Trauma Primary and Secondary Survey — Part 3: Damage Control Resuscitation & Transfusion

1. Damage Control Resuscitation — Overview

1.1 Concept and Evolution

Damage control resuscitation (DCR) is a systematic approach to the management of the severely hemorrhaging trauma patient that integrates permissive hypotension, hemostatic resuscitation with balanced blood product ratios, limitation of crystalloid administration, and aggressive prevention/correction of the lethal triad of hypothermia, acidosis, and coagulopathy. DCR is performed in parallel with damage control surgery (DCS), in which operative intervention is limited to the minimum necessary to control hemorrhage and contamination, with definitive repair deferred to a later stage after physiologic stabilization.^{1 2 3}

The traditional approach of aggressive crystalloid resuscitation to normalize blood pressure has been shown to worsen outcomes in hemorrhaging trauma patients by:

• Diluting coagulation factors and platelets (dilutional coagulopathy)
• Disrupting nascent clot formation at sites of vascular injury
• Increasing hydrostatic pressure and “popping the clot”
• Exacerbating hypothermia (unless fluids are warmed)
• Contributing to abdominal compartment syndrome and ARDS from fluid overload
• Worsening the inflammatory response

1.2 The Lethal Triad (Trauma Triad of Death)

The lethal triad describes three interrelated physiologic derangements that, when present together, create a self-reinforcing cycle of deterioration with high mortality. Each element worsens the other two, and all three must be addressed simultaneously.^{1 2}

1.3 Acute Traumatic Coagulopathy (ATC)

Acute traumatic coagulopathy is an endogenous coagulopathy that develops within minutes of severe injury and is present in approximately 25-35% of severely injured patients on arrival to the trauma center. It is distinct from the iatrogenic coagulopathy caused by dilution and hypothermia and is driven by:^{4 5}

• Tissue injury: Massive tissue factor release activates the extrinsic coagulation pathway and consumes clotting factors
• Hypoperfusion: Shock activates the thrombomodulin-protein C anticoagulant pathway, which inactivates factors Va and VIIIa and promotes fibrinolysis via tissue plasminogen activator (tPA) release
• Hyperfibrinolysis: Occurs in a subset of patients and is associated with extremely high mortality (> 70%); manifests as oozing from wound edges, IV sites, and mucosal surfaces
• Inflammation: The systemic inflammatory response to trauma activates complement, neutrophils, and endothelial glycocalyx degradation, all of which contribute to coagulopathy

Markers of ATC on arrival:

2. Permissive Hypotension (Hypotensive Resuscitation)

2.1 Rationale

In patients with active, uncontrolled hemorrhage, resuscitation to normal systolic blood pressure targets may worsen bleeding by increasing hydrostatic pressure at the site of vascular injury, disrupting early clot formation, and diluting coagulation factors. The landmark 1994 trial by Bickell et al. demonstrated improved survival with delayed fluid resuscitation in hypotensive patients with penetrating torso injuries.⁶

2.2 Targets

2.3 Duration and Endpoint

• Permissive hypotension is a temporizing strategy that should be maintained only until definitive surgical or angiographic hemorrhage control is achieved
• Once hemorrhage is controlled, normal resuscitation targets are resumed (MAP ≥ 65 mmHg, adequate urine output, normalizing lactate)
• Prolonged permissive hypotension (> 60-90 minutes) may worsen end-organ ischemic injury — the urgency of definitive hemorrhage control cannot be overstated^{1 2}

2.4 Practical Implementation

• Minimize crystalloid — use only enough to maintain the permissive hypotension target; replace volume primarily with blood products
• Titrate blood product administration — administer rapidly enough to maintain the target, but do not overshoot
• Avoid vasopressors as primary therapy for hemorrhagic shock — vasopressors increase afterload without restoring intravascular volume and may worsen tissue ischemia; they are used only as a temporizing bridge when blood products are not immediately available, or after adequate volume is restored
• Exception: Neurogenic shock may require vasopressors (norepinephrine) in addition to volume

3. Massive Transfusion Protocol (MTP)

3.1 Definition

Massive transfusion is classically defined as the replacement of the patient’s entire blood volume (approximately 10 units of packed red blood cells [PRBCs] in a 70-kg adult) within 24 hours, or the transfusion of > 4 units of PRBCs within 1 hour with anticipated ongoing need. The massive transfusion protocol is an institutional protocol that facilitates the rapid delivery of balanced blood products to the bedside.^{1 2 7 8}

3.2 Activation Criteria

MTP activation should occur early, before laboratory results are available, based on clinical assessment. Validated prediction scores include:^{8 9}

ABC Score (Assessment of Blood Consumption)

Score ≥ 2: activiate MTP (sensitivity 75-85%, specificity 85-90%)

Additional Clinical Triggers for MTP Activation

• Hemodynamic instability (SBP < 90 mmHg) not responding to initial crystalloid bolus (1 liter) with a mechanism consistent with hemorrhage
• Clinical evidence of ongoing significant hemorrhage (active external bleeding, expanding hematoma, hemodynamic deterioration)
• Shock Index > 1.0 with hemorrhagic mechanism
• Trauma surgeon or emergency physician clinical judgment

3.3 Balanced Resuscitation — The 1:1:1 Ratio

The cornerstone of damage control resuscitation is the administration of blood products in a balanced ratio that approximates the composition of whole blood, replacing not just oxygen-carrying capacity (red cells) but also coagulation factors (plasma) and platelets.^{7 10}

Evidence — The PROPPR Trial (2015):

The landmark Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial compared 1:1:1 (plasma:platelets:PRBCs) vs. 1:1:2 ratios in 680 severely injured patients. Key findings:⁷

• No significant difference in 24-hour or 30-day mortality between groups (overall mortality ~22% in both groups)
• The 1:1:1 group achieved hemostasis significantly more often (86% vs. 78%, p=0.006)
• The 1:1:1 group had significantly fewer deaths from exsanguination in the first 24 hours (9.2% vs. 14.6%, p=0.03)
• No increase in transfusion-related complications (ARDS, multiorgan failure) in the 1:1:1 group
• Conclusion: The 1:1:1 ratio is the current standard of care for massive transfusion in trauma

3.4 Practical MTP Implementation

3.5 Uncrossmatched and Emergency Release Blood

4. Tranexamic Acid (TXA)

4.1 Mechanism

Tranexamic acid is a synthetic lysine analogue that inhibits fibrinolysis by blocking the lysine-binding sites on plasminogen, preventing its conversion to plasmin and subsequent clot degradation. It stabilizes formed clot and reduces ongoing fibrinolytic hemorrhage.¹¹

4.2 Evidence — The CRASH-2 Trial

The CRASH-2 trial (2010) was a landmark international randomized controlled trial of 20,211 adult trauma patients with significant hemorrhage (or at risk of significant hemorrhage) randomized to TXA or placebo. Key findings:¹¹

• All-cause mortality was significantly reduced in the TXA group (14.5% vs. 16.0%, p=0.0035)
• Death due to bleeding was significantly reduced (4.9% vs. 5.7%, p=0.0077)
• No increase in vascular occlusive events (PE, DVT, MI, stroke)
• Time-dependent benefit: TXA was most effective when given within 1 hour of injury (mortality reduction from 7.7% to 5.3%); still beneficial at 1-3 hours (mortality reduction from 7.4% to 6.4%); NO benefit and possible harm if given > 3 hours after injury
• The study included both blunt and penetrating trauma patients

4.3 Dosing Protocol

Practical points:

• TXA should be administered as early as possible — ideally in the prehospital setting
• The loading dose can be given as a slow IV push over 10 minutes or mixed in 100 mL normal saline
• Do NOT give TXA > 3 hours after injury — there is no benefit and a signal toward increased mortality from vascular thrombotic events in the late administration group
• Rapid IV push of TXA can cause transient hypotension — administer over 10 minutes minimum
• No dose adjustment is needed for renal or hepatic impairment in the acute trauma setting

4.4 Indications in Trauma

5. Crystalloid Limitation

5.1 Rationale

Excessive crystalloid administration in the hemorrhaging trauma patient is associated with:^{1 2 3}

• Dilutional coagulopathy (dilution of clotting factors and platelets)
• Hypothermia (if fluids not warmed)
• Acidosis (normal saline contains supraphysiologic chloride — large-volume infusion causes hyperchloremic metabolic acidosis)
• Tissue edema (interstitial fluid accumulation), which causes:
  • Abdominal compartment syndrome (increased intra-abdominal pressure)
  • Pulmonary edema / ARDS
  • Extremity compartment syndrome
  • Cerebral edema (particularly harmful in TBI)
• Increased inflammation and immune dysfunction

5.2 Current Recommendations

• Limit crystalloid to the minimum volume necessary to maintain the permissive hypotension target while blood products are being prepared
• A reasonable initial crystalloid volume is 1 liter of warm balanced crystalloid (lactated Ringer’s or Plasma-Lyte is preferred over normal saline to reduce hyperchloremic acidosis)
• Once blood products are available, crystalloid infusion should be stopped and resuscitation should transition entirely to blood products
• Target total crystalloid < 1-2 liters in the resuscitation phase^{1 2 3}

6. Hypothermia Prevention and Management

6.1 Temperature Thresholds

6.2 Prevention and Treatment Strategies

7. Acidosis Correction

7.1 Monitoring

7.2 Treatment

• Primary treatment: Restore tissue perfusion through hemorrhage control and volume resuscitation — acidosis in trauma is predominantly due to hypoperfusion, and it will correct as perfusion improves
• Sodium bicarbonate: Generally not recommended for routine use in hemorrhagic shock; may be considered if pH < 7.1 with hemodynamic instability, but the evidence is weak. Risks include paradoxical intracellular acidosis, left-shift of the oxyhemoglobin dissociation curve (reducing oxygen delivery), hypernatremia, and hyperosmolality
• THAM (tromethamine): An alternative buffer that does not generate CO2; may be considered in severe acidosis, particularly with concurrent hypernatremia
• Avoid hyperventilation as a treatment for metabolic acidosis — while it may transiently improve pH, it reduces CO2 and causes cerebral vasoconstriction (harmful in TBI) and does not address the underlying cause

8. Calcium Supplementation During Massive Transfusion

8.1 Rationale

Citrate is the anticoagulant used in stored blood products (PRBCs, FFP, platelets). During massive transfusion, the rapid infusion of citrate-containing products overwhelms the liver’s capacity to metabolize citrate. Citrate chelates ionized calcium, causing hypocalcemia, which:¹³

• Impairs myocardial contractility (can cause cardiogenic shock and cardiac arrest)
• Worsens coagulopathy (calcium is essential for multiple steps in the coagulation cascade — it is Factor IV)
• Causes neuromuscular dysfunction (tetany, paresthesias)

8.2 Monitoring and Treatment

9. Viscoelastic Hemostatic Assays (TEG/ROTEM)

9.1 Overview

Thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are point-of-care viscoelastic assays that provide a comprehensive, real-time assessment of the entire coagulation process — from initial clot formation through clot strength to fibrinolysis. They provide results within 10-15 minutes (compared to 45-60 minutes for conventional coagulation studies) and can guide goal-directed transfusion therapy.^{14 15}

9.2 Key Parameters

9.3 TEG/ROTEM-Guided Transfusion Algorithm (Simplified)

9.4 Advantages Over Conventional Coagulation Testing

10. Whole Blood Resuscitation

10.1 Rationale

Whole blood contains all blood components (red cells, plasma, platelets, and coagulation factors) in physiologic ratios and concentrations. The concept of whole blood resuscitation represents a return to the approach used in the pre-component therapy era and in military settings, where it has demonstrated improved outcomes.^{16 17}

10.2 Types of Whole Blood

10.3 Current Evidence and Practice

• Military data demonstrate improved survival with warm fresh whole blood compared to component therapy in combat casualties¹⁶
• Civilian use of LTOWB is expanding rapidly, with multiple level I trauma centers incorporating it into MTP
• LTOWB provides a simulated 1:1:1 ratio in a single unit, simplifying logistics and reducing time to balanced resuscitation
• Typical dose: 1-2 units LTOWB as the initial resuscitation product, followed by component therapy as needed
• LTOWB is particularly valuable in the prehospital and early in-hospital phases when component therapy logistics may cause delays

11. Damage Control Surgery Integration

11.1 Principles

Damage control surgery is the surgical component of the damage control philosophy. It recognizes that in the most severely injured patients, definitive operative repair during the initial operation results in prohibitive mortality due to ongoing physiologic deterioration. The strategy is:^{1 2 18}

11.2 Indications for Damage Control Approach

• pH < 7.2
• Core temperature < 35 degrees C
• Clinical coagulopathy (non-surgical diffuse bleeding)
• Massive transfusion (> 10 units PRBCs)
• Anticipated need for prolonged operative time (> 90 minutes) in a physiologically compromised patient
• Inability to achieve definitive repair due to extent of injuries
• Need for reassessment of bowel viability after resuscitation

References