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42 Cards in this Set

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What do we generally screen for when a donor gives blood?
1. medical history questionnaire – determines risks based on transmissible diseases, behaviors, etc

2. Hb or Hct measurement – fingerstick Hb usually used and must be at least 12.5g/dL (Hct must be at least 38%)

3. Vital signs – BP, temp, pulse, and body weight
-- systolic BP cannot be >180; diastolic cannot be >100
-- acceptable pulse 50-100; <50 only acceptable if donor is otherwise healthy athlete
-- oral temp cannot be >99.5
-- donor >110 lbs less likely to suffer hypovolemia

4. Age, appearance of donor, and visual exam of donor arms
-- minimum age is 17; no max limit
-- donor must appear healthy
-- cannot have evidence of skin lesions or injection track marks in the antecubital area
Name the two methods for obtaining blood components.
1. From a unit of whole blood
2. By apheresis
Describe how whole blood is collected.
1. About 1pt whole blood drawn by gravity from an antecubital vein into a plastic primary blood collection bag which contains anticoag/preserve solution

2. Primary bag has been manufactured w/ additional satellite bags already attached by tubing to the primary bat, allowing a sterile closed environment from prep of components

3. Collection process lasts 15-20 minutes
Describe how whole blood is separated into components.
Two centrifugation steps used to separate whole blood into RBCs, platelets, and plasma. Components must be prepared w/in 8hrs of collection
1. First centrifugation step
-- bag of whole blood centrifuged to separate RBCs from plasma (platelets in plasma layer)
-- supernatant-rich plasma expressed off of the RBCs into a satellite bag
-- connecting tubing is heat sealed and the bag of platelet rich plasma is disconnected from the RBCs

2. Second centrifugation step
-- bag of platelet rich plasma is centrifuged to sediment out the platelets
-- most of supernatant plasma is expressed off into a satellite bag, leaving about 50mL of donor plasma in the bag of platelets
-- connecting tubing is heat sealed, and the bag of plasma is disconnected from the bag of platelets
What types of blood components can be prepared from one unit whole blood?
1. One unit packed RBCs

2. One unit of platelets
-- must be pooled w/ 5 more units of whole blood platelets to make adult dose

3. One unit of plasma
-- must be given w/ several more units plasma to make adult dose
What types of blood components can be prepared from one unit of frozen plasma which has been thawed slowly in the refrigerator?
One unit of cryoprecipitate
-- must be pooled w/ 9 more units to make adult dose
Describe the apheresis donation process.
1. Donor connected to apheresis machine via plastic tubing
2. Machine pumps whole blood from donor’s antecubital vein into centrifuge inside machine – machine programmed to collect selected component into collection/storage bag
3. Remainder of blood returned to donor via antecubital vein access in other arm
4. Process is continuous and donation process takes 1-2hrs
Types of apheresis components which can be donated?
1. single donor platelet
2. single donor (jumbo) plasma
3. single or double unit RBCs
4. Granulocytes
5. Hematopoietic progenitor (stem) cells
Describe the anticoagulant used in all blood components.
CITRATE used in all blood components
-- prevents coag by chelating (binding) ionized Ca and Mg
-- metab w/in minutes through the Krebs cycle by any tissue containing mitochondria (liver, muscle, kidney)
What is citrate toxicity?
Can occur if any blood component is given in large volumes at a fast rate
-- secondary to hypocalcemia and/or hypomagnesemia
-- pts w/ liver dysfxn may not be able to metab citrate rapidly enough to prevent symptoms

Symptoms include:
-- periooral tingling
-- extremity paresthesias
-- cardiac arrhythmia or arrest if severe hypocalcemia
How are RBCs stored?
REFRIGERATE
-- stored in preservative soln containing adenine, phosphate, and dextrose to help maintain adequate pH and ATP level
-- must be refrigerated (Btwn 1C and 6C)
-- Shelf life 35 to 42 days

Unit of RBCs contains about 250mL of RBCs, very small amt of donor plasma, citrate, and small amt of preservative soln
-- may contain WBCs if not previously filtered out
How are platelets stored?
ROOM TEMP; SHORTEST SHELF LIFE
-- stored in donor’s plasma; no preservative soln needed
-- must be stored room temp in thin plastic bags to allow good oxygen and carbon dioxide exchange
-- constant agitation req’d during storage
-- shelf life up to 5 days

Unit of platelets contains platelets, donor plasma, and citrate
-- may contain WBCs if not previously filtered out
How is plasma stored?
FREEZE; LONGEST SHELF LIFE
-- frozen below -18C w/in 8 hrs collection to preserve the labile coag factors VIII and V (fresh frozen plasma, FFP)
-- Shelf life is 1 yr while frozen
-- prior to transfusion, plasma thawed (37C); if not transfused, can be stored refrigerated up to 5 days if factor VIII replacement not needed

FFP contains citrate and a hemostatic level of all the coag factors that were present in donor blood
How is cryoprecipitate stored?
FREEZE
-- is prepared from FFP; FFP is thawed at refrigerated temp then centrifuged to sediment out the cryoprecipitated proteins
-- proteins then frozen and stored below -18C for up to one year
-- shelf life up to one yr while frozen
-- prior to transfusion, thawed at 37C and must be transfused w/in 4 hrs

Cryoprecip contains citrate, concentrated fibrinogen, vWF, factor VIII, factor XIII and fibronectin in a very small volume of plasma (10-20mL)
How are granulocytes stored?
ROOM TEMP
Must be transfused ASAP after collection; kept at room temp until transfused
-- collected by apheresis for specific pt at specific time
-- occasionally given to septic premature neonates w/ severe neutropenia (<500μL) and depleted marrow
How are hematopoietic progenitor cells stored?
FREEZE
Collected by apheresis for transplant to specific pt after high dose chemo
-- require further processing; may be frozen until needed
Therapeutic indications for RBC transfusion?
Transfused to increase oxygen carrying capacity
Given to pts:
-- with acute anemia due to active bleeding
-- who are symptomatic from chronic anemia

One unit RBC should increase Hb by 1g/dL and Hct by 3%
Therapeutic indications for platelet transfusion?
1. THROMBOCYTOPENIA
-- bleeding pts
-- nonbleeding pts w/ thrombocytopenia severe enough to possibly cause spont bleeding
-- nonbleeding pts who have thrombo which may cayse increased bleeding during invasive procedure or surgery

2. PLATELET DYSFXN
-- bleeding pt w/ normal platelet count, but acquired dysfxn due to drugs or uremia
-- pts w/ congenital d/o of platelet dysfxn
What are the equivalent platelet doses for an adult?
1. One unit of single donor apheresis platelets (SDP)

2. Pool of 6 random donor (whole blood) platelets. Number based on giving one unit per 10kg pt weight.

One dose should increase platelet count by 30K to 50K
When are platelet transfusions contraindicated?
Pts with:
-- thrombotic thrombocytopenic purpura (TTP)
-- heparin induced thrombycytopenia (HIT)
-- post-transfusion purpura (PTP)

Usually ineffective in pts with:
-- idiopathic thrombocytopenia purpura (ITP)
-- drug-induced immune mediated thrombocytopenia
Therapeutic indications for thawed FFP?
Given to pts w/ coagulopathy secondary to deficiency of multiple coagulation factors:
-- liver failure – lack of coag factors
-- massively transfused – dilution of own coag factors

Used to treat single factor deficiency ONLY if more conc component or derivative is unavailable.
The expected effect of an adequate dose of FFP is…?
Hemostasis

A bolus dose of 10-15mL of FFP per kg of body weight will provide hemostatic level of all coag factors (20-30%).

Four to six units usually used for an adult.
Therapeutic indications for Cryoprecipitate?
Given to replace FIBRINOGEN, usually in the setting of DIC. It is the only source of conc. fibrinogen

Contains vWF, but should not be used routinely to replace vWF since Factor VIII concentrate containing vWF is available

Not used routinely to replace Factor VIII since high purity conc is avb

One dose should increase fibrinogen level by at least 50mg/dL; dosing based on 1 unit per 10kg body weight
Name the two more common, less severe rxns to blood component transfusion.
1. Febrile non-hemolytic transfusion reaction (WBC rxn)

2. Allergic rxn
Describe the febrile non-hemolytic transfusion rxn.
Usually assoc only w/ transfusion of the cellular components (RBCs or platelets)

Symptoms: temp elevation (at least 2F), chills/rigors, headache; attributed to one or both of the following:
1. Ag-Ab rxn in which pt’s pre-existing Ab against WBC Ag react w/ Ag present on WBC in transfused component
2. Presence of cytokines released by WBCs during storage of blood
Treatment for febrile non-hemolytic transfusion rxn?
Antipyretic medication (premedication usually not recommended)

Leukoreduction of cellular blood components can help prevent these rxns – prestorage leukoreduction is preferred
-- current filters in the blood bank remove >99.99% of WBC in the component
Describe the allergic rxn from transfusion components.
May occur during transfusion of ANY blood component, as all blood components contain plasma

Symptoms consist of: itching, hives, or flushing w/o any other adverse findings

Rxn is IgE mediated rxn to foreign plasma proteins in the component
Treatment for allergic rxn from transfusion components?
Antihistamines
List the five types of rare, but possibly life-threatening reactions to transfusion of blood components.
1. acute intravascular hemolysis

2. anaphylaxis

3. septic rxn due to bacterial contamination

4. circulatory overload

5. transfusion related acute lung injury (TRALI)
Describe acute intravascular hemolysis.
Most due to transfusion of incompatible RBCs
-- ABO incompatibility is most likely to cause hemolysis
-- mech is Ag-Ab rxn w/ activation of complement, leading to intravascular lysis of RBCs

Symptoms include hypotension, renal failure w/ oliguria, DIC, hemoglobinuria, back pain, fever, chills – often fatal

Proper ID of pt, blood samples drawn, paperwork assoc w/ blood request, and red cell component, will help eliminate clerical errors
Describe anaphylaxis due to transfusion components.
Can occur during transfusion of ANY component

Sudden onset respiratory distress, hypotension, local edema, urticaria
-- IgE mediated rxn to donor plasma proteins
-- EX: IgA deficient pt who has preformed Ab against IgA
Treatment of anaphylaxis?
Epi
Corticosteroids
B-2 agonists
Antihistamines
Describe a septic rxn due to bacterial contamination of transfusion.
Believed to occur do to either:
-- improper cleaning of venipuncture site
-- unsuspected bacteremia in donor at time of blood collection

Rxn can be severe w/ hypotension, DIC, and fever. High mortality rate associated w/ sepsis and toxemia from bacterially contam RBCs

Components usually indicated are RBCs and platelets
-- G(-) orgs (primarily Yersenia entercolitica) are more commonly assoc w/ RBCs
-- G(+) orgs are usually assoc w/ bacterial contam of platelets
Treatment for sepsis?
IV antibiotics immediately, combined w/ treatment for shock, renal failure, and DIC, if present
Describe circulatory overload due to transfusion.
Iatrogenic complication of transfusion secondary to transfusing large volumes too fast to non-bleeding pts. Poorly tolerated by pts w:
-- compromised pulmonary status
-- compromised cardiac status
-- chronic anemia

Symptoms include dyspnea, cough, tachycardia, HTN, headache
Trtmt for circulatory overload?
Pt should be placed in upright position and given oxygen and IV diuretic as needed.
Describe TRALI due to transfusion.
Uncommon and likely underreported.

Rxn likely caused by Ag-Ab rxn in which WBC Ab in the transfused component react against Ag in pt’s own WBCs.
-- WBCs agglutinate in lung caps, complement is activated, and caps leak fluid into alveolar spaces

Pt suffers hypoxemia, respiratory failure, hypotension, fever
Treatment for TRALI?
Supportive
All blood donors are tested for…?
HIV
Hep B
Hep C
HTLV
Syphilis
West Nile may be done when indicated
When did HIV testing begin and what is the risk of transmission?
1985

Risk is 1 in 2,000,000 per unit transfused
Risk of Hep B and C transmission?
Hep B: 1 in 150,000 per unit

Hep C: 1 in 1,000,000 per unit

HIGHER RISK THAN HIV!
Other infectious disease that may be transmitted through transfusion?
PARASITIC DISEASES:
Malaria
Chagas disease
Leishmaniasis
Babesiosis
**Unusual in the US since many are not endemic; donor screening designed to help prevent transmission

DEGENERATIVE BRAIN DISEASES
Threoretically transmittable (prions)
-- no screening test is abv to detect Creutzfeldt-Jakob or variants
-- people who traveled or lived in countries w/ bovine spongiform encephalopathy (BSE) are not allowed to donate blood in US depending on length of time spent in those countries