Coagulation A Surgical Perspective (Exam III) Flashcards
What events occur in primary hemostasis (3)
1- vasoconstriction
2- platelet activation
3- platelet plug formation
What events occur in secondary hemostasis (2)
1- coagulation cascade
2- formation of fibrin clot
What molecule degrades the blood clot after it has done its job
Plasmin
What event initiates hemostasis
Vascular injury
What are three phases of hemostasis (normal)
1- vascular phase
2- platelet phase
3- coagulation phase
What causes the vasoconstriction following injury to a blow vessel
Vascular spasm
First step of the platelet phase
Exposed collagen bind and activates platelets
What is the second step of the platelet phase
Release of platelet factors
In the third step of the platelet phase after the release of platelet factors
Attracts more platelets
In the final step of the platelet phase
Platelet plug forms
The plug formed in the platelet phase is:
Loose and temporary
What molecule do platelets bind during the platelet phase
Collagen
What pathways make up the coagulation phase
Intrinsic and extrinsic and common
The common pathway ultimately leads to
Cross-linking of fibrin
Name the pathway that involves the conversion to fibrinogen to fibrin
Intrinsic and extrinsic
Drug that affects clotting
Warfarin
Drug that affects platelets
Aspirin
When someone has issues with ____ this results in a bleeding issue
Platelets
Partial or complete dissolution of the hemostatic plug by plasmin
Fibrinolysis
What activates plasmin
Thrombin
List factors affecting a normal hemostasis mechanism (5)
1- vessel wall integrity
2- adequate numbers of platelets
3- proper functioning of platelets
4- adequate levels of clotting factors
5- proper function of fibrinolytic pathway
You cannot perform oral surgery if the platelet count is:
Less than 50,000
Normal platelet range
150,000-400,000
People with a normal number of platelets (150-400k) can still have
Issues with platelet function
What medications can affect platelet function
Aspirin
Plavix
When someone has a platelet deficiency what can be an effective treatment
Platelet diffusion
Clotting disorders to be aware of as a clinician
Hemophilia A or B
Hemophilia A involves clotting factor
VIII
Hemophilia B involves clotting factor
IX
Platelet count is measured in a
CBC
Common laboratory tests to evaluate hemostasis
Platelet count
Bleeding time
Coagulation profile
What tests make up the coagulation profile (3)
- Prothrombin time (PT)
- Activated partial thromboplastin time (APTT)
- Internationalized normal ration (INR)
Advanced tests used to evaluate hemostasis (2)
- Platelet function tests
- Clotting factor assays (II-XII)
A test that may be recommended for those who bruise easily, have excessive bleeding or taking medications following stroke or heart attack that can alter platelet function
Platelet function test
Test that measures the levels of functional activity of one or more coagulation factors
Clotting factor assays (II-XII)
Standard range for WBCs
4.5-11.0
Standard range for RBCs
3.5-5.5
Standard range for Hgb
12-15