6th year medical student blood transfusion review blood transfusion review salwa hindawi medical...

6th year Medical Student

Blood Transfusion Blood Transfusion ReviewReview

Salwa HindawiSalwa HindawiMedical Director of Blood Transfusion ServicesMedical Director of Blood Transfusion Services

KAUHKAUH


The risks associated with transfusion can be reduced by: - Effective blood donor selection.- Screening for TTI in the blood donor population. high quality blood grouping, compatibility testing. - Component separation and storage.

- Appropriate clinical use of blood and blood products. - Quality assurance

Donor Patient


Blood Donation

• WB every 8 weeks, Hct > 38%• Plateletpheresis every 3 days or 24

times per year, Hct > 38%• Autologous Blood

– WB every 3 days– up to 3 days prior to surgery– Hct > 33%


Steps in Blood Banking

• Type and Screen (T & S): (Done for low probability of transfusion) – ABO and Rh type– Antibody screen– Antibody identification– DAT

• Type and Crossmatch (T & C) (Done for high probability of transfusion)

• above steps plus Crossmatch


Direct Antiglobulin Test (DAT)

• also called the direct Coombs test• adding anti-IgG to detect IgG that is

attached to the RBCs• also detects C3 complement fragments

on the RBC surface• DAT is performed in the investigation of

immune hemolytic anemia and transfusion reactions


Indirect Antiglobulin Test (IAT)

• detects free antibodies in the serum • the IAT test is performed during the

antibody screen and antibody identification


Type and Screen (T & S)

• an ABO and Rh type and an antibody screen and antibody identification are done when the patient is admitted

• only testing necessary if low probability of transfusion


Antibody Screen (IAT) • recipients serum is added to 3 test RBCs (in

test tubes 1 to 3 ) which have all of the important RBC antigens on them

• therefore if one or more of the three screening cells is positive then a RBC antibody is present in the serum

• then do an antibody panel to identify the antibody present


Antibody Identification (IAT)

• after the screening RBCs are positive then do an antibody identification

• recipients’ serum is added to 10 test RBCs in a panel (test tubes 1 to 10) which contain all of the important antigens

• the antibody in the serum is identified


Major Crossmatch (Compatibility testing)

• donor RBCs (unit of blood) are tested with recipient serum

• to detect unexpected recipient antibodies

• this checks to see if the transfusion is compatible


Type and Cross (T & C)

• includes an ABO and Rh type and antibody screen and antibody identification

• in addition includes a crossmatch where specific units of blood are held back for up to three days for a particular patient

• for a high probability of transfusion


Crossmatch to Transfusion ratio (C:T ratio)

• blood is used more efficiently when the number of units set aside for a particular patient (crossmatched) are actually transfused.

• when a patient does not need blood, it is good practice to get a T& S but not a T & C

• C:T ratio is less than 2:1


Maximum Surgical Blood Order Schedule (MSBOS)

• Is a guideline to order standard number of units of RBCs to be crossmatched for a specific surgical procedure, based on average use in the institution

• examples – angioplasty T&S– aortic dissection T&C 6


Red cell Antigens: ABO type

• present on RBCs, GI tract and vascular endothelium

• three alleles A, B, O, the A and B alleles code for glycosyltransferases

• specificity of the antigen is in its terminal sugar– galactosamine for A– galactose for B


ABO type continued

• Pt Cells Pt Serum• vs vs• anti -A anti-B A cells B cells• A + 0 0 + 40%• B 0 + + 0 11%• AB + + 0 0 4%• 0 0 0 + + 45%


Rh Type

• Five important antigens of the Rh system are D, C, E, c, and e

• These antigens are product of two genes RHD and RHCE located on chromosome 1p36

• These one set of three D/d C/c and E/e is inherited from each parent

• example father CDe and mother cde then the genotype is CcDdee and the phenotype is CcDe


Rh type

• Rh blood group antigens are present only on RBCs• Rh positive means that the D antigen is present

(85% on the population)• Rh negative means that the D antigen is absent

(15% of the population)• the D antigen is highly immunogenic• More than 80% of D negative persons receiving D

positive blood are expected to develop anti-D


Hemolytic Disease of the Newborn(HDN)

• D antigen is the most important cause of HDN• mother is D neg, father is D pos and fetus is D positive• fetus’ D positive RBCs enter mother’s circulation and

mother makes anti-D of IgG type which crosses the placenta

• first pregnancy not affected• Maternal IgG crosses the placenta and affects the second D

positive pregnancy• anti-D formation in mother prevented with Rhogam


Other Blood Group Systems

• clinically significant blood group systems are Kell (K), Kidd (Jk), Duffy (Fy) and Rh (E,e,C,c) systems.

• antibodies are made by people who lack the antigen on their RBCs

• and have been exposed to RBCs containing the antigen


Other Blood Group Systems

• The following are not clinically significant: – I I– Le Lewis love– M my– N new– H honda– P prelude


Blood Used on Emergency Basis

• Blood used on Emergency Basis – for a patient that is bleeding out – and the blood type is unknown

• group O, Rh negative, uncrossmatched• recipient may have an unexpected antibody• after 5 min use ABO and Rh type specific

blood


Whole Blood

• 450 ml of whole blood with 63 ml of anticoagulant• need for oxygen carrying capacity and volume

replacement• no viable platelets or WBC• decreased labile coagulation factors (Factor V and

VIII) • Not available since it is not efficient utilization of

blood


Packed Red Blood Cells (PRBCs)

• 200-250 ml of RBCs and 50 ml of plasma• Hematocrit 55-70% depending on

anticoagulant• shelf life 35 to 42 days depending on the

anticoagulant• treatment of symptomatic anemia where

oxygen carrying capacity is needed


Leukocyte Reduced RBCs

• RBCs with 99.99% of WBCs removed by leukocyte reduction filter

• prevents repeated nonhemolytic febrile transfusion reactions

• reduces immunosuppression of recipient by donor WBC

• decreases post-operative surgical infections due to reduced immunosuppression


Leukocyte Reduced RBCs continued

• prevents or delays HLA alloimmunization

• identical to CMV seronegative blood• does not prevent graft versus host

disease, only gamma irradiation prevents graft versus host disease


Indications for Leukocyte Reduced RBC continued

• after second nonhemolytic febrile transfusion reaction

• newly diagnosed leukemics• long term multiple transfused patients

– sickle cell disease– aplastic anemia– thalassemia


Frozen RBCs

• store RBCs for up to 10 years at -70C in glycerol

• glycerol is a cryopreservative solution• used for

– rare blood types for patients with multiple antibodies

– autologous blood for a postponed operation


(Gamma )Irradiated RBCs

• RBCs and platelets are exposed to gamma irradiation at 2500 rads for 4.5 minutes

• this inactivates the T lymphocytes in the donor unit and prevents graft versus host disease in an immunocompromised recipient


Indications for Gamma Irradiated RBCs

• bone marrow transplant recipients• congenital immunodeficiency syndromes• intrauterine transfusions• transfusions from all blood relatives• Hodgkin’s disease• WBC products (to neutropenic patient)

– (never Stem Cells)


Plateletpheresis

• donated by a single donor • 3.0 x 10 E11 platelets plus 300 ml of

plasma, expires after 5 days • raises the platelet count 30,000• used for all platelet transfusions until

less than 10,000 platelet increase


Pooled Platelets

• are prepared from the platelet portion of 6 whole blood units plus 300 ml of plasma (potential for 6 infectious disease exposures) expires after 5 days

• 6 X 5 X 10 E10 = 3.0 x 10 E 11 platelets• 6 x 5000 rise /RD plt = 30,000 • transfuse the patient with platelets from

many donors to see which platelets will raise the platelet count


Indications for Platelets

• low platelet count or functional abnormality

• major bleed, major surgery >100,000• minor bleed, minor procedure >50,000• prevent spontaneous bleed > 10,000


Low Post-transfusion Increment to Platelets

• 1 hour post (platelet recovery) poor– platelet alloantibodies– platelet autoantibodies– hepatosplenomegaly

• 24 hour post (platelet survival) poor– infection bleeding– DIC fever


Fresh Frozen Plasma (FFP)

• 200-250 ml of plasma frozen at -18C within 8 hours of collection

• no platelets are present• contains all coagulation factors• an unconcentrated source of fibrinogen

– use Cryo to correct a low fibrinogen level

• needs 20-30 min lead time to thaw prior to use


FFP Continued

• used in patients with multiple coagulation factor deficiencies:– liver disease– DIC– massive transfusion

• indicated when PT/PTT are >17/55 sec• not used if non bleeding or for volume

replacement


Cryoprecipitate (Cryo)

• a white precipitate that forms when FFP at -18C is thawed to 4C

• volume is 10 to 15 ml• adult dose is 10 to 20 pooled units• 30 minutes is needed for thawing and

pooling


Cryoprecipitate continued

• Cryoprecipitate can be used for the replacement of all of the following:– vWF vWD– Factor VIII Hemoplilia A– Factor XIII Factor XIII def– Fibrinogen dec. fibrinogen *

• head injury, massive bleed, trauma,


Complications of Blood Transfusion

Immediate Delayed

HTR GVHD FNTR PTP TRALI Iron overload Bacterial Infectious contamination diseases Allergic, Anaphylaxis Alloimmunization


Transfusion Transmitted Disease (TTD)

• HBV 1 in 63,000• HCV 1 in 103,000• HTLV-I 1 in 641,000• HTLV-II 1 in 641,000• HIV-1 1 in 587,000• HIV-2 < 1 in 1,000,000


Acute Hemolytic Transfusion Reaction

• a clerical error (wrong specimen, wrong patient)

• 1 in 6,000 to 25,000 transfusions • back pain, chest pain, fever, red urine,

oliguria, shock, DIC, death in 1 in 4• stop the transfusion


Work up of An AHTR

• start normal saline• treat patient symptomatically• send blood bag and tubing to culture• send red top and purple top tubes • urine specimen for hemoglobinuria• DAT is positive


Non Hemolytic Febrile Transfusion Reaction

• NHFTR (1:100)• Recipient has WBC antibodies to Donor

WBCs contained within RBCs and Plateletpheresis products

• DAT is negative• rise in temperature by 2F or 1C• other causes for fever are eliminated


Allergic (Urticarial) Transfusion Reaction

• Recipient has antibodies to the Donor’s plasma proteins (1 in 1000)

• offending protein is not identified• urticaria, itching, flushing, wheezing• this is the only transfusion reaction where the

blood that is hanging can be restarted after treatment with Benadryl

• if symptoms continue then STOP


Anaphlyactic Transfusion Reaction

• anaphylactic reaction (1 in 150,000)• 1 in 700-900 people never made IgA • occurs when exposed to normal blood

products which contain IgA• bronchospasm, vomiting and diarrhea

and vascular collapse• treat with Epinepherine, Solu-Medrol,


Circulatory Overload• marginal cardiovascular status• given blood components too rapidly• develops acute shortness of breath, heart

failure, edema (1: 10,000)• systolic BP increases 50 mm • infuse slowly, not to exceed 4 hours• split the unit of RBC and give half


Transfusion Related Acute Leukocyte Lung Injury

• TRALI reaction (1:10,000)• Donor plasma contains WBC antibodies

that when transfused to the recipient cause agglutination of recipient’s WBC in the pulmonary capillary beds

• Chest X ray looks like ARDS• Donor removed from donating blood


Sepsis from Bacterial Comtamination

• Platelets:– skin contaminants most common cause– plateletpheresis 1 in 5000– pooled platelets 1 in 1000

• RBC:– Sepsis from RBC due to Yersinia,

Enterics or Gram Positive 1 in 3,000,000

6th year medical student blood transfusion review blood transfusion review salwa hindawi medical...

Documents