Primary Survey [<C>ABCDE], Massive Transfusion & Damage Control Resuscitation

Catastrophic Exsanguination (<C>): Apply windlass limb tourniquet 5–7 cm proximal to high-velocity extremity bleed until distal pulse ceases; pack junctional wounds (groin/axilla/neck) with kaolin/chitosan hemostatic gauze + 3 min direct manual pressure; apply pelvic binder centered directly over greater trochanters [1,2].

Arrests external arterial pressure head via transmural mechanical compression (Pext > SBP); reduces pelvic retroperitoneal volume by converting an open-book cylinder into a closed sphere (V = ⁴⁄₃πr³) [1].

Airway & Cervical Spine (A) + Breathing (B): Maintain manual inline stabilization (MILS); jaw thrust; suction blood with DuCanto catheter; deliver high-flow O₂ at 15 L/min via NRB. Hemodynamic Resuscitation Before
Intubation: Never perform RSI prior to volume/blood loading in Class III/IV hemorrhagic shock [1,2]. If tension pneumothorax suspected: immediate finger thoracostomy at 4th or 5th ICS slightly anterior to mid-axillary line (MAL) [1].

Prevents positive-pressure ventilation (+Pintrathoracic) from collapsing right ventricular preload (venous return Q = [MSP − RAP] / Rv) and prevents induction-mediated sympatholysis from triggering post-intubation pulseless electrical activity (PEA).

Circulation (C) & Vascular Access: Insert two 14G or 16G short peripheral IVs in antecubital fossae (or humeral/femoral 15G IO, or 8.5 Fr cordis introducer sheath). Draw type & crossmatch, VBG, ionized calcium (iCa²⁺), lactate, fibrinogen, and viscoelastic hemostatic assay (TEG/ROTEM). Activate Massive Transfusion Protocol (MTP) if Assessment of Blood Consumption (ABC) score ≥ 2 or Shock Index (HR/SBP) > 1.0 [1,3,4].

Maximizes flow rate via Hagen-Poiseuille law (Q = ΔPπr⁴ / 8ηL): a short, wide-bore 8.5 Fr sheath or 14G IV provides exponentially greater flow than a long triple-lumen central venous catheter.

Damage Control Resuscitation (DCR) Initiation: Infuse warmed (39°C) uncrossmatched Low-Titer Group O Whole Blood (LTOWB) or 1:1:1 balanced blood products (1 unit pRBC : 1 unit FFP : 1 unit apheresis platelets) via rapid infuser [3,4]. Administer Tranexamic Acid (TXA) 1 g IV over 10 min (followed by 1 g over 8 hr, or single 2 g IV bolus per local trauma protocol) strictly if within 3 hours of injury [5,6].

Restores oxygen-carrying capacity (DO₂), replenishes labile clotting factors V and VIII, and competitively inhibits plasminogen activation on fibrin lysine-binding sites to arrest early hyperfibrinolysis [3,5].

Calcium Rescue, Target Pressures (D/E) & OR Transfer: Administer Calcium Chloride 10%, 1 g (10 mL = 13.6 mEq Ca²⁺) IV slow push (or Calcium Gluconate 10%, 3 g [30 mL] IV via peripheral line) after the first 1–2 units of blood [2]. Maintain permissive hypotension (SBP 80–90 mmHg, MAP 50–60 mmHg) unless concomitant severe TBI (GCS ≤ 8), where target is SBP ≥ 110 mmHg (MAP ≥ 80 mmHg) [1,2]. Perform rapid eFAST, apply active forced-air warming blanket, and move to OR/IR.

Reverses citrate-induced chelation of ionized calcium (Factor IV), restoring cardiac sarcoplasmic reticulum contractility and tenase/prothrombinase complex assembly; avoids hydrostatic “popping the clot” before surgical hemostasis [2,7].