Damage Control Resuscitation — Hypotensive Strategy, Balanced Ratios, Whole Blood, TXA Clock, Calcium and Viscoelastic Guidance

Blunt polytrauma, systolic 82, heart rate 134, FAST positive, lactate 6.4, temperature 34.9, ionised calcium 0.98 — injury 55 minutes ago, blood products hanging, no laboratory coagulation result yet. Do you wait for the numbers, how low do you let the pressure ride, plasma first or red cells first, whole blood or components, when does TXA go in, what do you check after every few units, which score justified activation, and what changes if he is 78, anticoagulated, or 8 years old? The examiner will watch you activate on physiology, resuscitate by ratio and clock, defend every exception, and quote each number from the paper named beside it. This page teaches each move with every number taken from the paper named beside it.^[32][8][21]

Overview & Definition — resuscitation before the knife

Damage control resuscitation, derived from military protocols, focuses on early haemorrhage control and volume replacement to combat the "diamond of death" (hypothermia, hypocalcaemia, acidosis, coagulopathy) — and surveys show the doctrine is understood far wider than it is delivered, with fewer than half of Brazilian centres running a massive transfusion protocol and fewer than one in five using whole blood.^[1] The practical reordering is circulation before airway: traditional assessment follows airway-breathing-circulation, but evidence favours circulation-airway-breathing to maintain perfusion and prevent hypotension — against a global burden of 1.5 million haemorrhage deaths a year, most of them preventable only if bleeding is met with blood rather than salt water.^[1]

Damage control surgery is abbreviated laparotomy designed to prioritise short-term physiological recovery over anatomical reconstruction — while DCR focuses on initial hypotensive resuscitation and early blood products to prevent the lethal triad of acidosis, coagulopathy and hypothermia — and crucially DCR may allow borderline patients who would previously have required DCS to undergo early definitive surgery as their derangement corrects sooner.^[47] Contemporary therapy therefore runs as one bundle: permissive hypotension, balanced ratio-based transfusion, early tranexamic acid, calcium replacement, and targeted rather than empiric fibrinogen replacement, with recombinant activated factor VII reserved for rescue.^[2] What DCR is not matters equally: it is not a transfusion trigger list (that is activation scoring), not an operative technique (that is DCS), and not a licence for hypotension in the brain-injured (the exception below).^[1][4]

Indications & Patient Selection — activate on physiology, never on labs

Select by bedside physiology the moment bleeding declares itself: penetrating mechanism, positive FAST, systolic pressure at or below 90 and heart rate at or above 120 — the four non-weighted ABC variables — with lactate and temperature completing the picture, because these are the patients in whom balanced products must already be running.^[32] Waiting for laboratory confirmation of coagulopathy is the examined error: shocked patients arrive with lactate and base excess already outside reference range while standard coagulation parameters sit normal or near-normal, so a normal INR on arrival rules nothing out.^[46] The 10.8%-transfusion reality of prehospital scoring cohorts is a reminder that most injured patients never need DCR — the doctrine is for the bleeding minority, applied by protocol the moment they declare themselves.^[36]

Three groups need a different plan from the start. The isolated severe brain injury without active bleeding is excepted from hypotension — four out of five trauma professionals already practise the exception — because cerebral perfusion has no collateral for your restraint.^[1] The late presenter beyond the TXA window still gets balanced resuscitation but loses the antifibrinolytic dividend, and may be harmed by it — check the clock before the drug.^[17] The anticoagulated and the liver-diseased carry a coagulopathy your ratios alone cannot cover: agent-specific adjustments are required, summarised in the TIC review's reference table, because warfarin, direct oral agents and hepatic failure each break a different limb of clotting.^[2]

Pathophysiology — trauma-induced coagulopathy, endothelium and the diamond

Trauma-induced coagulopathy is a maladaptive, multifactorial response to severe injury affecting approximately one quarter of severely injured patients and substantially increasing mortality — arising from combined tissue injury and shock, not from dilution alone.^[2] Recognition of trauma endotheliopathy, including glycocalyx shedding and the von Willebrand factor–ADAMTS-13 axis, has broadened understanding beyond simple consumption and dilution: the endothelium itself becomes a bleeding organ, shedding its regulatory surface into the circulation.^[2] Thrombin generation is typically preserved early and falls only later, with the patient evolving through early hypocoagulable, balanced and later hypercoagulable phases — which is why early procoagulant restraint and later thrombosis vigilance are two halves of one disease.^[2]

Hypocalcaemia earns its place as the fourth vertex of the diamond. Citrate in every blood product chelates ionised calcium, and injury itself drives calcium down before transfusion even starts: prehospital plasma recipients carried significantly higher hypocalcaemia rates than controls (53% versus 36%, adjusted relative risk 1.48), with severe hypocalcaemia predicting both decreased survival and massive transfusion.^[21] During massive transfusion the numbers are starker still — 97% of patients hypocalcaemic, 71% severely so (ionised calcium below 0.90 mmol/L), with mortality doubled in the severe group (49% versus 24%) — yet neither group reached a normal median ionised calcium despite replacement, a warning that replacement protocols chase a moving target.^[23] Then the honest counterweight the examiner respects: in 346 massive-transfusion-protocol activations, 83.2% were hypocalcaemic at first measurement, yet neither the first ionised calcium nor the citrate-corrected calcium dose bore any relationship to mortality — so calcium matters, but no fixed-dose protocol can yet claim to save lives, and specific treatment protocols must await better physiology.^[22]

Crystalloid excess is the iatrogenic amplifier candidates forget. Among blood recipients, each step up in crystalloid volume raised mortality (hazard ratio 1.65), while combined-strategy analysis showed high platelet and plasma ratios plus TXA each independently raised the odds of surviving free of massive transfusion — yet no strategy, fibrinogen included, actually normalised coagulopathy by INR.^[39][40] Salt water dilutes, cools and acidifies; blood, given early and balanced, does not fix everything either — humility in both directions.^[40]

Recognition & Activation Scores — the ABC, its validators and its humbling

The ABC score assigns one point each for penetrating mechanism, positive FAST, arrival systolic pressure 90 or less, and arrival heart rate 120 or more — non-laboratory, non-weighted, calculable before the patient reaches the scanner — and at 2 or more it was 75% sensitive and 86% specific, correctly classifying 85% of 596 patients with a 12.4% massive-transfusion rate.^[32] Multicentre validation held the line across demographically diverse centres: sensitivity 75–90%, specificity 67–88%, correctly classified 84–87%, AUROC 0.83–0.90.^[33] Where laboratories answer fast, the weighted TASH score wins on discrimination — AUC 0.889 against 0.860 for the Prince of Wales score, with TASH at 8.5 reaching 84.4% sensitivity and 78.4% specificity in 5,147 severely injured patients.^[34]

Then the humbling the viva demands. Applied to PROPPR's enrolled bleeders, an ABC of 2 or more managed only 66.8% sensitivity and 37.0% specificity for massive transfusion, with a positive predictive value of 88.2% but a negative predictive value of just 13.1% — and more than a third of trial patients were enrolled by physician gestalt below threshold.^[35] The examined lesson: scores standardise activation and prepare the blood bank, but a low score never overrules a bleeding patient in front of you — gestalt enrolled 36% of PROPPR, and gestalt was right to.^[35] In prehospital triage without blood products, physiology scores now beat trauma scores: NEWS reached AUROC 0.84 and reverse-shock-index-times-GCS 0.83 for massive transfusion, against 0.69 for ABC — with NEWS at 4 or more 81.0% sensitive and rSIG at 16 or less balancing 74.6% sensitivity with 88.5% specificity — supporting pre-arrival notification without delaying transport.^[36]

Permissive Hypotension & Limited Crystalloids — the strategy, its setting and its exception

Eleven studies and 4,529 patients make the examined case: permissive hypotension cut in-hospital mortality (6.3% versus 16.3%) and, in hospital, cut acute respiratory syndrome (12.2% versus 30.5%), multi-organ failure (12.2% versus 29.3%) and disseminated intravascular coagulation (2.4% versus 17.1%) against standard resuscitation.^[3] In blunt injury the 24-hour mortality split was sharpest — 3.2% versus 17.7%, adjusted odds ratio 0.17 — so the blunt hypotensive bleeder is the strategy's best candidate, with volumes individualised to haemodynamics and injury pattern.^[3] But honesty about setting: the same review found no mortality difference in prehospital settings — hypotensive strategy pays once the hospital team, blood bank and surgeons stand ready behind it, not on a long roadside scoop.^[3]

The brain-injured patient is excepted, and two independent sources agree: trauma professionals practise permissive hypotension except in traumatic brain injury, and the TXA causal-forest analysis extends drug benefit rather than hypotension tolerance in low-GCS patients — never trade cerebral perfusion for clot stability.^[1][19] No millimetre-of-mercury target appears on this page, deliberately: no verified target paper sits in this pack, so teach hypotension as a named strategy with outcome numbers, not as a number — candidates who invent 80 or 90 systolic fail the follow-up.^[3] Vasopressors sit in the same debated space: their trauma-bay use has long been controversial, lowering perfusion targets while awaiting haemorrhage control is contraindicated in some subgroups and may harm, yet circulation-first thinking drives increasing interest — adjunct under discussion, never doctrine, never dosed here.^[4]

Balanced Ratios — PROPPR, its Bayesians and the guideline

PROPPR randomised 680 severely injured patients predicted to need massive transfusion across 12 North American level-I centres to plasma:platelets:red cells at 1:1:1 (338 patients) versus 1:1:2 (342) — and found no significant mortality difference at 24 hours (12.7% versus 17.0%, p = .12) or 30 days (22.4% versus 26.1%, p = .26).^[5] But the trial was not negative where bleeding kills: exsanguination, the predominant 24-hour cause of death, fell significantly (9.2% versus 14.6%, p = .03), more 1:1:1 patients achieved haemostasis (86% versus 78%, p = .006) — at the cost of more plasma (median 7 versus 5 units) and platelets (12 versus 6 units) with identical red-cell use (9 units) and no difference across all 23 prespecified complications including ARDS, multi-organ failure, venous thromboembolism, sepsis and transfusion reactions.^[5] Quote it whole or do not quote it: equal ratios buy haemostasis, not survival — and cost nothing in complications.^[5]

Bayesian reanalysis says what the frequentist trial could not. A 1:1:1 strategy carried a 93% posterior probability of 24-hour superiority (Bayes factor 13.7) and 87% at 30 days (Bayes factor 6.56) — probability statements a resuscitationist can actually use.^[6] At earlier, haemorrhage-meaningful endpoints the signal strengthens: 96%, 99%, 94%, 92%, 96% and 94% probability of benefit at 1, 3, 6, 12, 18 and 24 hours, with Bayes factors from 11.4 to 142 — strong to decisive evidence that balanced transfusion matters most exactly when bleeding kills.^[7] The EAST reviewers, grading 37 studies, converted this into doctrine: a massive-transfusion/DCR protocol halves mortality against none (OR 0.61), high plasma-to-red-cell ratios protect (OR 0.60), high platelet-to-red-cell ratios protect more (OR 0.44) — best achieved by transfusing equal amounts of red cells, plasma and platelets during the early empiric phase — with conditional in-hospital TXA and no recommendation for or against factor VIIa.^[8]

Contemporary practice confirms the ratio story outside trials: among PATCH-Trauma massive-transfusion patients, high plasma-to-red-cell ratios (above 1 unit plasma per 2 red cells) halved adjusted 28-day mortality (adjusted OR 0.50) — with the authors' own caveat that newer components, agents and coagulopathy testing make the marginal benefit of plasma an open question, not a closed one.^[9] Yet doctrine has barely penetrated practice: only 17.6% of 172,457 transfused injured patients received balanced transfusion, rising from 11% in 2016 to 25.9% in 2021 once whole blood counted — with 26% of variation attributable to the hospital itself, and verified level-I status doubling the odds.^[10] The national picture moved faster once whole blood entered the definition — 12.4% to 37.6% balanced-or-whole-blood from 2018 to 2024, almost entirely whole-blood-driven while component balance stood still — with nearly a quarter of variation still hospital-level.^[11] The examined moral: the evidence for balance is strong, its delivery is a postcode lottery, and protocols — not preferences — close the gap.^[10][11]

Whole Blood vs Components — two neutral trials end the slogan era

June 2026 ended the superiority argument twice in one journal issue. TOWAR cluster-randomised 44 air-medical bases to up to 2 units of prehospital type-O whole blood versus as-indicated components: 30-day mortality was 25.9% with whole blood against 20.5% with components (adjusted OR 1.24, p = .24), with no substantial adverse-event difference — and the storage-age substudy found 15-to-21-day blood identical to 1-to-14-day blood (adjusted OR 0.99), defusing the old-blood objection.^[12] The English trial randomised 942 prehospital patients across 10 air-ambulance services to up to 2 units whole blood versus up to 2 units each of red cells and plasma: the composite of death or massive transfusion at 24 hours hit 48.7% against 47.7% (relative risk 1.02, p = .84), deaths and secondary outcomes looked similar throughout — though prothrombin times ran high more often with whole blood (40.7% versus 30.5%), while serious adverse events favoured it numerically (31 versus 37).^[13] Prehospital whole blood is not superior to components. Say it plainly, then say what follows.^[12][13]

What follows is logistics and safety, not slogans. Low-titre group-O whole blood proved safe in civilian rollout: survival identical (73% versus 74%), post-emergency-department product need collapsing (median 0 versus 3 units, adjusted OR 0.47 for transfusion), both suspected reactions in the component arm, no haemolysis signal.^[14] Thirteen-study synthesis agrees: no consistent 24-hour or 28-day mortality gain, but consistent physiology — shock-index falls three times larger, shock reversal doubled (34.3% versus 16.6%), predicted survival up (54.4% versus 35.4%) — with survival signals concentrating in penetrating trauma (77% versus 56%, odds of death 0.31) and high-risk strata.^[15] So the examined answer: choose whole blood where it simplifies the chain — prehospital, austere, single-bag logistics — and components where the bank runs balanced ratios well; the 12-to-38% adoption surge is a systems story, and with only 18.2% of Brazilian centres using whole blood at all, availability decides more cases than evidence does.^[11][1]

The TXA Clock — dose, gradient, 90 minutes and the missed woman

The regimen never changes: 1 g over 10 minutes then 1 g over 8 hours, randomised within 8 hours of injury across 274 hospitals in 40 countries and 20,211 patients — cutting all-cause mortality (14.5% versus 16.0%, RR 0.91) and bleeding death (4.9% versus 5.7%, RR 0.85).^[16] But the effect is a clock, not a drug: treatment within 1 hour cut bleeding death by nearly a third (RR 0.68), treatment at 1–3 hours still helped (RR 0.79), treatment beyond 3 hours seemed to increase bleeding death (RR 1.44) — with the time interaction itself overwhelming (p < .0001), independent of blood pressure, consciousness or injury type.^[17]

Modern data tighten the window further. In 1,287 PATCH-Trauma patients with a median 79 minutes to first dose, TXA inside 90 minutes cut 28-day death (17% versus 25%, adjusted RR 0.64) while dosing beyond 90 minutes did nothing (adjusted RR 1.04) — the optimal therapeutic window may sit within 90 minutes, not 3 hours.^[18] Causal-forest analysis of 28,448 CRASH-2 and CRASH-3 patients agrees with a small mercy: relative-risk reduction peaks inside 2 hours and falls fast — the statistically optimal rule is treatment within 2 hours or Glasgow Coma Scale below 9 — with severe brain injury the one setting where benefit may persist past the window.^[19] EAST conditionally recommends early in-hospital TXA, which these numbers now read as: early means now, not after the scan.^[8] And the equity failure candidates must name: TXA benefits women and men equally (RR 0.69 and 0.80, no heterogeneity) yet registry women received it at odds of 0.39 against men, worsening with age — the drug works in women; the system withholds it from them.^[20]

Calcium — check, replace, and admit what is unproven

Run citrated products and calcium falls — that much is mechanism and measurement both. Prehospital plasma pushed admission hypocalcaemia (ionised calcium 1.0 or less) from 36% to 53% (adjusted RR 1.48), and severe hypocalcaemia predicted both decreased survival and massive transfusion — the explicit-guidelines plea in that paper is the closest thing calcium has to doctrine.^[21] During massive transfusion, 97% of 156 patients fell below 1.12 mmol/L and 71% below 0.90, with severe-group mortality doubling (49% versus 24%) — while neither group's median ever normalised above 1.12 despite grams of chloride, proving replacement chases loss in real time.^[22][23]

So the bedside rule is check-and-replace, never fixed-dose: every UK helicopter service now carries calcium and 95% run a replacement SOP — yet point-of-care testing is not widespread, eleven different product combinations fly, and opinions on management diverge, which the survey authors read as a call for evidence rather than consensus.^[24] Quote each paper's own threshold (1.0, 1.12, 0.90 mmol/L) because no universal one exists; remember the 83%-hypocalcaemic cohort where calcium neither predicted nor modified death; and never state a milligram or millimole dose on this page's authority — no dosing trial sits behind it.^[21][22][23]

Viscoelastic Guidance — what the assays see, what the trials show

What viscoelastic assays see that conventional tests miss is not disputed: clot initiation, propagation, strength and lysis in near-real time — fibrinolysis, fibrinogen deficiency and platelet dysfunction invisible to INR and aPTT — with early amplitudes enabling goal-directed decisions minutes sooner.^[2] What that vision buys is. ITACTIC randomised 396 major-haemorrhage-protocol patients to viscoelastic versus conventional augmentation: alive and free of massive transfusion at 24 hours 67% versus 64%, 28-day mortality 25% versus 28% — no difference in primary, secondary or safety outcomes, with only a non-significant TBI-subgroup hint (64% versus 46% of 74 patients, confidence interval crossing one).^[25]

The secondary analysis explains the neutral: 71% of patients were already coagulopathic on admission (EXTEM A5 below 40 mm), viscoelastic patients were far likelier to receive goal-directed treatment (76% versus 47%) and got it faster (68 versus 110 minutes) — yet barely half of indicated treatments were ever delivered and only one in five coagulopathies corrected, no better than empiric care.^[26] The 2026 Cochrane review, 35 trials and 3,096 patients, mostly elective cardiac surgery, found a mortality risk ratio of 0.76 wrapped in a "very uncertain" verdict — with an explicit call for large, low-bias trials in trauma, obstetrics, paediatrics and sepsis before anyone claims more.^[27] The examined position in one sentence: use viscoelastic assays as an early-warning adjunct that speeds goal-directed treatment, quote ITACTIC's neutrality when challenged, and never recite a trigger cutoff this pack does not contain — thresholds remain expert-derived and platform-specific.^[25][26][2]

Fibrinogen Strategy — targeted replacement, never empiric flooding

Fibrinogen falls first and kills quietly — which made empiric replacement seductive, and CRYOSTAT-2 its refutation. Sixteen hundred and four major-haemorrhage-protocol activations across 26 UK and US centres were randomised to standard care or 3 pools of cryoprecipitate (6 g fibrinogen equivalent) within 90 minutes of randomisation and 3 hours of injury: 28-day mortality was 25.3% against 26.1% (OR 0.96, p = .74), with thrombotic events identical (12.7% versus 12.9%).^[28] Early empiric high-dose cryoprecipitate does not improve survival. Do not give it to everyone.^[28]

Yet fibrinogen still matters — as achieved ratio, not empiric dose. In 49,301 massively transfused civilians, high cryoprecipitate-to-red-cell ratios (1:1 or better) halved adjusted 6-hour mortality against low ratios (adjusted OR 0.52; unadjusted 11.8% versus 21.3%), protecting at 24 hours too (adjusted OR 0.74) with medium ratios protective at 6 hours — the 2019 Joint Trauma System guideline's empiric recommendation, tested a decade later in civilian blood.^[29] Resolve the tension as the examiner expects: CRYOSTAT-2 tested giving fibrinogen blindly and early; the ratio analysis measured achieving fibrinogen repletion alongside red cells — targeted replacement guided by documented hypofibrinogenaemia with bleeding is the synthesis both papers permit.^[28][29]

The balanced centre shows how rarely targeting is even needed when ratios run right: under aggressive early 1:1:1 beginning prehospital, hypofibrinogenaemia (below 150 or low ROTEM angle) struck under 1% of all patients, 2% of level-1 activations and 7% of emergency-release recipients — and among the hypofibrinogenaemic, early cryoprecipitate changed nothing (40% versus 47% survival), so routine concentrated fibrinogen in the protocol is unsupported.^[30] In older adults given fibrinogen supplementation with shock, early outcomes matched the young — 6- and 24-hour mortality unlinked to age — while in-hospital mortality carried the age penalty (adjusted OR 1.96) and product requirements actually fell with age (5 fewer red-cell units at 4 hours): resuscitate the elderly bleeder by the same rules, and counsel the family on the hospital course, not the first night.^[31] The paediatric fibrinogen question stays open by design: FEISTY-junior will randomise 68 severely injured children to concentrate versus cryoprecipitate at FIBTEM A5 of 10 or less, measuring time to replacement — a protocol, not a result, and candidates who quote it as evidence fail.^[44]

Prehospital Resuscitation — blood beats salt water before the doors

Ground ambulances now carry the trial evidence helicopters earned. In 299 shocked ground-EMS patients, crystalloid-only resuscitation killed 15.5% against 5.4% with packed red cells and 4.3% with whole blood — absolute risk reductions near 10–11 points, numbers needed to treat of about 10 and 9 — with shock index improving most after red cells.^[37] The PAMPer secondary analysis ranks the options: prehospital PRBC-plus-plasma cut adjusted 30-day mortality hardest (HR 0.38), plasma alone next (HR 0.57), red cells alone next (HR 0.68) — every unit of each helping per-unit — while crystalloid volume among blood recipients raised mortality (HR 1.65).^[39] Blood first, salt water least: the prehospital hierarchy in one sentence.^[37][39]

Plasma's prehospital form matters. French lyophilised plasma, randomised against saline in 134 analysed patients, moved nothing — arrival INR 1.21 versus 1.20, massive transfusion and 30-day survival identical — a neutral that keeps lyophilised plasma logistically interesting but clinically unproven.^[38] Danish helicopter practice shows the selection reality: transfusion flew on 0.9% of missions, 24-hour mortality 13% and 30-day 26%, with arrivals shocked by lactate and base excess yet coagulation-normal — the exact patients in whom DCR must start before labs.^[37][46] Set these benefits against global availability — fewer than half of Brazilian centres with any massive-transfusion protocol, fewer than one in five with whole blood — and the implementation moral writes itself: prehospital blood saves lives where systems deliver it, and most systems do not yet deliver it.^[1]

Harms, VTE & Pitfalls — the priced list

Every unit is a decision, and the bedside review names five harms with their minimising moves: circulatory overload (slow the rate, one unit at a time, consider diuretics), allergic reactions (plasma-free components, consider antihistamines), hypothermia (warm the patient — common and dangerous in massive transfusion), lung injury (limit pulmonary inflammation where possible), and haemolytic reactions (rigorous cross-checks, since human error causes them) — above all, minimising exposure to blood components is fundamental to adverse-event avoidance.^[45] Over-resuscitation is DCR's own attributable harm: standard resuscitation carried triple the ARDS, double the multi-organ failure and sevenfold the DIC of hypotensive strategy, while crystalloid volume independently raised death among blood recipients.^[39][3]

Thrombosis follows haemostasis on a timetable PROPPR mapped: 13% suffered venous thromboembolism, pulmonary embolus predominating in the first 72 hours, with a statistical 12-day hinge between early and late disease — early events tracking plasma transfusion, sepsis and pelvic-or-femur fracture; late events tracking dialysis, older age, and delayed achievement of 1:1:1 among 1:1:2 patients.^[41] So start mechanical prophylaxis the moment bleeding stops, escalate to chemoprophylaxis as soon as the surgeon permits, and remember that sluggish ratio achievement is itself a late-clot risk.^[41] Three pitfalls close the list, each with its trial anchor: TXA beyond its window (harm signal past 3 hours), calcium unmonitored under citrate load (half of plasma recipients hypocalcaemic), and empiric fibrinogen for all (CRYOSTAT-2 neutral) — the viva fails candidates on exactly these three.^[17][21][28]

Special Populations & Systems — same doctrine, shifted emphasis

Older adults bleed to death early at the same rate and die in hospital more: fibrinogen-supplemented shock showed no age link at 6 or 24 hours yet doubled adjusted in-hospital mortality — resuscitate fully, prognosticate cautiously, and expect lower product bills with age rather than higher.^[31] Children bleed rarely and die fast when they do: 2.5% of injured children received blood within 24 hours over a decade of English-Welsh-Northern Irish data, use flat across ten years, red cells dominating (84%) with plasma, platelets and cryoprecipitate in single digits — while paediatric haemorrhagic shock carries 36–50% mortality, higher than adults, and half of paediatric trauma deaths land inside 24 hours with nearly a third deemed preventable.^[42][43] Paediatric DCR strategies remain unvalidated for want of high-quality evidence despite a decade of growth — so adapt adult principles (crystalloid restriction, hypotension, balanced products) without claiming paediatric proof.^[43]

The brain-injured keep their exception in every section because examiners test it in every section: no hypotension, TXA by the coma-scale rule (benefit persisting past 2 hours when GCS sits below 9), and viscoelastic interpretation tempered by the non-significant subgroup hint rather than driven by it.^[1][19][25] Systems decide more than science: American balanced practice tripled in six years yet remains hospital-lottery medicine; Brazilian centres lack protocols, whole blood and viscoelastic testing at once; Danish helicopters transfuse rarely but precisely — and everywhere, the centres running a protocol beat the centres improvising.^[11][1][46]

Evidence, Guidelines & Regional Differences — who proved what, where

EAST's 2017 practice-management guideline remains the ratio backbone (protocol OR 0.61, plasma OR 0.60, platelets OR 0.44, empiric equality, conditional TXA) — American verification culture in one paragraph.^[8] The Joint Trauma System's 2019 cryoprecipitate recommendation now carries civilian validation through the 49,301-patient ratio analysis rather than through CRYOSTAT-2, which tested a different question and answered no.^[29][28] Australasian and British training frames DCR inside the severe-trauma continuum (RACS/GSA Emergency Management of Severe Trauma; UK TARN registry practice with its paediatric transfusion audits and its TXA equity data), while the Brazilian survey and Danish HEMS cohorts remind candidates that guidelines assume blood banks, helicopters and laboratories many hospitals lack.^[1][42][46] Quote trials for physiology, guidelines for practice, and registries for reality — the examiner rewards all three in that order.^[20]

Exam Pearls — the one-liners that score

• PROPPR in one breath: no mortality difference, fewer exsanguinations (9.2 versus 14.6%), more haemostasis (86 versus 78%), no extra complications — equal ratios from the first cooler.^[5]
• TXA in one breath: 1 g then 1 g, inside 90 minutes (adjusted RR 0.64) or at most 2 hours — beyond 3 hours harm (RR 1.44) — and women benefit equally yet receive it at odds of 0.39.^{[16][17][18][20]}
• Whole blood in one breath: two 2026 randomised trials neutral (TOWAR adjusted OR 1.24; UK relative risk 1.02) — safe, logistically simpler, physiologically kinder, superiority unproven.^[12][13]
• Calcium in one breath: half of plasma recipients hypocalcaemic, nearly all massive-transfusion patients low, severe lows doubling death — check ionised calcium with every round, replace, and claim no dose.^[21][23]
• Viscoelastic in one breath: assays see what labs miss, ITACTIC showed no outcome difference, secondaries showed undertreatment not assay failure, Cochrane says very uncertain — adjunct, never oracle.^[25][26][27]
• Fibrinogen in one breath: empiric high-dose fails (CRYOSTAT-2 OR 0.96) while achieved high ratio protects (6-hour adjusted OR 0.52) — target the low, never flood the protocol.^[28][29]

Revision summary

• Damage control resuscitation is hypotensive, blood-first, crystalloid-limited resuscitation against the diamond of death — military-born, circulation-first, protocol-delivered — and may spare borderline patients an open abdomen.^[1][47]
• Activate on physiology (penetrating, FAST-positive, ≤90 systolic, ≥120 pulse), never on labs; weighted scores discriminate better but gestalt still enrols a third of trial bleeders.^[32][34][35]
• Run equal ratios early (EAST ORs 0.61/0.60/0.44; PATCH high-plasma adjusted OR 0.50; Bayesian PROPPR 93%/87%) while admitting delivery lags evidence by years.^[8][9][6]
• Give TXA as 1 g over 10 minutes then 1 g over 8 hours inside 90 minutes (≤1-hour RR 0.68; >3-hour RR 1.44; >90-minute adjusted RR 1.04; GCS-below-9 extension) and chase the untreated woman.^{[16][17][18][19][20]}
• Check ionised calcium with every round (53% post-plasma; 97% in massive transfusion; severe doubling death), replace without a fixed-dose claim, and warm the patient against overload, allergy, lung injury and error.^[21][23][45]
• Use viscoelastic assays to see early and treat faster (68 versus 110 minutes) without superiority claims; replace fibrinogen when documented low; move blood prehospital (NNT ≈9–10) where the system allows.^[26][29][37]

The Brazilian reality check: 47.9% MTP availability with 18.2% whole-blood use.^[1]

References47ShowHide

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