Blood Component Therapy
One unit of FFP or thawed plasma is the plasma taken from a unit of whole blood. FFP is frozen within eight hours of collection. FFP contains all coagulation factors in normal concentrations. Thawed plasma may be transfused up to 5 days after thawing and contains slightly decreased levels of Factor V (66+/-9%) and decreased Factor VIII levels (41+/-8%). Plasma is free of red blood cells, leukocytes and platelets. One unit is approximately 250mL and must be ABO compatible. Rh factor need not be considered. Since there are no viable leukocytes, plasma does not carry a risk of CMV transmission or Graft Vs. Host Disease (GVHD).
Plasma transfusion is indicated in patients with documented coagulation factor deficiencies and active bleeding, or who are about to undergo an invasive procedure.
Deficiencies may be congenital or acquired secondary to liver disease, warfarin anticoagulation, disseminated intravascular coagulation, or massive replacement with red blood cells and crystalloid/colloid solutions. FFP should not be used for Hemophilia B (Factor IX) deficiency unless Factor IX concentrate is not available. FFP, but not thawed plasma, can be used for Factor V deficiency. Recombinant or Factor VIII concentrates should be used to replace Factor VIII.
Usually, there is an increase of at least 1.5 times the normal PT or PTT, or an INR ≥ 1.6 before clinically important factor deficiency exists. This corresponds to factor levels <30% of normal.
Reversal of warfarin anticoagulation with plasma is indicated only if significant bleeding or risk is present. Often it will require recurrent transfusion to maintain normal factor levels. Otherwise, reversal can be achieved by giving Vitamin K or holding warfarin two to three days prior to a planned procedure. Rapid reversal for life threatening bleeding may be achieved with recombinant Factor VIIa (Novo7®).
Plasma is indicated in the treatment of thrombotic thrombocytopenic purpura (TTP), usually in conjunction with plasma exchange.
Plasma should not be used for volume expansion unless the patient also has a significant coagulopathy and is bleeding. Pediatric patients dosing is 10-15mL/kg, to provide ~15-20% rise in factor levels.
Volume of 1 Unit Plasma: 200-250 mL
1 mL plasma contains 1 u coagulation factors
1 Unit contains 220 u coagulation factors
Factor recovery with transfusion = 40%
1 Unit provides ~80 u coagulation factors
70 kg X .05 = plasma volume of 35 dL (3.5 L)
80 u = 2.3 u/dL = 2.3% (of normal 100 u/dL) 35 dL
In a 70 kg Patient:
1 Unit Plasma increases most factors ~2.5%
4 Units Plasma increase most factors ~10%
Initial Dose of FFP
10cc/Kg (round up to nearest 200cc) = #units FFP / 200 cc/unit FFP
Usually an increase in factor levels of at least 10% will be needed for any significant change in coagulation status, so the usual dose is four units, but the amount will vary depending on the patient’s size and clotting factor levels. Hematology consultation is advised concerning the dose of plasma.
* These numbers assume normal platelet function. Conditions that may affect platelet function include renal failure, medications, leukemias and myelodysplasias, and congenital disorders. Bleeding Time is a poor predictor of surgical bleeding. The Usefulness of Platelet Function Analysis (PFA) in predicting surgical bleeding is unknown.
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