Flashcards in Hemostasis, Surgical Bleeding, & Transfusions Deck (86)
Define Hemostatic Process
Process involves interaction between blood vessel walls, platelets, & coagulation proteins
Initial Hemostasis Activity After Injury
Platelets adhere to site of vascular injury
After adhesion, platelets release ADP causing platelet aggregation
Formation of white thrombus
Formation of permanent thrombus with fibrin
Extrinsic: thromboplastin interacts with VII to covert X to Xa
Intrinsic: factors XII, XI, IX, & VIII to convert X to Xa
Common: X, V, II, & I; factor VIII
Deficiency of what factors causes bleeding?
Any EXCEPT XII
What can reduce the effectiveness of clotting?
Evaluation of a Bleeding Patient
Hx: OTC, ASA, clopidogrel (Plavix), warfarin (Coumadin)
Look for signs of bleeding disorder
Labs: platelets, PT, PTT, bleeding time, thrombin time
Signs of a Bleeding Disorder
Bleeding after dental procedures
Family history of bleeding
What does a platelet count verify?
An adequate number of platelets are available in the circulation
What is a normal platelet value?
What are some reasons for low platelets?
Meds: lasix, penicillins, sulfonamids, NSAIDs
What does prothrombin time measure?
Ability of the blood to form stable thrombi
Extrinsic & common pathway
When is a PT normally ordered?
Ratio of a patient's PT to a normal (control) sample
What does a partial thromboplastin time (PTT) measure?
Adequacy of intrinsic & common pathways
When is PTT most commonly used?
Unfractionated heparin therapy
Define Bleeding Time
Time from injury to cessation of bleeding
What may a prolonged bleeding time indicate?
Von Willebrand disease
What does thrombin time evaluate?
Fibrinogen to fibrin conversion with an external source of thrombin
What may a prolonged thrombin time indicate?
Low fibrinogen levels
Fibrin & fibrinogen split products
Blood or coagulation disorders
DIC Chronic liver disease
Von Willebrand's Disease Pathophysiology
Reduced factor VII activity & von Willebrand activity
Main Site of Bleeding for Von Willebrand's Disease
Lab Results for Von Willebrand Disease
Abnormal platelet function
Treatment of Von Willebrand Disease
Pathophysiology of Hemophilia A
Reduced or absent factor VII activity
Main Sites of Bleeding for Hemophilia A
Lab Results of Hemophilia A
Normal platelet function
Treatment of Hemophilia A
Purified factor VII products
Common People who get Hemophilia A
Causes of Acquired Bleeding Disorders
Advanced liver disease