Blood Product Usage Case Studies


CASE 2


Clinical History:

A 30 year-old pregnant woman presents to the emergency room with third trimester vaginal bleeding and the sudden onset of marked pelvic pain. She is quickly admitted to the labor and delivery floor, where fetal monitoring shows severe fetal distress and ultrasound reveals placental abruption. An emergent cesarean section is performed, and packed red cells are given for a maternal hematocrit of 25%. A few minutes after the infant is delivered, the vaginal bleeding increases notably. Laboratory tests are ordered and the results are as follows:

  • PT = 150 seconds (normal = 10.7-15 seconds)

  • PTT = 150 seconds (normal = 25-40 seconds)

  • Platelet count = 15 X 109/L (normal = 140-440 X 109/L)

  • Hematocrit = 25% (normal = 37-51%)

  • Fibrinogen = 30 mg/dL (normal = 150-350 mg/dL)

  • D-Dimer = 1:256

A correction study is performed by the laboratory to further evaluate the prolonged coagulation times. When normal plasma is added to the patient's plasma, the PT and PTT correct back to within normal ranges.

Questions:

  1. What process is occurring to cause the increased bleeding in this case?

    2. Disseminated intravascular coagulation (DIC) has caused these findings, since the D-Dimer test is markedly elevated. DIC is what is referred to as a "consumptive coagulopathy". Circulating thrombin results in the widespread generation and deposition of fibrin in small blood vessels. The main things that are consumed are platelets, fibrinogen, and coagulation factors, especially Factor V and Factor VIII. Fibrinogen is disproportionately affected, compared to other clotting factors, in DIC.

  2. Are there other types of obstetrical complications that can cause this?

    3. Yes, for example retained placenta or amniotic fluid embolus can cause DIC. Any process that leads to the generation of circulating thrombin can initiate the onset of DIC, but obstetrical complications are especially notorious for leading to rapid, life-threatening DIC.

  3. What blood products are indicated in this situation?

    1. Cryoprecipitate
    2. Platelets

    3. Packed red cells if the hematocrit drops to precipitously low percentages in this young, otherwise healthy, patient.

  4. Does cryoprecipitate have all of the clotting factors that a unit of fresh frozen plasma has?

    5. No. Cryoprecipitate contains Von Willebrand Factor, Factor VIII, Factor XIII, fibrinogen, and fibronectin. The primary use is to increase fibrinogen concentrations that have decreased to the point that the patient is bleeding due to low fibrinogen.

    This is a common mistake that clinicians make--to think that cryoprecipitate is simply a concentrated version of FFP. This is not correct, and in cases where the patient needs all clotting factors for hemostasis, FFP is the appropriate product to give.

  5. Why is cryoprecipitate indicated here?

    6. The clinical scenario and the laboratory findings support a diagnosis of DIC, and the patient's fibrinogen is too low. Life-threatening bleeding generally occurs when fibrinogen concentrations fall to 60 mg/dL or lower. Ideally, the fibrinogen should be at or above 100 mg/dL before we presume that the bleeding is not due to low fibrinogen.

  6. How many units at a time of cryoprecipitate would one order in the above situation?

    7. There are specific formulas that a blood bank physician can help you calculate. In general, a good "ball park" figure to start with is 15 to 20 units of cryoprecipitate. Each unit of cryoprecipitate has only about 30 cc of volume, so a patient should tolerate the volume change resulting from transfusion of 20 units without difficulty. Remember that each unit of cryoprecipitate represents one "donor exposure" in terms of risks of viral transmission, but in DIC, the life-threatening bleeding takes precedence over this consideration.

  7. Are blood products typically the "cure" for disseminated intravascular coagulation? What else is usually needed before the DIC will resolve?

    8. No, blood products are a "band-aid" until the underlying cause of the DIC is determined and treated. In this case, delivery of the infant and evacuation of the uterus is likely to help, and the patient's DIC may resolve quite quickly. If the patient does not stop bleeding, the surgeons will need to consider hysterectomy.