Blood Products and MBT Flashcards
Why transfuse platelets?
-Given for thrombocytopenia or dysfunctional platelets in the presence of bleeding
-Prophylactic transfusion for plt counts 10,000-20,000
How are platelets separated from whole blood?
Platelets separated from whole blood by 2 centrifugations
-Get single donor unit (with small amt of plasma)
-Volume of single unit: 30-50 mL
-Exposure to multiple donors with pooled platelets
T/F: ABO compatibility is required for platelet transfusions.
False: ABO compatibility not necessary, but desirable
What is plateletpheresis?
Obtained from single donor
-Blood withdrawal from single donor followed by return of the RBCs to the donor
-One unit of “pheresed” platelets is equal to 6 units of random donor platelets
-Minimizes donor exposure
-Volume of 200-400 mL
Apheresis is a technique of blood product donation made possible by a special machine that separates the blood components.
Describe storage and administration of platelets.
Stored at room temperature for up to 5 days with continuous gentle agitation
-Recovery of 5 day old platelets is 50%
-May take up to four hours until they are fully functional
Platelets should be administered through a filter
-Use the standard 170-micron filter
-Do not use 20-40 micron filters (blood administration)
Do not warm platelet infusions
T/F: Platelet preparations contain some volume of plasma and a few red cells
True
Why is it important that platelet preparations contain some volume of plasma?
-ABO compatibility is ideal but not required
-Patients with a history reactions to random donor platelets should receive ABO/HLA-matched platelets
Why is it important that platelet preparations contain some RBCs?
While the few red cells are not significant to cause a major hemolytic rxn, Rh sensitivity can be significant in Rh negative women of childbearing age as most plts are from Rh pos donors
-These women should be considered for Rh immunoglobin, Rhogam, to prevent Rh isoimmunization leading to future hemolytic disease of the newborn
-Rhogam can be used to treat idiopathic thrombocytopenic purpura in people who are Rh positive or used when Rh negative people receive Rh positive blood transfusion.
How does pooled platelets differ from pheresed platelets in raising the platelet count?
One unit from a pooled pack of platelets increases the platelet count about 5-10,000 platelets/μL.
One unit of pheresed platelets or 6 units of random donor platelet (6 pack) transfusion raises platelet count by 30,000-50,000/μL
How are platelets administered to children?
In Children, we usually give one unit pheresed platelets/10kg body weight to raise the platelet count by 50,000/µL
When should a platelet count of 10,000 trigger transfusion?
Non-surgical patients with thrombocytopenia and active bleeding
When should a platelet count of 30,000 trigger transfusion?
Minimally invasive procedures (central lines, thoracentesis, paracentesis, angiography)
When should a platelet count of 50,000 trigger transfusion?
Minor procedures: Lumbar puncture, epidural, endoscopy with biopsy, laparotomy in patients without other abnormalities, vaginal delivery
When should a platelet count of 75,000 trigger transfusion?
During massive blood loss
When should a platelet count of 100,000 trigger transfusion?
Risk of closed cavity bleeding: intracranial
If platelet count is between 50 - 100,000, what factors need to be considered for platelet transfusion?
1) Type of surgery
2) Extent of actual blood loss or microvascular bleeding
3) Presence of potent antiplatelet medications
4) Disorders known to affect platelet function
What are complications associated with platelet transfusion?
Minor Adverse Rxns:
-Non-hemolytic febrile reactions
-Mild allergic reactions
Major complications:
-TRALI
-TAS
-Major allergic reactions
What is TRALI?
Transfusion related acute lung injury:
-leading cause of transfusion related fatalities.
-1:5000 occurrence with a mortality rate ranging from 5-25%.
-Risk greatest for pheresis plts than any other blood component; it may even be higher than for pooled plts but this is still debatable.
-Presents as acute hypoxia and noncardiac pulm edema occurring within 6hr of blood product transfusion
What is TAS?
Transfusion Associated Sepsis
-Caused by bacterial!! contamination
-Is the 2nd or 3rd leading cause of transfusion related mortality
-Occurrence is around 1:50,000 transfusions
-Platelets carry the largest overall infectious risk in our blood supply
-Increases with duration of storage and greater with pooled plts than pheresis units
-There are tests for bacterial contamination but high rate of false negatives
-Reactions may be immediate or delayed for several hours
-Sxs: fever, rigors, flushing, abdominal cramps, myalgia, DIC, renal failure, cardiac arrest
How is FFP prepared and stored?
Preparation:
-Centrifuge blood and remove plasma
-Freeze at -18 C within 8 hours
-FFP can be stored for one year
-30 minutes to thaw → stored at 1-6° C
-Must be transfused within 24 hours for factors to be effective
-Warm FFP to 37°C prior to infusing
-Must be ABO compatible !!!!!!!!!
What is contained in FFP?
1 unit FFP = 220-250 mL
-All clotting factors in normal concentration
-Fibrinogen (1 mg per 1 mL plasma)
-Guided by PT or PTT results
What are indications for FFP administration?
1) Urgent reversal of warfarin therapy
-Alternative: Prothrombin complex concentrate—II, VII, IX, X
2) Multiple factor deficiencies with evidence of micro-vascular bleeding
-DIC with PT and/or a PTT > 1.5 times normal
3) Correction of single factor deficiencies without concentrates
4) Massive transfusion (transfusion of >1 blood volume in 24 hours, clotting factors get diluted. Need 2:1 PRBCS: FFP)
Effective coagulation can occur with factor levels 20-30% of normal.
What is Cryoprecipitate?
Made from FFP:
-FFP units thawed at 4-6° C
-During the thaw get a layer of white precipitate
-Quickly refrozen in 10-15mL of plasma at -18 C; store up to 1 year
Individual units of CRYO (10-20 mL):
-6-12 units are pooled to make a typical dose
-Given without regard to blood type (ABO) - no RBCs present
What is contained in Cryoprecipitate?
-Fibrinogen: about 30% more than found in unit FFP (150-300 mg)
-Factor VIII: 80-100 units per bag
-Von Willebrand factor
-Factor XIII
What is used instead of Cryo for the treatment of Hemophilia A and Von Willebrand’s Disease?
Humate P or Alphanate: Virally inactivated Factor VIII concentrates that also contain vWF.
-Far lower risk of blood-borne viral infection
What are indications for Cryo administration?
-Fibrinogen deficiency and microvascular bleeding: DIC, massive transfusion, severe liver disease. Keep fibrinogen above 100 mg/dL!
-Pre-surgical prophylaxis or tx of bleeding in hemophilia A and von Willebrand disease (If concentrate is not available)
-Fibrin glue: mixture of fibrinogen source and bovine thrombin (For local hemostasis)
-Uremic bleeding not responsive to DDAVP
-Factor XIII deficiency (If concentrate is not available)
Stored blood has decreased oxygen transport ability due to what metabolic changes in stored blood?
1) Decreased 2-3 DPG (within 14 days has essentially none)
-Repletion begins in hours and takes up to 36 hours to complete
2) Decreased ATP
3) Decreased RBC flexibility and flow through capillary beds
4) Up to 25% of transfused RBCs are non-viable (not capable of carrying oxygen) after 28 days of storage.
5) Hyperkalemia: ↑ 1-2 mEq/day of storage
6) Acid-Base Changes: pH of banked blood after 3 weeks of storage = 6.5; after 6 weeks of storage approaches 3
7) Citrate also binds ionized calcium = hypocalcemia in massively transfused patients.
8) Hypomagnesemia: citrate binds magnesium with equal affinity
9) Hypothermia can contribute to coagulopathy
-Platelet inhibition
-Enzymatic inhibition occurs at 34°C (rewarming may correct coagulopathy)
What is the definition of massive blood loss?
Usually 10-20 units/24 hr.
More practical: > 4 units in 1 hr with ongoing need OR blood loss > 150 mL/min with hemodynamic instability and ongoing need
What is Massive Transfusion Protocol (MTP)?
Activated by clinician in response to massive blood loss
-Blood bank ensures rapid, timely availability of blood components
-Damage control surgery
-Once control obtained, restrictive approach
What are risks associated with massive transfusions?
-Multiple organ failure
-Systemic inflammatory response syndrome (SIRS)
-TRALI
-Increased infection risk
-Increased mortality
What is SIRS?
Central mechanism is abnormal secretion of cytokines which are released by leukocytes, macrophages, monocytes, platelets, and endothelium.
-SIRS represents the earliest, nonspecific phase of the process which ends in organ dysfunction and ultimately, organ failure.
For Hgb above ____, hypovolemia should be treated with _____.
For Hbg above 7, hypovolemia treated with IV fluids.
-PRBCs may be needed for persistent base deficit, lactic acidosis, signs of organ ischemia, low mixed venous O2
What is the Assessment of Blood Consumption (ABC)?
Criteria (1 point assigned per item):
1. Penetrating mechanism of injury
2. Positive focused assessment sonography for trauma (FAST)
3. Arrival SBP ≤ 90 mm Hg
4. Arrival HR ≥ 120 BPM
Interpretation:
-Score 0-1: Massive transfusion unlikely
-Score ≥ 2: Predicts need for massive transfusion and triggers 1:1:1 protocol
What is a FAST exam?
Focused assessment with sonography for trauma (FAST) is a rapid bedside ultrasound used as a screening test for blood around the heart (pericardial effusion) or abdominal organs (hemoperitoneum) after trauma.
The four classic areas that are examined for free fluid are the perihepatic space, perisplenic space, pericardium, and the pelvis.
In the context of traumatic injury, this fluid will usually be due to bleeding
What is a normal order of administration of products during a MBT?
-6 units RBCs
-6 units plasma
-1 pheresed platelets
Alternate pheresed platelets with 10 units of cryo
What is Early Trauma Induced Coagulopathy (ETIC)?
Also called Acute Coagulopathy of Trauma
-Recognized in about 16-25% of trauma patients
-Defined as prolonged clotting times (PT and PTT)
-NOT strictly due to consumption of platelets and fibrinogen, but mechanism not completely known
-Patients presenting with ETIC have 35% increase in likelihood of mortality when compared with patients with normal coagulation parameters
-The mechanism of action is not completely known, but looks like there is a correlation with hypoperfusion (measured by increased base deficit) and an activation of C protein pathway (coagulopathy)
