Packed Red Blood Cell Transfusion Therapy
A Risks of transfusion
The longer blood is stored, the worse it performs. Over time, cells lyse, and 2,3-DPG levels fall, causing oxygen to
bind more avidly.
Febrile reactions/allergic: most common immune reaction. Usually related to either cytokines or donor
leukocyte or other contaminants, or a mild antibody response. Usually self-limited. Can be prevented by
leukodepletion and pretransfusion antipyretics.
Hyperkalemia: Lysed cells can cause hyperkalemia.
Hypocalcemia: Citrate in stored blood can bind calcium.
Coagulapathy: pRBC’s do not contain clotting factors or platelet. Large volume transfusion without these
other products can cause a coagulopathy.
ABO incompatibility: Etiology is intravascular immune reaction, leading to clumping and lysis of red cells
with mismatched blood. Signs and symptoms include hemoglobinuria, fever, chills, coagulopathy, renal
failure, and circulatory collapse. Prevention is key by ensuring correct patient identity and blood type to
avoid these preventable reactions.
ABO system: Patient’s blood type is based on the ABO antigen system. Type A people make
antibodies to B antigens, and type B to A. Type AB makes no ABO antibodies and hence is a
universal recipient. Type O makes antibodies to A and B, and so these patients are universal donors
(the cells have no ABO antigens), but they can receive only type O blood.
Delayed hemolytic reaction: Usually takes 3–7 days to manifest. Signs and symptoms include fever,
malaise, hyperbilirubinemia, and decreasing hematocrit. Usually related to minor antibody systems such as
the Rh system. Usually but not always preventable with recipient antibody screening. Treatment includes
hydration and supportive care.
Rh system: A system of minor antigen-antibody that can cause reactions.
Disease transmission: Many virsues can be transmitted by blood. Prior to screening, this was a real risk.
With modern screening methods such as nucleic acid technology screening, the risk is reduced but is not
HIV: Estimated to be 1:800,000.
Hepatitis C: Estimated to be 1:600,000.
Hepatitis B: Estimated to be 1:220,000.
Others: Risks less known but have been described. HTLV 1 and 2, West Nile virus, Creutzfeld-Jacob
Immunosuppression: Probably the most significant but least thought of risks of blood transfusion. Negative
Morbidity in the form of increased infectious complications, including ventilator-associated
Possible increases in cancer recurrence following potentially curative surgery.
Increased mortality in intensive care unit (ICU) patients
B Indications for transfusion
Given the negative effects of transfusions, who should be transfused?
Prior transfusion triggers of a hemoglobin of 10 mg/dL or hematocrit of 30% were artificially set.
Transfusion decisions should be based on individual patient circumstances. In general, it is safe to let the
Hgb drop to 7 mg/dL and even lower in healthy, young individuals.
Cardiac patients: May need higher Hgb levels, but this is debatable.
Trauma patients: Exsanguinating patients should be given blood as resuscitation, as their Hgb is still
high acutely, but they are losing blood and its attendant oxygen-carrying capacity.
Patients in class 3 hemorrhagic shock (1500 cc blood loss, signs of hypotension should be
ICU patients: If needed, direct measurements of oxygen delivery and extraction can help to guide
General patients: Only transfuse if symptomatic. Signs and symptoms from anemia can include
tachycardia, tachypnea, and acidosis
C Alternatives to transfusion
If the time of blood loss is known: elective surgery
Autologous banked blood
Epoetin alpha : Can increase the hematocrit preoperatively to help avoid transfusion.
Use of auto-transfusion technology: Recycle blood lost during surgery.
Acute normovolemic hemodilution: Once a patient is anesthetized, blood can be removed, stored,
and replaced with crystalloid or colloid to maintain euvolemia. This has two benefits. Blood lost
during surgery has a lower hematocrit, and therefore fewer red cells are shed. Those that are shed
can be replaced with fresh (not stored) autologous blood.
Directed donor: risk of virus transmission lower, but similar risks of immunomodulation and
Hemostatic agents prevent blood loss in the first place!
FFP/cryoprecipitate for patients with coagulopathy.
DDAVP for patients with platelet dysfunction.
Aprotinin: inhibits serine proteases, including plasmin.
Lysine analogs: ε-aminocaproic acid.
Topical hemostatics: fibrin glue.
Acute unexpected blood loss
Autotransfusion may still be an option, if readily available.
Emergent aortic rupture
Quick prevention of further blood loss is the best therapy.
Accept a lower Hematocrit.