What are the current evidence‑based guidelines for patient blood management, including anemia screening, iron supplementation, erythropoiesis‑stimulating agents, intra‑operative blood‑conserving strategies, transfusion triggers, and postoperative follow‑up?

Current Evidence-Based Guidelines for Patient Blood Management

Preoperative Assessment and Anemia Management

All patients should have hemoglobin checked before listing for surgery, with anemia defined as Hb <130 g/L in men and <120 g/L in women, and elective surgery should be delayed until the underlying cause is investigated and treated appropriately. 1

Mandatory Preoperative Evaluation

• Review previous medical records for history of blood transfusion, drug-induced coagulopathy (warfarin, clopidogrel, aspirin, anticoagulants, vitamins, herbal supplements), congenital coagulopathy, thrombotic events (DVT, pulmonary embolism), and risk factors for organ ischemia that influence transfusion triggers 1
• Conduct patient interview to identify bleeding history, medication use, and transfusion preferences 1
• Review laboratory results including hemoglobin, hematocrit, and coagulation profiles, ordering additional tests based on patient condition 1
• Inform patients of transfusion risks versus benefits and elicit their preferences 1

Preoperative Anemia Treatment

• Administer iron supplementation to patients with iron deficiency anemia when time permits before surgery 1
• Consider erythropoietin with or without iron to reduce allogeneic blood needs in selected populations (renal insufficiency, anemia of chronic disease, transfusion refusal) 1
• Establish patient pathways and pre-assessment clinics allowing timely management, delaying elective surgery if required 1

Anticoagulation Management

• Discontinue anticoagulation therapy (warfarin, anti-Xa drugs, antithrombin agents) for elective surgery in consultation with appropriate specialist 1
• Transition to shorter-acting drugs (heparin, low-molecular-weight heparin) in selected patients 1
• Discontinue non-aspirin antiplatelet agents (clopidogrel, ticagrelor, prasugrel) for sufficient time before surgery, except in patients with recent percutaneous coronary interventions 1
• Continue aspirin on case-by-case basis, weighing thrombosis risk versus bleeding risk 1

Intraoperative Blood Conservation Strategies

A restrictive red blood cell transfusion strategy should be used, with transfusion decisions for hemoglobin concentrations between 6-10 g/dL based on ongoing bleeding, intravascular volume status, signs of organ ischemia, and cardiopulmonary reserve—not hemoglobin level alone. 1, 2

Antifibrinolytic Prophylaxis

• Use antifibrinolytic therapy (tranexamic acid or ε-aminocaproic acid) for prophylaxis in patients undergoing cardiopulmonary bypass 1
• Consider antifibrinolytic prophylaxis in orthopedic surgery and liver surgery at high risk for excessive bleeding 1

Acute Normovolemic Hemodilution

• Consider acute normovolemic hemodilution (ANH) to reduce allogeneic transfusion in patients at high risk for excessive bleeding (major cardiac, orthopedic, thoracic, or liver surgery) 1

Cell Salvage

• Use cell salvage for high- or medium-risk surgery in non-obstetric adults where blood loss >500 mL is likely 1
• Use cell salvage in obstetric major hemorrhage with mandatory leucocyte filter 1
• Use leucocyte filter when cell salvage employed in patients with malignancy 1
• Bacterial contamination of surgical field remains absolute contraindication 1
• Continue cell salvage into postoperative period when appropriate 1

Blood Product Administration

• Administer blood without consideration of storage duration 1
• Consider leukocyte-reduced blood to reduce complications associated with allogeneic transfusion 1
• Reinfuse recovered red blood cells as blood-sparing intervention intraoperatively 1

Transfusion Triggers and Administration

Transfuse red blood cells when hemoglobin falls below 7 g/dL for most hospitalized, hemodynamically stable patients, or below 8 g/dL for patients with pre-existing cardiovascular disease. 2

Unit-by-Unit Transfusion Strategy

• Administer red blood cells unit-by-unit with interval reevaluation, rather than multiple units simultaneously 1
• Never base transfusion decisions solely on hemoglobin level—incorporate clinical symptoms, intravascular volume status, signs of shock, and cardiopulmonary parameters 2

Transfusion Safety Protocols

• Perform final identity check at patient's bedside between patient and blood product—this is the most critical safety step as ABO incompatibility represents the most serious transfusion complication 1, 2
• Complete red cell transfusions within 4 hours of removal from blood fridge 1
• Document all transfusion prescriptions appropriately 1
• Ensure all staff involved in blood administration are trained and competency-assessed per local policy 1

Intraoperative Monitoring

Periodically conduct visual assessment of the surgical field jointly with the surgeon to assess for excessive microvascular (coagulopathy) versus surgical bleeding. 1

Management of Excessive Bleeding

Laboratory-Guided Component Therapy

• Obtain platelet count before platelet transfusion if possible; obtain platelet function testing if available in patients with suspected or drug-induced (e.g., clopidogrel) platelet dysfunction 1
• Obtain coagulation tests (PT/INR and aPTT) before FFP transfusion if possible 1
• Assess fibrinogen levels before cryoprecipitate administration if possible 1

Pharmacologic Hemostatic Interventions

• Use desmopressin in patients with excessive bleeding and platelet dysfunction 1
• Consider topical hemostatics such as fibrin glue or thrombin gel 1
• Use antifibrinolytics (ε-aminocaproic acid, tranexamic acid) if fibrinolysis is documented or suspected and not already being used 1
• Use prothrombin complex concentrates (PCCs) in patients with excessive bleeding and increased INR 1
• Use fibrinogen concentrate when indicated 1
• Consider recombinant activated factor VII only when traditional options for treating excessive bleeding due to coagulopathy have been exhausted, with caution regarding arterial thrombosis risk especially in older patients 1

Urgent Anticoagulation Reversal

• For urgent warfarin reversal, administer PCCs in consultation with appropriate specialist, or administer FFP 1
• Administer vitamin K for selected patients requiring non-urgent warfarin reversal, except when rapid restoration of anticoagulation after surgery is required 1

Massive Transfusion Protocol

Use a massive transfusion protocol when available to optimize delivery of blood products to massively bleeding patients, maintaining 1:1 ratio of packed red blood cells to fresh frozen plasma during active hemorrhage. 1, 3

• Designate team leader immediately to coordinate management and communications 3
• Secure large-bore intravenous access (8-Fr central line preferred in adults) 3
• Obtain baseline labs including CBC, PT/INR, aPTT, fibrinogen, and cross-match for at least 6 units of packed red blood cells 3
• Initiate near-patient testing with thromboelastography (TEG) or thromboelastometry (ROTEM) if available to guide component therapy 3
• Platelet count and coagulation tests are not necessary when massive transfusion protocol is activated 1

Postoperative Management

Transfusion Monitoring

• Monitor heart rate, blood pressure, temperature, and respiratory rate before, during, and after transfusion 2
• If signs of transfusion reaction occur (tachycardia, rash, dyspnea, hypotension, fever), stop transfusion immediately and contact laboratory 2

High-Risk Patient Identification

• Identify patients at high risk for transfusion-associated circulatory overload (TACO): age >70 years, no active bleeding, heart failure, renal insufficiency, or hypoalbuminemia 2

Postoperative Optimization

• Ensure patients are optimized before hospital discharge, addressing residual anemia and planning outpatient follow-up 4

Institutional Protocols

• Use maximal surgical blood ordering schedule when available and in accordance with institutional policy to improve efficiency of blood ordering practices 1
• Employ multimodal protocols or algorithms as strategies to reduce blood product usage, though no single algorithm can be universally recommended 1
• Consider protocol for transfusion avoidance in patients who refuse transfusion or when transfusion is not possible 1

Critical Pitfalls to Avoid

• Do not use hemoglobin as sole transfusion trigger—always incorporate clinical context 2
• Do not delay surgery waiting for hemoglobin to stabilize in actively bleeding patients—ongoing bleeding will accelerate without source control 3
• Do not use crystalloid-only resuscitation in actively bleeding patients—this worsens dilutional coagulopathy 3
• Recognize that transfusion is associated with increased risk of nosocomial infections, multi-organ failure, and systemic inflammatory response syndrome 2