Damage control resuscitation in the bleeding trauma patient — ratio, clock, calcium, whole blood and limits

Examiner probes

1. He is hypotensive with a positive FAST and 2 units running at 60 minutes. Activate or wait — with what score, what ratio, and what do you do when the score says no?^[32][5]
2. TXA — exact dose, the three timing bands with numbers, the 90-minute refinement, and what happens if you miss the window?^[16][17][18]
3. Calcium 0.97 with citrated products running — replace, ignore, or protocol-bolus? Defend with both directions of the evidence.^[21]
4. Whole blood or components at this pressure — and fibrinogen for everyone or for the low? Answer with the 2026 trials and CRYOSTAT-2.^{[12][13][28][29]}
5. Viscoelastic testing and permissive hypotension — superiority or adjunct, and what changes with a severe head injury?^[25][3]

Model responses

1. Activate now — equal ratios fast, scored formally but never vetoed by the score. Hypotension with a positive FAST and blood running is DCR on physiology: score the four ABC variables (penetrating, FAST-positive, systolic 90 or less, pulse 120 or more) while transfusing equal amounts of red cells, plasma and platelets in the early empiric phase.^[32][5] Run PROPPR-honest: no mortality difference at 24 hours or 30 days, fewer exsanguinations, more haemostasis, complications equal — with Bayesian reanalyses assigning 93% and 87% probability of 1:1:1 superiority at those endpoints, strongest in the first hours of bleeding.^[5][6] And when the ABC totals 1 in a patient clearly bleeding, transfuse anyway: in PROPPR the score managed only 66.8% sensitivity with 37.0% specificity, and gestalt enrolled more than a third of the trial below threshold.^[35]

2. TXA 1 g now — inside every window that matters. Give 1 g over 10 minutes then 1 g over 8 hours: CRASH-2 all-cause 14.5% versus 16.0% (RR 0.91), bleeding death 4.9% versus 5.7% (RR 0.85).^[16] At 60 minutes he sits in the best gradient band — within 1 hour RR 0.68, 1 to 3 hours RR 0.79, after 3 hours harm RR 1.44 — and inside the PATCH 90-minute optimum (within aRR 0.64, beyond aRR 1.04).^[17][18] Missing the window converts benefit toward harm, so the loading dose travels with the first blood, never after the scan or the operation.

3. Check-and-replace calcium — both papers, one practice. Ionised 0.97 meets the verified 1.0-or-less threshold: prehospital plasma pushed hypocalcaemia from 36% to 53% (adjusted RR 1.48), with severe lows predicting decreased survival and massive transfusion — so measure with every round and replace under citrate load.^[21] But refuse the fixed-dose protocol claim: in 346 activations 83.2% were hypocalcaemic yet neither first calcium nor citrate-corrected dose touched mortality — the physiology demands vigilance, not a dosing algorithm, and no milligram figure leaves your mouth.^[22]

4. Components by default, whole blood by logistics; fibrinogen targeted, never empiric. Two 2026 prehospital randomised trials were neutral — TOWAR 30-day 25.9% versus 20.5% (adjusted OR 1.24), English composite 48.7% versus 47.7% (RR 1.02) — with LTO-WB safety proven (survival 73 versus 74%, post-department products median 0 versus 3, reactions confined to components).^[12][13] So choose whole blood where the chain is simplest and balanced components where the bank runs equality well — superiority belongs to neither.^[12] Fibrinogen goes only to documented lows with bleeding: empiric 3-pool cryoprecipitate changed 28-day death not at all (25.3 versus 26.1%), while high achieved cryoprecipitate ratios halved adjusted 6-hour mortality (aOR 0.52) — target, never flood.^[28][29]

5. VHA advises, hypotension individualises, the injured brain overrules both. Viscoelastic assays see fibrinolysis and fibrinogen failure that conventional tests miss, yet ITACTIC showed no outcome difference (67 versus 64% alive free of massive transfusion; 25 versus 28% dead) with undertreatment explaining more than assay failure — adjunct with honest limits, no cutoff quoted.^[25] Permissive hypotension earns its place in hospital (death 6.3 versus 16.3%, blunt 24-hour aOR 0.17, fewer respiratory and organ-failure complications) but not prehospital and never in brain injury.^[3] With a severe head injury: normal pressure targets for the brain, TXA by the coma-scale rule (within 2 hours or GCS below 9, benefit possibly persisting), calcium and ratios unchanged — the brain sets the pressure, the clock still sets the drug.^[19]