Understanding Plasma and Its Function
Plasma is the liquid, acellular component of blood that contains crucial proteins, including coagulation factors essential for blood clotting. Fresh Frozen Plasma (FFP) is prepared by separating plasma from whole blood and freezing it at -18°C or lower within eight hours of collection to preserve all coagulation factors, including the labile ones like Factor V and Factor VIII. This makes it a vital tool in transfusion medicine for managing or preventing bleeding in patients with clotting factor deficiencies.
Plasma is not a one-size-fits-all solution and is generally reserved for situations where more specific treatments, like clotting factor concentrates, are unavailable or inappropriate. Its administration requires ABO compatibility with the recipient's red blood cells. The amount required is determined by clinical factors and guidelines.
Primary Indications for Plasma Administration
Clinical guidelines outline several key scenarios where plasma transfusion is necessary. The decision to transfuse is typically based on the presence of active bleeding combined with documented coagulation abnormalities.
1. Massive Hemorrhage and Trauma In cases of massive blood loss, often defined as the loss of one's entire blood volume within 24 hours, the body loses coagulation factors along with red blood cells. Massive transfusion protocols (MTPs) are employed to replace lost blood volume and restore hemostatic function. These protocols often involve transfusing packed red blood cells, plasma, and platelets in a balanced ratio, such as 1:1:1, to mimic whole blood. Early administration of plasma in trauma-induced coagulopathy has been associated with improved survival.
2. Urgent Reversal of Warfarin Patients on warfarin, a vitamin K antagonist, who experience major bleeding or require emergency surgery need rapid reversal of its anticoagulant effects. While options like Prothrombin Complex Concentrates (PCCs) and Vitamin K are available, FFP serves as a classic and effective method for reversal. FFP works by supplying the vitamin K-dependent clotting factors (II, VII, IX, and X) that warfarin inhibits. Although PCCs may offer faster INR correction, FFP remains a crucial option, especially when PCCs are unavailable. Timely administration is critical; for instance, in warfarin-related intracerebral hemorrhage, delays in FFP administration can impact INR correction.
3. Coagulopathy in Liver Disease Severe liver disease impairs the synthesis of most coagulation factors, leading to an increased risk of bleeding. Plasma transfusions are frequently used to correct the resulting coagulopathy in these patients, particularly if they are actively bleeding or about to undergo an invasive procedure. However, the prophylactic use of FFP in non-bleeding cirrhotic patients before procedures is controversial and generally not recommended due to risks like volume overload. FFP may not effectively correct the INR in these patients and requires volumes that must be carefully weighed against the risks.
4. Other Key Indications
- Disseminated Intravascular Coagulation (DIC): In patients with acute DIC who are bleeding, FFP is used to replace consumed coagulation factors.
- Thrombotic Thrombocytopenic Purpura (TTP): Plasma exchange with FFP is a primary treatment for TTP, replacing the deficient ADAMTS13 enzyme.
- Congenital Factor Deficiencies: Plasma is used for patients with deficiencies for which a specific factor concentrate is not available.
Types of Plasma Products
While FFP is the most well-known, other plasma products exist with slight variations in processing and factor content.
| Product | Processing | Labile Factor Content | Common Use |
|---|---|---|---|
| Fresh Frozen Plasma (FFP) | Frozen at ≤ -18°C within 8 hours of collection. | Contains normal levels of all coagulation factors, including labile factors V and VIII. | Broad use for multiple factor deficiencies, massive transfusion, warfarin reversal. |
| Plasma Frozen within 24 Hours (PF24) | Frozen at ≤ -18°C within 24 hours of collection. | Reduced levels of labile factors V and VIII compared to FFP, but similar non-labile factors. | Similar indications as FFP, used when labile factor levels are not critically important. |
| Thawed Plasma | FFP or PF24 that has been thawed and stored at 1-6°C for more than 24 hours (up to 5 days). | Factor V and VIII levels decline progressively after thawing. | Used for similar indications, but not ideal when high levels of labile factors are needed. |
| Solvent/Detergent (S/D) Treated Plasma | Pooled plasma treated to inactivate lipid-enveloped viruses. | Reduced levels of Protein S and other factors. | Reduces infectious risk but may be associated with thrombotic events due to low Protein S. |
Risks and Contraindications
Plasma transfusion is not without risks. It should not be used for volume expansion alone or to correct a mildly prolonged INR in a non-bleeding patient.
Key Risks:
- Transfusion-Related Acute Lung Injury (TRALI): A leading cause of transfusion-related death, presenting as acute, noncardiogenic pulmonary edema.
- Transfusion-Associated Circulatory Overload (TACO): Occurs when the volume of the transfusion overwhelms the circulatory system, leading to cardiogenic pulmonary edema.
- Allergic and Anaphylactic Reactions: Can range from mild hives to severe anaphylaxis, especially in patients with IgA deficiency.
- Citrate Toxicity: Rapid, large-volume transfusions can lead to hypocalcemia as the citrate anticoagulant in the plasma binds to the patient's calcium.
- Infectious Disease Transmission: While the risk is very low due to screening, transmission of viruses and prions remains a theoretical possibility.
Contraindications:
- Situations where specific factor concentrates are available.
- Vitamin K deficiency or warfarin reversal that can be safely managed with vitamin K supplementation alone.
- Use solely for volume expansion.
- Severe Protein S deficiency.
Conclusion
The decision of when to administer plasma is a complex clinical judgment balancing the need to control or prevent bleeding against the potential risks of transfusion. The primary indications are centered on replacing multiple coagulation factors in patients with significant coagulopathy who are actively bleeding or require an invasive procedure. This includes scenarios like massive hemorrhage, urgent warfarin reversal, and complications from severe liver disease or DIC. Inappropriate use, such as for simple volume expansion or correcting minor laboratory abnormalities in non-bleeding patients, should be avoided to mitigate risks like TRALI and TACO. Adherence to evidence-based guidelines ensures that this critical resource is used safely and effectively.
For more detailed guidelines, consult the AABB (formerly American Association of Blood Banks).
