This document summarizes the mechanisms of hemostasis (prevention of blood loss), including vascular constriction, platelet plug formation, blood clot formation, and fibrinolysis. It describes the clotting factors and roles of calcium and platelets. Methods for controlling hemorrhage are discussed, including mechanical methods like direct pressure, ligation, and cauterization, as well as chemical/biological agents and radiological interventions. Supportive measures like fluid resuscitation and blood transfusion are also recommended.

1. Mechanism of hemostasis
Fibrinolysis
Control of hemorrhage
DR BIPUL BORTHAKUR
PROF OF
ORTHOPAEDICS,SILCHAR,ASSAM,INDIA

2. Hemostasis
Term ‘Hemostasis’ means prevention of blood
loss.
Arrest of blood flow and control of hemorrhage
from an injured blood vessel.
Process by which bleeding at any site is arrested
by formation of hemostatic plug.
Maintainance of normal blood flow within the
circulatory system.

3. Function of hemostasis
• Maintain blood in fluid state.
• Arrest bleeding followed by trauma.
• Removes platelet plug when healing is
complete.

5. Events
Vascular constriction
Platelet plug formation
Blood clot formation
Fibrous tissue growth into clot

6. Vascular constriction
• Localised myogenic spasm
• Local autacoid factors
• Nervous reflexes
platelets release thromboxane A2 which is
responsible for vasoconstriction of smaller
vessels

7. Platelet plug formation
• Platelet adhesion
• Platelet activation
• Platelet aggregation
• Temporary hemostatic plug formation

8. Platelet adhesion
• Done by von willebrand factor
• Fibronectin and other components of extra-
cellular matrix helps
• Degranulation occurs
• Ca2+ is essential

9. Platelet aggregation
• Follows adhesion and granule release
• Thromboxane A2 amplifies aggregation
• Forms primary hemostatic plug
• Aggregation is reversible
• This is followed by secondary hemostasis.

10. Blood clot formation
• The clot is a meshwork
• Fibrin fibers also adhere to damaged surfaces
of blood vessels
• Contraction causes expression of fluid from
clot serum

11. Initiation of coagulation
• Formation of prothrombin activator
• It starts by trauma to the vascular wall and the
adjacent tissues
• Contact of blood with damaged endothelial
cells

12. • Prothrombin activator is formed by
• EXTRINSIC PATHWAY
• INTRINSIC PATHWAY

13. CLOTTING FACTORS
• FACTOR 1- FIBRINOGEN
• FACTOR 2-PROTHROMBIN
• FACTOR 3-THROMBOPLASTIN TISSUE EXTRACT
• FACTOR 4-CALCIUM
• FACTOR 5-LABILE FACTOR/PROACCELERIN
• FACTOR 7-STABLE FACTOR
• FACTOR 8-ANTIHEMOPHILIN
• FACTOR 9-CHRISTMAS FACTOR
• FACTOR 10-STUART PROWER FACTOR
• FACTOR 11-PLASMA THROMBOPLASTIN ANTECEDANT
• FACTOR 12-HAGEMAN/CONTACT FACTOR
• FACTOR13-FIBRIN STABILIZING FACTOR

15. ROLE OF CALCIUM
• Except first two steps in intrinsic pathway
calcium ions are required for all clotting steps
• Calcium seldom falls low in our body as
significant as to affect clotting.

16. Fibrinolysis
• It is a process by which blood clot is prevented
from growing & becoming pathologic.
• It is physiological process
• It can be dangerous if it were to expand
beyond boundary
• It prevents clot formation but doesnot
destroys the clot.

17. • The clot stimulates tissue plasmin activator
• TPA converts plasminogen to plasmin
• Plasminogen is found in blood
• Plasmin further cleaves fibrin to degrade
thrombi
• Clot removal happens at a slow pace to enable
endothelial breach to heal.

19. Control of hemorrhage
• Initially one should classify hemorrage in
order to control it
• Source :-
External & internal
• Nature:-
Arterial (bright red,jet flow)
Venous(dark red)
Capillary

20. • Time:-
• Primary (at time of trauma)
• Reactionary(within 24 hours of trauma/surgery)
• Secondary (7-14 days of trauma/surgery)
• Volume:-
• Mild (<500ml)
• Moderate (500-1000ml)
• Severe (<1 litre)

21. Surgical hemostasis
Mechanical methods
Thermal methods
Chemical and biological methods
Radiological/interventional methods
Adequate blood/blood products transfusion

22. Mechanical
• Direct digital pressure
• Tourniquet
• Ligation
• Suturing
• Clips
• Bone wax

23. • Direct pressure will be suited for only bleeding
from capillary and vennules
• Limb elevation
• Tourniquet application at specific pressure
points for arteries.
• Splintage is used for long bone fractures as
bony fragments may lacerate vessels and
medullary bleeding.

24. • Ligature of large vessels with reef knot
• Main artery of limb is exposed by dissection at
the most accessible point.
• Thermal methods like cryosurgery
• Electrocautery
• Monopolar/bipolar diathermy
• Harmonic devices
• Laser surgery

25. Chemical and biological methods
• Tranexamic acid (antifibrinolytic)
• Epinephrine and oxytocin causes
vasoconstriction
• Microfibrillar collagen & thrombin causes
coagulation
• Absorbable collagen,gelatin,cellulose,quikclot
causes hemostasis by their hygroscopic effect.

26. • Interventional radiology is used for controlling
internal hemorrhage
• Especially in PPH

27. • Supportive measures with IVF,blood
transfusion should be done
• Analgesics
• Antiinflamatory drugs
• Early operative intervention.

28. अन्तवन्त इमे देहा नित्यस्योक्ता: शरीररण: |
अिाशशिोऽप्रमेयस्य तस्माद्युध्यस्व भारत || 18||
• antavanta ime dehā nityasyoktāḥ śharīriṇaḥ
anāśhino ’prameyasya tasmād yudhyasva
bhārata
• Meaning-Only the material body is perishable;
the embodied soul within is indestructible,
immeasurable, and eternal. Therefore, fight, O
descendent of Bharat.