Damage-control resuscitation and permissive hypotension

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Damage-control resuscitation is a bridge from injury to haemostasis. It avoids attempting to normalise every variable while blood is still leaving the circulation. The components are early recognition and protocol activation, immediate control of accessible bleeding, restrained crystalloid, haemostatic component therapy, timely antifibrinolysis, active warming, calcium and coagulation monitoring, and rapid operative, radiological or combined source control. No fluid strategy compensates for delayed haemostasis.

Permissive hypotension describes restricted volume and pressure during uncontrolled bleeding in selected patients. It is not a universal systolic target and must be time-limited. A palpable central pulse, consciousness, peripheral perfusion, blood pressure trend, lactate and response to small resuscitation increments guide care under local protocol. Excess pressure can increase bleeding; excessive restriction produces organ ischaemia. The safest balance changes minute by minute as haemostasis approaches.

Traumatic brain injury is the central exception. Cerebral perfusion depends on arterial pressure minus intracranial pressure, so systemic hypotension adds secondary ischaemia to structural injury. Suspected spinal cord injury also requires avoidance of hypoperfusion, and pregnancy requires maternal circulation adequate for uteroplacental flow. Frail, older and chronically hypertensive people may have altered autoregulation. In mixed injury, senior teams explicitly state which perfusion objective is dominant rather than applying a generic target.

Haemostatic resuscitation begins with the locally defined balanced blood pack because rapid laboratory precision is initially unavailable. As conventional coagulation or viscoelastic data return, individualise plasma, platelets and fibrinogen. Blood should be warmed. Serial ionised calcium identifies citrate-related deficiency; falling fibrinogen or clot strength indicates substrate failure. Correcting acidosis principally requires restoring flow and ending blood loss, not using bicarbonate to disguise ongoing oxygen debt.

Damage-control intervention shortens the first operation or procedure to what is necessary for survival: pack bleeding, control or shunt vessels, limit contamination, stabilise the pelvis or long bones, and use temporary closure when swelling and physiology make reconstruction unsafe. Interventional radiology may embolise arterial sources, while hybrid pathways combine approaches. The decision uses shock severity, temperature, coagulopathy, injury burden and expected duration of definitive surgery rather than one laboratory threshold.

Reassessment separates an appropriate temporary strategy from therapeutic inertia. A stable responder may proceed to CT and targeted intervention; a transient responder has continued loss and needs accelerated control; a non-responder may require immediate theatre or hybrid care. Rising vasopressor dose is not evidence of haemostasis. Positive-pressure ventilation and induction can precipitate collapse by reducing preload, so airway and surgery teams coordinate drugs, blood and incision readiness.

After control, resuscitation priorities reverse. Restore adequate organ perfusion, clear oxygen debt, rewarm, correct specific coagulation deficits, assess kidney and lung function and return for planned definitive surgery when physiology permits. Avoid ongoing empiric transfusion once bleeding has stopped. Review anticoagulation and initiate mechanical then pharmacological venous-thromboembolism prevention when safe, because the post-trauma state becomes strongly prothrombotic.

Key points

Damage-control resuscitation combines restricted volume before control, haemostatic blood-component support, tranexamic acid, warming, calcium surveillance and rapid anatomical haemostasis.
Permissive hypotension is a temporary bleeding-control strategy, not a fixed number or endpoint; judge consciousness, pulses, refill, lactate and response within the local protocol.
Do not use a low-pressure strategy indiscriminately in traumatic brain or spinal cord injury, where avoiding hypotension and maintaining perfusion takes priority.
Prefer warmed blood components to large crystalloid loads during active major bleeding and use the local major-haemorrhage pack until laboratory or viscoelastic results individualise therapy.
Give adult tranexamic acid 1 g IV over 10 minutes followed by 1 g over 8 hours as early as possible and within 3 hours of injury.
Measure core temperature, ionised calcium, blood gas, fibrinogen and platelets repeatedly; correct the physiology that permits clot formation while the source is treated.
Damage-control surgery controls contamination and bleeding quickly, accepting temporary packing or closure when definitive reconstruction would prolong lethal physiological stress.
Once haemostasis is achieved, transition deliberately to normal perfusion, targeted component replacement, definitive repair, critical-care surveillance and thromboprophylaxis planning.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Uncontrolled traumatic bleeding

Thoracic, abdominal, pelvic, vascular and multiple long-bone injuries create continuing loss that cannot be corrected by infusion until the anatomical source is treated.

Resuscitation-related dilution

Excess crystalloid and unbalanced component replacement dilute coagulation proteins and platelets, cool the patient and increase endothelial and tissue oedema.

High-risk physiology

Prolonged entrapment, delayed presentation, hypothermia, anticoagulation and severe tissue destruction accelerate coagulopathy and reduce tolerance of further hypotension.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Clot disruption
Raising hydrostatic pressure and disturbing early clot before vessel control may increase bleeding, especially when coagulation and vascular tone are already impaired.
2
Oxygen debt
Insufficient circulating volume and haemoglobin reduce tissue oxygen delivery, producing lactate, cellular dysfunction and eventual loss of vasomotor compensation.
3
Haemostatic failure
Shock-driven fibrinolysis combines with consumption, dilution, acidosis, hypothermia and hypocalcaemia to weaken clot formation and accelerate blood loss.
4
Competing perfusion targets
A restricted pressure that limits torso bleeding may inadequately perfuse an injured brain or spinal cord, so physiological priorities depend on the dominant injury.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Appropriate restricted resuscitation

An adult with active torso bleeding, no brain or cord concern and preserved minimal perfusion may receive restrained volume while immediate haemostasis is arranged.

Brain-perfusion exception

Head mechanism, reduced GCS, unequal pupils, seizure or CT brain injury requires avoidance of hypotension rather than routine acceptance of a low pressure.

Physiological exhaustion

Falling temperature, worsening base deficit, loss of radial pulse, reduced consciousness and coagulopathic ooze show dwindling reserve and mandate faster control.

Transient response

Short-lived improvement after components indicates continued bleeding; repeating the same resuscitation without changing the route to control is unsafe.

Citrate burden

Hypotension, poor contraction, prolonged QT or low measured ionised calcium during transfusion suggests clinically important hypocalcaemia requiring protocol-led correction.

Control achieved

Stable haemodynamics without escalating support, improving perfusion, controlled operative field and correcting laboratory trends permit transition from damage control to definitive resuscitation.

Red flags requiring action

Persistent shock, a transient response or escalating blood requirement means damage-control resuscitation is failing unless definitive haemorrhage control is occurring simultaneously.
Traumatic brain injury, spinal cord injury, pregnancy and some older or chronically hypertensive patients can be harmed by indiscriminate permissive hypotension because organ perfusion must be preserved.
Core hypothermia, low ionised calcium, worsening acidosis, low fibrinogen or diffuse microvascular ooze signals a self-reinforcing haemostatic collapse requiring immediate correction and source control.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line serial blood gasFirst stepFirst line
Why
Track oxygen debt, ventilation and ionised calcium during resuscitation.
Interpretation and limitations
Lactate or base deficit trends help judge perfusion; lack of clearance suggests continued shock, while calcium and potassium identify transfusion-related hazards.
02
Fibrinogen and coagulation tests
Why
Identify clotting-substrate deficiency and anticoagulant effect.
Interpretation and limitations
Repeat fibrinogen, PT, APTT and platelet count; interpret alongside bleeding, dilution and component timing rather than waiting for results before initial support.
03
Preferred viscoelastic assay when availablePreferred
Why
Individualise haemostatic component therapy rapidly.
Interpretation and limitations
Clot onset, strength and lysis patterns can direct plasma, fibrinogen or platelet treatment under a validated protocol, but do not diagnose the anatomical source.
04
Focused echocardiography and eFAST
Why
Distinguish selected obstructive, cardiac and haemorrhagic causes at bedside.
Interpretation and limitations
Use findings to redirect immediate intervention; a negative abdominal view cannot exclude retroperitoneal bleeding or justify delay in a non-responder.
05
Contrast CT in a suitable responder
Why
Map injuries and direct embolisation or operation.
Interpretation and limitations
Active extravasation and organ or vascular injury guide definitive care, while deteriorating physiology during preparation should redirect away from conventional CT.
06
Core temperature monitoring
Why
Detect a reversible driver of coagulopathy.
Interpretation and limitations
Peripheral measurements may underestimate central cooling; persistent hypothermia despite active measures increases concern about exposure, cold infusion and continuing shock.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Neurogenic hypotension

Loss of sympathetic tone after spinal injury produces vasodilatation and relative bradycardia, but occult haemorrhage must be excluded before vasopressor-led treatment.

Obstructive physiology

Tension pneumothorax and tamponade impair venous return and need immediate decompression or surgical management rather than additional blood alone.

Cardiac dysfunction

Contusion, infarction, arrhythmia or stress cardiomyopathy may produce poor output despite haemostasis and can be assessed with ECG and focused echocardiography.

Anaesthetic vasodilatation

Induction, positive-pressure ventilation and sedatives remove compensatory tone and preload, revealing or worsening shock around airway and operative interventions.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01InitialStart damage-control resuscitationFirst stepMajor bleeding is suspected before anatomical control.

1Control external and junctional bleeding, splint fractures and apply a trochanteric pelvic binder when indicated while activating the major-haemorrhage protocol.
2Use warmed blood components with minimal crystalloid, administer early tranexamic acid and establish rapid access and monitoring.
3State whether restricted pressure is acceptable or whether head, spinal, pregnancy or other physiology requires stronger perfusion support.
4Mobilise the relevant surgical and interventional team and select CT only if response makes the journey safe and useful.

02EscalationMove to damage-control interventionDefinitiveEscalationShock persists, physiology deteriorates or definitive reconstruction would be excessively long.

1Choose the shortest operative, embolisation or hybrid route to stop bleeding, with anaesthesia, transfusion and trauma leadership continuing resuscitation in parallel.
2Control contamination, pack or ligate bleeding, shunt selected vessels and stabilise major skeletal sources, deferring complex reconstruction when necessary.
3Use serial gas, temperature, calcium, fibrinogen and clot assessment to correct reversible haemostatic failure during the procedure.
4Transfer to critical care with explicit packing, temporary closure, device, relook and ongoing transfusion plans.

03RecoveryTransition after haemostasisEscalationMechanical control is credible and perfusion no longer needs escalating support.

1Restore organ-appropriate pressure and oxygen delivery, rewarm and replace only the component deficits supported by ongoing bleeding or testing.
2Trend lactate, renal function, potassium, calcium, respiratory status and abdominal pressure where massive resuscitation or packing creates risk.
3DefinitivePlan definitive fixation or reconstruction after physiological recovery, with clear timing for pack removal or re-exploration.
4Reassess thrombosis and anticoagulation daily, initiating safe prophylaxis and mobilisation as bleeding risk recedes.

Key medicines and prescribing safety1 treatment · regimens, roles and cautions

Supports early haemostasis by limiting fibrinolysis during active or suspected major traumatic bleeding.

Tranexamic acid

Give 1 g by intravenous injection over 10 minutes, then infuse 1 g intravenously over the following 8 hours; initiate as soon as possible after injury and within 3 hours.

It is not a volume expander or source-control treatment; avoid routine delayed use after 3 hours, consider renal accumulation and never postpone surgery or embolisation to finish the infusion.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Secondary brain injury

Hypotension and hypoxaemia worsen neuronal ischaemia and outcome, making prolonged restricted pressure particularly dangerous when traumatic brain injury is suspected.

Multiple-organ failure

Continued oxygen debt and reperfusion inflammation injure kidney, lung, liver, heart and gut even after delayed bleeding control.

Abdominal compartment syndrome

Large-volume resuscitation, visceral oedema and packing can raise intra-abdominal pressure, reducing ventilation, venous return and renal perfusion.

Thrombotic and transfusion harm

After haemostasis, inflammation and immobility increase thrombosis, while blood exposure can cause lung injury, overload, haemolysis and alloimmunisation.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Trend pressure, pulse, capillary refill, consciousness, urine output and lactate or base deficit through each resuscitation cycle and procedure.
Measure core temperature and use active patient, room and infusion warming until normothermia is sustained.
Repeat ionised calcium, potassium, fibrinogen, platelet count and coagulation or viscoelastic testing during major transfusion.
Record blood products, crystalloid, TXA timing, estimated loss and response, linking each escalation to a source-control decision.
After haemostasis, monitor for recurrent bleeding, organ dysfunction, abdominal compartment syndrome, lung injury and venous thromboembolism.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Permissive is not passive

A temporary restricted target is safe only when source control is actively approaching and organ perfusion is repeatedly assessed.

The brain changes the target

Preventing renewed torso bleeding cannot justify hypotension that compounds traumatic cerebral ischaemia.

Vasopressors cannot create volume

Increasing vascular tone may support selected physiology but can conceal ongoing loss and never substitutes for blood and haemostasis.

Definitive surgery can be harmful

Long reconstruction in a cold, acidotic and coagulopathic patient may be less safe than temporary control followed by planned return.

Recovery needs a deliberate switch

Empiric component packs suitable during exsanguination become unnecessary and harmful once bleeding is controlled.

11Common pitfallsFrequent interpretation and management errors.

01
Using one low systolic target for every bleeding patient regardless of brain, spinal or pregnancy physiology.
02
Calling recurrent improvement after blood stability instead of recognising a transient response.
03
Continuing large crystalloid boluses that worsen dilution, cooling and tissue oedema.
04
Starting complex reconstruction while hypothermia, acidosis and coagulopathy are rapidly worsening.
05
Using vasopressor escalation to postpone identification and control of the bleeding source.
06
Continuing balanced transfusion packs unchanged after haemostasis without repeat laboratory assessment.