Chapter 37 - Coagulopathy and hemorrhage Flashcards
Rapaport 4 level risk stratification scheme for bleeding disorder
LEVEL 1 = no history no signs LEVEL 2 = no history but major operation LEVEL 3 = history raise concerns LEVEL 4 = highly suggestive history
Pre-operative assessment based on Rapaport 4 level risk stratification
LEVEL 1 = no test LEVEL 2 = aPTT, plt count LEVEL 3 = bleeding time, plt count, PT, aPTT, test factor 13 and fibrinolysis screening LEVEL 4 = bleeding time after ASA (wWD or plt disorder), factor 8 and 9 levels, TT (dysfibrinogenemia)
Proper blood to citrate ratio when drawing blood
9:1 tests done within 2 hr if room temp 4 hours if 4C
Test of coagulation and clinical uses
TABLE 37.1
Bleeding time cut off
5 min = abnormal
Euglobulin lysis time (ELT)
1) assess global function of plasma fibrinolytic system 2) time required for clot to lyse in tube 3) normal 90-240 min 4) help to differentiate primary fibrinolytic state from DIC
wWF function
1) bind platelet and endothelial component 2) contribute to clot formation 3) carrier protein for factor 8
wVD incidence
1% of population only 5% affected as symptomatic worse if taking antiplatelet or NSAID
Types of vWD
TABLE 37.2
tests for vWD
TABLE 37.3
Giant platelet disorders
1) Bernard-Soulier syndrome - structural defect 2) May Hegglin anomaly - abnormal neutrophil inclusion 3) Hereditary macrothrombocytopenia with hearing loss 4) Mediterranean macrothrombocytopenia - non-specific
Bernard Soulier syndrome
1) thrombocytopenia 2) large platelets 3) bleeding 4) dysfunction or absence of GP-Ib/IX/V complex 5) treat with platelet transfusion
Glanzmann’s thrombasthenia
1) Defect GP-IIb/IIIa 2) platelet attach to endothelium but cannot aggregate 3) mucocutaneous bleeding
Platelet dense granules
ADP, serotonin
Gray platelet syndrome
1) Alpha-granule storage disorder 2) bleeding, moderate thrombocytopenia and prolonged bleeding time 3) preprocedural DDAVP and plt transfusion as treatment
Platelet dense granule storage disorder
1) Chédiak-Higashi syndrome 2) Wiskott-Aldrich syndrome 3) thrombocytopenia-absent radius syndrome
Wiskott-Aldrich syndrome
1) X-chromosome linked immunodeficiency 2) thrombocytopenia 3) eczema 4) defect glycoprotein L115 = unable to aggregate 5) treat = bone marrow transplant
Factor 8 half life
12 hours protected from premature degradation by vWF
Hemophilia bleeding along the coagulation stages
Secondary hemostasis failure platelet plug forms but fibrin plug defective
Mild moderate and major hemophilia
Mild: factor 8 or 9 level 5-40% normal moderate: 1-5% normal Severe: < 1% normal
Hemophilia A, B, C
A = X-linked deficiency Factor 8 B = X-lined Factor 9 C = Autosomal Factor 11
Treatment of hemophilia
1) DDAVP 2) factor 8 or 9 concentrates 3) activated prothrombin complex concentrates
Uremia effect on hemostasis pathway
1) intrinsic platelet defects 2) alteration of platelet-endothelial interaction 3) treatment = DDAVP, transfusion, estrogen, dialysis
Molecular causes of DIC
uncontrolled production of thrombin leads to systemic intravascular deposition of fibrin
Diseases that cause DIC
TABLE 37.4
Coaguation parameteres in DIC
TABLE 37.5
Fibrinogen target in DIC
> 100 mg/dl
Primary fibrinolysis
1) pathologic direct activation of plasminogen 2) plasmin overwhelms PAI-1 and alpha 2 antiplasmin 3) cleaves fibrin and clotting factors 5, 8 4) excessive thrombin generation as counter measure 5) microvascular thrombosis
Causes of primary hyperfibrinolytic state
1) malignancy 2) liver failure 3) trauma 4) congenital deficiency of fibrinolysis inhibitors
Differentiating DIC from primary fibrinolysis
PRIMARY FIBRINOLYSIS HAS 1) Short euglobulin lysis time 2) no thrombocytopenia 3) schistocytes
Treatment of fibrinolysis
1) lysine analogues 2) factor replacement, 5, 8
Heparin molecule
1) sulfated glycosaminoglycan 2) binds and activates antithrombin
Half life of heparin
SC 8 hours IV 1.5 hours
Reversal of heparin
protamine 1 mg / 100 Units
Direct thrombin inhibitors
TABLE 37.6
Treatment of warfarin induced skin necrosis
Stop warfarin IV heparin
Off label use of DOAC reversal
1) prothrombin concentration complex (PCC) 2) recombinant factor 7a
ASA effect
inactivate platelet cyclooxygenase –> blocks thromboxane A2 production
Clopidogrel and ticlopidine effect
block ADP receptor –> reduce GPIIb/IIIa expression
Abciximab and eptifibatide effect
block GPIIb/IIIa short half life so return to normal 24-48 hours
P2Y12 receptor antagonists
IV (elinogrel, cangrelor ORAL (ticagrelor, elinogrel)
Blood transfusion products for hemostasis
TABLE 37.7
Cautery setting
Cutting (continuous) = high current density –> heat rapidly vaporization Coag (interrupted) = less heat and produce coagulum
Ligasure
Bipolar electrocautery with pressure application Fuse collage and elastin in vessel wall
Argon beam coagulator
Monopolar with stream of argon innerg gas disperses pooled blood arcing of current to produce diffuse coagulation
Tissuelink device
Combines radiofrequency with continuous saline irrigation can cause steam popping which is undesirable
Pusateri description of ideal topic hemostatic
1) stop bleeding within 2 min even in pooled blood 2) ready to use without mixing 3) apply with minimal training 4) lightweight and durable 5) easy to store and last long 6) safe to use without infection risk 7) cheap
Gelatin foam key points
1) Gelfoam 2) absorbed within 4-6 weeks 3) non-antigenic 4) pH neutral so can use with thrombin
Oxidized cellulose key points
1) surgicel 2) trimmable 3) applied dry 4) decreases pH cannot be used with thrombin 5) hematin generation from RBC lysis discolors this
Microfibrillar collagen
1) powder, sheet, sponge, pad 2) hemostasis 2-5 min with platelet aggregation 3) cannot return blood back to patient because materials pass through filters
Polysaccharide spheres
1) Arista, trauma Dex 2) absorb plasma/blood to concentrate clotting factors and platetes 3) swells and contains high sugar
Active hemostatic agents
1) thrombin liquid/gel 2) thrombin solid
Sealants types
1) Tisseel - fibrinogen, thrombin, calcium + aprotinin 2) Evicel - firinogen, thrombin 3) Floseal - bovine collagen, microgranules, glytaraldehyde, human thrombin 4) dry fibrin sealant - gauze with fibrinogen and thrombin 5) tissue glue - glutaraldehyde with bovine serum
Newer hemostatic agents
1) Chitins: stimulate coagulation and agglutination; generate thrombin and fibrin 2) Chitosan: deacetylated chitin 3) Mineral zeolite: absorb water, concentrate factors and activate factor 12; exothermic 4) lysine analogues
Types of hemostatic agents
Mechanical 1) gelatin 2) oxidized cellulose 3) microfibrillar collage 4) polysaccharide spheres Active agents 1) synthetic or plasma derived Sealants 1) polyethylene glycol 2) fibrin sealants 3) thrombin sealants 4) bovine-derived factors New agents 1) chitin 2) chitosan 3) mineral zeolite 4) lysine analogues
Management of perioperative bleeding flow chart
FIGURE 37.1
