Red Blood Cells
Group & Screen and Crossmatch
- ABO blood type (O, A, B, or AB)
- Most important antigen group
- RhD group (positive or negative)
- Second most important antigen group
- There are more than 30 minor blood group antigens, including Kell (K and k), Kidd (Jk^a^ and Jk^b^), Duffy (Fy^a^ and Fy^b^) and MNS (S and s)
- Group and screen
- Group tests recipient for ABO and RhD status
- Screen tests the recipient plasma for unexpected and clinically significant minor antigen incompatibility
- Takes about 45 minutes, but if the screen is positive then can take days to determine which specific antibodies are causing the problem
- Crossmatch confirms that a specific unit of RBCs is safe to give to the recipient
- If screen was negative, an abbreviated crossmatch is done either as immediate spin or as electronic
- If screen was positive, then a full antiglobulin crossmatch is done
Basics
- Each unit is about 300 mL with a hematocrit of 65 to 70%, and raises the recipient's hemoglobin by about 10 g/L
- Usually transfused over 2 hours
- Can do up to 3 or 3.5 hours in elderly over 70 years old, heart failure, LV dysfunction, prior MI, renal dysfunction, or volume overload (usually with concurrent diuretics at the start of the transfusion)
Indications
- Acute blood loss
- Maintain hemoglobin above 70 g/L during active bleeding
- Maintain hemoglobin higher (e.g. above 80 g/L) during active bleeding in patients with:
- Unstable or acute coronary syndrome
- Coronary artery disease
- Uncontrolled or unpredictable bleeding
- Anemia
- Consider for hemoglobin below 70 g/L in stable patients
- Consider for hemoglobin below 80 g/L in patients undergoing orthopedic or cardiac surgery or with cardiovascular disease
Platelets
Plasma
- Each unit has a volume of 250 mL and requires 30 minutes to thaw
- It must be ABO compatible
- The usual dose is 10 to 15 mL/kg (3 to 4 units for average human)
- Units are transfused over 30 minutes to 2 hours (maximum 3.5 hours)
- A single dose (10 to 15 mL/kg) should normalize the INR and PTT if within 1.3 to 1.8 times normal, and lasts 6 hours (the half-life of factor VII)
Indications
- Before a procedure or during active bleeding where the INR, PT, or PTT is at least 1.8 times normal, and no other therapies are available
- During massive transfusion protocols (6 to 10 units of RBCs expected within 6 hours)
- Before a procedure or during active bleeding in patients with severe liver disease and INR greater than 2 times normal
- Not useful when INR less than 1.8, when used 1:1 with RBCs, if there is no pending surgery or bleeding, for the reversal of warfarin, for the reversal of other anticoagulants, or as nutritional support
Transfusion Reactions
| Risk | Event |
|---|---|
| 1 in 13 | Red cell sensitization, increasing risk of hemolytic transfusion reaction and hemolytic disease of the fetus and newborn |
| 1 in 20 | Febrile non-hemolytic transfusion reaction, per pool of platelets |
| 1 in 100 | Transfusion-associated circulatory overload |
| 1 in 100 | Minor allergic reaction (urticaria) |
| 1 in 300 | Febrile non-hemolytic transfusion reaction, per unit of RBCs |
| 1 in 7,000 | Delayed hemolytic transfusion reaction |
| 1 in 10,000 | Transfusion-related acute lung injury (TRALI) |
| 1 in 10,000 | Symptomatic bacterial infection, per pool of platelets |
| 1 in 40,000 | ABO mismatch, per unit of RBCs |
| 1 in 40,000 | Anaphylaxis |
| 1 in 100,000 | Post-transfusion purpura |
| 1 in 200,000 | Death from bacterial infection, per pool of platelets |
| 1 in 250,000 | Symptomatic bacterial infection, per unit of RBCs |
| 1 in 500,000 | Death from bacterial infection, per unit of RBCs |
| <1 in 1,000,000 | Transmission of West Nile virus |
| 1 in 4,000,000 | Transmission of Chagas disease |
| 1 in 7,500,000 | Transmission of hepatitis B virus |
| 1 in 7,600,000 | Transmission of HTLV |
| 1 in 13,000,000 | Transmission of hepatitis C virus |
| 1 in 21,000,000 | Transmission of HIV |
- Other transmissible infections include:
- Viruses: parvovirus B19, hepatitis A virus, hepatitis E virus, Zika virus, dengue virus, and chikungunya virus
- Protozoa: malaria, Chagas disease, toxoplasmosis, leishmaniasis, babesiosis
- Helminths: filariasis
- Spirochetes: syphilis, Lyme disease
- Rickettsiae: Rocky Mountain spotted fever, Coxiella burnetii, and Ehrlichia
Fever
- Differential diagnosis includes bacterial infection, acute hemolytic transfusion reaction, and febrile non-hemolytic transfusion reaction
- Stop transfusion, check vitals, compare patient name to name on blood product
- If severe:
- Collect blood bank samples to recheck ABO group
- Send unit to blood bank for bacterial cultures and compatibility testing
- Send blood cultures
- If mild: give acetaminophen 325 mg and continue transfusion
Dyspnea
- Differential includes transfusion-related acute lung injury, transfusion-associated circulatory overload, and anaphylaxis
- Stop transfusion, check vitals q15min, compare patient name to name on blood product
- Chest x-ray
Allergic Reactions
Minor Allergic Reactions
- Minor reactions may include urticaria, flushing, erythema, pruritis, cough, wheeze, nausea, vomiting, abdominal pain, and diarrhea
- For minor reactions
- Stop the transfusion
- Give diphenhydramine 25 to 50 mg p.o. or IV
- If urticarial rash is less than 2/3 BSA and no other concerning symptoms, restart the transfusion slowly
- For recurrent urticarial reactions, consider premedication with diphenhydramine, cetirizine, and/or steroids
Anaphylaxis
- Anaphylaxis usually starts immediately or up to 45 minutes of starting the transfusion
- Symptoms include:
- Urticaria and flushing are usually present
- May have airway obstruction with dyspnea, chest pain, wheezing, and stridor
- Hypotension
- Nausea and vomiting
- For severe allergic reactions:
- Stop the transfusion and do not restart
- Diphenhydramine 25 to 50 mg IV
- For anaphylaxis, epinephrine and steroids
Cytopenias
- Differential includes transfusion-associated graft-versus-host disease and post-transfusion purpura
