Table of contents
- 1. Packed RBC Transfusions
- 1.1. Introduction / Basic Compatibility
- 1.2. Important Points
- 1.3. Blood Preparations
- 1.4. EPO
- 2. Transfusion Indications/Tresholds
- 2.1. Important Trial
- 3. Transfusion Reactions
- 4. Platelets
- 5. Plasma
- 6. Cryoprecipitate
- 7. Other
- 8. Coagulopathy Principles
- 8.1. Investigations
- 8.2. Treatment:
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Source: MKSAP 16
Packed RBC Transfusions
Introduction / Basic Compatibility
- ABO antigen groups
- Anti-A/B developed even if never exposed to the major blood antigens
- Rh system
- Consists of antigens: C/D/E (D most immunogenic, in fact "Rh+" only refers to "D" antigen).
- "Type and Screen" (aka forward and back-type)
- Determine antigens present on recipient's RBCs and what antibodies in recipient's serum.
- Antibody screen: alloantibodies that patient has (prior blood exposure or pregnancy)
- "Crossmatch"
- Find compatible unit, and mix patient's serum with donor RBCs, to see if agglutinates.
- (donor's serum against patient's RBC's not tested, thought packed RBCs have very little serum)
- Bottom Line:
- "Type and Screen" --> if unsure if will give blood
- "Crossmatch" --> if sure will give blood (all crossmatching prior to transfusion).
Important Points
- 1 unit of pRBCs = 250-300cc of volume
- 1 unit of pRBC expected to increase Hb by 10 g/L
- Only true indication for pRBC transfusion is to improve oxygen carrying capacity of blood.
Blood Preparations
- Leukoreduction of pRBCs
- Removal of leukocytes (either at time of collection or leukocyte filter in-line)
- Recommended extra washings if patient had febrile non-hemolytic reaction
- RCTs: Decreases HLA alloimmunization, decreases febrile non-hemolytic reactions, reduce CMV transfusion.
- Washed Red Cells
- For pts with transfusion-related urticaria or anaphylaxis (antibodies to donor blood plasma proteins)
- pRBCs are washed with saline
- Patients with IgA deficiency can have Anti-IgA, can react to donor blood (anaphylactic). Washing x5 is protective
EPO
- Used in renal insufficiency (reduces need for transfusion).
- Targeting >100-120 g/L should NOT be done (high risk of VTE, CV events, etc..)
- Use of EPO in cancer is highly controversial (risk of tumor progression, increased mortality)
Transfusion Indications/Tresholds
Erythrocytes
|
Platelets (Treatment)
|
Platelets (Prophylaxis)
|
FFP
|
Cryoprecipitate
|
Source: MKSAP16 - ACP
Important Trial
- TRIC Trial
- Pop'n: 838 critically ill pts NOT ACTIVELY BLEEDING with euvolemia after initial treatment after 72hrs post-admission.
- Restrictive strategy: tfsn threshold 70 g/L --> transfuse to maintain 70-90 g/L
- Liberal strategy: tfsn threshold 100 g/L --> transfuse to maintain 100-120 g/L
- Outcomes:
- 30 day mortality: NO difference
- Hospital Mortality: Restrictive BETTER
- Less Critically Ill: Restrictive BETTER
- ≤ 55yo: Restrictive BETTER
- Cardiac Disease: NO difference
- Conclusion: Restrictive (70 g/L) strategy is at least as effective or superior to liberal (100 g/L) patients with no active bleeding and no cardiac compromise.
Transfusion Reactions
Transfusion Complication | Preventive/Treatment Measures |
---|---|
Febrile reaction | Prevention: antipyretics, leukoreduction Treatment: stop the transfusion and rule out an acute hemolytic |
Allergic reaction | Prevention: antihistamine, washing of cellular blood products Treatment: antihistamine, epinephrine if severe |
Anaphylaxis | Prevention: washing cellular blood products, IgA-deficient donor Treatment: stop the transfusion, IV fluids, epinephrine, supportive care |
Transfusion-related acute lung injury | Prevention: eliminate multiparous women as blood donors Treatment: supportive care, supplemental oxygenation |
Graft-versus-host disease (RISK: Bone marrow transplant pts) | Prevention: γ-irradiation Treatment: supportive care |
Cytomegalovirus transmission | Prevention: leukoreduction, cytomegalovirus-negative donor Treatment: antivirals including ganciclovir or foscarnet |
Source: MKSAP16/ACP
Fever
- Stop transfusion to R/O acute hemolytic transfusion reaction (most dreaded complication)
- Consider antibiotics
Allergic Reaction
- Urticaria
- Does not require interruption of transfusion
- Anaphylaxis / Anaphylactic Shock
- Manage accordingly
- Test for IgA deficiency
- Washed RBCs with plasma removed advised for future transfusions
Transfusion-Related Acute Lung Injury (TRALI)
- Indistinguishable from ARDS (1 in 5000 risk)
- Anti-Leukocyte antibodies in donor blood bind granulocytes in recipient blood --> become trapped in pulmonary circulation --> inflammatory lung injury
- Leading cause of death from blood transfusions
- Usually 6h post-transfusion
- Management:
- Stop transfusion (first sign of resp compromise)
- Supportive care (as in ARDS)
- Repeat Transfusions: unclear recommendations... theoretically can use washed RBCs (no WBCs, no plasma)
Immune Suppression
- Transfusions known to suppress immune system (think twice in sepsis!)
Bacterial Contamination
- Septic transfusion Reaction
- Criteria: (any of the following within 5 hours)
- Temp > 39.0 (or 2 deg higher than before transfusion)
- Rigors
- HR > 120/min (or >40 higher than pre tranfusion)
- Decrease or Increase in BP > 30mmHg
- Treatment:
- Majority Staph, although gram negatives common.
- Seal transfusion bag + send to micro to culture.
- Broad spectrum antibiotics (i.e. vancomycin + cefepime)
Under Construction (other transfusion reactions)
Platelets
- Obtained by either pooled random-donor platelet concentrates or single-donor apheresis.
- Stored for max 5 days at room temperature. (high risk of bacterial growth at room temp).
- Highest risk blood product for sepsis (S. aureus is most common) + fevers (high leukocytes)
- If fevers is an issue, can leukoreduce (but removes 25% of platelets too!)
- Single adult dose of platelets raises count by 20,000-30,000 /uL 1hr post-transfusion (Marino ICU book says 7000-10000?)
- Transfused platlets survive 7-9 days
- Check platelet level 1 hour post-transfusion to check if refractory.
Matching
- ABO/Rh(D) matching generally not required for plts.
- Alloimmunization to HLA can happen, leads to refractoriness to future transfusions (must match HLA class if happens).
Guidelines for Platelet Transfusions
- Based on "Evidence-based platelet transfusion guidelines" Hematology Am. Soc. Hematol. Euc. Program (2007)
-
Platelet Target Indication 100,000/uL Neurosurgical / CNS bleeding 50,000/uL Non-neurosurgical procedures and non-CNS bleed 10,000/uL ** controversial ** Prophylactic platelet transfusion trigger (efficatious and cost-effective)
Studied in nonbleeding patients with leukemia (no increase in bleeding)
(see below for discussion) - Prophylatic platelet transfusion trigger is controversial:
Transfuse chronic thrombocytopenic patients <10,000 or only transfuse when bleeding?- "only transfusion when bleeding" option shown safe in select groups (autologous peripheral blood stem cell transplantations). - 50% reduction in need for platelet transfusions.
- Trials ongoing.
-
Milestone Notes 100,000/uL - ACTIVE Intracranial bleed or RISK of intracranial bleed
- ACTIVE bleeding + hemostasis Impaired (i.e. platelet dysfunction)
50,000/uL - ACTIVE Non-CNS Bleeding (normal platelet function) 40,000/uL - PREVENTION: Sufficient for laparotomy, craniotomy, tracheostomy, percutaneous liver biopsy, bronch, endoscopy+bx 20,000/uL - PREVENTION: Lumbar punctures
- PREVENTION: Risk of bleed from pre-existing lesions (i.e. peptic ulcer disease)
10,000/uL - Central Venous Catheter 5000/uL - Studied: very small risk of bleed (if vasculature intact)
Refractoriness of Platelet Transfusion
- Inappropriately low increment in plts following transfusion (sometimes defined as <10,000 /uL increment).
- Non-Immune Causes:
- Fever, DIC, Drugs (amphotericin B).
- Immune Causes:
- Alloimmunization to HLA platelet antigens (1/3 of platelet refractoriness, often in multiple transfusions).
- Non-Immune Causes:
- If Identified:
- Freshest single-donor, ABO-matched platelets transfused
- If unsuccessful and HLA antibodies identified, HLA-matched platlets or cross-matched compatible platlets should be used.
- Source: MKSAP 16 (ACP)
Plasma
- Fresh Frozen Plasma (FFP)
- Typical 1 unit = 200-300cc's
- (1-2 doses usually not effective for coagulation, need 10-15 cc/kg)
- (Hence 70kg man = 700cc's --> 4 units of FFP)
- Contains all coagulation factors
- Indications:
- Warfarin reversal in bleeding patients
- TTP treatment (exchange)
- Dilutional coagulopathy (massive transfusions)
- Bleeding patients with factor deficiencies (DIC)
- Prophylactic use is not proven. (not recommended)
- Risks:
- Infectious risk is similar to pRBCs
- Volume Overload (large volume, stays intervascularly)
- TRALI (Lung Injury --> FFP causes agglutination of recipient leukocytes)
- Febrile/Alleric Rections
- Anaphylactic (Rare)
Cryoprecipitate
- FFP frozen --> thaw to 4°C --> spin down precipitate
- Unlike FFP does not contain all clotting factors
- Used: 1-2u per 10kg.
- Contains:
- F VIII (not high enough for Hemophilia A)
- vWF
- F XIII
- Fibronectin
- Fibrinogen.
- Indications:
- Bleeding patients with Hypofibrinogenemia (Liver disease, thrombolytic disease, DIC)
- Factor XIII deficient (RARE)
Other
- Other Blood Products
- IVIG (immunoglobulin)
- Factor VIII and IX
- Alpha-1-antitrypsin
- Protein C
- Anti-thrombin concentrates
- Albumin
- Risks are smaller (samples processed)
Coagulopathy Principles
- Types:
- Thrombocytopenia - Primary hemostasis
- Petechiae, Mucosal Bleeding,
- Causes:
- DIC
- End-Stage Liver Failure
- Thrombocytopenia - Primary hemostasis
Investigations
- Platelets, aPTT, PT/INR
- Peripheral blood smear
- Platelet morphologic abnormalities, red-cell fragmentation, dysplasia?
- Extra Tests: Fibrinogen Level, D-Dimer, Bleeding Time (clinical)
- Interpretation:
Treatment:
- DO NOT treat to correct lab abnormalities
- Treatment only indicated if actively bleeding or surgical procedure is needed.
- Transfusing Fresh Frozen Plasma principles:
- In old days widespread to transfuse 1:1 (pRBC:FFP) or 2:1, but survival advantage studies were flawed (survival bias). Now new study shows in (non-massive transfusion): FFP tsfn worsens ARDS by 12x and multiple organ dysfunction syndrome by 6x. The best ratio is unknown.
- DO NOT TRANSFUSE PLATELETS WITH pRBC IN NON-MASSIVE TRANSFUSIONS (<10u).
- FFP Transfusions:
- High incidence of Transfusion Related Lung Injury (TRLI)
- High incidence of infections: HIV infection, Creutzfeld-Jakob
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