coagulation cme 2007

Coagulation

Blood clot

• Platelets (150 - 400K)– Activated by collagen, thrombin, etc.

– Release platelet and coagulation factors

• Insoluble fibrin molecules– Prothrombin is converted to thrombin

– Thrombin binds soluble fibrin into insoluble mesh

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Controlling Clotting

• AntithrombinIII: inhibits the formation of thrombin by binding to and inactivating:•prothrombin•factor 9•factor 10

• Heparin is a mixture of polysaccharides that bind to antithrombin III & enhance inhibition of thrombin synthesis.– prothombin (Factor II) to Thrombin

Vitamin K

• Vitamin K is required (as a cofactor) for the body to make four of the blood's coagulation (clotting) factors: particularly prothrombin and also factors VII, IX, and X

• K was for Koagulation (Danish for coagulation)

Coumadin (Warfarin)

Prothrombin time, PTCoumadin/warfarin

• PT reflects the depression of vitamin K dependent Factors VII, X and II.

• A system of standardizing the PT International Normalized Ratio (INR) provides a common basis for communication of PT results and interpretations of therapeutic ranges– 1 is baseline (normal), 2-3.5 is therapeutic

Activated Partial Thromboplastin Time

Heparin inactivates factor II, prothrombin• Evaluates function of

– Intrinsic (XII, XI, IX, VII)– Common(V, X, II, I)

• Used to evaluate heparin therapy• Also used as first step evaluation of coagulopathy.

Standard heparin (Unfractionated)

• Variety of molecule lengths.

• Smaller molecules much more effective.

• Must test, PTT, for therapeutic level.

Low molecular weight heparinLovenox,

• More consistent dosing

• No need to test PTT

• SQ administration, twice daily

• Costs more

• Lower rates of HITQuickTime™ and a

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Heparin induced thrombocytopenia

• Decrease in platelet count• Increased risk of arterial and venous thrombosis• DVT risk is most common complication

• Type I, 10 to 20% of heparinized patients, PLTs fall 50% but rarely under 100K

• Type II rare but serious autoimmune disorder.

Thrombolytics

Tissue plasminogen activator (TPA)

Dissolves existing blood clots

Therapeutic for Ischemic heart disease and strokes

Risk of bleeding

What does this have to do with EMS?

• Recognize symptoms of stroke

• Transport to Appropriate facility

• Consider effect of Anticoagulant therapy with patients with falls and head trauma

• AIRWAY