that endoscopic sinus and skull base surgeons are prepared to manage this complication. Using a modified Delphi method with a multidisciplinary expert panel, a protocol for management of intra-operative ICA injury was developed.

Comparison of Bacterial Risk in Cryo AHF and Pathogen Reduced Cryoprecipitated Fibrinogen Complex

Until November 2020, cryoprecipitated antihaemophilic factor (cryo AHF) was the only United States Food and Drug Administration (FDA)-approved fibrinogen source to treat acquired bleeding. The post-thaw shelf life of cryo AHF is limited, in part, by infectious disease risk. Concerns over product wastage demand that cryo AHF is thawed as needed, with thawing times delaying the treatment of coagulopathic patients. In November 2020, the FDA approved Pathogen Reduced Cryoprecipitated Fibrinogen Complex for the treatment and control of bleeding, including massive hemorrhage, associated with fibrinogen deficiency. Pathogen Reduced Cryoprecipitated Fibrinogen Complex (also known as INTERCEPT^® Fibrinogen Complex, IFC) has a five-day post-thaw room-temperature shelf life. Unlike cryo AHF, manufacturing of IFC includes broad spectrum pathogen reduction (Amotosalen + UVA), enabling this extended post-thaw shelf life. In this study, we investigated the risk of bacterial contamination persisting through the cryoprecipitation manufacturing process of cryo AHF and IFC. Experiments were performed which included spiking plasma with bacteria prior to cryoprecipitation, and bacterial survival was analyzed at each step of the manufacturing process. The results show that while bacteria survive cryo AHF manufacturing, IFC remains sterile through to the end of shelf life and beyond. IFC, with a five-day post-thaw shelf life, allows the product to be sustainably thawed in advance, facilitating immediate access to concentrated fibrinogen and other key clotting factors for the treatment of bleeding patients.

Guidelines on enhanced recovery after cardiac surgery under cardiopulmonary bypass or off-pump

OBJECTIVE

To provide recommendations for enhanced recovery after cardiac surgery (ERACS) based on a multimodal perioperative medicine approach in adult cardiac surgery patients with the aim of improving patient satisfaction, reducing postoperative mortality and morbidity, and reducing the length of hospital stay.

DESIGN

A consensus committee of 20 experts from the French Society of Anaesthesia and Intensive Care Medicine (Société française d'anesthésie et de réanimation, SFAR) and the French Society of Thoracic and Cardiovascular Surgery (Société française de chirurgie thoracique et cardio-vasculaire, SFCTCV) was convened. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. The entire guideline process was conducted independently of any industry funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide the assessment of the quality of evidence.

METHODS

Six fields were defined: (1) selection of the patient pathway and its information; (2) preoperative management and rehabilitation; (3) anaesthesia and analgesia for cardiac surgery; (4) surgical strategy for cardiac surgery and bypass management; (5) patient blood management; and (6) postoperative enhanced recovery. For each field, the objective of the recommendations was to answer questions formulated according to the PICO model (Population, Intervention, Comparison, Outcome). Based on these questions, an extensive bibliographic search was carried out and analyses were performed using the GRADE approach. The recommendations were formulated according to the GRADE methodology and then voted on by all the experts according to the GRADE grid method.

RESULTS

The SFAR/SFCTCV guideline panel provided 33 recommendations on the management of patients undergoing cardiac surgery under cardiopulmonary bypass or off-pump. After three rounds of voting and several amendments, a strong agreement was reached for the 33 recommendations. Of these recommendations, 10 have a high level of evidence (7 GRADE 1+ and 3 GRADE 1-); 19 have a moderate level of evidence (15 GRADE 2+ and 4 GRADE 2-); and 4 are expert opinions. Finally, no recommendations were provided for 3 questions.

CONCLUSIONS

Strong agreement existed among the experts to provide recommendations to optimise the complete perioperative management of patients undergoing cardiac surgery.

Early postoperative bleeding impacts long-term survival following first-time on-pump coronary artery bypass grafting

Background

Significant bleeding following cardiac surgery is a recognised complication, associated with a requirement for re-exploration and blood transfusion, both associated with increased morbidity and early mortality. The aim of this study was to examine the impact of the volume of early postoperative bleeding on long-term survival for patients undergoing coronary artery bypass grafting (CABG).

Methods

A retrospective analysis was performed of patients undergoing first-time isolated CABG at a single centre between January 2003 and April 2013, conditional from 30-day survival.

Results

Six thousand two hundred and sixty-five patients were analysed, with a mean Logistic EuroSCORE of 4.9%. The mean age was 67.8 years. Median follow-up was 11.5 years. The overall 10- and 15-year survival was 70.6% and 51.9% respectively. Following surgery, 4.6% (n=291) required return to theatre for re-exploration, and 43.6% (n=2,733) received at least one red cell transfusion. In multivariable analysis, the strongest correlates of mortality were age, smoking history, BMI, COPD, renal impairment, preoperative left ventricular function and preoperative haemoglobin (Hb) level. Twelve-hour blood loss was an additional predictor of inferior long-term survival. Five-year survival was 89.6% for patients with <500 mL blood loss, 86.8% for 500–1,000 mL and 83.8% for >1,000 mL. Re-exploration and receiving blood transfusion were not associated with reduced long-term survival.

Conclusions

Significant 12-hour blood loss is associated with inferior long-term survival following CABG. This observation supports efforts aimed at improving intra-operative haemostasis and aggressive management of patients with early signs of bleeding.

Thromboelastography-Platelet Mapping Allows Safe and Earlier Urgent Coronary Artery Bypass Grafting

BACKGROUND

Current STS guidelines recommend delaying CABG for several days or performing platelet function testing in stable patients who received P2Y12 inhibitors. Our program routinely uses thromboelastography-platelet mapping (TEG-PM) to expedite CABG in P2Y12 non-responders (NR). We hypothesize that P2Y12 NR had no difference in LOS to surgery and blood product transfusion compared to patients undergoing urgent inpatient CABG not treated with a P2Y12 inhibitor.

METHODS

A total of 221 patients from 2015-2019 were P2Y12 NR based on TEG-PM result of < 50% ADP inhibition. The control group was 232 consecutive patients who also had urgent inpatient CABG but were not treated pre-operatively with a P2Y12 inhibitor. Exclusion criteria were identical between groups.

RESULTS

Sixty-seven percent of inpatient CABG patients who were treated pre-operatively with a P2Y12 inhibitor were NR. The mean number of days from cardiac surgical consultation to CABG in the TEG-PM NR group was 1.6 ± 0.1 versus 2.1 ± 0.1 in the control group (p<0.01). The mean total number of blood product units transfused was 1.6 ± 0.2 in the TEG-PM NR group versus 1.6 ± 0.4 in controls (p=0.91).

CONCLUSIONS

Our results demonstrate a very high incidence of P2Y12 non-responders in patients undergoing urgent CABG at our program. These patients underwent surgery at least 3 days earlier than STS recommendations and common practice with no difference in transfusion requirement. Routine use of TEG-PM to identify P2Y12 NR can safely decrease pre-operative hospital LOS and associated cost and improve resource utilization and patient satisfaction.

Barriers and facilitators to implementing evidence based bleeding management in Australian Cardiac Surgery Units: a qualitative interview study analysed with the theoretical domains framework and COM-B model

Background

Bleeding during cardiac surgery is a common complication that often requires the transfusion of blood products. The combination of bleeding and blood product transfusion incrementally increases adverse outcomes including infection and mortality. Following bleeding management guideline recommendations could assist with minimising risk but adherence is not high, and the cause for lack of adherence is not well understood. This study aimed to identify barriers and facilitators to practicing and implementing evidenced-based intra-operative, bleeding management in Australian cardiac surgery units.

Methods

We used a qualitative descriptive design to conduct semi-structured interviews with Australian cardiac surgeons, anaesthetists and perfusionists. The Theoretical Domains Framework (TDF) was utilised to guide interviews and thematically analyse the data. Categorised data were then linked with the three key domains of the COM-B model (capability, opportunity, motivation - behaviour) to explore and understand behaviour.

Results

Seventeen interviews were completed. Nine of the 14 TDF domains emerged as significant. Analysis revealed key themes to improving capability included, standardisation, monitoring, auditing and feedback of data and cross discipline training. Opportunity for change was improved with interpersonal and interdepartmental collaboration through shared goals, and more efficient and supportive processes allowing clinicians to navigate unfamiliar business and financial models of health care. Results suggest as individuals, clinicians had the motivation to make change and healthcare organisations have an obligation and a responsibility to partner with clinicians to support change and improve goal directed best practice.

Conclusion

Using a theory-based approach it was possible to identify factors which may be positively or negatively influence clinicians ability to implement best practice bleeding management in Australian cardiac surgical units.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06269-8.

Role of Using a Thromboelastometry-Based Protocol for Transfusion Management in Combined Coronary Artery Bypass Grafting and Valve Surgery: A Randomized Clinical Trail

The aim of this study was to evaluate the impact of using a thromboelastometry-based protocol on transfusion requirements in patients undergoing combined coronary artery bypass grafting (CABG) and valve surgery. 80 adult patients scheduled for elective combined CABG and valve surgery were included in this clinical trial study. Patients were randomly allocated to the thromboelastometry (ROTEM) (n = 40) or control groups (n = 40). In the ROTEM group, transfusion was directed according to a thromboelastometry-based protocol. In the control group, transfusion was conducted according to the routine practices including conventional coagulation testing and clinical judgments. Finally, transfusion requirements were compared between groups. Use of thromboelastometry- based protocol resulted in 67% reduction in blood products units' consumption as well as 23% in the percentage of patients transfused. This reduction was especially evident in relation to fresh frozen plasma (FFP) and platelet consumption. No significant differences were found both in the percentage of patients receiving RBC and number of transfused RBC units. Using thromboelastometry tests incorporated a protocol results in reduction of transfusion requirements in patients undergoing elective combined CABG and valve surgery.

Overcoming barriers to evidence-based patient blood management: a restricted review

Background

Blood transfusions are associated with a range of adverse patient outcomes, including coagulopathy, immunomodulation and haemolysis, which increase the risk of morbidity and mortality. Consideration of these risks and potential benefits are necessary when deciding to transfuse. Patient blood management (PBM) guidelines exist to assist in clinical decision-making, but they are underutilised. Exploration of barriers to the implementation and utilisation of the PBM guidelines is required. This study aimed to identify common barriers and implementation strategies used to implement PBM guidelines, with a comparison against current expert opinion.

Methods

A restricted review approach was used to identify the barriers to PBM guideline implementation as reported by health professionals and to review which implementation strategies have been used. Searches were undertaken in MEDLINE/PubMed, CINAHL, Embase, Scopus and the Cochrane library. The Consolidated Framework for Implementation Research (CFIR) was used to code barriers. The Expert Recommendations for Implementing Change (ERIC) tool was used to code implementation strategies, and subsequently, develop recommendations based on expert opinion.

Results

We identified 14 studies suitable for inclusion. There was a cluster of barriers commonly reported: access to knowledge and information (n = 7), knowledge and beliefs about the intervention ( = 7) and tension for change (n = 6). Implementation strategies used varied widely (n = 25). Only one study reported the use of an implementation theory, model or framework. Most studies (n = 11) had at least 50% agreement with the ERIC recommendations.

Conclusions

There are common barriers experienced by health professionals when trying to implement PBM guidelines. There is currently no conclusive evidence to suggest which implementation strategies are most effective. Further research using validated implementation approaches and improved reporting is required.

Bleeding Management Practices of Australian Cardiac Surgeons, Anesthesiologists and Perfusionists: A Cross-Sectional National Survey Incorporating the Theoretical Domains Framework (TDF) and COM-B Model

Purpose

Excessive bleeding is an acknowledged consequence of cardiac surgery, occurring in up to 10% of adult patients. This clinically important complication leads to poorer patient outcomes. Clinical practice guidelines are available to support best practice however variability in bleeding management practice and related adverse outcomes still exist. This study had two objectives: 1) to gain insight into current bleeding management practice for adult cardiac surgery in Australia and how that compared to guidelines and literature; and 2) to understand perceived difficulties clinicians face implementing improvements in bleeding management.

Methods

A national cross-sectional questionnaire survey was utilized. Perspectives were sought from cardiac surgeons, cardiac anesthesiologists and perfusionists. Thirty-nine closed-ended questions focused on routine bleeding management practices to address pre and intra-operative care. One open-ended question was asked; “What would assist you to improve bleeding management with cardiac surgery patients?” Quantitative data were analysed with SPSS. Qualitative data were categorized into the domains of the Theoretical Domains Framework; the domains were then mapped to the COM-B model.

Results

Survey responses from 159 Anesthesiologists, 39 cardiac surgeons and 86 perfusionists were included (response rate 37%). Four of the recommendations queried in this survey were reported as routinely adhered to < 50% of the time, 9 queried recommendations were adhered to 51–75% of the time and 4 recommendations were routinely followed >76% of the time.

Conclusion

There is a wide variation in peri-operative bleeding management practice among cardiac anaesthesiologists, surgeons and perfusionists in Australian cardiac surgery units. Conceptualizing factors believed necessary to improve practice with the TDF and COM-B model found that bleeding management could be improved with a standardized approach including; point of care diagnostic assays, a bleeding management algorithm, access to concentrated coagulation factors, cardiac surgery specific bleeding management education, multidisciplinary team agreement and support, and an overarching national approach.

Patient Blood Management in Pediatric Cardiac Surgery: A Review

Efforts to reduce blood product transfusions and adopt blood conservation strategies for infants and children undergoing cardiac surgical procedures are ongoing. Children typically receive red blood cell and coagulant blood products perioperatively for many reasons, including developmental alterations of their hemostatic system, and hemodilution and hypothermia with cardiopulmonary bypass that incites inflammation and coagulopathy and requires systemic anticoagulation. The complexity of their surgical procedures, complex cardiopulmonary interactions, and risk for inadequate oxygen delivery and postoperative bleeding further contribute to blood product utilization in this vulnerable population. Despite these challenges, safe conservative blood management practices spanning the pre-, intra-, and postoperative periods are being developed and are associated with reduced blood product transfusions. This review summarizes the available evidence regarding anemia management and blood transfusion practices in the perioperative care of these critically ill children. The evidence suggests that adoption of a comprehensive blood management approach decreases blood transfusions, but the impact on clinical outcomes is less well studied and represents an area that deserves further investigation.

Continuous hemoglobin and plethysmography variability index monitoring can modify blood transfusion practice and is associated with lower mortality

To determine the effect of implementing an algorithm of fluid and blood administration based on continuous monitoring of hemoglobin (SpHb) and PVI (plethysmography variability index) on mortality and transfusion on a whole hospital scale. This single-center quality program compared transfusion at 48 h and mortality at 30 days and 90 days after surgery between two 11-month periods in 2013 and 2014 during which all the operating and recovery rooms and intensive care units were equipped with SpHb/PVI monitors. The entire team was trained to use monitors and the algorithm. Team members were free to decide whether or not to use devices. Each device was connected to an electronic wireless acquired database to anonymously acquire parameters on-line and identify patients who received the monitoring. All data were available from electronic files. Patients were divided in three groups; 2013 (G1, n = 9285), 2014 without (G2, n = 5856) and with (G3, n = 3575) goal-directed therapy. The influence of age, ASA class, severity and urgency of surgery and use of algorithm on mortality and blood use were analyzed with cox-proportional hazard models. Because in 2015, SpHb/PVI monitors were no longer available, we assessed post-study mortality observed in 2015 to measure the impact of team training to adjust vascular filling on a patient to patient basis. During non-cardiac surgery, blood was more often transfused during surgery in G3 patients as compared to G2 (66.6% vs. 50.7%, p < 0.001) but with fewer blood units per patient. After adjustment, survival analysis showed a lower risk of transfusion at 48 h in G3 [OR 0.79 (0.68-0.93), p = 0.004] but not in G2 [OR 0.90 (0.78-1.04) p = 0.17] as compared to G1. When adjusting to the severity of surgery as covariable, there was 0.5 and 0.7% differences of mortality at day 30 and 90 whether patients had goal directed therapy (GDT). After high risk surgery, the mortality at day 30 is reduced by 4% when using GDT, and 1% after intermediate risk surgery. There was no difference for low risk surgery. G3 Patients had a lower risk of death at 30 days post-surgery [OR 0.67 (0.49-0.92) p = 0.01] but not G2 patients [OR 1.01, (0.78-1.29), p = 0.96]. In 2015, mortality at 30 days and 90 days increased again to similar levels as those of 2013, respectively 2.18 and 3.09%. Monitoring SpHb and PVI integrated in a vascular filling algorithm is associated with earlier transfusion and reduced 30 and 90-day mortality on a whole hospital scale.

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

Rotational thromboelastometry (ROTEM) is a point-of-care viscoelastic method and enables to assess viscoelastic profiles of whole blood in various clinical settings. ROTEM-guided bleeding management has become an essential part of patient blood management (PBM) which is an important concept in improving patient safety. Here, ROTEM testing and hemostatic interventions should be linked by evidence-based, setting-specific algorithms adapted to the specific patient population of the hospitals and the local availability of hemostatic interventions. Accordingly, ROTEM-guided algorithms implement the concept of personalized or precision medicine in perioperative bleeding management (‘theranostic’ approach). ROTEM-guided PBM has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and health care costs. Accordingly, several randomized-controlled trials, meta-analyses, and health technology assessments provided evidence that using ROTEM-guided algorithms in bleeding patients resulted in improved patient’s safety and outcomes including perioperative morbidity and mortality. However, the implementation of ROTEM in the PBM concept requires adequate technical and interpretation training, education and logistics, as well as interdisciplinary communication and collaboration.

Effectiveness of adherence to a preoperative antiplatelet and anticoagulation cessation protocol in cardiac surgery

OBJECTIVES

Reduction of blood loss after cardiac surgery remains challenging. The effectiveness of adherence to a protocol on cessation of anticoagulants and platelet-inhibiting medications was investigated together with the influence of protocol violations on blood loss after surgery, use of blood products, surgical re-explorations and 30-day mortality.

METHODS

Between 2009 and 2013, data were collected prospectively for all elective cardiac surgery procedures in adult patients (n = 1637). Two groups were distinguished: Group 1 adhered to the protocol for cessation or continuation of medication (n = 1287, 79%) and Group 2 violated the protocol (n = 350, 21%).

RESULTS

Median blood loss was 300 ml (interquartile range 175-500 ml). Eighty patients underwent re-exploration due to blood loss (5%). Thirty-day mortality was 2% (n = 27). Protocol violation was associated with increased blood loss [median 275 ml (175-475 ml) vs 350 ml (250-612); P ≤ 0.001] and with increased average use of fresh frozen plasma (226 ml vs 139 ml; P  << 0.00001), red blood cell transfusion (115 ml vs 87 ml; P = 0.081) and thrombocyte transfusions (52 ml vs 37 ml; P = 0.0082). The number of re-explorations (4% vs 6%; P = 0.39) and mortality risk (1% vs 2%; P = 0.72) did not differ.

CONCLUSIONS

Balancing the benefit of continuing platelet inhibitors or anticoagulants versus cessation before surgery remains challenging. Adherence to the protocol will lead to lower blood loss and in a lower consumption of blood products although the decision to go for re-exploration and 30-day mortality does not differ compared with the protocol violation. Stopping medication does not lead to thromboembolic events.

Platelets function assessment in patients qualified for cardiac surgery - clinical problems and a newer diagnostic possibilities

Background

As the incidence of cardiovascular diseases increases, the use of antiplatelet therapy is widely recognized. This presents clinicians with the challenge of balancing the risk of thrombotic and bleeding complications. Platelet dysfunction is one of the causes of postoperative bleedings and their etiology is not fully understood. Platelets receptors point-of-care investigation is of a remarkable value in assessing patients risk of bleeding. Reliable assessment of platelet function can improve treatment. The aim of this study was to evaluate the activity of platelet receptors in patients qualified for cardiac surgery, taking into account organ dysfunctions and pharmacological therapy applied in these patients.

Methods

Seventy-one cardiac surgical patients were analyzed before surgery using multiple electrode aggregometry with the use of the ADP test and ASPI test. The cut-off values were determined based on the manufacturer’s recommendations. Patients were divided into four groups: Group I (33/71 patients, without platelet dysfunctions), Group II (6/71 patients, ADP < 710 AU x min), Group III (13/71 patients, ASPI < 570 AU x min) and Group IV (19 / 71 patients, ADP < 710 AU x min and ASPI < 570 AU x min). Biochemical data defining the efficiency of the liver and kidneys, the list of preoperative drugs used and the requirement for transfusion throughout the study group were collected.

Results

The study group included 41 males (57.7%) and 30 females (42.3%), mean age 66 years. The majority of patients (94.4%) had platelet counts within the normal range, but platelet function was impaired in more than half of the studied patients (53.5%). No relationship was found between the biochemical markers of the kidneys and liver and the function of the ADP and ASPI receptors, while receptors activities were related (rs = 0.72, p < 0.001), and both associated with platelet count (rs = 0.55, p < 0.001 and rs = 0.42, p < 0.001, respectively). Platelet receptors activity was not related to the postoperative need for any type of transfusion as well as the applied preoperative pharmacological therapy.

Conclusions

Early identification of patients at high risk of bleeding, using point-of-care platelet function assessment tests, enables a targeted therapeutic pathway. Due to the variety of factors affecting the activity of platelets, finding a specific cause of this pathology is extremely difficult. According to our study, the correlation between platelet receptor disorders and mild to moderate liver and kidney injury has not been demonstrated. However, platelet receptors dysfunction has been shown to be associated with a decreased number of platelets.

Evaluation of the real-world impact of rotational thromboelastometry-guided transfusion protocol in patients undergoing proximal aortic surgery

BACKGROUND

Complex aortic procedures are potentially associated with important blood loss and coagulopathy. The aim of this study was to assess the impact of rotational thromboelastometry (ROTEM, Tem International GmBH, Munich, Germany) on transfusion requirements after proximal aortic operations in a real-world setting.

METHODS

This single-center retrospective analysis based on 385 consecutive patients undergoing cardiac surgeries involving the aortic root, ascending aorta, or aortic arch compared 197 controls managed according to routine transfusion protocol before the introduction of the ROTEM in 2012 with 188 patients operated afterward. With the use of a 1:1 propensity score match, 224 patients were included in paired analysis (112 in each group). The primary end point was erythrocytes transfusion rate. The secondary end points comprised the transfusion of other allogeneic blood products, number of units transfused, postoperative blood loss, massive transfusion rate, and use of other hemostatic products.

RESULTS

ROTEM implementation was associated with a trend toward reduction in the rate of erythrocytes transfusion (57% vs 46%, P = .08) and a decreased median number of units transfused for erythrocytes (1.0 [0.0-4.0] unit vs 0.0 [0.0-2.0] unit, P = .03) and plasma (0.0 [0.0-4.0] unit vs 0.0 [0.0-2.0] unit, P = .04). After sensitivity analysis, ROTEM displayed a comparable rate of erythrocytes transfusion (58% vs 47%, P = .15).

CONCLUSIONS

In a real-world setting, ROTEM-based algorithm implementation could help reduce excess erythrocytes transfusion for complex aortic procedures. We advocate for a strict adherence and concerted team effort to maximize the benefits of such addition to patients' management.

A retrospective explanatory case study of the implementation of a bleeding management quality initiative, in an Australian cardiac surgery unit

BACKGROUND

Bleeding management in cardiac surgery is challenging. Many guidelines exist to support bleeding management; however, literature demonstrates wide variation in practice. In 2012, a quality initiative was undertaken at The Prince Charles Hospital, Australia to improve bleeding management for cardiac surgery patients. The implementation of the quality initiative resulted in significant reductions in the incidence of blood transfusion, re-exploration for bleeding; superficial leg and chest wound infections; length of hospital stay, and cost. Given the success of the initiative, we sought to answer the question; "How and why was the process of implementing a bleeding management quality initiative in the cardiac surgery unit successful, and sustainable?"

METHODS

A retrospective explanatory case study design was chosen to explore the quality initiative. Analysis of the evidence was reviewed through phases of the 'Knowledgeto Action' planned change model. Data was derived from: (1) document analysis, (2) direct observation of the local environment, (3) clinical narratives from interviews, and analysed with a triangulation approach. The study period extended from 10/2011 to 6/2013.

RESULTS

Results demonstrated the complexity of changing practice, as well as the significant amount of dedicated time and effort required to support individual, department and system wide change. Results suggest that while many clinicians were aware of the potential to apply improved practice, numerous barriers and challenges needed to be overcome to implement change across multiple disciplines and departments.

CONCLUSIONS

The key successful components of the QI were revealed through the case study analysis as: (1) an appropriately skilled project manager to facilitate the implementation process; (2) tools to support changes in workflow and decision making including a bleeding management treatment algorithm with POCCTs; (3) strong clinical leadership from the multidisciplinary team and; (4) the evolution of the project manager position into a perpetual clinical position to support sustainability.

Use of an intraoperative checklist to decrease the incidence of re-exploration for postoperative bleeding after cardiac surgery

OBJECTIVES

We have implemented an intraoperative checklist aiming to reduce the incidence of re-exploration for bleeding after cardiac surgery. The present report addresses the results of adopting such a checklist regarding the incidence of postoperative bleeding.

METHODS

The checklist was implemented by presenting it in several staff meetings of the Catharina Heart Center. Copies of the checklist were presented in every operating room. Data were collected by the Catharina Heart Center, aligned with the 'Meetbaar Beter' data manual and validated by 'Meetbaar Beter' through their data quality system. The incidence of re-exploration for bleeding was analysed in a variable life-adjusted display curve. The patient population operated after the implementation of the checklist was compared with a recent historical population before its implementation.

RESULTS

From January 2013 through April 2016, 4817 cardiac surgical procedures were performed in our institution. Before May 2015, 3210 procedures were performed (Group 1), complicated by 112 re-exploration for bleeding (3.5%). The 'reoperation for bleeding checklist' was implemented on 1 May 2015. After this date, the number of re-explorations for bleeding decreased to 29 (1.8%) of the 1607 cardiac surgical procedures (Group 2) (P < 0.05).

CONCLUSIONS

An intraoperative checklist is feasible to implement, low cost, quick and simple to measure with a significant reduction in the incidence of re-exploration for bleeding. This report shows an example of the positive effects of transparency in publishing outcomes' data in cardiac surgery.

Transfusion Medicine and Coagulation Management in Organ Transplantation

Organ transplantation recipients present unusual challenges with regard to blood transfusion. Although this patient population requires a larger proportion of blood product resources, liberal transfusion of allogeneic blood products can lead to a plethora of complications. Recent trends suggest that efforts to minimize bleeding, conserve products, and target transfusion to specific deficits and needs are increasingly becoming the standard practice; these must all occur with optimization of graft function and preservation in mind. With newer monitoring modalities and factor concentrates, the approach toward transfusion and bleeding in organ transplantation has rapidly improved in recent years.

Evidence of altered haemostasis in an ovine model of venovenous extracorporeal membrane oxygenation support

Background

Extracorporeal membrane oxygenation (ECMO) is a life-saving modality used in the management of cardiopulmonary failure that is refractory to conventional medical and surgical therapies. The major problems clinicians face are bleeding and clotting, which can occur simultaneously. To discern the impact of pulmonary injury and ECMO on the host’s haemostatic response, we developed an ovine model of smoke-induced acute lung injury (S-ALI) and ECMO. The aims of this study were to determine if the ECMO circuit itself altered haemostasis and if this was augmented in a host with pulmonary injury.

Methods

Twenty-seven South African meat merino/Border Leicester Cross ewes underwent instrumentation. Animals received either sham injury (n = 12) or S-ALI (n = 15). Control animal groups consisted of healthy controls (ventilation only for 24 h) (n = 4), ECMO controls (ECMO only for 24 h) (n = 8) and S-ALI controls (S-ALI but no ECMO for 24 h) (n = 7). The test group comprised S-ALI sheep placed on ECMO (S-ALI + ECMO for 24 h) (n = 8). Serial blood samples were taken for rotational thromboelastometry, platelet aggregometry and routine coagulation laboratory tests. Animals were continuously monitored for haemodynamic, fluid and electrolyte balances and temperature. Pressure-controlled intermittent mandatory ventilation was used, and mean arterial pressure was augmented by protocolised use of pressors, inotropes and balanced fluid resuscitation to maintain mean arterial pressure >65 mmHg.

Results

Rotational thromboelastometry, platelet aggregometry and routine coagulation laboratory tests demonstrated that S-ALI and ECMO independently induced changes to platelet function, delayed clot formation and reduced clot firmness. This effect was augmented with the combination of S-ALI and ECMO, with evidence of increased collagen-induced platelet aggregation as well as changes in factor VIII (FVIII), factor XII and fibrinogen levels.

Conclusions

The introduction of an ECMO circuit itself increases collagen-induced platelet aggregation, decreases FVIII and von Willebrand factor, and induces a transient decrease in fibrinogen levels and function in the first 24 h. These changes to haemostasis are amplified when a host with a pre-existing pulmonary injury is placed on ECMO. Because patients are often on ECMO for extended periods, longer-duration studies are required to characterise ECMO-induced haemostatic changes over the long term. The utility of point-of-care tests for guiding haemostatic management during ECMO also warrants further exploration.

Targeted Coagulation Management in Severe Trauma: The Controversies and the Evidence

Hemorrhage in the setting of severe trauma is a leading cause of death worldwide. The pathophysiology of hemorrhage and coagulopathy in severe trauma is complex and remains poorly understood. Most clinicians currently treating trauma patients acknowledge the presence of a coagulopathy unique to trauma patients-trauma-induced coagulopathy (TIC)-independently associated with increased mortality. The complexity and incomplete understanding of TIC has resulted in significant controversy regarding optimum management. Although the majority of trauma centers utilize fixed-ratio massive transfusion protocols in severe traumatic hemorrhage, a widely accepted "ideal" transfusion ratio of blood to blood products remains elusive. The recent use of viscoelastic hemostatic assays (VHAs) to guide blood product replacement has further provoked debate as to the optimum transfusion strategy. The use of VHA to quantify the functional contributions of individual components of the coagulation system may permit targeted treatment of TIC but remains controversial and is unlikely to demonstrate a mortality benefit in light of the heterogeneity of the trauma population. Thus, VHA-guided algorithms as an alternative to fixed product ratios in trauma are not universally accepted, and a hybrid strategy starting with fixed-ratio transfusion and incorporating VHA data as they become available is favored by some institutions. We review the current evidence for the management of coagulopathy in trauma, the rationale behind the use of targeted and fixed-ratio approaches and explore future directions.

Applying the Cell-Based Coagulation Model in the Management of Critical Bleeding

The cell-based coagulation model was proposed 15 years ago, yet has not been applied commonly in the management of critical bleeding. Nevertheless, this alternative model may better explain the physiological basis of current coagulation management during critical bleeding. In this article we describe the limitations of the traditional coagulation protein cascade and standard coagulation tests, and explain the potential advantages of applying the cell-based model in current coagulation management strategies. The cell-based coagulation model builds on the traditional coagulation model and explains many recent clinical observations and research findings related to critical bleeding unexplained by the traditional model, including the encouraging results of using empirical 1:1:1 fresh frozen plasma:platelets:red blood cells transfusion strategy, and the use of viscoelastic and platelet function tests in patients with critical bleeding. From a practical perspective, applying the cell-based coagulation model also explains why new direct oral anticoagulants are effective systemic anticoagulants even without affecting activated partial thromboplastin time or the International Normalized Ratio in a dose-related fashion. The cell-based coagulation model represents the most cohesive scientific framework on which we can understand and manage coagulation during critical bleeding.