Blood & Lymphoreticular

Massive transfusion protocol: ratios and complications

Clinical Overview and When to Suspect Massive Hemorrhage

— ≥10 units PRBC in 24 hours (classic definition)

— ≥4 units PRBC in 1 hour with ongoing bleeding

— Replacement of total blood volume (~70 mL/kg) within 24 hours

— Loss of >50% blood volume within 3 hours

— Penetrating torso trauma with hypotension

— Blunt trauma with positive FAST and SBP <90

— Postpartum hemorrhage with ongoing bleeding after uterotonics

— Massive GI bleed (variceal) with hemodynamic collapse

— Ruptured AAA, ectopic pregnancy, aortic dissection with tamponade

— ABC score (Assessment of Blood Consumption): penetrating mechanism, SBP ≤90, HR ≥120, positive FAST — ≥2 points predicts massive transfusion (sensitivity ~75%, specificity ~86%)

— Shock Index (HR/SBP) >1.0 in trauma suggests significant hemorrhage

— Hemorrhagic shock triggers the "lethal triad": hypothermia, acidosis, and coagulopathy — each potentiates the others

— Trauma-induced coagulopathy (TIC) develops within minutes via activated protein C, hyperfibrinolysis, and endothelial glycocalyx shedding — present before iatrogenic dilution

— Crystalloid-heavy resuscitation worsens dilutional coagulopathy, endothelial damage, and abdominal compartment syndrome

Board pearl: MTP activation should be a clinical decision based on mechanism, vitals, and trajectory — do not wait for the hemoglobin to drop, because acute hemorrhage produces an isovolemic loss and Hgb lags 4–6 hours behind true blood loss.

Massive transfusion protocol (MTP) is a pre-defined, institution-wide pathway delivering balanced blood products in fixed ratios for life-threatening hemorrhage, bypassing usual type-and-crossmatch delays.

Operational definitions of "massive transfusion" — any of the following triggers MTP activation:

When to suspect need for MTP at the bedside:

Predictive scores to trigger early activation:

Pathophysiology rationale for MTP:

Presentation Patterns and Key History

— Mechanism: high-speed MVC, fall >20 ft, penetrating wound to chest/abdomen/groin, crush injury

— Time since injury — "golden hour" framing; mortality climbs steeply after 60 minutes of uncontrolled hemorrhage

— Prehospital tourniquet, prehospital blood products, prehospital TXA already administered

— Anticoagulant/antiplatelet use: warfarin, DOACs (apixaban, rivaroxaban, dabigatran), clopidogrel, ticagrelor, aspirin — drastically alter reversal needs

— Postpartum hemorrhage >1000 mL or with hemodynamic instability

— Placenta accreta spectrum (prior C-section + placenta previa is the classic stem)

— Uterine atony, retained products, lacerations, uterine inversion

— Amniotic fluid embolism — DIC dominates the picture

— Class I (<15% loss): minimal tachycardia

— Class II (15–30%): tachycardia, narrowed pulse pressure, anxiety

— Class III (30–40%): hypotension, confusion, decreased urine output — transfusion required

— Class IV (>40%): obtunded, no urine, impending arrest — MTP territory

Key distinction: Young, healthy patients (especially pregnant women and athletes) compensate well until they crash — relying on hypotension as a trigger leads to delayed activation. Use the shock index and mechanism in these populations.

Step 3 management: Always ask about anticoagulant timing and last dose — this changes whether you add 4-factor PCC, idarucizumab, andexanet alfa, vitamin K, or platelets to your resuscitation bundle.

Trauma presentations dominate MTP literature; key history elements drive activation speed:

Obstetric hemorrhage — the leading non-trauma MTP scenario:

GI hemorrhage — variceal bleed in cirrhosis, aortoenteric fistula (prior aortic graft + GI bleed = pathognomonic stem), Dieulafoy lesion

Vascular catastrophes — ruptured AAA (classic triad: hypotension, back pain, pulsatile mass), aortic dissection rupturing into pericardium or pleura, ruptured ectopic pregnancy

Symptom progression of hemorrhagic shock (ATLS classes):

Physical Exam and Hemodynamic Assessment

— Airway: ensure patency; intubate early if shock is profound, but anticipate post-intubation hypotension — induction agents (propofol, even etomidate) blunt sympathetic tone

— Breathing: bilateral breath sounds, chest rise; tension pneumothorax and massive hemothorax must be excluded

— Circulation: pulse quality (radial = SBP ~80, femoral ~70, carotid ~60), capillary refill, skin color/temperature, two large-bore (16–18 g) peripheral IVs or intraosseous access

— Disability: GCS, pupils — altered mentation from shock vs head injury

— Exposure: log-roll, identify all wounds, prevent hypothermia with warmed blankets and fluid warmers

— External (scalp lacerations bleed massively)

— Chest (massive hemothorax — initial output >1500 mL or >200 mL/hr × 4 hr = thoracotomy)

— Abdomen (FAST, DPL)

— Pelvis (unstable pelvic ring → retroperitoneal hemorrhage)

— Long bones (femur fracture ~1.5 L blood loss each)

— Persistent tachycardia despite 2 L crystalloid or 2 U PRBC = transient or non-responder → MTP

— Narrow pulse pressure (early), then frank hypotension (late)

— Cool, mottled extremities; delayed cap refill >3 sec

— Lactate >4 mmol/L or base deficit worse than −6 = significant hypoperfusion

Board pearl: Permissive hypotension (SBP target ~80–90, MAP ~65) is the resuscitation target in penetrating trauma without TBI until surgical hemostasis — pushing pressure higher pops the clot. TBI requires SBP ≥110 to maintain cerebral perfusion — these goals conflict and TBI wins.

Primary survey (ABCDE) drives the first 60 seconds:

Sources of hemorrhage — "blood on the floor and four more":

Hemodynamic markers of ongoing hemorrhage:

Pelvic exam: mechanical instability on lateral compression — do not repeatedly spring the pelvis (dislodges clot); apply binder over greater trochanters

Diagnostic Workup — Initial Labs and Bedside Studies

— Type and crossmatch (release type O immediately — O-negative for women of childbearing age, O-positive acceptable for males and post-menopausal females to preserve O-neg stock)

— CBC — baseline Hgb/Hct lag, but trending matters

— PT/INR, aPTT, fibrinogen — fibrinogen <150–200 mg/dL in trauma or <200 in obstetric hemorrhage predicts mortality and triggers cryoprecipitate

— Comprehensive metabolic panel — baseline K+, Ca²⁺, Cr

— Arterial or venous blood gas with lactate and base deficit — best early markers of shock severity

— Ionized calcium — citrate in transfused products chelates Ca²⁺ causing hypocalcemia

— β-hCG in any woman of reproductive age

— Ethanol, tox screen in trauma

— Troponin if chest trauma or elderly

— Reaction time (R) prolonged → give FFP

— K time / α-angle abnormal → give cryoprecipitate (fibrinogen)

— Maximum amplitude (MA) low → give platelets

— LY30 >3% (TEG) or ML >15% (ROTEM) → hyperfibrinolysis → give TXA

— FAST (focused assessment with sonography for trauma) — 4 views: pericardial, RUQ (Morison's pouch), LUQ (splenorenal), pelvic (pouch of Douglas/rectovesical). Positive + hypotension → OR

— Extended FAST (eFAST) adds bilateral pleural views for pneumo/hemothorax

— Portable chest X-ray, pelvic X-ray (the "trauma series")

— Pelvic binder placement guided by AP pelvis

Step 3 management: In a hemodynamically unstable trauma patient with positive FAST, the next step is operative exploration, not CT scan — "the CT scanner is the tunnel of death" for unstable patients.

Send simultaneously with MTP activation (do not delay product release):

Viscoelastic testing (TEG/ROTEM) — increasingly standard at level 1 centers:

Bedside imaging:

Diagnostic Workup — Advanced and Confirmatory Studies

— Identifies solid organ injury (AAST grading of spleen, liver, kidney)

— Contrast extravasation ("blush") on arterial phase → angioembolization candidate

— Retroperitoneal hematoma, pelvic vascular injury

— Active aortic injury, traumatic pseudoaneurysm

— Pelvic arterial bleeding (superior gluteal, internal pudendal branches)

— Splenic salvage (grade III–IV blunt splenic injury with blush)

— Hepatic injury with persistent bleeding after damage control surgery

— Postpartum hemorrhage refractory to medical management (uterine artery embolization)

— CBC, PT/INR, fibrinogen, ionized Ca²⁺, K+, ABG with lactate

— Goals: Hgb >7 (>8 if cardiac), platelets >50 (>100 if CNS bleed), INR <1.5, fibrinogen >150–200, ionized Ca²⁺ >1.1 mmol/L, pH >7.2, temp >35°C

Board pearl: Hyperfibrinolysis on TEG (LY30 >3%) within 3 hours of injury is the strongest indication for TXA — beyond 3 hours, TXA may increase mortality in trauma (CRASH-2 substudy).

Key distinction: Solid organ injury grade alone does not dictate operative management — hemodynamic stability does. A grade IV splenic laceration in a stable patient may be managed nonoperatively with embolization.

CT pan-scan (head, C-spine, chest, abdomen/pelvis with IV contrast) — for hemodynamically stable or stabilized trauma patients:

CT angiography for suspected aortic dissection, ruptured AAA (if stable enough), mesenteric ischemia

Diagnostic peritoneal lavage (DPL) — largely supplanted by FAST, but still useful when FAST equivocal and CT unavailable

Endoscopy for upper GI bleed — within 12 hours; emergent if variceal or hemodynamic instability persists

Interventional radiology (IR) — angioembolization for:

Echocardiography — pericardial effusion/tamponade (chest trauma, dissection), RV strain (PE-mimic), volume status

Repeat labs every 30–60 minutes during active MTP:

Risk Stratification and MTP Activation Logic

— ABC score ≥2

— Shock index >1.0 with mechanism

— Anticipated need based on clinical gestalt (ruptured AAA en route, placenta accreta in OR)

— Persistent hemodynamic instability after 2 U PRBC

— Call blood bank, state "Activate MTP"

— Designate a single physician communicator and a single nurse runner

— Blood bank issues coolers in rounds/packs (e.g., 6 PRBC : 6 FFP : 1 apheresis platelet unit, ± 10 U cryoprecipitate)

— Subsequent packs released q15–30 min until deactivation ("Stop MTP")

— 1:1:1 ratio (plasma : platelets : RBCs) is the preferred resuscitation strategy in trauma — improved hemostasis at 24 hours and reduced death from exsanguination compared to 1:1:2

— In practice, 1 apheresis platelet unit = ~6 pooled platelet units, so the ratio is often expressed as 6 FFP : 1 apheresis platelets : 6 PRBC

— TXA 1 g IV over 10 min, then 1 g over 8 hr — within 3 hours of trauma onset (CRASH-2); within 3 hours of postpartum hemorrhage (WOMAN trial); reduces all-cause and bleeding-related mortality

— Calcium replacement — 1 g calcium chloride (central) or 1–2 g calcium gluconate (peripheral) after every 4 U PRBC, or guided by ionized Ca²⁺

— Fibrinogen concentrate or cryoprecipitate if fibrinogen <150–200 mg/dL

— PCC (4-factor) for warfarin reversal; andexanet alfa for apixaban/rivaroxaban; idarucizumab for dabigatran

CCS pearl: Order "activate massive transfusion protocol" as a single order — the simulation engine will deliver products in the institutional ratio. Order TXA, calcium, and reversal agents separately and explicitly.

MTP activation criteria — institution-specific but commonly include any of:

Activation logistics (CCS-flavored):

Target ratios — based on PROPPR trial:

Adjuncts:

Deactivation criteria — surgical control achieved, hemodynamic stability sustained, lab goals met

Pharmacotherapy — Adjuncts and Reversal Agents

— Lysine analog that inhibits plasminogen activation, preventing clot breakdown

— Trauma (CRASH-2): 1 g IV bolus over 10 min, then 1 g infusion over 8 hr; must be given within 3 hr of injury

— Postpartum hemorrhage (WOMAN): 1 g IV, repeat after 30 min if bleeding persists; within 3 hr of delivery

— Contraindications: known intracranial thrombosis, active intravascular clotting (DIC with thrombotic phenotype is nuanced)

— Ionized hypocalcemia → hypotension, arrhythmia, impaired coagulation (Ca²⁺ is factor IV)

— Replace empirically: 1 g CaCl₂ central or 2–3 g Ca gluconate peripheral per 4 U PRBC; target ionized Ca²⁺ >1.1 mmol/L

— Cryoprecipitate 10 units (or fibrinogen concentrate 2–4 g) when fibrinogen <150–200 mg/dL

— Obstetric hemorrhage tolerates fibrinogen poorly — keep >200

— Warfarin: 4-factor PCC (Kcentra) 25–50 U/kg + vitamin K 10 mg IV

— Dabigatran: idarucizumab 5 g IV (two 2.5 g vials)

— Apixaban/rivaroxaban: andexanet alfa (high cost, limited availability) or 4-factor PCC 50 U/kg as alternative

— Heparin: protamine sulfate (1 mg per 100 U heparin given in last 2–3 hr)

— Antiplatelet agents: platelet transfusion controversial in spontaneous ICH (PATCH trial showed harm); reserved for surgical bleeding or neurosurgical intervention

Board pearl: TXA in trauma given after 3 hours has been shown to increase mortality — timing is critical. The exception is isolated TBI (CRASH-3), where benefit extends through the acute window in mild-to-moderate TBI.

Tranexamic acid (TXA):

Calcium replacement — citrate in stored products chelates Ca²⁺:

Fibrinogen replacement:

Anticoagulant reversal:

Vasopressors are a last resort — they mask hypovolemia and worsen tissue perfusion; use only after adequate volume restoration or as bridge to OR

Recombinant factor VIIa — no longer routinely recommended due to thrombotic complications

Procedures and Definitive Hemostasis

— Stage 1: abbreviated laparotomy/thoracotomy for hemorrhage and contamination control — pack, clamp, shunt, leave abdomen open with temporary closure

— Stage 2: ICU resuscitation — correct the lethal triad (warm, transfuse, correct coagulopathy)

— Stage 3: return to OR in 24–48 hr for definitive repair, anastomoses, and abdominal closure

— Indications: penetrating chest trauma with signs of life en route or in ED within 15 minutes; blunt trauma with witnessed loss of pulses (lower yield)

— Performed via left anterolateral thoracotomy in 4th/5th intercostal space

— Goals: release pericardial tamponade, control intrathoracic hemorrhage, cross-clamp descending aorta, perform open cardiac massage

— Femoral arterial access with balloon inflation in zone I (above celiac) for abdominal/pelvic hemorrhage or zone III (infrarenal) for pelvic hemorrhage

— Bridges to definitive surgical or IR control; time-limited due to distal ischemia

— Pelvic binder → preperitoneal packing or angioembolization → external fixation

— Bimanual uterine massage → oxytocin → methylergonovine (avoid in HTN) → carboprost (avoid in asthma) → misoprostol → intrauterine balloon tamponade (Bakri) → uterine artery embolization → B-Lynch suture → hysterectomy

— Octreotide + ceftriaxone + emergent EGD with band ligation; balloon tamponade (Blakemore/Minnesota) as bridge; TIPS for refractory bleeding

CCS pearl: In a hemodynamically unstable trauma patient with positive FAST, the next order is "transfer to OR" — not CT, not more labs. The OR is the diagnostic and therapeutic destination.

Damage control surgery (DCS) — the operative philosophy for the unstable bleeding patient:

Resuscitative thoracotomy — emergency department thoracotomy:

REBOA (resuscitative endovascular balloon occlusion of the aorta):

Pelvic hemorrhage algorithm:

Postpartum hemorrhage stepwise:

Variceal hemorrhage:

Special Populations — Elderly and Renal/Hepatic Impairment

— Lower physiologic reserve — "occult shock" with normal vitals; SBP <110 in elderly should be treated as hypotension (vs <90 in younger adults)

— High prevalence of beta-blocker use blunts tachycardia — heart rate is unreliable

— Frequent anticoagulant use (AFib, mechanical valves, recent VTE) — early reversal is mandatory

— Increased risk of fall-related TBI on antiplatelet/anticoagulant therapy — low threshold for head CT and reversal

— TACO (transfusion-associated circulatory overload) risk much higher — diuretics may be needed between units

— Uremic platelet dysfunction — qualitative defect despite normal count; treat with DDAVP (desmopressin) 0.3 µg/kg, cryoprecipitate, conjugated estrogens

— Hyperkalemia risk amplified by transfusion (older PRBC units have high extracellular K+) — monitor ECG, consider washed/fresh PRBC

— Volume management — avoid TACO; coordinate with nephrology for emergent dialysis if needed

— Baseline coagulopathy is rebalanced — INR does not reliably predict bleeding risk; viscoelastic testing more useful

— Avoid over-correction with FFP — risk of volume overload, portal pressure spike, variceal rebleed

— Fibrinogen often low — cryoprecipitate is targeted therapy

— Thrombocytopenia from hypersplenism — platelet transfusion if <50 with active bleeding

— Variceal bleed: octreotide, ceftriaxone (SBP prophylaxis), EGD with banding

— Alloimmunization risk → phenotype-matched units when feasible

— Sickle cell: exchange transfusion may be preferred for acute chest syndrome or stroke

Step 3 management: In elderly anticoagulated patients with ICH, reverse first, image second is wrong — image immediately and reverse simultaneously; do not delay reversal awaiting INR confirmation if the history is clear.

Elderly trauma patients:

Chronic kidney disease and dialysis-dependent patients:

Cirrhosis and hepatic failure:

Pre-existing anemia / chronic transfusion-dependent disease (sickle cell, thalassemia):

Special Populations — Obstetric, Pediatric, and Jehovah's Witness

— Leading cause of maternal mortality worldwide; pregnant women compensate until ~30% blood loss then crash precipitously

— Tilt patient left lateral (15°) to relieve aortocaval compression

— Use O-negative blood until type-specific available (Rh sensitization risk for future pregnancies); give RhoGAM if Rh-negative mother receives Rh-positive blood

— Fibrinogen physiologically elevated in pregnancy (400–600 mg/dL); a "normal" 200 is actually low — target fibrinogen >200

— TXA within 3 hours (WOMAN trial — reduces death from bleeding by ~30%)

— Definitive: uterine massage → uterotonics → balloon tamponade → embolization → B-Lynch → hysterectomy

— Weight-based: 10–20 mL/kg PRBC, 10–20 mL/kg FFP, 10–20 mL/kg platelets per round

— Total blood volume ~70–80 mL/kg; "massive" = >40 mL/kg in 3 hr or replacement of 50% blood volume in 3 hr

— TXA 15 mg/kg (max 1 g) bolus, then 2 mg/kg/hr

— Hypothermia and hypocalcemia develop faster due to small body mass — aggressive warming

— IO access readily acceptable when IV difficult

— Refusal of blood products is a competent adult's right — document informed refusal carefully, with discussion of specific products (some accept albumin, factor concentrates, cell salvage — ask specifically)

— Strategies: cell salvage (intraoperative recovery), aggressive iron/EPO, TXA, factor concentrates (PCC, fibrinogen), surgical hemostasis, permissive anemia (Hgb tolerated to 4–5 g/dL)

— Minors: parental refusal can be overridden via court order for life-threatening hemorrhage — contact hospital ethics/legal urgently

Board pearl: A pregnant trauma patient at >20 weeks needs left lateral tilt, continuous fetal monitoring for ≥4 hours, and assessment for placental abruption (Kleihauer-Betke test in Rh-negative mothers).

Obstetric hemorrhage:

Pediatric MTP:

Jehovah's Witness patients:

Complications and Adverse Outcomes of Massive Transfusion

— Citrate anticoagulant in stored products chelates ionized Ca²⁺

— Manifests as paresthesias, QT prolongation, hypotension, decreased contractility, coagulopathy (Ca²⁺ is factor IV)

— Replace per ionized Ca²⁺; check after every 4 units

— Older PRBC units leak K+ from RBCs; rapid transfusion (>1–2 U over short interval) can cause peaked T waves, arrhythmia

— Use washed or fresh (<7 day) units in pediatrics, renal failure, and large-volume neonatal transfusion

— Stored products are cold; massive infusion drops core temp; impairs platelet function and coagulation enzyme kinetics

— Use fluid/blood warmers (Level 1 rapid infuser); warming blankets; remove wet clothing

— Initial metabolic acidosis from shock (lactate, hypoperfusion)

— Late metabolic alkalosis as citrate is metabolized to bicarbonate

— Acute hemolytic (ABO incompatibility — clerical error): fever, flank/back pain, hemoglobinuria, DIC, renal failure → stop transfusion, supportive care, alert blood bank

— Febrile non-hemolytic: rise in temp ≥1°C, no hemolysis; treat with acetaminophen

— Anaphylactic (IgA-deficient recipient with anti-IgA antibodies): epinephrine, washed products thereafter

— TRALI (transfusion-related acute lung injury): noncardiogenic pulmonary edema within 6 hr; donor anti-HLA/anti-neutrophil antibodies — supportive, lung-protective ventilation

— TACO (transfusion-associated circulatory overload): hydrostatic pulmonary edema, elevated BNP, hypertension; diuresis, oxygen

Key distinction: TRALI vs TACO — TRALI: normal or low CVP, normotensive/hypotensive, fever, BNP normal. TACO: elevated CVP, hypertensive, no fever, elevated BNP. TRALI is the leading cause of transfusion-related mortality in the US.

Citrate toxicity / hypocalcemia:

Hyperkalemia:

Hypothermia:

Acid–base derangements:

Acute transfusion reactions:

Coagulopathy of trauma resuscitation: dilutional + consumptive + hyperfibrinolytic — best mitigated by 1:1:1 ratios and TXA

When to Escalate — ICU, Consults, and Operative Triage

— Positive FAST + hemodynamic instability → trauma OR

— Ruptured AAA → vascular surgery, OR

— Refractory postpartum hemorrhage → OB/GYN ± IR

— Massive GI bleed with persistent instability → GI for emergent EGD, surgery if unresponsive

— Pelvic arterial blush on CT

— Splenic injury with extravasation in stable patient

— Uterine artery embolization for PPH

— Bronchial artery embolization for massive hemoptysis

— Ongoing transfusion requirement

— Hemodynamic instability requiring vasopressors

— Persistent acidosis (pH <7.2, lactate >4)

— Hypothermia <35°C

— Open abdomen / damage-control surgery

— Mechanical ventilation

— Need for CRRT (hyperkalemia, AKI)

— Penetrating torso/neck injury

— Multisystem trauma in patient on anticoagulation

— Pediatric trauma to designated pediatric trauma center

— Burns >20% TBSA, complex pelvic fracture, complex vascular injury

— Use EMTALA-compliant transfer: stabilize within facility capability, accepting physician, transfer agreement, copy of records

CCS pearl: In CCS cases, "transfer to ICU" and "consult trauma surgery / vascular surgery / OB" are explicit orders that advance time and unlock interventions. Place them early — do not let the simulation clock tick while you finish workup.

Immediate operative consultation (trauma surgery, vascular surgery, OB/GYN, or GI):

Interventional radiology activation:

ICU admission criteria post-MTP:

Transfer to level 1 trauma center if at lower-acuity facility:

Hematology consultation: DIC management, TTP/HUS mimics, refractory coagulopathy

Ethics / palliative care: futile resuscitation, surrogate decision-making, comfort transition

Key Differentials — Same-Category (Hemorrhagic Shock)

— Solid organ (liver, spleen, kidney) — blunt mechanism, FAST positive

— Vascular injury — penetrating, expanding hematoma, hard signs (pulsatile bleeding, bruit, absent pulses, distal ischemia, expanding hematoma)

— Pelvic ring disruption with retroperitoneal hemorrhage — high-energy mechanism

— Long bone fractures — femur ~1.5 L, pelvis up to 3 L, tibia ~750 mL

— Scalp lacerations — deceptively high blood loss in pediatrics

— Ruptured AAA — sudden abdominal/back pain, pulsatile mass, hypotension; bedside US shows aorta >3 cm with periaortic hematoma

— Ruptured ectopic pregnancy — positive β-hCG, free fluid on US, hemodynamic instability

— Aortic dissection with rupture — tearing chest/back pain, pulse differential, mediastinal widening

— Variceal hemorrhage — known cirrhosis, hematemesis, melena

— Peptic ulcer bleed — NSAID use, H. pylori, melena/hematemesis

— Diverticular bleed / angiodysplasia — painless lower GI bleed

— Aortoenteric fistula — prior aortic graft + GI bleed; "herald bleed" precedes massive hemorrhage

— Postpartum hemorrhage — atony (80%), trauma, retained tissue, thrombin/coagulopathy ("4 T's")

— Tumor hemorrhage — hepatocellular carcinoma rupture, renal cell carcinoma

Key distinction: Hemorrhagic shock is hypovolemic with cool extremities, narrow pulse pressure, and responds to volume/blood. Distinguish from distributive shock (warm, wide pulse pressure, sepsis/anaphylaxis), cardiogenic (elevated JVP, pulmonary edema), and obstructive (tamponade, tension PTX, massive PE — JVP elevated, focal exam findings).

Board pearl: In an unstable patient with hypotension and a history of prior aortic graft surgery + any GI bleed, the answer on Step 3 is aortoenteric fistula until proven otherwise — emergent CT angiography and vascular surgery.

Trauma-related hemorrhage subtypes:

Non-traumatic hemorrhagic etiologies:

Iatrogenic: post-procedural bleeding (post-cath, post-biopsy, post-surgical), anticoagulant-related ICH or GI bleed

Key Differentials — Non-Hemorrhagic Mimics

— Septic shock — infection source, fever, leukocytosis, lactate elevation; treat with early broad-spectrum antibiotics + fluids + vasopressors (norepinephrine first line)

— Anaphylactic shock — urticaria, angioedema, wheezing, recent exposure; epinephrine IM 0.3–0.5 mg

— Neurogenic shock — spinal cord injury above T6; bradycardia + hypotension (vs hemorrhagic tachycardia); fluids + vasopressors, atropine for bradycardia

— Acute MI with mechanical complication (papillary muscle rupture, VSD, free wall rupture)

— Decompensated heart failure

— Myocarditis, stress cardiomyopathy

— Elevated JVP, pulmonary edema, cool extremities, oliguria; echocardiogram is key

— Cardiac tamponade — Beck's triad (hypotension, muffled heart sounds, JVD), pulsus paradoxus; echo with pericardial effusion + RV diastolic collapse → pericardiocentesis

— Tension pneumothorax — absent breath sounds, tracheal deviation, JVD; clinical diagnosis — needle decompression at 4th–5th ICS midaxillary or 2nd ICS midclavicular

— Massive PE — sudden hypoxia, RV strain on echo, S1Q3T3; systemic thrombolysis or thrombectomy

— Beta-blocker / calcium channel blocker overdose — bradycardia + hypotension; glucagon, calcium, high-dose insulin

— Adrenal crisis — hypotension refractory to fluids, hyperkalemia, hyponatremia; hydrocortisone 100 mg IV

— DKA / severe dehydration — hypovolemia without bleeding

Key distinction: Pseudohemorrhage presentations — beta-blocker poisoning can mimic the hypotension of hemorrhagic shock but with bradycardia instead of tachycardia; this single vital sign mismatch should redirect the differential.

Step 3 management: When shock is undifferentiated, perform RUSH exam (Rapid Ultrasound for Shock and Hypotension): heart (effusion, contractility), IVC, abdomen (FAST), aorta, pneumothorax — guides resuscitation within minutes.

Distributive shock — high cardiac output, low SVR, warm extremities (early):

Cardiogenic shock — pump failure:

Obstructive shock:

Toxin/metabolic mimics:

Secondary Prevention and Post-Resuscitation Plan

— Post-massive-transfusion patients are typically iron-deplete despite recent transfusion

— Oral iron (ferrous sulfate 325 mg daily–TID) or IV iron (iron sucrose, ferric carboxymaltose) if oral intolerant or rapid replenishment needed

— Check ferritin, transferrin saturation at follow-up

— Post-bleed patients are at high VTE risk; reinitiate mechanical prophylaxis (SCDs) immediately

— Pharmacologic prophylaxis (enoxaparin 40 mg SC daily, or 30 mg BID in trauma) typically resumed 24–48 hr after hemostasis, individualized by bleeding risk and injury type

— Earlier in solid organ injury (after 48 hr if stable); delayed in TBI (typically 72 hr if stable repeat CT)

— Mechanical valve: bridge with heparin, resume warfarin once bleeding risk acceptable (often 3–7 days)

— AFib without mechanical valve: resume DOAC after 1–2 weeks for GI bleed, individualize for ICH

— Recent VTE (<1 month): reinitiate within days; consider IVC filter if anticoagulation truly contraindicated

— Transfusion-transmitted infection screening is robust in US (HIV, HBV, HCV, HTLV, WNV, syphilis, Zika in season, Chagas) but residual risk exists — counsel patients on follow-up testing if multiple-unit recipients

— Bacterial contamination risk highest with platelets

— Variceal bleed: nonselective beta-blocker (nadolol/propranolol), repeat band ligation, consider TIPS

— PUD: PPI, H. pylori eradication, NSAID avoidance

— Trauma: injury prevention counseling, seatbelt/helmet, fall risk assessment in elderly

Board pearl: After massive transfusion, resume VTE prophylaxis as early as bleeding control allows — the post-hemorrhage thrombotic risk is high and underappreciated, especially in trauma and obstetrics.

Iron repletion:

VTE prophylaxis:

Anticoagulant resumption:

Infection screening:

Source-specific secondary prevention:

Follow-Up, Monitoring, and Rehabilitation

— Serial CBC, coagulation panel, ionized Ca²⁺, BMP, lactate q4–6 hr until stable

— ABG with mixed venous saturation; lactate clearance target >10%/hr

— Strict I/O, urine output goal >0.5 mL/kg/hr (>1 mL/kg/hr in pediatrics)

— Telemetry monitoring for arrhythmia from electrolyte shifts

— Surveillance for abdominal compartment syndrome (bladder pressure >20 with organ dysfunction) — common after large-volume resuscitation; decompressive laparotomy if confirmed

— Document any reaction, notify blood bank, send post-transfusion sample for repeat type and antibody screen

— Premedication or washed products for future transfusions if indicated

— CBC at 1–2 weeks to assess hemoglobin recovery

— Iron studies at 4–6 weeks

— Source-specific follow-up: outpatient GI within 2–4 weeks for ulcer/variceal patients; trauma clinic; OB postpartum visit

— Trauma patients — physical therapy, occupational therapy, psychiatric screening for PTSD (high incidence after near-death events)

— Obstetric hemorrhage — postpartum depression screening (Edinburgh scale), counseling regarding future pregnancy risk (e.g., recurrent placenta accreta)

— ICU survivors — assess for post-intensive care syndrome (PICS): cognitive, psychiatric, physical impairments

— Discuss transfusion history at every future medical encounter — alloimmunization affects future crossmatch

— Iron-rich diet, smoking cessation, alcohol counseling for variceal patients

Step 3 management: Schedule trauma clinic or primary care follow-up within 1–2 weeks post-discharge; screen explicitly for PTSD, depression, and chronic pain at the 4–6 week mark — these are the dominant long-term morbidities after near-fatal hemorrhage.

Immediate post-MTP monitoring (first 24–72 hr):

Transfusion reaction surveillance:

Outpatient follow-up:

Rehabilitation:

Counseling:

Ethical, Legal, and Patient Safety Considerations

— Implied consent applies for life-threatening hemorrhage when the patient cannot consent and no surrogate is available

— When capacitated, document patient's wishes regarding blood products in real time

— A competent adult may refuse all blood products even if death is certain — document the discussion, specific products refused (some accept albumin, factor concentrates, cell salvage, EPO), and the patient's understanding of consequences

— Use blood-conservation strategies: TXA, factor concentrates, cell salvage, permissive anemia, surgical hemostasis

— For minors, parental refusal of life-saving transfusion can be overridden by court order — emergency court orders are obtainable in hours; contact hospital legal/ethics urgently

— For pregnant women, balance maternal autonomy against fetal interests; in the US, maternal autonomy generally controls

— Gunshot/stab wounds → law enforcement (state-specific statutes)

— Suspected intimate partner violence → offer resources; mandatory reporting varies by state and patient age

— Child abuse / elder abuse → mandatory in all 50 states

— Wrong-blood-in-tube is the most common cause of acute hemolytic transfusion reaction — enforce two-identifier verification at bedside both at sample draw and at administration

— Cooler chain of custody during MTP — track every product; return unused products to blood bank, not to subsequent patients without re-verification

— Handoff communication during shift change — explicit verbal sign-out about MTP status, total products given, pending labs

— Discharge after massive transfusion requires explicit communication to outpatient providers about transfusion history, antibody screen results, iron status, and VTE prophylaxis duration

— Anticoagulant resumption decisions must be clearly documented with dates and indications

— Blood is a scarce resource — MTP deactivation is as important as activation; explicitly call "stop MTP" once hemostasis achieved

Board pearl: The single highest-yield patient safety intervention in transfusion medicine is bedside two-identifier verification — fatal ABO mismatch is almost always a clerical error, not a laboratory one.

Informed consent in emergencies:

Jehovah's Witness and blood refusal:

Mandatory reporting:

Patient safety pitfalls:

Transition-of-care risk:

Resource stewardship:

High-Yield Associations and Rapid-Fire Facts

Board pearl: Memorize the PROPPR ratio (1:1:1), CRASH-2 timing (3 hr), and the lethal triad — these three concepts anchor virtually every MTP question on Step 3.

PROPPR trial (2015): 1:1:1 vs 1:1:2 plasma:platelets:RBCs — 1:1:1 superior for hemostasis and 24-hr mortality from exsanguination

CRASH-2 (2010): TXA within 3 hr of trauma reduces all-cause mortality

CRASH-3 (2019): TXA in mild-moderate TBI within 3 hr reduces head-injury-related death

WOMAN trial (2017): TXA in postpartum hemorrhage reduces death from bleeding by ~30%

ABC score elements: penetrating mechanism, SBP ≤90, HR ≥120, positive FAST

Lethal triad: hypothermia + acidosis + coagulopathy (some texts add hypocalcemia → "diamond of death")

Massive transfusion definitions: ≥10 U PRBC in 24 hr, OR ≥4 U in 1 hr with ongoing need, OR replacement of total blood volume in 24 hr

Permissive hypotension: SBP target ~80–90 in penetrating trauma without TBI; do NOT use in TBI (need SBP ≥110)

Calcium replacement: every 4 U PRBC; ionized Ca²⁺ target >1.1 mmol/L

Fibrinogen target: >150–200 mg/dL trauma; >200 obstetric

TRALI: noncardiogenic pulmonary edema within 6 hr — leading cause of transfusion-related death in US

TACO: hydrostatic pulmonary edema, elevated BNP, hypertension

O-negative: universal donor; reserve for women of childbearing age — O-positive acceptable for males

Type-specific blood available within ~10 min; full crossmatch 30–45 min

PRBC storage: up to 42 days; potassium leaks with age — fresh units for pediatrics, renal failure

Cryoprecipitate: contains fibrinogen, factor VIII, vWF, factor XIII, fibronectin — 10 U pool raises fibrinogen ~70 mg/dL

FFP: all coagulation factors; 10–15 mL/kg raises factors by ~30%

Apheresis platelets: one unit ≈ 6 random donor units; raises count ~30–50K

PCC (Kcentra): factors II, VII, IX, X + proteins C and S; warfarin reversal 25–50 U/kg

Idarucizumab: dabigatran reversal; andexanet alfa: apixaban/rivaroxaban reversal

Board Question Stem Patterns

— "A 24-year-old man arrives by EMS after a high-speed MVC. SBP 78/40, HR 138, GCS 13. FAST is positive in Morison's pouch. He has received 2 L normal saline en route." → Activate MTP, transfer to OR; avoid further crystalloid

— "A 32-year-old G3P2 woman delivers a healthy infant and now has heavy vaginal bleeding. Estimated blood loss 1500 mL after uterine massage and oxytocin." → TXA + methylergonovine (if no HTN) → Bakri balloon → uterine artery embolization → hysterectomy

— "A 72-year-old man on apixaban for AFib presents with GCS 9 after a fall. CT shows acute SDH." → Andexanet alfa (or 4-factor PCC if unavailable), neurosurgery consult, BP control

— "Hypoxemia, bilateral infiltrates, normal CVP within 4 hr of transfusion." → TRALI — stop transfusion, supportive care, notify blood bank

— "Hypertension, JVD, elevated BNP, response to furosemide." → TACO

— "Patient receiving rapid transfusion develops perioral paresthesias, prolonged QT, hypotension." → Ionized hypocalcemia from citrate — administer calcium gluconate or chloride

— "Competent adult refuses blood products with full understanding." → Respect autonomy; cell salvage, TXA, factor concentrates, EPO

— "Minor with parents refusing transfusion for life-threatening hemorrhage." → Obtain emergency court order; transfuse to save life

— Penetrating abdominal trauma without head injury → SBP target 80–90 until OR

— Same patient with concomitant TBI → SBP ≥110 — TBI overrides permissive hypotension

— Trauma patient presents 4 hours after injury → do not give TXA (may increase mortality after the 3-hour window)

Step 3 management: When the stem says "ongoing transfusion requirement and persistent acidosis" — the answer is damage control surgery and ICU admission, not more lab work or another CT.

Classic Step 3 trauma stem:

Obstetric hemorrhage stem:

Anticoagulant-on-board stem:

Transfusion reaction stem:

Citrate toxicity stem:

Jehovah's Witness stem:

Permissive hypotension trap:

TXA timing trap:

One-Line Recap

— Activate early using ABC score ≥2 or clinical gestalt; do not wait for hemoglobin to drop, because acute hemorrhage is isovolemic and Hgb lags hours behind true loss

— 1:1:1 ratio (PROPPR) is the gold standard; add TXA within 3 hours (CRASH-2, CRASH-3, WOMAN), calcium every 4 units PRBC, and fibrinogen replacement when <150–200 mg/dL

— Permissive hypotension (SBP 80–90) for penetrating trauma without TBI; SBP ≥110 when TBI present (TBI overrides)

— Reverse anticoagulants emergently: 4-factor PCC + vitamin K for warfarin, idarucizumab for dabigatran, andexanet alfa or PCC for apixaban/rivaroxaban

— Definitive hemostasis — surgery, IR embolization, or endoscopic control — is the only durable answer; blood products are a bridge, not a destination

— Anticipate complications: citrate-induced hypocalcemia, hyperkalemia, hypothermia, dilutional coagulopathy, TRALI (leading transfusion-related death), TACO, acute hemolytic reaction from clerical error

— Special populations: O-negative for women of childbearing age; left lateral tilt and TXA for obstetric hemorrhage; weight-based dosing in pediatrics; bloodless strategies (cell salvage, TXA, factor concentrates) for Jehovah's Witness patients; court order for minors when parents refuse life-saving transfusion

— Post-resuscitation: restart VTE prophylaxis as soon as bleeding control allows, replete iron, screen for PTSD/depression at follow-up, document transfusion history for future encounters

Board pearl: The single most testable concept across Step 3 MTP questions is the integration of 1:1:1 ratio + TXA timing + permissive hypotension + early surgical control — every other detail orbits these four anchors.

Core teaching point: Massive transfusion protocol delivers balanced 1:1:1 plasma-platelets-RBCs with TXA, calcium, and targeted reversal agents to interrupt the lethal triad of hypothermia, acidosis, and coagulopathy in life-threatening hemorrhage — activated early by clinical mechanism and shock indices rather than awaiting confirmatory labs.

High-yield recap bullets: