◊ Hemorrhage And Hemostasis ◊

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Hemorrhage And Hemostasis

Definition: -

It is the flow or escape of blood out from an injured blood vessel inside or outside the body cavities

Classification of hemorrhage: -


1-Arterial Hemorrhage

It is the most persistent type of hemorrhage, and it may be fatal or serious according to the size, site and importance of the bleeding artery

Characteristics: -

1-Bright red in color

2-Occurs in jets

3-Often appears at both ends of the cut vessels and being more profuse from the proximal end (heart side)

2-Venous Hemorrhage

It is relatively less serious than arterial hemorrhage

Characteristics: -

1-It is dark red or blackish red in color

2-Flows continuously in a steady stream without pulsation

3-Appears chiefly from the distal end of the divided vessel

3-Capillary Hemorrhage

It is less serious than the other types

Characteristics: -

1-The blood color changes gradually from dark bluish color (venous blood) to bright reddish color (arterial blood)

2-Appears as generalized oozing from the injured surface

3-The flow has short duration


1-External Hemorrhage

It either occurs from a skin wound or from natural orifice of the body accordingly certain terms are used like;


Bright red bleeding from the nose


Bright red frothy blood is coughed up from the lung or respiratory passage


Blood is vomited from the stomach, and its color depends on the amount of gastric secretion and elapsed time of its contact with the blood, accordingly large amount of HCl and prolonged action produces dark-brown clotted blood


Blood voided in the urine and its color depends on the site of bleeding and its rapidity


Blood passed per rectum with feces, and according to the origin, the color of blood changes. The color is black when bleeding comes from upper part of GIT (effect of HCl) and it is bright red when it comes from the rectum

2-Internal Hemorrhage

It may be difficult to recognize the location and quantity, and it may not be noticed until signs of severe blood loss develop

Causes: -

1-Trauma (accident)



A-Subcutaneous or tissue hemorrhage

Definition: -

It is extra-vasation of blood into intercellular spaces in subcutaneous and sub-mucosa tissues while the surface remains intact

i-Petechiae   or   petechial    hemorrhage: -

Definition: -

It is small   multiple extravasations beneath the skin, or mucous or serous membrane, forming rounded or irregular minute red spots. This type of hemorrhage usually associates viral diseases.  

ii-Ecchymosis: -

Definition: -

It is blood extravasations of a size larger than petechiae, this hemorrhage disseminates through the intercellular spaces without formation of growth collection of blood

iii-Hematoma: -

Definition: -

It is collection of relatively large quantity of blood in localized area subcutaneously while the skin remains intact.  It will be discussed in the wound chapter.

B-Deep or Concealed Hemorrhage: -

Location: -

1-Tissues deeper than skin

2-Internal organs

3-Body cavities

Examples: -


bleeding into pleural cavity


bleeding into peritoneal cavity


bleeding into testicular tunica vaginalis


bleeding into joint


bleeding into the uterus


bleeding into fallopian tubes

Hemorrhage into spinal cord




bleeding into extradural space

bleeding into intradural space


1-Primary Hemorrhage

It occurs immediately either during surgery or during accident

2-Intermediate or Reactionary Hemorrhage

It occurs within 24 hours after surgery or accident

Causes: -

1-Failure of the temporary natural arrest

2-Faulty ligation of blood vessel

3-Rise of blood pressure

3-Secondary hemorrhage

It occurs after elapse of long time (more than 24 hours) after operation or injury

Causes: -

1-Sepsis of the wound with bacterial proteolysis and softening of the temporary clot

2-Subsidiary etiological factors include arterial diseases, high blood pressure, and toxemia


Pathogenesis of coagulation process: -

1-Prothrombin of the blood plasma changed into thrombin under effect of co-enzyme thrombokinase or thromboplastin (librated from blood platelets and tissue cells when they burst), in presence of calcium ions

2-Thrombine changes the plasma fibrinogen to fibrin that forms a network in which the blood corpuscles are entangled, so that the blood hardens to a red gelatinous mass (the coagulum)

3-Later on, the fibrin threads shrink and close the wound lips

Prothrombin + Thromboplastin + Calcium → Thrombin

Thrombin + Fibrinogen → Fibrin

Factors enhance rupturing of blood platelets: -

1-Application materials of rough surface like gauze, tampon or cotton wool in a bleeding surface

2-Change in osmotic pressure like intravenous injection of hypertonic solutions as sodium chloride 10%, Glucose 25-40%, or calcium chloride 10%


Usually hemorrhage stops spontaneously within 10-20 minutes, due to reflex action on the suprarenal gland and adrenaline release that causes vasoconstriction of blood vessels.


1-Elevation of the bleeding part

2-Pressure bandage over the wound to arrest hemorrhage and prevent contamination

3-Elastic ligature, tourniquet, or Esmarch bandage above the wound especially for the limbs and tail, and it should not remain in position more than 2 hours to avoid necrosis


1-Physical Methods

1-Application of cold water or ice at the bleeding surface, as on the frontal bone in case of epistaxis

2-The use of hot red iron especially if the area is wide with difficulty to ligate the bleeding vessel

2-Chemical Methods



2-Copper sulfate

3-Silver nitrate   

4-Ferric per-chloride  

B-Locally and Systemically

1-Gelatin 10% to elevate the viscosity of the blood, it is used locally or per os (intestinal hemorrhage), or by subcutaneous injection in concentration of 2-5% sterile ampoules which are heated to body temperature

2-Adrenaline 1/1000 locally over the bleeding surface by piece of cotton for vasoconstriction of blood vessels

3-Coaguline that can be used subcutaneously

4-Ergometrine (Methergen) injection to control uterine hemorrhages


1-Vit. C

2-Vit. K

3-Calcium salts

3-Mechanical Methods

1-Crushing of the bleeding vessel by haemostatic forceps for few minutes

2-Torsion of the bleeding vessel by haemostatic forceps (as in case of castration in cats and dogs)

3-Ligature by suture materials

4-Mass ligature by catgut, if the bleeding either comes from tissue mass or more than one vessel

5-Cross ligature around the bleeding area in cases of embedded bleeding vessel

6-Crushing by using crushing instruments as emasculator, sand crusher and ecraseur (as in case of castration in equines and ovariectomy in mares and cattle)

7-Tamponade and packing, by using gauze bandage, especially if hemorrhage is coming from cavities as in cases of eyeball extirpation or castration (the tampon remains in position for 2 hours)

8-Ligation of large blood vessel far away from the site of hemorrhage as in cases of hemorrhage in the head, it is possible to ligate the carotid artery

9-In cases of internal organ hemorrhage as splenic hemorrhage or hepatic hemorrhage due to its injury, it is possible to arrest hemorrhage by omentisation using greater omentum and sutures are applied to fix the omentum on the bleeding organ


When hemorrhage is arrested by haemostatic forceps, it causes rolling or traction and retraction of tunica intima and tunica media thus exposing the rough surface of these layers to the blood to enhance the formation of thrombus.


Signs: -

1-Pale or yellowish white mucous membranes

2-Hypothermia and coldness of ears, lips, tongue, and extremities 

3-Fast weak heart beats and the very weak pulse and difficult to palpate

4-Shallow and rapid respiration

5-Excessive sweating


7-Finally, the muscles become relaxed with involuntary defecation and urination

N.B.: -

It is contraindicated to let the animal to drink to neutralize severe thirsty to hydremia or over hydration with subsequent hemolysis

Treatment: -

1-Arrest of hemorrhage

2-Heart tonics as camphor, caffeine, adcopherine or cardiazole

3-Keep the animal warm by blankets or rags, or exposure to sun heat or fire

4-Lowering of the head to maintain minimum blood supply to the brain

5-Auto-transfusion by applying pressure bandages over the limbs to assist in elevation of lowered blood pressure

6-Compensation of the blood losses by either blood transfusion from the same species or by fluid therapy       

Fluids used: - 

1-Normal saline

2-Dextrose 5%

3-Ringers solution

4-Blood transfusion

Amount, dose, and rate of injection: -

It is discussed in fluid therapy