Coagulopathy Wendy Blount DVM Practical Hematology Anemia 101 Blood Loss Anemia Hemolysis NonRegenerative Anemias Transfusion Medicine Polycythemia Bone Marrow Disease Coagulopathy Central IV Lines ID: 722212
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Practical HematologyTreating Coagulopathy
Wendy Blount, DVMSlide2
Practical Hematology
Anemia 101
Blood Loss Anemia
Hemolysis
Non-Regenerative Anemias
Transfusion Medicine
Polycythemia
Bone Marrow Disease
Coagulopathy
Central IV Lines
Leukophilia
Leukopenias
Splenic DiseaseSlide3
Assessment of CoagulationIs bleeding appropriate to injury or pathology?
Control arterial bleeding with ligation
If not, assess coag status ASAP
Platelet count
PT, PTT/ACT
BMBT
FDPs, d-dimers
Factor assays & DNA
Tests
Cornell Comparative Coag for crazy stuffSlide4
Treating Primary Hemostatic DefectsSimulate primary hemostasis until secondary can kick inDirect pressure (bandages)Topical epinephrineCauterize – AgNitrate, Styptic, Electrocautery
J0313 – cautery + 3 tips + case $72.00
J0313A – cautery <$40.00
J0313W, J0313 X, J0313Y, J0313Z – replacements tips <$15
J0313D1 – sterile sleeves, 10 for $30
Runs on 2AA batteriesSlide5
Treating Primary Hemostatic DefectsSimulate primary hemostasis until secondary can kick inDirect pressure (bandages)Topical epinephrinecauterizeTreat hypovolemiaColloids and fluids with packed cells or Oxyglobin
Whole blood transfusion
Identify and treat cause
Vasculitis
Thrombocytopenia <20-50,000/ul
Platelet function defectSlide6
Treating Primary Hemostatic DefectsSupportive therapyCage rest – avoid injuryAvoid poking holes in big veins or any arteriesSlide7
1st Round Treatment - VasculitisRound 1 Tests: CBC, panel, UA, assess proteinuria, Urine C&S, FeLV/FIV, HWTestTreat underlying cause if obvious
Doxycycline 5-10 mg/kg PO BID x 3 weeks
If response, may need to treat as long as 6 weeks total
Anti-inflammatory prednisone only if chronic infection ruled out by imaging, culture, & appropriate PCRs or other tests
0.5 mg/lb/day
prednisone
Monitor for improvement of clinical signs for 2-4 weeksSlide8
2nd Round Treatment - VasculitisRound 2 Tests: infectious Disease testingEchocardiogram, blood C&S during fever
Tick panels, Bartonella, Brucella
Mira Vista Fungal Tests
Consider bone marrow, skin biopsy, anti-platelet antibody, ANA
Treat underlying cause
May
need to increase to immunosuppressive prednisone
1-2 mg/lb/day
Highest dose no longer than 2 weeks
Primary
IM
cases respond within
a week
Wean off over 2-3 months or moreSlide9
3rd Round Treatment - VasculitisIf first bone marrow showed no increase in megakaryocytes, can repeat in 1-2 weeksPersistent lack of megakaryocytes when IMT is suspected – antimegakaryocyte Ab assay
Repeat diagnostics looking for infection after immunosuppressive therapy for 1-2 weeks
X-rays, abdominal ultrasound, GlobalFAST®
Urine
culture, blood culture, other inf dz testsSlide10
3rd Round Treatment - VasculitisIf suspecting infectious disease, can take samples for paired seraIf suspecting
IM,
may need to add
azathioprine,
cyclosporine or Danazol
Vincristine 0.02 mg/kg IV q7days
Begin weaning when platelets reach 100,000/ul
Decrease one drug every 1-2 weeks, checking CBC
Wean off drugs over 3-6
monthsSlide11
Rosalie Cooper-ChaseCrockett TXSlide12
von Willebrand DiseaseTreat when bleeding from injury, or perioperativelyDDAVP (deamino 8 D-arginine vasopressin)Use commercial nasal drops1-4 ug/kg SC 30 minutes prior to surgeryDuration 2 hoursWorks best for Type 1Desmopressin acetate for injectionSame protocolThyroxine – no longer recommendedSlide13
von Willebrand DiseaseFor active bleedingFresh whole blood if significant blood loss or anemiaFresh frozen plasma or cryoprecipitateSmaller volume prevents volume overloadGreatly reduces risk of transfusion reactionTransfusing RBC and von Willebrand Factor to support primary hemostasisPlatelet transfusion is difficult in practiceLifespan of transfused platelets is less than 24 hours in fresh whole bloodConsider when bleeding into the CNS or life threatening uncontrolled bleedingSlide14
von Willebrand DiseaseFor active bleedingStored whole blood and packed cells contain no appreciable active plateletsType 2 and 3 may need 2nd & 3rd transfusion over the next 24-48 hoursSurgery can decompensate any dog with subclinical coagulopathyUses up platelets, factors, in short supplySlide15
CryoprecipitatePreferred for vWDz, but very expensivePrepared from fresh frozen plasmaSupernatant is decanted off during a slow thawWhite precipitate forms during the thaw CPT high in Factor 8, 13, vWF and fibrinogenContains 5-10x concentration of vWF10% volume of FFP5% volume of whole bloodPreferred for
von Willebrand Disease
Hemophilia A (factor 8 deficiency)
Fibrinogen deficiency – cockers, Kerry BluesSlide16
Congenital ThrombocytopathiaTreat when bleeding from injury, or perioperativelyFresh whole blood transfusionPlatelet transfusionDraw immediately prior to transfusionStore at room temperature until administeredCitrate-based coagulantSlide17
Platelet Rich PlasmaCentrifuged with low G force within 6 hours of collection80% of the platelets are harvestedSuspended in 1/3 of whole blood volumeLow volume platelet concentrates prepared from PRP by a second centrifugation.Maintain at room temperature until transfused, as soon as possibleSlide18
HemophiliaOnly vitamin K dependent factor deficiency in Devon Rex is treatableRestrict activity to avoid traumaAvoid surgery, venipuncture, restraint, IM injections.Avoid medications that interfere with primary hemostasisNSAIDs, phenothiazinesTransfuse active bleeding or perioperativelyFresh whole blood if bleeding or anemic
Plasma if not bleeding or anemic
Cryoprecipitate preferred for vWDz, fibrinogen deficiency or hemophilia ASlide19
Vitamin K antagonismInduce vomiting if known ingestion within several hoursActivated charcoal and catharticInject vitamin K 2.5-5 mg/kgThen vitamin K 2.5 mg/kg/day POMinimum 2 weeksContinue until 2 weeks past normal PTRecheck PT 2 days after stopping vitamin KIf elevated again, 2 more weeks vitamin KSlide20
Vitamin K antagonismIdentify and treat gall bladder, intestinal or nutritional disease that may be contributingAvoid drugs that inhibit enzyme that activates vitamin K dependent factorsVitamin K epoxide reductaseSulfonamides and cephalosporinsAvoid drugs that decrease protein binding of toxinsSulfonamides
Corticosteroids
Phenylbutazone
Avoid drugs that cause thrombocytopenia, thrombocytopathia, etc.Slide21
Treating Liver Failure CoagulopathyReplace coagulation factorsPlasma 3-5 ml/kg up to every 8 hoursTransfuse prior to surgeryUsed to incubate with heparin 30 minutes to transfusion, to activate AT350 U/kg added to plasma transfusionOr fresh whole blood if anemic or actively bleedingVitamin K 2.5 mg/kg/day as long if PT prolongedSlide22
Snake Bite CoagulopathySupportive treatment for snake bite toxicityAntivenin accelerates resolution of thrombocytopeniaMust be given within 24 hours of envenomationWithin 4 hours for maximum effectAntivenin will not affect tissue necrosis2 kinds of antiveninACP – contains entire equine IgG to venomNot effective against Mojave rattlersHalf life 60-200 hours
1-5 vials IV, give subsequent vials every 2 hours
Measure circumference every 15-30 minutes
Continue antivenin until swelling slows or stopsSlide23
Snake Bite CoagulopathyFab – contains fragment of ovine IgG to venom5x more effectiveEffective against Mohave rattler and othersmust repeat every 18 hoursLess likely to cause anaphylaxis or serum sicknessPremedicate with diphenhydramineSkin testing prior to IV administration is controversial – many false positives and negativesThrombocytopenia often resolves within 72 hours
Heparin and blood products are not likely to helpSlide24
Snake Bite CoagulopathySerial coags are important because coagulopathy can be delayedSerum sickness can occur in 3 days to 3 weeks (immune complex disease)Fever, joint pain, myalgia, edema, etc.Slide25
ThromboembolismReduce thrombogenesisHeparin (UF) 200 U/kg SC TIDProlong PTT to 1.5 x normalDalteparin (Fragmin© - LMW heparin)Dogs 150 U/kg SC TIDCats 180 U/kg q4-6 hrsEnoxaparin (Lovenox© - LMW heparin)Dogs 0.8-1 mg/kg TID-QIDCats 1.25 mg/kg q TIDLWMH Monitoring - anti-xA activity at Cornell
Many argue that heparin therapy helps little if AT3 is low – must give plasma concurrentlySlide26
ThromboembolismReduce thrombogenesisAntiplatelet drugsAspirinCats 5-25 mg/kg PO twice a weekSome use dose as low as 5 mg/catDogs 0.5 mg/kg PO BIDClopidogrel (Plavix©)Cats 18.75 mg (1/4 tablet) per cat PO SIDCoumadin – not used much any moreMonitor INR (international Normalization Ratio)
Calculate using PTT and coefficients from your lab
Plasma 3-5 ml/kg PRN q8hrsSlide27
ThromboembolismThrombolytic therapyRisk of reperfusion injury (which can be fatal) is highRisk also of smaller emboli causing more problems further downstreamtPA, streptokinase and urokinase are used24-hour monitoring is required to use thrombolyticsSlide28
Treating DICTreat the underlying causeIf cause is untreatable, prognosis is dismalEnsure adequate tissue perfusion despite widespread thrombosisReplace consumed blood componentsAnticoagulant therapyHeparin (UF) 50 U/kg SC TID if no gross thrombosis200 U/kg SC TID if apparent thrombosisDalteparin, EnoxaparinSlide29
AcknowledgementsChapter 2: The Complete Blood Count, Bone Marrow Examination, and Blood BankingDouglass Weiss and Harold TvedtenSmall Animal Clinical Diagnosis by Laboratory Methods, eds Michael D Willard and Harold Tvedten, 5th Ed 2012
Chapter
5: Hemostatic Abnormalities
Harold
Tvedten
Small Animal Clinical Diagnosis by Laboratory Methods, eds Michael D Willard and Harold Tvedten, 5
th
Ed 2012Slide30
AcknowledgementsChapter 63: Bleeding Disorders: Epistaxis and HemoptysisTracy GiegerTextbook of Veterinary Internal Medicine, eds Stephen J Ettinger and Edward C Feldman, 6th
Ed 2005
Chapter
64: Petechiae and Ecchymoses
Mary Beth Callan
Textbook of Veterinary Internal Medicine, eds Stephen J Ettinger and Edward C Feldman, 6
th
Ed 2005