Principles of transfusion Flashcards
(37 cards)
most common organ transplantation in the US is
blood transfusion
Blood Bank
unit of clinical laboratory that stores, tests for compatibility and releases blood products
Transfusion Medicine
Study and practice of effective and safe use of blood products
Serologic
ABO (donor and recipient)
Rh (D) (donor and recipient)
Recipient antibody screen (for unexpected alloantibodies - react with antigens from the same species)
Preservatives and Storage Life: Summary
CPD - Citrate Phosphate Dextrose 21 days
CP2D - Citrate phosphate double dextrose 21 days
CPDA1- Citrate phosphate dextrose adenine 35 days
AS-1 Adenine Solution #1 42 days
AS-3 Adenine Solution #3 42 days
Anticoagulant =
Citrate
Preservatives =
Phosphate, Dextrose, Adenine
Physical Characteristics
“Unit of Packed Cells (RBCs)”
Total volume:
200-250 mL CP2D or CPDA-1
275-325 mL AS-1 + CPD
Plasma volume:
30-50 mL CP2D & CPDA = 15-25% normal plasma volume
70-90 mL AS-1 = 40-50% normal plasma volume
Hematocrit (depends on blood donor hematocrit):
65-80% CPD2D or CPDA-1
50-65% AS-1
Total hemoglobin:
42.5-80 grams
Total Iron:
~147-278 mg; vast majority in hemoglobin
Monitoring During a Transfusion
Before and During Transfusion: Visual and Clinical
The initial few minutes of transfusion are the most important observation period since hemolysis of as little as 10 mL red cells can give rise to clinical evidence of a reaction
Patients should be observed for 24 hours after completion of last transfusion (never happens in outpatient setting).
what are we looking for when monitoring a transfusion?
Key symptoms to monitor include:
Pain at the infusion site
Sudden onset of lower back pain
Change in urine color (dark or red) urine
Dyspnea or shortness of breath
Sudden increase in patient anxiety
These suggest there may be acute hemolytic transfusion reaction
Transfusion-Related Acute Lung Injury (TRALI)
Acutely increased permeability of the pulmonary microcirculation allows the massive
leakage of fluids and protein into the alveolar spaces and interstitium
Associated with the presence of leukocyte antibodies in the donor or recipient
Signs and symptoms
• Acute respiratory distress within 6 hours of administration
• Hypoxemia (oxygen saturation under 90% on room air)
• Bilateral pulmonary infiltrates on frontal chest x-ray
Indications for Red Cell Transfusions General Guidelines
Treatment of a symptomatic O2-carrying deficient when patient’s condition and symptoms require acute replacement
Acute severe hypovolemia following massive hemorrhage with shock
Exchange transfusion (hemolytic disease of the newborn) or red cell exchange (sickle cell disease) requiring replacement RBCs
when do we give blood?
7 grams or less of hemoglobin
Goals RBC Transfusion
Severe hemorrhage/shock, replace RBCs sufficient to maintain vascular volume and provide sufficient oxygen-carrying capacity for oxygenation
Symptomatic anemia and surgical replacement
Each unit in an adult theoretically raises hemoglobin how much?
1 g/dL or hematocrit 3%
how much blood to give?
Old Rule
As a general rule, two or more units of RBCs are always ordered for any given patient”.
Replacement with 1 unit indicates
Clinical situation that doesn’t require transfusion
Can be handled by bone marrow production of rbcs
No longer true!
Contraindications for RBC Transfusion
First of All Do No Harm
There should be a definite purpose for the transfusion
The theoretical benefits should outweigh the potential harm, both short-term and long-term.
Inappropriate Indications and Contraindications:
• Chronic, steady-state (asymptomatic anemia)
• Uncomplicated pain episodes
• Infection
• Minor surgery that does not require general anesthesia
• Aseptic necrosis of the hip or shoulder (unless indicated for surgery)
• Uncomplicated pregnancy
Incompatible ABO blood group
O patients should not receive A, B or AB red cells
A patients should not receive B or AB red cells
B patients should not receive A or AB red cells
AB patients can receive any red cell product
blood costs
Cost $225
Costs have doubled
Cost to transfuse have quadrupled
Safety
Mistransfusion is the single most serious
Greater than HIV or HB or HC
Why? Infection Febrile and allergic reactions Hemolytic “Storage defects”
Temporary immunodeficiency
Transfusion related immmunomodulation
Cellular
NK and helper/suppressor
Humoral
Outcomes
7-10X increase in post op infections
Increase in Ca
Increase in mortality CABG
Transfusion triggers
Who came up with the 10/30 rule? (1950s)
8.5 Hg is average ICU trigger
No evidence base!
7 g is the perfect trigger
Hg greater than 7-9 did not improve outcomes!
Even in ICU or MI’s
MI’s with TFX had poor Px
Blood conservation
Epo (Erythropoietin) [can bring up hematocrit 1-2%]
Platelet gel [spun down, given back]
Cell savers
Normovolemic hemodilution [drain a unit of blood before surgery, give it back after- bloodless surgery]
