What is the approach to blood component therapy in a patient with significant bleeding due to trauma or surgery, considering their condition, past medical history, and laboratory parameters such as hemoglobin levels, platelet count, and coagulation studies?

Blood Component Therapy in Trauma and Surgical Bleeding

Immediate Action: Activate Massive Transfusion Protocol

In patients with significant bleeding from trauma or surgery, immediately activate massive transfusion protocol with 1:1:1 ratio of packed red blood cells (RBC):fresh frozen plasma (FFP):platelets, administer tranexamic acid 1g IV within 3 hours of injury, and prioritize surgical hemorrhage control over waiting for laboratory results. 1, 2

Initial Resuscitation Strategy

Hemorrhage Control Takes Priority

• Surgical or interventional radiological hemorrhage control is the definitive treatment and must not be delayed for laboratory results or attempts at medical optimization. 1, 2
• Use temporary hemostatic devices immediately while arranging definitive surgical control. 1
• Maintain permissive hypotension during active bleeding—do not attempt to normalize blood pressure, as this disrupts clot formation and worsens outcomes. 1, 2

Tranexamic Acid Administration

• Give tranexamic acid 1g IV immediately upon recognition of significant traumatic bleeding, followed by 1g over 8 hours—this must occur within 3 hours of injury to reduce mortality. 1, 2
• Do not withhold tranexamic acid while waiting for laboratory confirmation; the 3-hour window is absolute. 1, 2

Blood Product Administration During Active Hemorrhage

Balanced Ratio Transfusion

• Deliver RBC, FFP, and platelets in 1:1:1 ratio empirically during massive transfusion without waiting for coagulation studies. 1, 2
• This balanced approach prevents dilutional coagulopathy that occurs when RBC are given alone. 2

Specific Component Targets

• RBC: Transfuse to maintain oxygen delivery; in active hemorrhage, transfusion thresholds are superseded by the need for volume replacement with blood products rather than crystalloids. 1, 2
• FFP: Give in 1:1 ratio with RBC during ongoing bleeding to replace coagulation factors consumed during hemorrhage. 1, 2
• Platelets: Maintain platelet count >50 × 10⁹/L during active bleeding; target >100 × 10⁹/L in traumatic brain injury or multiple trauma. 1, 2
• Cryoprecipitate: Administer two pools (10 units total) empirically during massive transfusion before fibrinogen results are available, as each pool contains approximately 2g of fibrinogen. 1, 3

Laboratory-Guided Therapy After Hemorrhage Control

Point-of-Care Testing

• Use viscoelastic testing (TEG/ROTEM) over traditional PT/APTT for real-time coagulation assessment once available. 1
• Traditional coagulation studies take too long to guide therapy during active hemorrhage. 1

Target Laboratory Values

Once bleeding is controlled, aim for:

• Fibrinogen >1.5 g/L (>2 g/L in obstetric hemorrhage). 1, 3
• Platelet count >50 × 10⁹/L. 1
• INR <1.5. 1

Fibrinogen Replacement Specifics

• If fibrinogen <1.5 g/L with ongoing bleeding, give two pools of cryoprecipitate (10 units), which provides approximately 4g of fibrinogen. 3
• This is far more efficient than FFP, which provides only 2g of fibrinogen per four units. 3
• Administer through standard blood giving set with 170-200 μm filter. 3

Critical Pitfalls to Avoid

Do Not Delay Surgery

• Never delay surgical hemorrhage control to obtain or correct laboratory values—deliver blood products empirically and operate immediately. 1, 2
• The "lethal triad" of coagulopathy, hypothermia, and acidosis does not establish futility if appropriate damage control resuscitation is provided. 2

Do Not Use Crystalloids for Volume Replacement

• Avoid crystalloid administration during hemorrhagic shock, as this worsens dilutional coagulopathy, hypothermia, and disrupts clot formation. 1, 2
• Use blood products for volume replacement during active hemorrhage. 1, 2

Temperature Management

• Aggressively maintain normothermia by reducing heat loss and actively warming hypothermic patients, as hypothermia severely impairs coagulation. 1, 2

Hemoglobin Thresholds in Non-Hemorrhagic Settings

For context in stable patients without active bleeding:

• RBC transfusion is rarely indicated when hemoglobin >10 g/dL and almost always indicated when <6 g/dL. 4
• Between 6-10 g/dL, transfusion decisions should be based on the patient's risk of complications from inadequate oxygenation rather than a single trigger value. 4

However, these thresholds do not apply during active hemorrhage, where empiric massive transfusion protocol supersedes hemoglobin-based triggers. 1, 2