Optimize Preop | Minimize Blood Loss | Transfuse Appropriately
- Preoperative anemia (Hb less than 130 g/L men, less than 120 g/L women) increases transfusion risk 3-4 fold
- Tranexamic acid (TXA) 15-20 mg/kg IV reduces transfusion by 30-50% without increasing VTE
- Restrictive transfusion threshold (Hb less than 70 g/L) is safe and reduces complications vs liberal (less than 100 g/L)
- Cell salvage contraindicated in malignancy, infection, bowel contamination
- Massive transfusion protocol: 1:1:1 ratio RBC:FFP:Platelets to prevent dilutional coagulopathy
- “CRASH-2 trial: TXA within 3h of trauma reduces mortality (not just blood loss)
- “Iron therapy takes 4-6 weeks - plan elective surgery timing accordingly
- “Jehovah's Witness patients: multi-modal approach (EPO, TXA, cell salvage, accept lower Hb)
- “Hypotensive anesthesia (MAP 50-60 mmHg) reduces blood loss but requires experienced anesthetist
Screen ALL elective patients. Hb less than 130 g/L (men) or less than 120 g/L (women) = anemia. Treat with oral iron 4-6 weeks preop or IV iron if time limited. EPO if renal failure or severe anemia.
Give TXA to ALL major ortho cases unless contraindicated. Loading dose 15-20 mg/kg IV at induction, maintenance 1-2 mg/kg/h. CRASH-2 showed mortality benefit in trauma.
Transfuse at Hb less than 70 g/L (asymptomatic stable patients). Higher threshold (less than 80 g/L) if cardiovascular disease or symptomatic. Liberal transfusion increases complications.
Multi-modal approach: EPO preop, TXA, cell salvage (if acceptable), meticulous hemostasis, hypotensive anesthesia, accept Hb 60-70 g/L. Document consent clearly.
- Timing
- 4-6 weeks preop
- Evidence/Effect
- Increases Hb by 10-20 g/L
- Key Considerations
- Need time - not effective if less than 2 weeks
- Timing
- 1-2 weeks preop
- Evidence/Effect
- Rapid Hb increase 10-30 g/L
- Key Considerations
- More expensive, use if time limited
- Timing
- 3-4 weeks preop
- Evidence/Effect
- Increases Hb 20-40 g/L with iron
- Key Considerations
- Expensive, renal failure or severe anemia
- Timing
- At induction and intraop
- Evidence/Effect
- 30-50% reduction in transfusion
- Key Considerations
- Safe, no VTE increase, give to all major cases
- Timing
- Intraoperative
- Evidence/Effect
- Reduces allogeneic transfusion 30-40%
- Key Considerations
- Contraindicated: malignancy, infection, bowel
- Timing
- Intraoperative
- Evidence/Effect
- Reduces blood loss 20-30%
- Key Considerations
- MAP 50-60 mmHg, requires experienced anesthetist
CRASHTranexamic Acid Indications
Hook:Think of CRASH-2 trial - TXA saves lives in trauma and reduces transfusion in elective ortho!
MIBCell Salvage Contraindications
Hook:MIB are absolute contraindications - Malignancy, Infection, Bowel contamination - do NOT salvage!
Overview and Clinical Significance
The Patient Blood Management (PBM) approach has replaced the old "type and cross" reactive model. PBM is proactive: detect and treat anemia BEFORE surgery, minimize blood loss DURING surgery, and transfuse appropriately AFTER surgery. This reduces transfusion rates by 30-50% and improves outcomes.
- Preoperative anemia present in 30-40% elective ortho patients
- Anemia increases transfusion risk 3-4 fold
- Allogeneic transfusion increases infection, LOS, mortality
- Blood is scarce resource - donor shortages worldwide
- Cost - 1 unit RBC typically costs the equivalent of $500-1000 (USD) including administration
- Optimize hematopoiesis - detect and treat preop anemia
- Minimize blood loss - surgical technique, TXA, cell salvage
- Harness physiologic reserve - restrictive transfusion thresholds
WHO-endorsed approach used across international PBM programmes
Allogeneic blood transfusion is NOT benign. Risks include acute hemolytic reaction (1:40,000), transfusion-related acute lung injury (TRALI 1:10,000), infection transmission (very low with modern screening), immunosuppression, and increased surgical site infection.
Pathophysiology
Physiology of Hemostasis
Coagulation Cascade:
- Intrinsic pathway: Contact activation (XII → XI → IX → VIII → X)
- Extrinsic pathway: Tissue factor exposure (VII → X) - primary initiator in surgical bleeding
- Common pathway: X → V → thrombin → fibrinogen → fibrin clot
- Fibrinolysis: Plasminogen → plasmin → fibrin degradation (target of TXA)
Physiological Response to Blood Loss:
- Hemodynamic Changes
- Minimal
- Symptoms
- None - compensated
- Hemodynamic Changes
- Tachycardia, narrow pulse pressure
- Symptoms
- Anxiety, delayed capillary refill
- Hemodynamic Changes
- Tachycardia, hypotension, tachypnea
- Symptoms
- Confusion, decreased urine output
- Hemodynamic Changes
- Severe hypotension, absent pulses
- Symptoms
- Lethargy, anuria, impending death
Oxygen Delivery Physiology
DO₂ = CO × CaO₂ = CO × (1.34 × Hb × SaO₂ + 0.003 × PaO₂)
- Hemoglobin is the primary oxygen carrier (1.34 mL O₂/g Hb)
- Normal DO₂: 900-1100 mL/min; VO₂: 200-250 mL/min
- Critical DO₂: ~300 mL/min - below this, anaerobic metabolism ensues
- Compensatory mechanisms: increased cardiac output, oxygen extraction ratio
- Young healthy patients tolerate Hb 70 g/L due to compensation; elderly/cardiac patients less so
Impact of Anemia on Surgical Outcomes
- Increased 30-day mortality (OR 1.4-2.9 depending on severity)
- Increased postoperative complications (infections, AKI, cardiac events)
- Increased length of stay and readmission rates
- Often triggers transfusion, which compounds risks
- Hypothermia impairs enzyme function in coagulation cascade
- Acidosis reduces clotting factor activity (pH 7.2 = 50% activity)
- Hemodilution from crystalloid/colloid resuscitation
- Consumption coagulopathy in massive hemorrhage
- Lethal triad: Hypothermia + acidosis + coagulopathy
Differential Diagnosis
When a surgical patient is anaemic preoperatively or bleeding unexpectedly, the cause must be characterised before it can be treated. The two key differentials are the type of anaemia (which directs optimisation) and the cause of intraoperative coagulopathy (which directs product choice).
- Clue (indices/labs)
- Low ferritin, low transferrin saturation
- Typical Causes
- Iron deficiency, thalassaemia trait
- Key Action
- Treat iron deficiency; check ferritin to exclude thalassaemia
- Clue (indices/labs)
- Normal/high ferritin, raised CRP
- Typical Causes
- Anaemia of chronic disease/inflammation, renal impairment, acute blood loss
- Key Action
- Treat underlying disease; consider IV iron plus ESA if renal
- Clue (indices/labs)
- Low B12/folate, abnormal LFTs
- Typical Causes
- B12/folate deficiency, alcohol, hypothyroidism, myelodysplasia
- Key Action
- Replace B12/folate; investigate marrow if unexplained
- Clue (indices/labs)
- Raised LDH/bilirubin, low haptoglobin, positive DAT
- Typical Causes
- Autoimmune, hereditary spherocytosis, drug-induced
- Key Action
- Haematology referral; caution with transfusion crossmatch
- Distinguishing Feature
- Discrete bleeding point; normal coagulation
- Targeted Treatment
- Direct haemostasis - the primary remedy
- Distinguishing Feature
- Diffuse ooze after large-volume resuscitation
- Targeted Treatment
- Balanced FFP/platelets (1:1:1), limit crystalloid
- Distinguishing Feature
- Clot lysis on viscoelastic testing (ROTEM/TEG)
- Targeted Treatment
- Tranexamic acid
- Distinguishing Feature
- Fibrinogen less than 1.5 g/L
- Targeted Treatment
- Cryoprecipitate or fibrinogen concentrate
- Distinguishing Feature
- Drug history; raised INR/aPTT/anti-Xa
- Targeted Treatment
- Reverse: PCC/vitamin K (warfarin), specific agents for DOACs
- Distinguishing Feature
- Core temp less than 35C, pH less than 7.2 with ooze
- Targeted Treatment
- Active warming, correct acidosis, restore perfusion
Pillar 1: Preoperative Optimization
Preoperative Anemia Screening
WHO Definition of Anemia:
- Men: Hb less than 130 g/L
- Women: Hb less than 120 g/L
- Pregnancy: Hb less than 110 g/L
International PBM guidelines (WHO-endorsed, and bodies such as the NHMRC/NBA, NICE and AABB) recommend screening hemoglobin and ferritin for ALL patients undergoing elective surgery with expected moderate-high blood loss (greater than 500 mL). This includes most major orthopaedic procedures.
- Interpretation
- Anemia present
- Action
- Investigate cause, treat 4-6 weeks preop
- Interpretation
- Iron deficiency anemia
- Action
- Oral iron 200 mg elemental iron daily
- Interpretation
- Functional iron deficiency
- Action
- Consider IV iron if time limited
- Interpretation
- Microcytic anemia
- Action
- Iron deficiency vs thalassemia - check ferritin
- Interpretation
- Macrocytic anemia
- Action
- B12/folate deficiency - supplement
Most common causes in elective ortho patients: (1) iron deficiency (chronic blood loss, poor intake), (2) anemia of chronic disease (inflammatory arthritis), (3) renal impairment (hip OA patients often elderly with CKD). Check FBC, ferritin, CRP, creatinine as minimum.
This completes the screening protocol overview.
Managing the patient's own antiplatelets and anticoagulants is the complementary half of blood management - stopping nothing risks bleeding, but stopping the wrong agent risks fatal thrombosis.
- Aspirin: the bleeding-risk increase is modest for most major surgery and it is increasingly continued, especially for secondary cardiovascular prevention - individualise (often continued through hip fracture/arthroplasty).
- P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor): stop before elective surgery - clopidogrel and ticagrelor about 5 days, prasugrel about 7 days. The overriding rule is the coronary stent: do NOT interrupt dual antiplatelet therapy within the mandatory window - defer elective surgery (bare-metal stent at least about 6 weeks, drug-eluting stent ideally about 6 months) and discuss with cardiology, because premature DAPT cessation causes catastrophic stent thrombosis.
- Warfarin: stop about 5 days pre-op and check INR (target under about 1.5 for major surgery); bridge with therapeutic LMWH only for high thrombotic risk (mechanical mitral valve, VTE within 3 months, AF with prior stroke) - routine bridging increases bleeding without benefit (BRIDGE trial). Urgent reversal is vitamin K plus four-factor PCC.
- DOACs (apixaban, rivaroxaban, dabigatran): stop by drug, bleeding risk and renal function - typically 24-48 hours for high-bleeding-risk surgery, longer for dabigatran with renal impairment; no routine bridging. Reversal: idarucizumab for dabigatran, andexanet alfa for factor Xa inhibitors, with PCC as an alternative.
Restart antithrombotics once haemostasis is secure, balancing rebleed against thrombosis. Exam point: never stop dual antiplatelet therapy within the post-stent window, bridge warfarin only for high thrombotic risk, and base DOAC stop-timing on renal function.
Pillar 2: Minimize Intraoperative Blood Loss
Tranexamic Acid (TXA) - Evidence and Protocols
TXA is a lysine analogue that competitively inhibits plasminogen activation, preventing fibrinolysis. It stabilizes formed clot by blocking plasmin from degrading fibrin. Effect lasts 3-4 hours. Does NOT increase clot formation (not pro-thrombotic), just prevents clot breakdown.
TXA Dosing Regimens:
- Loading Dose
- 15-20 mg/kg IV
- Maintenance
- Optional 1-2 mg/kg/h infusion
- Timing
- At induction before tourniquet
- Loading Dose
- 20 mg/kg IV
- Maintenance
- 2 mg/kg/h for 3-6 hours
- Timing
- At induction, continue postop
- Loading Dose
- 10-15 mg/kg IV
- Maintenance
- 1 mg/kg/h for duration
- Timing
- At incision, throughout case
- Loading Dose
- 1 g IV bolus
- Maintenance
- 1 g IV over 8 hours
- Timing
- Within 3 hours of injury (critical)
- Loading Dose
- 1-3 g in 50-100 mL saline
- Maintenance
- Leave in joint 5 min before closure
- Timing
- At closure before drain placement
The CRASH-2 trial (20,211 trauma patients) showed TXA within 3 hours of injury reduced all-cause mortality from 16% to 14.5% (NNT=67). Given between 3-8 hours, NO benefit. After 8 hours, HARM (increased mortality). Time is critical in trauma.
TXA Contraindications:
- Active thromboembolic disease (DVT, PE, MI, stroke less than 3 months)
- History of seizures (TXA crosses BBB, rare seizure risk at high doses)
- Known allergy to TXA
- Renal impairment (reduce dose if CrCl less than 30 - risk of accumulation)
Multiple meta-analyses (over 100 RCTs) show TXA does NOT increase VTE, MI, or stroke rates in orthopaedic surgery. It is safe and effective. The theoretical thrombosis risk is not seen in practice. Give TXA to ALL major ortho cases unless contraindicated.
This completes the tranexamic acid section.
Distinct from both PABD and cell salvage, acute normovolaemic haemodilution (ANH) is a classic examinable blood-conservation technique this topic should include.
- Technique: immediately after induction, 1-3 units of the patient's own whole blood are withdrawn into citrate (CPD) collection bags while the volume is simultaneously replaced with crystalloid (about 3:1) or colloid (about 1:1) to keep the patient normovolaemic. The patient then bleeds dilute (lower-haematocrit) blood during the high-loss part of the operation, and the collected fresh whole blood is reinfused at the end (last unit out, first back in).
- Advantage over cell salvage: the reinfused product is fresh autologous whole blood containing functional platelets and clotting factors (cell salvage returns washed RBCs only); it is also low-cost, avoids storage, and is acceptable to many Jehovah's Witnesses if a continuous circuit is maintained.
- Indications: anticipated large blood loss with an adequate starting haemoglobin; rare blood types or multiple antibodies.
- Contraindications: pre-existing anaemia, significant coronary/cardiac disease (cannot tolerate the dilutional anaemia), severe pulmonary disease, coagulopathy, or inability to maintain normovolaemia.
Evidence for transfusion reduction is modest and ANH is used less than TXA and cell salvage, but exam point: ANH needs a good starting Hb and a heart that tolerates dilutional anaemia, and uniquely returns fresh whole blood with platelets and factors.
Pillar 3: Appropriate Transfusion Management
Restrictive vs Liberal Transfusion Thresholds
The TRICC trial (1999) and multiple subsequent trials showed restrictive transfusion (Hb less than 70 g/L) is as safe as liberal (Hb less than 100 g/L) and reduces transfusion-related complications. This changed practice worldwide. Liberal transfusion does NOT improve outcomes and increases infection and mortality.
- Transfusion Threshold
- Hb less than 70 g/L
- Evidence
- TRICC, FOCUS trials - safe, reduces transfusion
- Transfusion Threshold
- Hb less than 80 g/L
- Evidence
- Subset analysis suggests higher threshold safer
- Transfusion Threshold
- Hb less than 80 g/L or symptoms
- Evidence
- MINT trial - restrictive non-inferior
- Transfusion Threshold
- Symptoms (dyspnea, tachycardia, angina)
- Evidence
- Transfuse for symptoms regardless of Hb
- Transfusion Threshold
- Transfuse to maintain Hb greater than 70-80 g/L
- Evidence
- Replace ongoing losses
Transfusion triggers are GUIDELINES, not absolutes. Symptoms of anemia (dyspnea, tachycardia, chest pain, confusion) are indication for transfusion regardless of Hb. Patient with Hb 75 g/L who is asymptomatic does NOT need transfusion. Patient with Hb 85 g/L with angina DOES need transfusion.
Signs/Symptoms Suggesting Need for Transfusion:
- Tachycardia (HR greater than 100 at rest) not explained by pain/anxiety
- Dyspnea or increased work of breathing
- Chest pain or ECG changes (ischemia)
- Postural hypotension or dizziness
- Confusion or altered mental state
- Oliguria (less than 0.5 mL/kg/h)
This completes the transfusion threshold section.
OPTPatient Blood Management Pillars
Hook:OPT for optimal blood management - optimize preop, protect intraop, transfuse appropriately!
RATIOMassive Transfusion Protocol Components
Hook:Remember RATIO 1:1:1 for massive transfusion - RBC:FFP:Platelets in equal amounts!
Jehovah's Witness Patient Management
Jehovah's Witness patients refuse allogeneic blood transfusion (RBC, FFP, platelets) based on religious beliefs. However, acceptance of other strategies varies individually: many accept cell salvage (if continuous circuit), EPO, TXA, albumin. Must discuss and document individual preferences preoperatively. Do NOT assume all refuse all products.
- Erythropoietin (EPO) preoperatively
- Tranexamic acid (TXA)
- Cell salvage (if continuous circuit)
- Crystalloid and colloid (albumin often accepted)
- Hypotensive anesthesia
- Iron supplementation (oral or IV)
- Accepting lower Hb (60-70 g/L) postoperatively
- Allogeneic RBC transfusion
- Fresh frozen plasma (FFP)
- Platelet transfusion
- Cryoprecipitate
- Whole blood
- Some refuse cell salvage if circuit is not continuous
- Some refuse albumin or factor concentrates
Multi-Modal Blood Management Strategy:
Preoperative optimization - screen Hb, start EPO 40,000 units weekly x 4 + IV iron 1000 mg. Goal: Hb greater than 140 g/L preop.
Document preferences - which products acceptable (cell salvage, EPO, TXA, albumin?). Document in chart and consent. Discuss acceptable minimum Hb (usually 60-70 g/L).
Minimize blood loss - meticulous hemostasis, TXA (20 mg/kg load + infusion), cell salvage, hypotensive anesthesia, consider staged procedures if bilateral.
Accept lower Hb - most Jehovah's Witness patients tolerate Hb 60-70 g/L. Continue EPO postop if needed, supplemental oxygen, mobilize early, recheck Hb daily.
Obtain informed consent documenting patient refuses transfusion even if life-threatening. Have patient sign specific Jehovah's Witness refusal form. Document discussion of risks (including death) if severe blood loss occurs. Consider having witness to consent. Respect patient autonomy.
If Jehovah's Witness patient presents for high blood loss procedure (revision THA, spine tumor resection) with preop Hb less than 100 g/L and refuses transfusion, consider: (1) delay surgery to optimize with EPO + iron (if elective), (2) frank discussion of mortality risk, (3) may need to refuse surgery if risk unacceptable. Document decision-making thoroughly.
Guidelines, Registries and Global Practice
Across the major guideline bodies the message is remarkably consistent: screen and treat preoperative anaemia, give tranexamic acid, use cell salvage for high-loss cases, and transfuse restrictively (single-unit, Hb-triggered). Patient Blood Management (PBM) is endorsed by the WHO as a global standard of care. The principal differences between countries lie in funding/reimbursement of IV iron and erythropoiesis-stimulating agents, not in the core clinical recommendations.
Global Epidemiology
- Present in approximately 30% of major non-cardiac surgical patients worldwide (227,425-patient NSQIP cohort)
- Independently raises 30-day mortality (adjusted OR 1.42) and morbidity (OR 1.35)
- In elective hip and knee arthroplasty, reported prevalence ranges roughly 15-40%, driven by iron deficiency and anaemia of inflammation
- Anaemia is the strongest modifiable predictor of perioperative allogeneic transfusion
- Allogeneic red cells are a finite, donor-dependent resource with periodic shortages in most health systems
- O-negative (universal donor) is chronically scarce - only about 7-9% of most populations
- PBM programmes reduce red-cell utilisation by 20-40% without harm
- Low- and middle-income countries face the greatest supply constraints, magnifying the value of TXA and cell salvage
Side-by-Side Guideline Comparison
- Anaemia / Iron
- Endorses PBM; treat anaemia preop
- Tranexamic Acid
- Supports antifibrinolytics
- Transfusion Threshold
- Restrictive, evidence-based triggers
- Anaemia / Iron
- Screen and treat all elective major surgery
- Tranexamic Acid
- Recommended (cell salvage too)
- Transfusion Threshold
- Restrictive; transfuse for Hb less than 70 g/L or symptoms
- Anaemia / Iron
- Offer iron before/after surgery if iron-deficient
- Tranexamic Acid
- Offer TXA for expected major blood loss
- Transfusion Threshold
- Threshold Hb 70 g/L (80 g/L if ACS); single-unit
- Anaemia / Iron
- PBM and anaemia management endorsed
- Tranexamic Acid
- Supported in surgery
- Transfusion Threshold
- Restrictive 70 g/L (75 g/L cardiac surgery)
- Anaemia / Iron
- Detect and treat iron-deficiency anaemia
- Tranexamic Acid
- Strongly recommended
- Transfusion Threshold
- Restrictive; individualise in cardiac disease
- Anaemia / Iron
- Preop optimisation pathway for arthroplasty
- Tranexamic Acid
- Routine in THA/TKA unless contraindicated
- Transfusion Threshold
- Restrictive, symptom-guided
The recommendations for TXA (Level I, multiple meta-analyses and CRASH-2) and restrictive transfusion (Level I, TRICC/FOCUS and the Cochrane transfusion-threshold review) are among the most robust in perioperative medicine. Preoperative anaemia treatment rests largely on high-quality observational data (Musallam) plus RCTs of IV iron with more variable transfusion-outcome effects, hence guideline wording is often "offer/consider" rather than "must".
Registry and Programme-Level Evidence
- National and statewide PBM programmes have reported large reductions in red-cell, plasma and platelet use alongside reduced length of stay and in-hospital mortality - the strongest real-world endorsement of PBM.
- Arthroplasty registries (AOANJRR, NJR, AJRR) do not collect transfusion as a core variable but track the revision and infection outcomes that transfusion-associated immunomodulation can influence, reinforcing the rationale for blood conservation.
Practice Variation
- IV iron and ESA funding differ markedly: many systems restrict erythropoiesis-stimulating agents to chronic kidney disease and chemotherapy, leaving elective-surgery use hospital- or patient-funded.
- Topical versus intravenous TXA preference varies by unit; both are effective, with combined regimens used in some high-loss cases.
- Cell salvage availability is resource-dependent and concentrated in higher-volume centres.
Most national blood services rely on voluntary, non-remunerated donors and issue periodic shortage alerts. This finite supply - not just patient outcomes - is a core driver of Patient Blood Management: conserve product, transfuse appropriately, and minimise waste.
MCQ Practice Points
Q: What is the evidence-based transfusion threshold for hemodynamically stable patients following major orthopaedic surgery?
A: Hb 70 g/L (7 g/dL) for most patients. The FOCUS, TRACS, and TRICC trials demonstrated no benefit of liberal (100 g/L) over restrictive (70-80 g/L) transfusion thresholds. Exceptions requiring higher thresholds (80-100 g/L): acute coronary syndrome, symptomatic anaemia, ongoing significant bleeding. Single unit transfusion is appropriate unless ongoing hemorrhage.
Q: What dose of tranexamic acid (TXA) is recommended for total joint arthroplasty and what is its mechanism?
A: 1-2g IV given preoperatively (10-15mg/kg), with optional repeat dose at wound closure. TXA is an antifibrinolytic that competitively inhibits plasminogen activation, preventing clot breakdown. Reduces blood loss by 30-50% and transfusion risk by 50%. Contraindicated in active thromboembolic disease. NOT contraindicated in patients with DVT/PE history with adequate thromboprophylaxis.
Q: What are the key elements of a Patient Blood Management (PBM) program in orthopaedic surgery?
A: Three pillars: (1) Optimize red cell mass preoperatively - treat iron deficiency (IV iron if Hb under 130), EPO in selected cases. (2) Minimize blood loss - surgical technique, TXA, controlled hypotension, cell salvage. (3) Optimize physiological tolerance - restrictive transfusion thresholds, multimodal analgesia, early mobilization. Major bodies including the WHO and the National Blood Authority publish specific PBM guidelines for surgery.
Q: When is intraoperative cell salvage indicated in orthopaedic surgery?
A: Expected blood loss greater than 1000-1500mL (or anticipated need for greater than 2 units allogeneic blood). Common indications: revision arthroplasty, major spine surgery, pelvic/acetabular trauma, bilateral TKA. Cell salvage reinfuses the patient's own washed red cells. Contraindicated in malignancy (relative) and infection (absolute). Processing removes activated clotting factors.
Q: What is the recommended management of anticoagulation in a patient on warfarin requiring urgent hip fracture surgery?
A: Reverse with IV Vitamin K 5-10mg + Prothrombin Complex Concentrate (PCC, 25-50 IU/kg) for INR greater than 1.5. Surgery can proceed once INR under 1.5. Fresh frozen plasma (FFP) is second-line if PCC unavailable. Do NOT delay surgery more than 48 hours waiting for INR to normalize with vitamin K alone. Bridging with LMWH is NOT recommended for most hip fracture patients.
Exam Viva Scenarios
Practise clinical reasoning and management decisions out loud
“A 72-year-old woman is listed for elective TKA in 6 weeks. Preoperative Hb is 105 g/L, ferritin 18 mcg/L, CrCl 55 mL/min. How would you manage her preoperatively?”
“You are performing revision THA for aseptic loosening. During acetabular component removal, the patient develops massive hemorrhage from pelvic vessels. BP drops to 70/40, HR 130. Anesthetist estimates 2L blood loss in 10 minutes. How do you manage this?”
“A 68-year-old Jehovah's Witness patient presents for bilateral TKA. Preoperative Hb is 118 g/L. She refuses all blood products. How would you counsel and manage this patient?”
Three Pillars of Patient Blood Management
- **Pillar 1: Optimize** - Detect and treat preop anemia (iron, EPO)
- **Pillar 2: Minimize** - Reduce intraop blood loss (TXA, cell salvage, technique)
- **Pillar 3: Manage** - Appropriate transfusion (restrictive threshold Hb less than 70 g/L)
Preoperative Anemia Management
- **Screen:** Hb less than 130 g/L (men), less than 120 g/L (women) = anemia. Check ferritin, CRP, creatinine
- **Oral iron:** 200 mg elemental iron daily x 4-6 weeks (increases Hb 10-20 g/L)
- **IV iron:** Ferric carboxymaltose 1000 mg single dose (increases Hb 10-30 g/L in 1-2 weeks) - use if time limited
- **EPO:** 40,000 units SC weekly x 3-4 weeks + iron (increases Hb 20-40 g/L) - CKD, severe anemia, Jehovah's Witness
- **Recheck Hb** 1 week preop to confirm response
Tranexamic Acid (TXA)
- **Mechanism:** Inhibits plasminogen activation, prevents fibrinolysis, stabilizes clot
- **Dosing:** 15-20 mg/kg IV load at induction, optional 1-2 mg/kg/h maintenance
- **Evidence:** 30-50% reduction in transfusion, NO increase in VTE/MI/stroke
- **CRASH-2:** 1g bolus + 1g over 8h in trauma - reduces mortality if given within 3h
- **Use:** All major ortho cases (THA, TKA, spine, trauma) unless contraindicated
Cell Salvage
- **Indications:** Expected blood loss greater than 500-1000 mL (revision THA/TKA, spine, pelvis)
- **Mechanism:** Collects shed blood, washes RBCs, reinfuses autologous Hct 50-60%
- **Contraindications (MIB):** Malignancy, Infection, Bowel contamination (all absolute)
- **Effect:** 30-40% reduction in allogeneic transfusion
- **Jehovah's Witness:** Many accept if continuous circuit
Transfusion Thresholds
- **Restrictive:** Hb less than 70 g/L (asymptomatic stable patients) - SAFE and reduces complications
- **Liberal:** Hb less than 100 g/L (old practice) - NO benefit, increases complications
- **Cardiovascular disease:** Threshold Hb less than 80 g/L (slightly higher)
- **Symptomatic anemia:** Transfuse for symptoms (dyspnea, tachycardia, angina) regardless of Hb
- **Evidence:** TRICC, FOCUS trials - restrictive is as safe as liberal with less transfusions
Massive Transfusion Protocol
- **Definition:** Loss of 1 blood volume in 24h OR greater than 4 units in 1h
- **1:1:1 ratio:** RBC:FFP:Platelets in equal amounts - prevents dilutional coagulopathy
- **TXA:** 1g IV bolus, then 1g over 8h (CRASH-2 protocol - within 3h of injury)
- **Lethal triad:** Hypothermia, Acidosis, Coagulopathy - monitor and correct
- **Lab monitoring:** Hb, INR, fibrinogen, platelets every 30-60 min
Jehovah's Witness Management
- **Discuss:** Individual beliefs vary - many accept EPO, TXA, cell salvage (continuous circuit)
- **Document:** Signed refusal form, documented risks including death, witness to consent
- **Optimize:** EPO 40,000 units weekly x 4 + IV iron 1000 mg. Goal Hb greater than 130 g/L preop
- **Minimize:** TXA, cell salvage, meticulous hemostasis, hypotensive anesthesia, consider staging bilateral procedures
- **Accept:** Lower Hb postop (60-70 g/L). Supplemental O2, early mobilization
Key Trials and Evidence
- **CRASH-2 (2010):** TXA in trauma reduces mortality (16.0% to 14.5%) if given within 3h. After 8h, harmful.
- **TRICC (1999):** Restrictive (Hb less than 70) vs liberal (less than 100) - restrictive safe, reduces transfusions
- **FOCUS (2011):** Hip fracture patients - restrictive (Hb less than 80) safe even in elderly with comorbidities
- **Cochrane TXA (2015):** 60 RCTs ortho - TXA reduces transfusion 30-50%, NO VTE increase
- **NBA/NHMRC PBM Guidelines (2012):** a foundational, evidence-graded PBM standard - optimize, minimize, manage transfusion appropriately
Key Evidence and Trials
CRASH-2 Trial (2010)
- All-cause mortality 16.0% to 14.5% (RR 0.91, p=0.0035)
- Greatest benefit when given within 3 hours of injury
- No excess myocardial infarction, stroke or thromboembolism
- Dosing: 1 g bolus then 1 g over 8 hours
TRICC Trial (1999)
- Restrictive threshold 70 g/L vs liberal 100 g/L
- 30-day mortality 18.7% vs 23.3% (not significant)
- Restrictive at least as effective and possibly superior
- Possible exception: acute MI / unstable angina
FOCUS Trial (2011)
- Largest transfusion RCT in orthopaedic (hip-fracture) patients
- Restrictive threshold approx 80 g/L (or symptoms)
- No difference in death or independent walking at 60 days
- Restrictive strategy safe even in high cardiovascular-risk elderly
Preoperative Anaemia and Surgical Outcomes (2011)
- Preoperative anaemia present in ~30% of surgical patients
- 30-day mortality OR 1.42 (1.31-1.54) after adjustment
- Even mild anaemia is independently harmful
- Justifies routine preoperative anaemia screening
IV TXA Safety in Major Orthopaedic Surgery (2018)
- 73 RCTs in major orthopaedic surgery
- VTE 2.1% (TXA) vs 2.0% (control) - not significant (RR 1.067)
- Confirms TXA reduces blood loss and transfusion safely
- Supports routine intravenous TXA in arthroplasty
National Blood Authority Patient Blood Management Guidelines (Module 2: Perioperative)
- Three pillars: optimise red-cell mass, minimise blood loss, manage anaemia/tolerance
- Routine preoperative anaemia screening and treatment
- TXA and cell salvage recommended
- Restrictive transfusion thresholds endorsed