Transfusion medicine Flashcards
Blood should be treated like a _____ ; there are indications, contraindications and benefits
drug or translpant
Process of donation \_\_ years of age Limited\_\_\_\_ and physical* – Donation interval for Whole Blood = – Approx \_\_\_\_ml of blood taken
16
history
8 weeks
500 (+/-50)
What is looked at in the donor physical and exam
• Exam: vital signs, general appearance,
venipuncture site
• Donor medical history
• Hemoglobin level
What three products do we get from blood
Plats
RBCs
Plasma
Preservative Solutions to Maintain Function and
Viability of Cells:
Anticoagulant that binds Calcium =
Maintiains 2,3 DPG levles =
Citrate
Phosphate
What is for cell metablosin when storing blood
what about for ADP, ATP production
Dextrose
Adenine
What happens to cell when stored for long time
becomes distorted, eventually sphere like
Key biological effects seen in RBC storage
Decrease in ATP, 2,3 DPG and pH
• Extracellular plasma changes (potassium increases)
• Increased free hemoglobin (iron) and NTBI
• Increased oxidative stress (ROS)
What is processed or tested for in blood
- Infectious Disease Testing
- ABO and Rh type
- Antibody Screen
The one infectious disease we still have issues with
Hep B~ has a chronic carrier state in people
• Most important red cell blood group system • Antibodies are naturally occurring, very potent, and can activate complement – Responsible for many acute and fatal hemolytic transfusion reactions
ABO group system
Group A blood has antibodies against:
What type of blood can pt receive?
Anti-B
type: A, O
Group B has antiB against:
what type of blood can it recieve?
AntiA
recieve: B and O
Group AB blood has antiB against:
Can receive what type of blood:
NONE
all types
Group O blood has antiB vs:
can receive:
antiA, AntiB, anit AB
O
What are the major antiGs associated with Rh blood group:
MOst important?
most immunogenic?
- Major Antigens are D, C, c, E, e
- Most important Antigen is D
- D is highly immunogenic- 80% sensitization risk
- Rh antibodies develop through pregnancy or transfusion
Implicated in Hemolytic Disease of the Newborn and
hemolytic transfusion reactions
Rh antibodies
In Antibody screens what do they detect?
• Antibody screens detect most clinically relevant antibodies (~30 antigens)
How does Indirect Antiglobin Test work?
Take patients plasma that has antiB in it and add it to tube with RBC (either known or donor). If RBC has lots of antiB on it like in plasma, they will link up and RBC aggregate
***Detects antibody in patients serum
Use of IAT
Antibody detection/ID, Red
Cell Typing, Compatibility Testing
• ABO and Rh (D) type patient and donor • Antibody Screen (IAT): Test Cells of known phenotype + patient serum • Crossmatch: Donor cells + patient serum – Electronic – Serologic All above are examples of
Compatibility testing of RBCs
What is the DAT and it’s purpose?
Direct Antiglobulin Test
The DAT detects antibody attached to red cells in vivo
(take pts RBC, add antiB and antiB binds if its present on RBCs)
Causes of (+) DAT
- Autoimmune Hemolytic Anemia
- Drug Induced Hemolytic Anemia
- Hemolytic Transfusion Reaction
- Hemolytic Disease of the Newborn
What happens in pre-transfusion testing?
Pt blood sample, ABO typing/ antiB screen/ identify antiBs and select ABO/D compatible donor
What are the total Blood Products used?
- Whole Blood
- Packed RBCs
- Fresh Frozen Plasma
- Platelets
- Cryoprecipitate
What is key in Whole Blood transfusion, when is it used?
must have same ABO type only!
not really used, hard to come by and hard to get very close match
How are RBC prep/stored and what do they have?
Cells separated by centrifugation, plasma removed. 4C, 42 days.
Contains 300 ml, HCT 55-60%, No viable platelets or WBC’s
What is the outcome of pt given RBC
raise Hgb 1g/dL in adult
RBC transfusion \_\_\_ cells to A, AB patient \_\_ cells to B, AB patient \_\_\_ cells to A, B, AB, O patient \_\_ cells to AB patient only
A
B
O
AB
In a critical care setting, which is better, lots of RBC to get HgB to 10 or restrictive to get HgB to 7
Restrictive to 7~ only give when pts are symptotic, not to boost HgB
Factors in Transfusion\Decision
• Patients symptoms, signs, baseline functional
capabilities
• Etiology and anticipated course of anemia
• Alternative Therapies
• Underlying cardiovascular or respiratory disease
• Risk/benefit analysis
HgB guidelines: HgB: Probablity of impairment Strategy >10 8-10 6-8 <6
> 10 Very low Avoid
8-10 Low Avoid, consider transfusion “trial”
6-8 Moderate Transfusion if symptomatic
<6 High Frequently requiresTransfusion
Fresh Frozen plasma: plasma seperated from whole blood via centrifugation, RBC removed; contains
all plasma proteins
Outcome of FFP transfustion
10-15 mL/kg raises all clotting factors by 20-30%
in average size adult (run into issue if try to correct competely d/t volume overload)
A plasma to
B plasma to
AB plasma to
O plasma to
A plasma to
B plasma to
AB plasma to anyone
O plasma to O patient only
– Multiple factor deficiency
• Liver Disease
• Vitamin K deficiency/reversal of warfarin
• DIC
• Isolated factor deficiency if no factor concentrate available (factor XI)
These guys can receive:
FFP!
Use FFP in Replacement of Plasma Proteins for hemostasis: (2 examples)
– Abnormal bleeding with documented coagulopathy
– Multiple factor deficiency
– Prophylaxis for surgery /procedure with coagulopathy
What do we use for replacement fluid in therapeutic plasma exchange like TTP?
FFP
FFP is not indicated for:
– Volume expansion
– Reversal of Heparin
• FFP not usually needed to correct:
FFP never completely corrects the:
minor prolongation of PT (3 Sec or INR<1.5)
PT in patients with severe liver disease
FFP
• Usual Dose=10 ml/kg or ____units in average adult. 1
unit is homeopathic
3-4
In INR graph, when do we see FFP having biggest effect?
When INR is REALY high, FFP helps lower that fast, but the closer INR gets to normal, the more FFP units you need
How is Cryprecipiate made?
Thaw out FFP and store at -18
What factors does Cryoprecipitate contain?
What is is most useful for?
F-VIII, Fibrinogen, vWF, F-XIII, Fibronectin
most useful for fibrinogen, not for vWF
**Goal = Fibrinogen level >150 mg/dl
Outcomes of giving pt Cryoprecipitate
1 unit/ 10 kg will raise fibrinogen by 50 mg/dL
in an average size adult.
Contains: 15 ml/ unit, enriched for Fibrinogen.
No viable platelets, RBCs or WBC’s
Cryoprecipitate
Indications for Cyroprecipitate:
• Hypofibrinogenemia – DIC – Severe liver disease – Congenital – Trauma with massive transfusion • Dysfibrinogenemia – Acquired (liver disease) – Congenital
_____units WB-derived Platelet or Platelet Concentrate= ___ units Apheresis Platelet
6-8
1
Prep/Storage of Plats
-Cells separated by centrifugation of whole blood
or apheresis.
-Stored at room temperature for 5 days.
Outcomes in Plat transfustion
-Raise plt count 30,000 – 60,000 in an average
size adult.
-Can trigger anti-D formation
Plats considered as Prophylaxsis in Marrow failure pts:
<10k:
10-20 K:
– <10K: Transfusion indicated
– 10-20K: Transfusion reasonable
• Concurrent risks: fever, mucositis, bleeding history
Prophylaxis of Plats before surgery
____: General Surgery, Procedures
____: Eye, CNS, high risk surgery
– <100K
At what point of Plat count do we really see pts run into bleeding issues when in hospital?
below 10K
How long does it take to consume Plats in health person?
Ill person?
Antibody mediated destruction?
healthy: last over a day
Disease: see drop very quickly
AntiB: never really rises
