Chapter 16: Transfusion Therapy_Quiz 1 Coverage

Transfusion therapy definition

Encompasses all aspects of transfusion; includes product selection, indications, outcomes, and patient-specific strategies.

Main purposes of transfusion therapy

(1) Restore oxygen-carrying capacity (anemia, blood loss), (2) Provide hemostasis (coagulation proteins, platelets).

Transfusion as transplantation

Transfused cells must survive/function; rejection can occur (e.g., hemolytic transfusion reaction, platelet refractoriness).

Conditions not always requiring transfusion

Stable iron-deficiency anemia, compensated thrombocytopenia with no bleeding risk.

Whole blood main indication

Rapid blood loss requiring replacement of both RBC mass and plasma volume.

Whole blood contraindication

Severe chronic anemia (risk of pulmonary edema/heart failure due to volume overload).

Whole blood expected effect (70-kg adult)

↑ Hematocrit by ~3% or ↑ Hemoglobin by ~1 g/dL per unit.

Whole blood volume adjustment effect

Increase may not be apparent until 48-72 hours when blood volume readjusts.

Whole blood transfusion requirements

Must be ABO identical with recipient.

RBCs preparation

Separated from whole blood via centrifugation; stored in anticoagulant-preservative solutions.

RBCs main indication

Increase oxygen-carrying capacity in anemia, blood loss, decreased RBC survival, or marrow failure.

Clinical signs of anemia needing RBCs

Tachycardia (>100 bpm), tachypnea (>30/min), dizziness, angina, weakness, confusion.

Physiologic compensation in anemia

↑ Plasma volume, ↑ heart rate, ↑ respiratory rate, ↑ O₂ extraction (up to 50%).

Critical hemoglobin level for transfusion

≤6 g/dL. Guidelines: <7 g/dL for most, ≤8 g/dL for cardiac patients.

Hemoglobin tolerance in healthy individuals

Levels as low as 5 g/dL can be tolerated with minimal effects.

RBC transfusion contraindication

Well-compensated anemia, nutritional anemia (iron, B12, folate) unless decompensated.

Expected effect of 1 unit RBC (70-kg adult)

↑ Hemoglobin by 1 g/dL, ↑ Hematocrit by 3%.

Expected effect of pediatric RBC dose

10-15 mL/kg raises Hb by 2-3 g/dL or Hct by 6-9%.

RBC volume in additive solutions

300-400 mL (lower Hct, more additive fluid) vs. 160-275 mL in CPDA-1 RBCs.

RBC hematocrit differences

65-80% (CPDA-1) vs 55-65% (additive solution RBCs).

Leukocyte-reduced RBCs definition

Average unit contains <5 × 10⁶ WBCs; achieved by leukocyte filters.

Leukocyte-reduced RBCs purpose

Prevent febrile nonhemolytic transfusion reactions, HLA alloimmunization, CMV transmission, TRIM.

Residual WBC standard (U.S.)

<5 × 10⁶ WBCs per unit.

Leukoreduction timing

Pre-storage (preferred, prevents cytokine buildup) or post-storage (less effective).

Limitations of leukoreduction

Does not prevent TA-GVHD; effect on wound infection/cancer recurrence controversial.

Indications for leukoreduced RBCs

Febrile nonhemolytic transfusion reactions, HLA alloimmunization prevention, reduce CMV risk.

Washed RBCs purpose

Remove plasma proteins to prevent severe allergic or anaphylactic transfusion reactions (e.g., IgA deficiency).

Other uses for washed RBCs

Patients with anti-IgA or anti-haptoglobin antibodies; severe allergic reactions.

Storage of washed RBCs

Open system: 24 hours at 1-6°C; Closed system: up to 14 days.

Frozen/deglycerolized RBCs purpose

Long-term storage of rare blood, autologous units, intrauterine transfusion.

Frozen/deglycerolized RBCs characteristics

≥80% RBC recovery, similar post-transfusion survival to standard RBCs.

Storage after thawing (deglycerolized RBCs)

Open system: 24 hours; Closed system: up to 14 days.

Rejuvenated RBCs definition

Stored RBCs treated with inosine-phosphate-adenine solution to restore ATP and 2,3-DPG.

Timing for rejuvenation

May be performed up to 3 days after RBC expiration (CPD, CPDA-1, AS-1 units).

Rejuvenated RBCs requirements

Must be washed before transfusion to remove inosine; then transfused within 24h or frozen.

Platelet function

Form primary hemostatic plug and support normal hemostasis.

Clinical signs of platelet deficiency

Petechiae, ecchymoses, mucosal bleeding, spontaneous hemorrhage.

Causes of thrombocytopenia

Decreased production (chemo, marrow failure), increased destruction (DIC), dilution from massive transfusion.

Platelet transfusion indications

Active bleeding due to thrombocytopenia or platelet dysfunction; prophylaxis in severe thrombocytopenia.

Prophylactic platelet threshold

<5,000-10,000/µL in clinically stable patients with intact vasculature.

Minimum content per unit (whole blood platelets)

≥5.5 × 10¹⁰ platelets/unit.

Expected increment (whole blood platelet unit)

↑ Platelet count by 5,000-10,000/µL in 70-kg patient.

Minimum content (apheresis platelets)

≥3 × 10¹¹ platelets/unit.

Expected increment (apheresis platelets)

↑ Platelet count by 20,000-60,000/µL in 70-kg adult.

Equivalence of platelet dose

1 apheresis platelet unit ≈ 4-6 pooled whole blood platelet units.

Bacterial testing in platelets

Required for each product (apheresis and pooled); culture performed by collection center.

Leukocyte-reduced platelets

Used to reduce febrile reactions and alloimmunization.

Washed platelets

Used for patients with severe allergic reactions or neonatal alloimmune thrombocytopenia; short 4-hour shelf life if open system.

Effect of washing platelets

Removes plasma proteins but may decrease platelet count and function due to activation/adhesion.

Granulocyte transfusion indication

Severe neutropenia (<500/µL) with infection unresponsive to antibiotics, reversible marrow hypoplasia, and reasonable survival chance.

Granulocyte transfusion in neonates

Used in overwhelming infection with neutropenia due to poor marrow reserve and immature neutrophil function.

Granulocyte transfusion dose

Adults: 1 unit daily for 4+ days; neonates: portion of unit once or twice.

Granulocyte product content

>1 × 10^10 granulocytes, plus platelets and 20-50 mL RBCs.

Granulocyte storage

20-24°C without agitation; transfuse ASAP.

Granulocyte crossmatch

Required due to RBC content.

Granulocyte irradiation

Often performed to prevent TA-GVHD in immunocompromised patients.

Effect of granulocyte transfusion

May raise neutrophil count to >1,000/µL (esp. with G-CSF-mobilized donors).

Plasma products

Include FFP, PF24, PF24RT24, thawed plasma.

FFP definition

Frozen within 8 hours; contains normal levels of all factors including FV and FVIII.

PF24 definition

Frozen within 24 hours; reduced FVIII and protein C compared with FFP.

PF24RT24 definition

Apheresis plasma held at room temp ≤24 h before freezing; similar to PF24.

Thawed plasma definition

FFP/PF24/PF24RT24 thawed and stored 1-6°C for up to 4 days after initial 24 h.

Plasma indications

Multiple factor deficiencies (liver disease, DIC, massive transfusion), urgent warfarin reversal, rare factor XI deficiency, TTP (ADAMTS13 source).

Plasma not for

Volume expansion or nutritional protein replacement.

Plasma compatibility

ABO compatible with recipient's RBCs; Rh type ignored.

Plasma dosing

4-6 units usually adequate; aim ≥30% activity for hemostasis.

Plasma limitations

Volume overload risk; repeated transfusion needed due to short factor half-lives.

Cryoprecipitate definition

Cold-insoluble plasma fraction rich in fibrinogen, FVIII, vWF, FXIII, fibronectin.

Cryoprecipitate QC

≥150 mg fibrinogen and ≥80 IU FVIII per unit (usually higher).

Cryoprecipitate pooling

Typically 5 units pooled; yields 750-1250 mg fibrinogen.

Cryoprecipitate indications

Hypofibrinogenemia (congenital or acquired), DIC, massive transfusion, FXIII deficiency.

Cryoprecipitate dosing

~1 unit/7-10 kg raises fibrinogen by 50-75 mg/dL.

Cryoprecipitate not for

Volume expansion, hemophilia A, or vWD (factor concentrates preferred).

Thawed plasma, cryo-reduced

Contains II, V, VII, IX, X, XI, albumin, ADAMTS13; deficient in fibrinogen, FVIII, FXIII, vWF.

Factor VIII deficiency

Hemophilia A; treated with recombinant or plasma-derived FVIII (recombinant preferred).

Factor VIII storage

Refrigerated; reconstituted with saline for infusion; allows self-therapy.

Factor VIII dose calculation

[Desired - initial] × plasma volume = units required.

Plasma volume formula

Blood volume = weight × 70 mL/kg; plasma volume = BV × (1 - Hct).

vWD treatment

Requires FVIII product containing vWF (or DDAVP in mild cases).

Factor IX deficiency

Hemophilia B; treated with recombinant FIX (preferred) or FIX complex from plasma.

Prothrombin complex concentrate (PCC)

Contains II, VII, IX, X; used in FIX deficiency, rare FVII/X deficiency, warfarin reversal.

Risk with PCC

May cause thrombosis, especially in liver disease.

Factor IX dose note

About 50% diffuses into tissues; initial calculated dose must be doubled.

Antithrombin function

Protease inhibitor that inactivates thrombin; activity enhanced by heparin.

Hereditary antithrombin deficiency

Associated with venous thrombosis.

Acquired antithrombin deficiency

Most common in DIC.

Antithrombin concentrates

Approved for hereditary deficiency; pasteurized for viral safety; no proven benefit in acquired deficiency.

Alternative source of antithrombin

Thawed plasma.

Protein C and Protein S function

Protein C inactivates factors V and VIII (anticoagulant); Protein S is a cofactor for Protein C.

Protein C/S deficiency

Leads to hypercoagulability and thrombosis.

Protein C concentrate

Approved for hereditary deficiency; recombinant activated Protein C used experimentally in DIC and sepsis.

Recombinant factor VIIa (rFVIIa) use

Controls bleeding in hemophilia A/B patients with inhibitors; also used in liver disease, trauma, and massive transfusion (not fully established).

Albumin preparation

Produced by fractionating pooled plasma; available in 5% and 25% solutions; heat-treated and virus-safe.

Albumin content

96% albumin protein.

Albumin uses

Volume replacement, plasmapheresis replacement, burn therapy, diuresis in hypoalbuminemia with diuretics.

Albumin 25% effect

Draws ~5× its volume of extravascular water into vascular space; requires adequate extravascular water and compensatory mechanisms.

Immune globulin (Ig) composition

Mainly IgG; some products may contain IgM/IgA.

Immune globulin administration

Available IM or IV; IM form must NOT be given IV due to risk of anaphylaxis.

Immune globulin uses

Hypogammaglobulinemia, post-exposure prophylaxis (hepatitis A, measles), autoimmune diseases (ITP, myasthenia gravis).

Immune globulin dosing

Hypogammaglobulinemia: monthly injections; Hepatitis A prophylaxis: 0.02-0.04 mL/kg IM; IV dose ~100 mg/kg.