Presentation on theme: "Second Year Medical Student Fall Pathology Lab and Indiana Blood Center Tour: Transfusion Medicine and Blood Banking October, 2014."— Presentation transcript:
1Second Year Medical Student Fall Pathology Lab and Indiana Blood Center Tour: Transfusion Medicine and Blood BankingOctober, 2014
2Outline Pre-test Major blood group basics Trauma ABO incompatibility Bag o’bloodMassive blood transfusion protocol (MBTP)ABO incompatibilityAcute hemolytic transfusion reactionHemolytic disease of the fetus/newborn (HDFN)Post-test
3What is bloodBlood has an interesting medical and philosophical history, it permeates our lives and cultureHippocrates postulates that similar to the four elements, the body is comprised of four humors -- blood, phlegm, black bile, and yellow bile -- and their imbalance causes disease – circa 400 BCBram Stroker’s Dracula centralizes around a character who can drink the blood of his victims and attain immortality (with huge pop culture implications)I was born with music inside me. Music was one of my parts. Like my blood. It was a force already within me when I arrived on the scene. It was a necessity for me - like food or water. Ray CharlesEgyptian hieroglyphics show treatment of patients by bleeding from the neck and ankle – circa BC“I was a queen, and you took away my crown; a wife, and you killed my husband; a mother, and you deprived me of my children. My blood alone remains: take it, but do not make me suffer long.” Marie Antoinette 1793Surgeon General of the U.S. Army and Navy, the American Red Cross agrees to organize a civilian blood donor service to collect blood plasma for the war effort -1941French physician Jean-Baptiste Denis transfuses a teenage boy suffering from a persistent fever with nine ounces of lamb's blood – 1667Shakespeare’s Macbeth plays at the Global theater with the theme of blood representing a character’s masculinity and remorse – circa 1600Clara Barton, “Angel of the battelfield” during American civil War, founded the American Red CrossChristianity teaches the blood shed by Jesus Christ formed a new covenant and is the sacramental symbol of the Eucharist AD to present
4Entire process: Blood transfusion safety What the Blood Blanker does for the clinicians and patients Transfusion therapy is a set of processes, not just a productRecruit donorMedical reason to TXScreen donorPre-TX testingCollect unitIssue unitPrepare componentsAdminister at bedsideInfectious diseasestestingMonitor & evaluateProduct: Blood safetyEntire process: Blood transfusion safetyAfter S. Dzik, MD Blood Transfusion Service, MGH, Boston
5Some blood bank basics Basically, there are 4 major blood groups ABOThese groups are defined by surface antigens present on the Red Blood Cell (RBC)Which antigens are present is determined by the expression of genes which code for enzymes found on the long arm of chromosome 9 (9q34)These genes are expressed co-dominantly
6A geneIf you have the A gene (N-acetyl galactosyltransferase), you make the A antigenThus you are blood Type AA Blood typeA geneN-acetyl GalT
7B geneIf you have the B gene (galactosyltransferase), you make the B antigenThus you are blood Type BB Blood typeB geneGalT
8Both A and B genes AB Blood Type If you have the A and B genes on separate chromosomes, you make both the A and B antigensThus you are blood group ABAB Blood TypeGalTA geneB geneN-acetyl GalT
9Neither A or B genes O Blood Type If neither A or B genes are present, you will make neither A no B antigensThus you are blood group OO Blood Type
10Why do we care? Try to stay awake because it has to do with immunology Recognition of self and non-selfA and B like antigens are found constitutively in natureWe are exposed to them early in lifeAs a result the body will make antibodies against the antigens it doesn’t have (non-self) and not make antibodies against the antigens it does (self)
11Major antigens and antibodies Type AType ABBBBBBBAAA,BBAAAAABA,BAABBAAA,BAType BType O
12A, B, and A,B allo-antibodies Allo-antibody is an antibody against an antigen of the same speciesAll potent activators of complement and the membrane attack complexCause massive intravascular hemolysis of RBCs
13So what happens when… We mix type A whole blood with… Type AB whole bloodBBBBBBBB
14When transfusing whole blood the blood types must be identical. So what happens when…We mix type A whole blood with…Type AB whole blood?BBBBBBBBWhen transfusing whole blood the blood types must be identical.
15But if we just… Mix type A RBCs… with type AB whole blood… B B B B B B
16And if we apply this to patients… DonorRecipientIt is the basis for blood component therapy
17Blood Component Therapy For RBC unitsFor plasma based unitsDonor blood typeDonor blood typeRecipient blood typeRecipient blood typeWho is the universal RBC donor?Type OWho it the universal RBC recipient?Type ABWho is the universal plasma donor?Type ABWho it the universal plasma recipient?Type OApproximately 45% of the population is Type O, 40% type A, 11% type B, and 4% AB.
18Case presentation #1You have been accepted to Emergency Medicine residency in Washington DC and are enjoying a nice day off of sight seeing following three days on 16 hour shifts when you walk past a TV wall and see this….
19Olympus Has Fallen!https://www.youtube.com/watch?feature=player_detailpage&v=kWPNediW79I
20Yes, this could happen to you! Case presentationWithin a minute your pager goes off.You return the page and you are informed that Emergency Response Plan has been initiated and you are to report to your training hospital for assignment.Yes, this could happen to you!Calling in all available resources including clinicians is a part of IU Health’s emergency response plan – this will be mimicked at several institutions.
21Case presentationYou are assigned to trauma management as a team leaderYou meet the EMS at the ED entrance to accept your first patientAs you take the patient the driver quickly states “this is a 27 year old male with proximal lower limb injuries secondary to large caliber gunshot, GCS 15/15, vitals are 98.0F, 135, 32, 108/62, O2 sats 95% NC. Approximately 2 liters of blood loss at the scene. Intraosseous lines placed – patient has received approximately 1000ccs NS”
22What do you Do?ABCDEsAirway assessment and protection possible cervical spine stabilizationBreathing and Ventilation assessment for oxygenationCirculation assessment to control hemorrhage and maintain end organ perfusionDisability assessment by basic neurologic evaluationExposure by undressing patient and searching for additional injury while preventing hypothermiaThese are typically done all at once with priority given in alphabetical order – a patient who cannot protect his/her airway will generally die before they exsanguinate. When an issue is identified the remaining steps are paused until the issue is resolved.
23A & BAs you move the patient into the ED you ask the patient his name – He states “Channing Tatum” between rapid breathsBesides realizing that’s the wrong movie, you just covered your A and B (patient’s ability to “mentate” & phonate generally indicates an ability to breath and protect his/her airway)You note the tachypnea and maintain a low threshold for intubation
24C &DPulse in upper extremities is 1+ weak and thready with regular tachycardic, approximately 130, while the posterior tibia and dorsus pedis pulses are absent bilaterally.An abnormality is identified in the lower extremities (C), now you must look for a cause while assessing for disability (D) of the injury which may change treatmentBlood soaked gauze is present at the upper thigh bilaterallyYou remove the patient’s socks to reveal two pale, grey feet and 10 pale toes.You run the sharp end of you reflex hammer up the plantar aspect of the patient’s feet – the toes curl in and the patient groans – you just assessed for disabilityThis is a normal Babinski’s reflex, plantar reflex, or negative Babinski’s testA positive Babinski’s sign is dorsiflexion of the big toe with splaying of the smaller digits – which would indicate nerve damage.
25EYou order your staff to start undressing the patient as you arrive in Triage and demand a trauma room.To which they respond “All of the trauma rooms are full!”You turn your attention to the blood soaked gauze at the thighsRemoving the gauze reveals two entrance and exit puncture wounds with pulsatile bloodA scan of the rest of the body including back reveals no other injuries but the patient’s skin is cold and clammy
26Diagnosis and additional management Diagnosis: Traumatic laceration of bilateral femoral arteries complicated by probable hemorrhagic shockWhat can you do for this patient?What studies or labs should you order?Intravenous access?Environment?Will review questions on next slide
27Traumatic laceration of bilateral femoral arteries StudiesEKG with telemetryContinuous pulse oxLabsCBC statCMP statBlood gas statLactate statType and Cross statThromboelastography (TEG)?InterventionsOxygen therapyTwo large-bore 16 gauge catheters with continuous NS pushDirect pressure/turniquet/BP cuff/upstream occlusionArterial lineWarm blankets to prevent hypothermiaElevate extremities/ TrendelenburgFoley catheterWill differentiate between a type & screen and a type & cross in the next caseWhy use NS if patient is bleeding – 2 reasons– Volume resuscitation is essential– dilution of the blood means less true blood volume is lostDirect pressure to reduce bleedingArterial line for real time monitoring of BPWarm blankets… bleeding not only causes hypovolemia but blood maintains body temperature. Massive loss of blood = massive drop in body temp.Elevate extremities to get blood back to the central circulationFoley catheter to monitor urine output – urine production will indicate correction of hypovolemia.Can you manage this patient on your own?To whom do you need to communicate this patient?
28Transition of care and support You page the trauma/vascular surgery teamNurse returns the page and says that due to the volume the soonest they can evaluate the patient is in 20 minutesYou call the blood bank and they haven’t received the specimen for type and cross.They say, due to the volume, it will take 5-10 minutes before a type can be done.Still, they ask what products you want?You try to think back tomedical school and recall ifanyone ever taught you anythingabout blood therapy.Get them to internalize that the patient will not live twenty minutes in his current state without blood productsBlood flow through the femoral artery in a healthy male is generally at least 500ml/min– Blood volume is approximately 70ml/kg, in a 70kg male that’s ~5L (70x70 = 4900mL)– Hemorrhagic shock occurs when blood volume drops to 30% or below.– This patient has approximately 3.5 minutes before they develop shock/organ failure (70% is ~3500ml at a rate of loss of 1000ml/min) if no blood loss hadoccurred at the sceneGive them a moment to respond to what products the patient needs – bleeding whole blood so they need either whole blood or a combination that recapitulates whole blood.
29Irradiated or not irradiated? OptionsWhole bloodPacked red blood cellsLeukocyte reducedWashed RBCCMV negativePlateletsPooled random donorApheresisPlasmaFresh Frozen PlasmaPlasma frozen <24 hrsThawed PlasmaLiquid plasmaPlasma cryoprecipitate reducedCryoprecipitateIrradiated or not irradiated?
30Whole Blood Description: Storage: Indications: 500+/- 50 ml mixed with 70 ml CPDStorage:21 days stored at 1-6ºIndications:Recently used in military hospitals in combat areas settingsProposed clinical trials to examine feasibility and efficacy in civilian setting
31Packed Red Blood cells Description: Storage = 42 days Indications: 200 ml of RBC with 111 ml of additive solutionPacked cell volume = 60%Storage = 42 daysIndications:Acute blood loss exceeding 15-20% of blood volume (pediatric patients ml/Kg) and failure to obtain hemodynamic stability with reasonable volume of crystalloid and/or colloid solutionsAcute blood loss of any amount if there is clinical evidence of inadequate oxygen carrying capacity
32Packed Red Blood cells Indications: Contraindications: Hemoglobin of ≤ 7 gm/dl (hematocrit ≤ 21%), if not due to a treatable cause (treatment of underlying case is preferable if patient is not symptomatic)Symptomatic anemia regardless of hemoglobin levelHemoglobin ≤ 8 gm/dl (hematocrit ≤ 24% ) and acute cardiac disease / or shockContraindications:For volume replacementIn place of a hematinicTo enhance wound healingTo improve general “well-being”
33Leukocyte reduced pRBC Description:Packed red cells with leukocytes reduced (residual leukocyte count less than 5x106)Processing of Product:Product made during transfusion with filter attached to unitPre-storage leukocyte reduction at blood centerIndications:Prevention of HLA/WBC alloimmunizationPrevention of recurrent non-hemolytic febrile reactionsPrevention of CMV transmission in select groups of patients
34Saline washed pRBC Description: packed red cells washed with saline 99% of plasma proteins are removed85% of leukocytes are removedPost-wash K + is 0.2 meq/LProcessing: manual and automatic methodsStorage: once washed, 24-hour outdateIndications:History of allergic or febrile reactions secondary to plasma proteins not prevented by pre-transfusion administration of antihistamines and leukocyte reductionIgA deficiency with documented IgA antibodiesHistory of anaphylactic reaction to blood components
35Platelet Concentrates Description:Random donor unit contains 5.5 X 1010 platelets suspended in ml of plasmaApheresis donor unit contains3.0 X 1011 platelets suspended in ml of plasmaDosage:4-6 platelet concentrates1 apheresis unitPlatelet count should increase 25,000 – 30,000/cc3Each dose has equivalent of one unit of fresh plasma*Storage:Stored at 20-24º C on a rotator5-day outdate
36Platelet Concentrates D Indications: prevention and cessation of bleedingSeverely thrombocytopenic (less than 10,000 or 20,000 depending on institution)Moderately thrombocytopenic and bleeding (less than 50,000)Surgery or invasive procedure (less than 50,000)Diffuse microvascular bleeding following cardiopulmonary bypass or with intra-aortic balloon pump (less than 100,000)Bleeding with qualitative platelet defectMassive Transfusion Protocols (MTP)E Contraindications:Idiopathic Thrombotic Thrombocytopenic Purpura (ITP)Thrombotic Thrombocytopenic Purpura (TTP)
37Plasma Description: Storage: 1 year at -18ºC ml of plasma and CPDA-1, including 25 meq of citric acidJumbo plasma 400 cc or greaterFrozen within 8 hrs = FFPFrozen within 24 hrs = 24FPStorage: 1 year at -18ºCOutdate once thawed (1-6ºC)24 hours for FFP or 24FPhours if relabeled as Thawed Plasma
38Plasma Indications: Contraindications: Treatment of coagulopathy due to clotting factor deficienciesPatient is bleeding actively with PT and/or PTT greater than 1.5 normal (INR > 1.8) and platelet count above 50,000Coumadin overdose with major bleeding or impending surgeryTreatment of TTPMassive Transfusion Protocol (MTP)Contraindications:Volume expansionTreatment of nutritional deficiencies
39CryoprecipitateDescription: each unit consists of ml residual plasma80 units of factor VIII250 mg of fibrinogenStorage: 1 year at -18ºCIndications:Hypofibrinogenemia (≤ 100 mg/dl)DysfibrinogenemiaFactor XIII deficiency - rareMTP
40Irradiated Units Products irradiated: Whole blood, packed red cells, platelets, and granulocyte concentratesIndications: preventing graft versus host diseaseImmunocompromised patientsDirected donations from blood relativesPremature infants ≤ 1200 gmsFetuses receiving intrauterine transfusionsNeonatal exchange transfusionsProcessing and final product:Irradiate with 2500cGyMitotic capacity of lymphocytes is reduced or eliminated without significant functional damage to other cellular elementsStorage:Red cells outdate 28 days from irradiation (or original expiration if less than 28 days)
41“Would you like to initiate a Massive Blood Transfusion Protocol?” Confused?As you are running through the options in your head…. you hear the technician, still on the line, ask…“Would you like to initiate a Massive Blood Transfusion Protocol?”
42Massive Blood Transfusion Protocol (MBTP) Massive blood transfusion – transfusion of 10 or more blood components within a 24 hour windowBlood bank maintains an adequate inventory of type-specific and type compatible units for emergent situationsWhen the patient’s blood type is unknown O Rh positive red blood cells and AB plasma products will be releasedSpecial component processing cannot be provided due to urgencyOnce blood type has been identified type specific units will be released; if incompatible blood has been released the clinician will be notified retrospectively
43Massive Blood Transfusion Protocol (MBTP) Since the patient is bleeding whole blood each component of the blood must be replacedAt IU Health components are released in the following ratios8 units packed, leukoreduced red blood cells4 units plasma1 unit leukoreduced, apheresis platelets
44Back to the case You initiate that massive blood transfusion protocol You order rapid infusion as units arriveLab results come back
45Labs/StudiesVenous bloodTotal white blood cell (WBC) count = 7,400 WBCs /mm3(normal = 4,000 to 11,000)Differential WBC count revealed 59% neutrophils(normal = 55-70%)Hematocrit = 46%(normal = 42-54%)Hemoglobin = 15.0 gm / dl(normal = gm / dl)Sodium (Na+) = 138 mEq / L(normal = mEq / L)Potassium (K+) = 5.1 mEq / L(normal = mEq / L)Chloride (Cl-) = 104 mEq / L(normal = mEq / L)BUN = 27 mg / dl(normal = mg / dl)Creatinine = 1.9 mg / dl(normal = mg / dl)Glucose = 165 mg / dl(normal = mg / dl)SGPT = 41 IU / L(normal = 0-33 IU / L)SGOT = 48 IU / L(normal = 0 41 IU / L)Lactate = 4.2 mmol/L(normal = mmol/L)Arterial bloodBlood pH = 7.28(normal = )pCO2 = 31 mm Hg(normal = 40 mm Hg)pO2 = 78 mm Hg(normal = mm Hg)Hemoglobin - O2 saturation = 88%(normal = %)[HCO3-] = 14 mEq / L(normal = mEq / L)Urinary output in first 60 minutes in ER was 20 ml (color was dark yellow). Urine specific gravity = (normal = ). Central venous pressure ranged from 1 to 3 cm H2O throughout the cardiac cycle (normal = range = 5.5 to 13 cm H2O). ECG revealed normal sinus rhythm with slight ST-depression in most leads
46Final Diagnosis and Treatment Hemorrhagic shockAnion gap secondary to lactate acidosis from glycolytic pathway, indicating poor oxygenation and end organ dysfunction.As units are infused and new labs are ordered the trauma surgery team arrives to evaluate the patient.They commend you for your excellent work and indicate that they are taking the patient to surgery now.
47You’re thinking “Now this is more like it!” Case presentation #2You decided Emergency medicine just wasn’t for you so you transfer into General Surgery at a small community hospital outside Seattle, WA that didn’t fill.You are asked to admit a 35 year old female for non-urgent cholecystectomy for symptomatic cholelithiasis confirmed by ultrasound.You’re thinking “Now this is more like it!”
48Case Presentation #2 HPI PMHx Started feeling intermittent RUQ pain with fatty meals during her third trimester. Pain brief and resolves spontaneously. Last attack was 3 weeks ago. No fevers, N/V, change in bowel habits. Wants the surgery preformed while on maternity leave.PMHxJust gave birth to her second child 1 month ago, she claims to have lost some blood during birth but felt fine, did not get transfused, and was discharged at 48hrsNo other significant history
49Case Presentation #2 Medication: FmHx/SocHx/RoS: unremarkable multivitaminFmHx/SocHx/RoS: unremarkablePhysical exam: unremarkableVitals within normal limitsPertinent positives/negativesAbd: Soft non-distended, normal bowel sounds; No guarding or rebound tendernessYou order standard pre-op labsCBC, CMP, Type & screen
50Labs CBC CMP Normal Hemoglobin levels Men: 13.8 – 18.0 g/dLFemale 12.1 – 15.1 g/dLHematocrit is the proportion of whole blood occupied by RBC, calculated %HCT = RBC volume/total blood volume (or Hgb x 3)5.29.822029.44.9140102250.801980Ca: 9 mg/dLAlk: 100 U/LBili: 0.4mg/dLAST: 5 U/LALT: 2 U/LProtein: 7g/dLAlbumin: 4g/dL
51Diagnosis Mild anemia, otherwise ready for surgery You discuss the patient with your staff on rounds.He tells you to change the Type & Screen to a Type and CrossHe says transfuse two units when available… He never operates on a patient with a Hgb < 10 g/dLA single unit of packed RBC will increase a normal adults hemoglobin 1gm/dL
52T&C vs T&SType and Screen – used in patients without and immediate need for transfusion (pregnant and pre-surgical patients)Identify blood and Rh type (with RBC and serum)Screen serum for minor blood group antibodies which could cause hemolysisType and Cross – used in patients with an imminent need for transfusion (trauma patients, sickle cell crisis, invasive surgical patients)Perform a Type and screenIdentify compatible units for transfusion and mix patient serum with RBC product to prove there is no reaction/hemolysis (CROSS-match)Units are then reserved for that patient if needed
53Patient’s T&C 4+ A+ A Forward Reverse Anti-A Anti-B Anti-Rh Type? Red blood cell typing – done two ways, remember ABO antigen and antibodies correlateForward – Patient’s red blood cells with known anti-seraReverse – Patient’s serum with known red blood cell typesForwardReverseAnti-AAnti-BAnti-RhType?A CellB Cell4+A+A
54TransfusionScreen is negative and serum sample cross-matched with two unitsUnits arrive in the OR as the patient receives anesthesia prior to intubationThe nurse checks the patient labels and everything matches, confirms that they are A+ units which is witnessed by the anesthesia tech, and takes the patient’s vitals which are normalShe starts the transfusion and goes about her pre-op routineAs she places the foley catheter she notes dark urine
55TransfusionThere is no one besides the anesthesia tech in the room, so the nurse pages youOn the phone the nurse tells you about the urineYou quickly request an update on her vitalsThe patient is now intubates but otherwise vitals show increased temperature of 1.9˚C, increased heart rate, and decreased blood pressureShe includes that the patient is now oozing from all IV sitesWhat is the next, MOST important step you need to take to decrease morbidity and mortality for your patient?
56Suspected Transfusion Reaction STOP THE TRANSFUSION
57Suspected Transfusion Reaction The nurse stops the transfusionYou tell her to call a code, start a transfusion reaction work-up, and you will be there as soon as possibleYou arrive in the midst of aggressive resuscitation effortsUltimately the team is unsuccessful and the patient is pronounced dead
58Transfusion reaction work-up Post-mortem labs are drawnDirect anti-globulin testPlasma free hemoglobinUrine for hemoglobin testingBlood bank receives a specimen for retyping and cross matchBody bank notes the serum is pink that does not change with centrifugationClerical paper work review revealed no errors
59Transfusion reaction work-up ForwardReverseAnti-AAnti-BAnti-RhType?A CellB CellO-4+OWhat is the patient's blood type?Original pretransfusion specimen retyped A+DAT is positiveRepeat cross-match strongly positive (4+)Plasma free hemoglobin elevatedUrine hemoglobin elevatedWhat is the diagnosis and how did this happen?
60Acute hemolytic transfusion reaction Rapid destruction of donor RBC by recipient AbMedical emergencyMost severe transfusion reactionCan be fatal, thus treat all transfusion reactions as possible AHTR (Stop the transfusion for all possible reations)PathophysiologyAb bind donor RBCs Complement activation formation of MAC RBC lysisAg-Ab complexes coagulation cascade activation intravascular thrombi and consumption of coag factors DIC and schistocytesBoth pathways result in the release of numerous cytokines causing symptomsAll dose dependant
61Acute hemolytic transfusion reaction Signs and symptomsLaboratory findingsTriadFever/Chills (>2˚F or >1 ˚C)Flank painDark urineAdditionalTachycardiaDyspneaN/VBleedingHypotensionFeeling of impending doomHemoglobinemia (pink or red serum/plasma)Hemoglobinuria (NOT hematuria)Usually positive direct antiglobulin test (DAT) but can be negative (all Ab coated cells already lysed)Elevated indirect bilirubin and LDHDecreased haptoglobinHyperkalemiaPeripheral smear: Schistocytes
62Acute hemolytic transfusion reaction Treatment is supportiveCase resolutionPatient in a two person roomPatient asked to switch beds with roommate because she liked to be by the windowWhen nurse came to draw Type and Cross specimen, she drew the specimen from the patient in the door bed (where the patient was assigned) without checking patient IDThe patients roommate typed A+ while our patient was actually O-Anti-A, Anti-B, and Anti-A,B antibodies in patient destroyed A+ transfused cells
63Risk of transfusion reaction Carson J L et al. Ann Intern Med doi: /
64Case Presentation #3You decide that General Surgery isn’t for you either. You love babies, so you figure Ob/Gyn is the place for you.You transfer into a residency program in a large metropolitan city with a diverse population.You think, its just catching babies – They’re about as big as a blood bag and inside someone else. I’m finally done with these pesky transfusions!!
65Case presentation #3A 25 year old pregnant Chinese female presents to your clinic for her first obstetric appointment. She just immigrated from China and is late in her second trimester. She received her prenatal care in rural China.
66Case presentation #3 PMHx Medication FmHx/SocHx/RoS Birth history None, reports always being healthyMedicationNoneFmHx/SocHx/RoSUnremarkableBirth historyG3 P2002First pregnancy uncomplicatedSecond child born “golden” which resolved after several weeksHer husband is the father of all children
67Case presentation #3 Physical exam Routine labs and exams ordered Vitals within normal limitsPertinent physical exam findings: Fundal height 26cm (correlates with weeks of gestation)Routine labs and exams orderedCBC, CMPInfectious serology (ToRCHeS)Group B strep screenType and ScreenFetal heart rate by dopplerFetal ultrasound
68Lab and Exam results Fetal heart rate: 170 bpm (normal 120-150 bpm) Awaiting ultrasound findingsLaboratory work up shows a mild anemia but is otherwise unremarkableRemember pregnant patients will develop a physiologic anemia due to a disproportionate increase in blood volume over red blood cell volume
69Type and Screen Results ForwardReverseAnti-AAnti-BAnti-RhType?A CellB CellO-4+OAntibody screen is positiveReflex red blood cell panel is performed and an Anti-D antibody was identifiedWhat diagnosis do these findings suggest?What does the Rh +/- mean?Does it have anything to do with the Anti-D antibody?
70Hemolytic Disease of the Fetus/Newborn (HDFN) Defined as the destruction of fetal and neonatal red blood cells by maternal antibodiesHistorically IgG anti-Rh (anti-D) minor blood group alloantibodies were first identifiedOther Minor blood group antibodies are implicated as well – however Anti-D alloantibodies are the most immunogenic/potentWalk through of mechanism/pathophysiology of disease
71Hemolytic Disease of the Fetus/Newborn (HDFN) The Rh Minor blood group antigen system contains multiple antigensHowever during typing the Rh +/- demarcation refers only to the Rh(D) antigenThus Anti-Rh allo-Ab are often incorrectly used interchangeably with Anti-D allo-AbWalk through of mechanism/pathophysiology of disease
72A B A B Minor blood groups e k D Jka Fya E c K Fyb Jkb C Genetics Similar to Major ABO genesMinor blood group genes code for surface proteins (Rh system), enzymes, or nothing (silent/amorph)Minor genes are also inherited in a Co-dominant patternEach parent contributes half of the inheritanceIndividual traits are inherited independent of each otherSerologyAllo-antibodies can be formed against any minor blood group antigenRequires exposure which is often by unnatural means, i.e. exposure to bloodAekDJkaBFyaEcKFybABJkbC
73Development of fetal allo-antibodies Mother must be antigen negativeAntigen positive individuals will not form antibodies to selfMother must be exposed to minor antigenFeto-maternal hemorrhageTransfusion with ABO compatible, minor group incompatible bloodInjection with needles contaminated with minor group antigen positive bloodMinor blood group mismatch allogeneic stem cell transplantMinor antigen exposure induces antibody formationExact volume unknown (varies between individuals) but as little as 0.1 mL of Rh+ RBC have been shown to stimulate antibody productionLarger volume of exposure tends to produce a more robust responseFollowing antibody production mother must become pregnant with an antigen positive fetusThe initial response will be IgM which will not cross the placentaIn most cases, the first minor group incompatibility between mother and fetus will not be affected, with exceptionsSubsequent exposure will induce memory cells to produce IgG antibodies which will in turn cross the placenta and cause hemolysis or clearanceSelf explanatory
74Development of fetal alloantibodies Rh+Rh -RhUnlike A and B antibodies,many minor antibodies arenot naturally occurringD dd dFirst Rh + child sensitizes MotherMother develops Anti-D antibodies- First round IgM antibodiesSecond child conceivedIgG Alloantibodies havedeveloped whichcross placenta and…Second ChildD dFirst ChildD dd dd dRh +Rh +Rh -Rh -
75IgG antibodies Only IgG type antibodies can cross the placenta Actively transported via a receptor specific to IgG Fc regionStarts in the second trimester and continues until birth (passive immunization )
76Pathophysiology of HDFN Maternal IgG antibodies cross the placenta and attach to fetal red blood cellsRed blood cells hemolyzed or removed via reticulo-endothelial systemResultant anemia causes accelerated production of RBCs by bone marrow, termed erythroblastosis fetalisIn severe disease, bone morrow inevitably falls short of necessary RBC productionBody responds with extramedullary hematopoesis in the spleen and liverHepato-splenomegaly causes portal hypertension and hepatocellular damageAnemia coupled with hypoproteinemia (decreased osmotic pressure) leads to massive, diffuse edema (hydrops fetalis) and high cardiac output heart failureMore detailed explanation
77Hydrops and Erythroblastosis Fetalis Two pics on top – hydropsLower left – precursor RBCs in peripheral blood showing erythroblastosis fetalisLower right – extramedullary hematopoesis
78Sequelae of HDFN Hyperbilirubinemia RBC destruction does not cease with deliveryIgG due to its small size as a monomer distributes throughout tissues (intravascular and extravascular)IgG has a half life of 25 daysPrior to delivery bilirubin is transported across placenta and conjugated by maternal liver preventing hyperbilirubinemia in uteroBilirubin conjugation system in a neonate is immatureWithout therapy unconjugated/indirect bilirubin can reach toxic levels (18-20 mg/dL) and diffuse into the brain causing kernicterus and acute bilirubin encephalopathy
80Risk Stratification and Management for Anti-D HDFN Type and screen at first prenatal visitIf Rh(D) positive there is no risk of alloimmunizationIf Rh(D) negative, fetus may be at riskDetermine biological fathers Rh(D) status and zygocityIf dd homozygote there is no risk of allommunization – fetus is Rh(D) negativeIf DD homozygote fetus is Rh positive – fetus may be at risk depending on screen resultsIf Dd heterozygote risk of fetus being Rh(D) positive is 50% - fetal DNA studies can be performed to confirm status – fetus may still be at risk depending on screen resultsFetus Rh(D) positive and screen is negative – no antibodies have developed, but may yetRepeat screen at 28 weeks and following any incident in which there is increased risk of feto-maternal hemorrhageFetus Rh(D) positive and screen is positive, fetus is at riskPerform titer of Anti-D antibodies (>1:32 is clinically significant)Perform diagnostic techniques followed by treatment if indicatedUsual approach to diagnosis – did not apply to patient due to third world health care during first pregnancy
81Diagnosis and Treatment of Intrauterine fetal anemia Diagnostic techniques:UltrasoundDoppler assessment of MCA peak velocityPercutaneous umbilical cord sampling for fetal hematocritAllele-specific PCR on fetal cells in amniotic fluidTreatment:Intrauterine fetal transfusionTransfuse when fetal hematocrit falls below 2 standard deviations of mean hematocrit for gestational ageCan be performed between 18 and 35 weeksIntraperitoneal transfusions not as effective as intravascular transfusions in hydropic fetus due to congested lymphaticsABO type O, Rh- packed RBC utilizedFetal loss 1-2% with overall survival of 85% after transfusionSelf explanatory
83Prevention of Rh Alloimmunization Anti-D immune globulin/RhIGIgG anti-D manufactured from human plasma (primarily male who undergo repeat injections of Rh+ blood)Preparation methodsHyperRho S/D®, RhoGAM®Cohn cold ethanol fractionation followed by viral-clearance ultrafiltration – intramuscular only as IgA and other plasma proteins have the potential to produce anaphlyaxisRhophylac®, WinRho SDF®Ion-exchange chromatography isolation – intramuscular or IVMore than one product… have optionsSome IM onlySome IV or IM
84Prevention of Rh Alloimmunization Anti-D immune globulin/RhIGMechanism of action: not well understood, epitope masking?, rapid clearance of fetal RBC?GuidelinesWeak D positive managed as Rh-Mother Rh-, fetus confirmed or suspected Rh+300 micrograms early in third trimester300 micrograms if there is increased risk of feto-maternal hemorrhageRepeat doses if risk is ongoing, guided by titers or Kleinhauer-Bethke test300 micrograms within 72 hrs after deliveryIf inadvertently not administered, give ASAP – partial protection has been seen up to 13 days after birthCan tell anecdotal story about the 72hr rule and how it originated in Singapore by testing inmates investigators only allowed re-admittance 72hrs after administration of Rh+ cells for administration of RhIgRemind them that you can give RhIg two weeks out or later if neglected to administer within 72 hrs
85Case Presentation Finalizing the case What do you order? Maternal Anti-D titer1:64US of fetus and MCA peak velocitySlightly hydroptic fetusMCA peak velocity elevatedFetal CBCModerate anemiaIntrauterine fetal transfusion performed by IRMom transferred to high risk OB service where last you heard she was doing very well and expecting to be dischargedPrevious US looking for blood in trauma setting – may miss details of fetus
86…You decide to go into psych. Questions?All of these blood bank situations and complications have driven you so crazy......…You decide to go into psych.