Hematology & Immunology Part 2 Flashcards
Withdrawal of patient’s own blood in OR just prior to surgery (blood replaced w/ crystalloid).
-During the case, the patient is losing blood with a Hct of 24/25 instead of a Hct of 30. -If you KNOW patient is going to bleed, let them bleed out low Hgb blood, and then replace with their own blood
-Some patients can’t tolerate low Hgb - watch for coronary ischemia, cerebral changes (mentation)
-Large, orthopedic surgery and are healthy.
Acute Normovolemic Hemodilution
Patient donates 2 units of blood, give erythro and iron so Hgb normal. Must be planned well in advance of surgery; consider pt underlying condition
-Pt must be able to tolerate lower Hgb (not kidney patients, AS, CAD, or anemic)
-Orthopedic surgeries
-Questionable value, very expensive, doesn’t prevent patients from getting transfusions of other blood
Autologous Donation
Helpful to reduce bleeding and risk of transfusion for patients at risk of excessive bleeding
TXA and Amicar
Has an immediate effect
-Misidentification of patient/blood specimen
-Donor ABO incompatibility
-Complement activation -> acute intravascular hemolysis (release of bradykinin, histamine, & serotonin) -> CV collapse
Acute Hemolytic Transfusion Rxn
Fever, chills, flushing, chest/flank/back pain, hypotension, nausea, oliguria, anuria, hemoglobinuria, diffuse bleeding
-Difficult to detect in anesthetized patient - inc temp, unexplained tachycardia, dec BP, hemoglobinuria, bronchospasm, diffuse ooziness in field
S/Sx of Acute Hemolytic Transfusion Rxn
Treatment: stop transfusion, maintain UOP 75-100 ml/hr, assay urine/plasma hgb conc, return blood to bank, prevent hypotension, recheck labeling
Acute Hemolytic Transfusion Rxn
Mild reaction, Re-exposure issue (caused by antibodies to non-D antigens- either Kells, Kidd, or Rhesus)
-Clinical: low grade fever, mild jaundice, unexpected drop in Hgb
-Treatment: Supportive (monitor hgb, hydration, transfusion)
Delayed Hemolytic Rxn
Post-multiple transfusions (develop alloantibodies to HLAs on donated blood leukocytes) → subsequent transfusions antibody attacks donor leukocytes
-Symptoms: fever, shaking chills, resp distress, anxiety, HA, myalgia
-Treatment: acetaminophen (leukoreduction may prevent these)
Febrile Non-hemolytic Transfusion Rxn
Donor lymphocytes become engrafted, proliferate, & establish an immune response against the recipient → only w/ cell transfusions (RBC & plt)
Immunocompromised patients especially at risk
Transfusion Associated Graft vs Host
S/Sx:
-progresses rapidly to pancytopenia (high fatality rate!)
-sloughing mucous membranes (Attacks fast dividing tissues -orally and in GI tract), profuse diarrhea, rash, hepatomegaly
Consider irradiated blood products in high risk (BMT recipients, Hodgkin’s dz, SCID, intrauterine transfusions, leukemia, transplant)
Transfusion Associated Graft vs Host
Administration of allogeneic blood leads to immune suppression by modifications in T helper cell/suppressor ratio, changes in B cell fxn, down regulation of antigen presenting cells, decreased # circulating lymphocytes
May impact: accelerated recurrence of malignancy, increased mortality, increased rates of infection
Transfusion Related Immunomodulation (TRIM)
When blood is stored, biologic substances accumulate (cytokines, complement, membrane lipid breakdown products) → produce inflammatory response → contribute to multi-organ dysfunction
Ex: in CV surgery patients w/multiple blood products, have inc ICU LOS
Transfusion Related Inflammatory Response
Noncardiogenic pulmonary edema occurring after blood product administration
-Associated with anti-HLA antibodies -> leukocytes sequester in lungs -> mediators -> capillary endothelial damage -> inc capillary permeability
-Humoral response to stress primes granulocytes, causing lung sequestration
Transfusion Related Acute Lung Injury (TRALI)
S/Sx: begins within 6 hours of transfusion! Dyspnea, chills, fever, pulmonary edema, pulmonary compromise, hypotension/hypertension
Treatment: largely supportive (stop transfusion, O2/ventilation-low tidal volumes, rule out TACO-transfusion associated circulatory overload)
Prevention: universal leukoreduction, restriction of multiparous donors for plasma products (pregnant), HLA antibody testing
Transfusion Related Acute Lung Injury (TRALI)
Estimate Blood Volume Calculation
Estimated Blood Volume = typical blood volume x patient weight
Allowable Blood Loss Calculation
EBV x (hct initial - hct final) / hct initial
Present if <30% of normal
-Rare bleeding disorder that can be inherited or acquired
-Mild: no evidence of regular/spontaneous bleeding
-Severe: relentless spontaneous bleeding (nasal, oral, GI, GU)
-Inherited subtypes: Type 1 (most common - mild to severe), Type 2, and Type 3 (near complete deficiency)
-Acquired: malignancy, autoimmune, hypothyroidism
Von Willebrand Disease (vWF)
Failure to synthesize/secrete or accelerated clearance of vWF
-Unable to bind to receptors on plt surface to form the plt plug
Tx:
-Desmopressin (administer slowly to avoid hypotension, flushing, tachycardia, and HA). Can have tachyphylaxis - loss of efficacy with large, repeated doses
-TXA (antifibrinolytic)
-Factor VIII/vWF concentration
-Cryo
-Avoid anti-plt drugs
Von Willebrand’s Disease
X-linked hematologic recessive disorder characterized by unpredictable bleeding patterns: affects mostly males, females carry the gene
-A: deficient factor 8 (Mild - severe)
-B: deficient factor 9 (Christmas Disease)
Hemophilia
-Mild: factor levels 5-30%, bleed only after surgery/trauma
-Moderate: factor levels 1-5%, occasional spontaneous bleeding
-Severe (most common): factor levels <1%, frequent spont bleeding
Hemophilia A
Exhibit spontaneous bleeding, muscle hematomas, join pain leading to progressive arthropathy → often requires orthopedic surgical intervention
Preop:
-Inhibitor screening/inhibitor assay done within 1 week of surgery
-Hematology consult
-Detailed coags
-Detailed factor replacement plan prior to DOS
-Plan for monitoring levels periop
-Elective procedures occur early in the day and week for availability of lab support and factor concentrates
Hemophilia
No procedure is too minor for adequate hemostasis (ABG, dental procedures, etc)
Treatment:
-Viral inactivated plasma-derived or recombinant concentrates preferred over Cryo/FFP
-Hemophilia A: cryo preferred over FFP
-Hemophilia B: FFP
-Desmopressin: helpful w/ mild-mod Hemophilia A; no help w hemophilia B (overall varied response, difficult to predict)
-TXA & Amicar (antifibrinolytics)
-Factor 7a → directly activates 10 w/o participation of 8, 9, 11
Treatment of Hemophilia
