Blood Products and MBT

Question 1

Why transfuse platelets?

Answer 1

-Given for thrombocytopenia or dysfunctional platelets in the presence of bleeding
-Prophylactic transfusion for plt counts 10,000-20,000

Question 2

How are platelets separated from whole blood?

Answer 2

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

Question 3

T/F: ABO compatibility is required for platelet transfusions.

Answer 3

False: ABO compatibility not necessary, but desirable

Question 4

What is plateletpheresis?

Answer 4

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.

Question 5

Describe storage and administration of platelets.

Answer 5

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

Question 6

T/F: Platelet preparations contain some volume of plasma and a few red cells

Answer 6

True

Question 7

Why is it important that platelet preparations contain some volume of plasma?

Answer 7

-ABO compatibility is ideal but not required
-Patients with a history reactions to random donor platelets should receive ABO/HLA-matched platelets

Question 8

Why is it important that platelet preparations contain some RBCs?

Answer 8

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.

Question 9

How does pooled platelets differ from pheresed platelets in raising the platelet count?

Answer 9

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

Question 10

How are platelets administered to children?

Answer 10

In Children, we usually give one unit pheresed platelets/10kg body weight to raise the platelet count by 50,000/µL

Question 11

When should a platelet count of 10,000 trigger transfusion?

Answer 11

Non-surgical patients with thrombocytopenia and active bleeding

Question 12

When should a platelet count of 30,000 trigger transfusion?

Answer 12

Minimally invasive procedures (central lines, thoracentesis, paracentesis, angiography)

Question 13

When should a platelet count of 50,000 trigger transfusion?

Answer 13

Minor procedures: Lumbar puncture, epidural, endoscopy with biopsy, laparotomy in patients without other abnormalities, vaginal delivery

Question 14

When should a platelet count of 75,000 trigger transfusion?

Answer 14

During massive blood loss

Question 15

When should a platelet count of 100,000 trigger transfusion?

Answer 15

Risk of closed cavity bleeding: intracranial

Question 16

If platelet count is between 50 - 100,000, what factors need to be considered for platelet transfusion?

Answer 16

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

Question 17

What are complications associated with platelet transfusion?

Answer 17

Minor Adverse Rxns:
-Non-hemolytic febrile reactions
-Mild allergic reactions

Major complications:
-TRALI
-TAS
-Major allergic reactions

Question 18

What is TRALI?

Answer 18

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

Question 19

What is TAS?

Answer 19

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

Question 20

How is FFP prepared and stored?

Answer 20

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 !!!!!!!!!

Question 21

What is contained in FFP?

Answer 21

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

Question 22

What are indications for FFP administration?

Answer 22

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.

Question 23

What is Cryoprecipitate?

Answer 23

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

Question 24

What is contained in Cryoprecipitate?

Answer 24

-Fibrinogen: about 30% more than found in unit FFP (150-300 mg)
-Factor VIII: 80-100 units per bag
-Von Willebrand factor
-Factor XIII

Question 25

What is used instead of Cryo for the treatment of Hemophilia A and Von Willebrand’s Disease?

Answer 25

Humate P or Alphanate: Virally inactivated Factor VIII concentrates that also contain vWF.
-Far lower risk of blood-borne viral infection

Question 26

What are indications for Cryo administration?

Answer 26

-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)

Question 27

Stored blood has decreased oxygen transport ability due to what metabolic changes in stored blood?

Answer 27

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)

Question 28

What is the definition of massive blood loss?

Answer 28

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

Question 29

What is Massive Transfusion Protocol (MTP)?

Answer 29

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

Question 30

What are risks associated with massive transfusions?

Answer 30

-Multiple organ failure
-Systemic inflammatory response syndrome (SIRS)
-TRALI
-Increased infection risk
-Increased mortality

Question 31

What is SIRS?

Answer 31

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.

Question 32

For Hgb above ____, hypovolemia should be treated with _____.

Answer 32

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

Question 33

What is the Assessment of Blood Consumption (ABC)?

Answer 33

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

Question 34

What is a FAST exam?

Answer 34

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

Question 35

What is a normal order of administration of products during a MBT?

Answer 35

-6 units RBCs
-6 units plasma
-1 pheresed platelets

Alternate pheresed platelets with 10 units of cryo

Question 36

What is Early Trauma Induced Coagulopathy (ETIC)?

Answer 36

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)