Hemostasis, Surgical Bleeding, & Transfusion

Question 1

Extrinsic Pathway

Answer 1

Tissue Factor - III

VII

Triggered by Tissue Damage

Question 2

Intrinsic Pathway

Answer 2

XII

XI

IX

VIII

Question 3

Common Pathway

Answer 3

X

V

II (prothrombin)

I (fibrinogen)

X is activated by both Extrinsic and Intrinsic pathways to cause fibrin clot formation

Question 4

Only factor deficiency that doesn’t cause coagulopathy

Answer 4

Factor XII

Question 5

Platelet Count

Answer 5

Normal is 150,000-400,000

If abnormal get smear

Low platelets may be caused by: Lasix, NSAIDs, sulfonamides, PCN, Autoimmune disease

Question 6

Prothrombin Time

Answer 6

Used to monitor Warfarin (INR)

Normal uncoagulated INR: 0.8-1.2

Evaluates VII (extrinsic), X, V, prothrombin, fibrinogen

Question 7

Partial Thromboplastin Time (PTT)

Answer 7

Monitor unfractionated Heparin therapy - also Warfarin

Not effective monitor for LMWH

Evaluates fibrinogen, prothrombin, V, VIII, IX, X, XI, XII (intrinsic and common pathway)

Question 8

Thrombin Time

Answer 8

Fibrinogen to fibrin conversion with abundant thrombin time

Prolonged: low/abnormal fibrinogen, low split products, Heparin

Used to check for DIC and chronic liver disease

Question 9

Bleeding time

Answer 9

Gash time for bleeding sensation X2

Normal 5-10 minutes

Prolonged: thrombocytopenia, medication (ASA), von Willebrand Disease

Question 10

Von Willebrand Disease

Answer 10

Most common congenital bleeding disorder

Reduced VIII and vWF activity

vWF binds to factor VIII to prevent degradation

Mucocutaneous bleed

Prolonged PTT and abnormal platelet function

PT normal

Treat with Cryoprecipitate infusion or Desmopressin (DDAVP)

Question 11

Hemophilia A

Answer 11

Reduced/absent factor VIII activity

Males only

Joint or intramuscular bleed

Prolonged PTT

Normal PT and platelet function

Tx: Purified factor VIII products

Question 12

Liver Disease Acquired Bleeding Disorder

Answer 12

Most common - no protein synthesis

Results in low prothrombin, V, VII, X

Obstructive jaundice and cirrhosis may also cause these

-Will respond well to Vitamin K

Question 13

Warfarin

Answer 13

Effects II, VII, IX, X

Reverse with FFP or Vitamin K in a hurry

Question 14

Heparin

Answer 14

Increases antithrombin III

Neutralizes IXa, Xa, XIIa and thrombin

Prolonged PTT and thrombin time

Often given during vascular surgery

Reverse with protamine sulfate

Question 15

OTC Herbal Supplements that Affect Bleeding

Answer 15

Dong quai

Garlic

Ginger

Ginko Biloba

Ginseng

St. John’s Wort

Question 16

Primary, Secondary, and Reactive Bleeding

Answer 16

Primary: happens during surgery

Secondary: happens 7-10 days post-op; caused by erosion commonly w/ infection into vessel

Reactive: w/in 24 hours operation; from untied vessels or reduced vasospasm and adequate perfusion

Question 17

Immunologic Reaction MC Presentations

Answer 17

Febrile reaction: MC with anti-leukocyte antibodies

Hemolytic reaction: MC with ABO mismatch

Graft v Host reaction: MC with immunosuppressed - get delayed sx onset

Question 18

Metabolic Derangements Common Causes

Answer 18

Hypocalcemia with rapid infusion: get ST segment prolongation, delayed T waves, and muscle tremors

Hyperkalemia: Blood >35 days old

Hypokalemia: red cells take up potassium after infusion

Hypothermic: Fluid warmer with multiple transfusions