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Transfusion Medicine. Cheryl Pollock 13 November 03. Objectives. An understanding of: Available blood products Appropriate selection of blood products according to the clinical setting Potential complications of the transfusion. Outline. Blood banking Emergency transfusions
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Transfusion Medicine Cheryl Pollock 13 November 03
Objectives • An understanding of: • Available blood products • Appropriate selection of blood products according to the clinical setting • Potential complications of the transfusion
Outline • Blood banking • Emergency transfusions • Transfusion reactions and risks • Component therapy
Blood Bank Basics • Type & screen • Blood group (ABO) identification • Rh typing • Antibody screening • Cross-matching
ABO Identification • >400 RBC antigens have been identified • Major ones are ABO type, and Rh type • Anti-ABO Abs are IgM that bind complement and cause agglutination and destruction of red cells => acute intravascular hemolysis • Presence of A&B antigens are determined by testing with anti-A and anti-B Abs
Rh Typing • Major Rh system Ag is the ‘D’ Ag • Rh status determined by testing with anti-D antibodies • Rh-neg females of child-bearing age always get Rh neg blood products • Rh-neg males and elderly females can get Rh-pos blood if emergent transfusion required
Antibody Screening • To determine presence of: • Complete (agglutinating) antibodies • Agglutinate RBCs in saline • Usually IgM • Responsible for HTR • Incomplete (non-agglutinating) antibodies • special techniques to visualize agglutination • Usually IgG • Not responsible for HTR
Antibody Screening • All antibody screens are negative • Patient has no unexpected anti-bodies • Donor blood released after an abbreviated or electronic cross-match • Any antibody screens are positive • Patient has one/more unexpected antibodies which need identification • Donors must be antigen-negative • Full cross-match required
Antibody Screening:Coombs Test • Direct Coombs: • To detect Abs or complement on surface Ags of RBCs • Agglutination= IgG antibodies in the patient’s serum have bound to recipient RBCs • Indications: • Hemolytic disease of newborn • Hemolytic anemia • Hemolytic transfusion reaction
Antibody Screening:Coombs Test • Indirect Coombs • Indirect antiglobulin test • Detect Abs in serum that can recognize Ags on RBC. • i.e. detect Abs capable of hemolysing RBCs • By mixing serum with donor RBC and then anti-antibody Abs: RBC agglutination = +test • Indications: • Cross-matching -bl gr Abs in pregnant pts • Atypical bl gr
Pre-transfusion Testing • Donor • ABO and Rh status confirmed • Recipient • Abo and Rh determined • Antibody screening • For 18 clinically-relevant antigens • Indirect Coombs • If positive: specific identification, transfusion ideally delayed
Cross-Matching • Test of donor/recipient RBC compatibility • Immediate “spin” cross-match • Recipient serum + donor RBCs, spin tube, read immediately • Detects ABO incompatibility only • Complete cross-match • If antibody screen + • Donor units w/out specific Ag are each tested with indirect Coombs
Cross-Matching • Electronic cross-match • Donor blood issued based on blood bank info • Recipient’s ABO and Rh type has been done twice and filed in computer • No clinically significant antibodies found in current or past blood samples • Contraindications: • Significant antibodies present (current or past)
Emergency Transfusions • PRBCs are the only blood product that can be used for emergency transfusion • Plasma products contain too many Abs • Patient stability and the time available before intervention is needed will determine what is chosen • Prior to transfusion, draw blood for typing and cross-matching
Indications for ED Transfusion • Consider • Comorbidity -Cardiac status • Rate of bleeding • Acute/subacute bleed with impaired oxygen delivery to tissues • Hb <60-70 g/L • Symptomatic chronic anemia with Hb <60-70 g/L • Pre-op
Pediatric Pearls • Hemodynamic parameters can be deceiving • Normotensive until ~30% blood volume lost acutely • In pediatric trauma, emergency transfusion of >20 ml/kg is associated with increased mortality
Emergency transfusions • Case 1 • 56 y.o. male, motorcycle vs. car, with open femur fracture, unstable pelvis • HR 130, bp 80/50, intubated at scene for GCS=6. • Blood? How soon?
Emergency Transfusions • Universal Donor Group O • Uncross-matched type O+ • Indications • Massive, uncontrolled hemorrhage from any cause • e.g. trauma, massive GI bleed, ruptured AAA • Women of child-bearing age need group O-
Emergency Transfusions: Other Options • Type-Specific: • 5-10 min • ABO grouping, Rh typing • pt can be initially stabilized with crystalloid • Incomplete cross-match • 30 min • ABO group, Rh type, “spin” cross-match • Fully cross-match • 45-60 min • Reserved for specific patient for 48h
Administration • PRBCs • 1 unit= 250ml, Hct= 60-70% • 1 unit= 10 g/L increase in Hb • Peds: 1ml/kg PRBCs = 1% increase in hematocrit • Bedside check • Recipient & unit i.d., compatibility, expiration • Large-bore needles to prevent hemolysis • Blood warmers if massive transfusion • Blood only mixed with NS; no meds in same IV line
Complications • Transfusion reaction • Immediate • Delayed • Infectious disease transmission • Transfusion-associated coagulopathies
Immediate Hemolytic Intravascular Non-hemolytic Febrile Allergic Acute lung injury Hypervolemia Delayed Hemolytic (extravascular) Infectious Graft v. Host disease Electrolyte imbalance Transfusion Reactions
Transfusion Reactions • Case 2 • 70 y.o. male transfused for UGI bleed • Transfusion of first unit PRBCs • Acutely dyspneic, chest and low back pain, with burning at IV site. • O/E: T 39C; HR 120; BP 100/60
Acute Hemolytic Transfusion Reaction (Intravascular) • Medical emergency due to ABO incompatibility (usually clerical error) • Incompatible donor cells are destroyed by recipient antibodies • Intravascular cell lysis=> hemoglobinemia and hemoglobinuria • Incidence ~1/20 000 transfusions • Fatal 1/100 000 transfusions
Acute Hemolytic Transfusion Reaction • Presentation • chills, headache, N/V, burning at infusion site, • Chest tightness, dyspnea, low back pain • O/E: fever, tachycardia, hypotension • Complications • Cardiogenic shock, respiratory failure • ATN • DIC
Acute Hemolytic Reaction:Treatment Principles • Prevention • Slow infusion for 15 min, Q5min VS • STOP THE TRANSFUSION • Replace IV tubing • ABCs • Hemodynamic stability: crystalloid+/- pressors • Adequate renal blood flow • Low-dose dopamine infusion • Urine output >100ml/h (fluid + furosemide)
Acute Hemolytic Reaction • Evaluation • Retype and cross-match • Direct & indirect Coombs • CBC, creatinine, PT/PTT • Haptoglobin, indirect BR, LDH, plasma free Hb • Urine for Hb
Immediate Transfusion Reactions • Non-hemolytic • Febrile • Allergic • Acute lung injury • hypervolemia
Transfusion Reactions • Case 3 • 58 y.o. female post-elective TAH. • During transfusion of 1st unit PRBCs, c/o malaise, chills, ‘feels warm’. • O/E: T 39C; HR 90; BP 120/80
Immediate Transfusion Reactions • Febrile non-hemolytic • Impossible to clinically distinguish from acute hemolytic reaction • Caused by Ag-Ab reaction involving plasma/components passively transfused • Usually mild • Worse if poor CV status, critically ill • Multi-transfused, multiparous patients
Febrile Non-hemolytic Reaction • Presentation • Fever, chills • Mgmt • Stop transfusion; • Initial Rx as per acute hemolytic reaction • Acetaminophen, meperidine • Evaluation • Hemolytic W/U +/- infectious W/U
Allergic Transfusion Reaction • Anaphylaxis • Rare (1/20 000 transfusions) • Suggests IgA deficiency • Presentation • Dyspnea, bronchospasm, shock • Mgmt • Epi, steroid, anti-histamine, pressors • Do not restart transfusion • Hemolytic W/U
Allergic Transfusion Reaction • Minor • Presentation • Urticaria, pruritis, erythema • Mgmt • Stop transfusion • Anti-histamine • If symptoms resolve, can restart transfusion • No further W/U
Transfusion-Related Acute Lung Injury • Anti-WBC donor Abs + recipient WBC -> complement activation in lung -> non-cardiogenic pulmonary edema • Clinical diagnosis • Empiric treatment with steroids and respiratory support • Usually resolves within 48-96h
Delayed Transfusion Reactions • Extravascular hemolytic transfusion reaction • Days to weeks • Non-ABO Abs bind to RBCs -> deformation -> splenic sequestration -> extravascular hemolysis • Presentation • Mild reaction • Fever, jaundice; hemoglobinuria rare • No specific treatment
Delayed Transfusion Reactions • All blood tested for: • HIV Ag -HTLV I,II -HBsAg -syphilis • Ab to HIVI, II -HCV -HCAg • Infectious • Hep A 1: 1 000 000 • Hep B 1: 30 000- 1: 250 000 • Hep C 1: 30 000 – 1: 150 000 • HIV 1: 200 000 – 1: 2 000 000 Data from Goodnough et al. NEJM 340:440, 1999
Delayed Transfusion Reactions • Case 4 • 44 y.o. male with Non-Hodgkin’s lymphoma 1/52 post-chemo • c/o fatigue, presyncope, SOBOE • Hb 68 • Risks of transfusion….
Graft v. Host Disease • Rarely encountered in ED • Keep in mind if considering transfusion in anemic leukemic/lymphoma pts • Viable lymphocytes transfused with PRBCs • Multiplying, histoincompatible lymphocytes attack recipient->more BM suppression
Graft v. Host Disease • Sx • Fever, N/V, rash, diarrhea, hepatomegaly • Increased LFTs, pancytopenia • No effective treatment • Fatal • Prevention • Gamma irradiation of all cell components, rendering donor lymphocytes incapable of proliferating
Delayed Transfusion Reactions • Electrolyte imbalance • Hypocalcemia • Citrate preservative. • Hyperkalemia • K+ leakage across membrane • Problem in renal failure, neonates
Dilutional Coagulopathy • Massive transfusion • Dilution of platelets & coagulation factors • Check platelets & coags after 5-10u PRBC • Platelet transfusion only if thrombocytopenia+microvascular bleeding • FFP only if PT/PTT >1.5x norm
Component Therapy • Platelets • FFP • Cryoprecipitate
Platelet Transfusion • Indications • count < 20 x 109/L; < 50 x 109/L if bleeding or planned invasive procedure • Therapy • Should be ABO-specific • Usually 6u at a time: increase of 50-60 x109/L • BUT…consider cause of thrombocytopenia • DIC, splenomegaly, antibodies may be refractory to platelet transfusion
Fresh Frozen Plasma • All coagulation factors + fibrinogen • Indications • Emergent reversal of warfarin therapy • Correction of coagulation deficiencies • Therapy • Must be ABO compatible • 1u = ~250ml • Dose 10-15 ml/kg
Cryoprecipitate • Contains • Factor VIIIC, vonWillebrand Factor, fibrinogen • Indications • Bleeding associated with: • Hypo-/dysfibrinogenemia (e.g. DIC) • vonWillebrand’s disease if FVIII not available • Hemophilia A if FVIII not available • Therapy • Should be ABO compatible (no cross-match) • Usual dose ~ 10u
References • Marx: Rosen’s Emergency Medicine: concepts and Clinical Practice, 5th ed. • Tintinalli. Emergency Medicine: A Comprehensive Study Guide, 5th ed. • Ross, AK. Pediatric trauma. Anesthesia management. Anesthesiol Clin North Amer. 01 June 2001; 19(2): 309-37