Transfusion Flashcards
Describe the basic process of donor qualification and blood collection relating specific steps to blood safety (there are 7)
• Screening, ie weight and age restrictions– are you bigger than a breadbox?
• Donor interview and questions– ever been to a Turkish prison?
• Review of high risk behavior– how come and how long?
• Instructions for donor to call back with symptoms or questions
• Abbreviated physical exam- general appearance, vitals, skin, extremities
• Hematocrit count
• Skin prep and phlebotamy technique (no bacterial introduction)
Some of these have to do with donor safety, others with recipient safety. It’s pretty simple which is which.
Discuss whole blood
Volume: 500-575 mL, HCT 36-40%
Store at 4-6C, expires in ~35 days.
Loses platelet and neutrophil function w/i 24h
Loses clotting factors more slowly but quicker than expiration of unit
Used to restore O2 carrying & blood volume
Discuss PRBCs
Volume: 200-250 mL, HCT 70%
Store at 4-6C, expires in ~35 days (BUT can be stored in special preservative for ~1 week longer).
Can specifically filter out any remaining white blood cells.
Can also glycerolize and freeze PRBCs. Good for at least 10 years.
Used to restore O2 carrying (Anemia Hct <25-30)
Discuss FFP
No cells, but contains anti-coagulation, clotting proteins, and complement.
Store at -18 degrees C, expires in ~1 year.
Used to treat coagulopathy related to procoagulant deficiency (administer specific type)
Discuss cryoprecipitate
FFP that’s partially thawed at 4C for 18 hours, centrifuge and remove the supernatant; what’s left is your cryoprecipitate). You do this to get particular clotting factors (Factor 13, which are in what’s left) at a particularly high concentration.
Store at -18 C, expires in ~1 year.
Used to treat: low or absent fibrinogen assoc w/ factor 13 def. (factor 8 used for hemophiliacs)
Discuss platelets
Two types: donated from whole blood, or apheresed (more conc)
Store at RT in dark, on rocker, in gas-perm bags. Expires ~5-7 days later b/c clotting factors degrade throughout storage.
As with PRBCs, can leukoreduce (filter out WBCs) to stop adverse reactions.
Used to treat: bleeding associated with thrombocytopenia and/or platelet dysfunction.
Discuss granulocyte concentrate
Granulocyte concentrate: either apheresis or buffy coat from centrifuged blood.
Store at RT and administer w/i 8-12hrs.
Note that there’s a 3-5% hematocrit that comes along with these, as well as a bunch of platelets.
Used to treat: severe bacterial / fungal infection in pts w/ ANC <500/μl (secondary to poor marrow production and not responding to aggressive medical management after 72 hrs)
Discuss expiration criteria
The criterion of an expiration (or “outdate”) time is that 70% of the solution has to still have normal function. And it’s not 100%, 100%, 100%, oh crap, 69%: function decreases slowly over time. “Valid” blood products can still be suboptimal.
Discuss the basic blood groups (ABO and Rh) and contrast the different compatibility requirements of basic blood components
- Bombay people have A, B, and O antibodies).
- All blood products should be microfiltered
- Whole blood, PRBCs, Granulocytes: Has to be typed and crossmatched.
- FFP: Have to be ABO type specific, but not crossmatched.
- Cryoprecipitate & platelets: “Consider giving ABO type specific or compatible”.
Notice that for whole blood and PRBCs, matching (ABO, Rh), screening (vs known antigens), and cross-matching should take about 45 minutes.
If you haven’t got 45 minutes, just match and screen.
If you haven’t got any time at all, use O-negative blood (if male or “non-child-bearing woman,” can use O-positive).
Explain the basic rules of blood administration.
- Do not add IV solutions to blood bag or tubing.
- Blood products should not be exposed to Ca2+ containing solutions (e.g., lactated Ringer’s). This will reverse the effect of citrate anticoagulant and cause clotting in the administration set.
- Do not warm components over 37°C.
- When blood bag is entered, sterility is breached. Discard after 4 hours at RT or 24 hours at 1-4°C.
- Transfuse PRBCs ≤4 hours.
- Visually inspect all components before infusion.
- Identify the unit and recipient.
- Administer all products through 170-260 mm aggregate filter (standard in the blood administration set).
- Observe the patient during all transfusions and investigate all adverse events promptly.
- In vivo crossmatch should be completed when transfusing red cells in the presence of an autoantibody. Infuse 10% of the unit or volume required over 15 min. Monitor vital signs before and after the test infusion. If vital signs change and the patient develops symptoms (anxiety, dyspnea, back pain, etc.), look for signs of hemolysis in a blood sample or urine sample from the patient. If any of the above signs of hemolytic transfusion reaction occur, do not finish transfusing the unit. If transfusion is required, repeat this procedure with the next unit. If there is no reaction to the test dose, complete the infusion.
- For the neonate, crossmatch can be completed with either baby’s or mother’s serum/plasma.
Explain the infectious risks of blood transfusion and describe testing strategies to reduce risks of specific agents.
- Test for Ab against and/or Ag for each infectious agent.
- NAT for HCV, HIV, WNV
- CJD: use questionnaire for family, social, travel, exposure hx
- Screening for Chagas disease is completed depending on region of donation in the U.S.
- CMV transmission is infrequent with seronegative or leukoreduced products.
- Positive & confirmed donors are deferred from further donation.
- Vaccinia vax = temp deferral
- Deferral for travel to a malaria area or defined malaria disease is currently based on travel and personal medical history.
- There is concern about parvovirus, EBV, dengue and malaria, and screening tests may be implemented in the future.
Risks of transmission:
Syphilis < 1/2,500,000;
WNV <1/300,000.
Classify the non-infectious adverse events of transfusion, assess a constellation of symptoms and signs of the prototypic reactions, and describe the clinical management.
Febrile non-hemolytic transfusion reactions (≥ 1°C fever) and mild allergic reactions (skin) are most common (1/200 and 1/400, respectively). After confirming that other types of reactions are not occurring in the patient, treatment with antipyretics (e.g., Tylenol) and antihistamines (e.g., Benadryl) are required before re-instating the infusion. Future transfusions may require pre-medication with antipyretics and/or antihistamines or leukoreduced cell containing blood products.
Immediate hemolytic transfusion reactions as a result of infusing incompatible blood products (usually ABO) present an infrequent (<1/30,000) but severe and possibly life-threatening event. The cause is usually misidentifying or mislabeling samples from the patient or donor. Activation of complement and intravascular hemolysis may lead to shock, acute renal failure and disseminated intravascular coagulation. Vigorous supportive care, diuretics and heparin may be required.
Delayed hemolytic reactions represent the process of alloantibody production (1/2,500 transfusions) and slow destruction of the sensitizing red cells with very few symptoms and signs. Documentation of these alloantibodies should become part of the medical record since their existence may increase the risk of immediate hemolytic transfusion reactions with future transfusions.
Anaphylactic reactions are fortunately rare (1/150,000 transfusions) and usually occur without identifying the specific reagent. The bronchospasm and/or large airway response is treated with epinephrine, benadryl and steroids. May be seen in IgA deficient individuals (the most common humoral immunodeficiency syndrome).
Transfusion related lung injury (TRALI) is acute lung injury (development of diffuse lung infiltrates, problems breathing and difficulty maintaining peripheral oxygen saturation on room air) within 6 hours of a transfusion. Vigorous ventilatory support may be required but the syndrome resolves quickly in 90% of those affected. The risk is 1/5,000-1/3,000 per transfusion depending on the product (all products can cause this reaction).
Transfusion associated circulatory overload (TACO) is volume (fluid overload) related to excessive amounts of products and/or cardiac dysfunction. Diuretics will help resolve the problem.
Other complications are rare in clinical practice, but include graft vs. host disease, alloimmunization to HLA and platelet specific antigens, dilutional coagulopathy, sepsis and/or endotoxemia and iron overload.
