L5: Hemorrhage & hemostasis

Question 1

What is hemorrhage

Answer 1

-An abnormal escape of blood from an artery, vein, arteriole, venule or capillary network.
-Caused by traumatic injury or medical condition.
-It can be external or internal.
-Primary occurs soon after an injury
-Secondary follows an injury after considerable lapse of time (usually self limiting if normal physiology)
-Arterial /venous /capillary/parenchymatous

Question 2

What is arterial hemorrhage?

Answer 2

-Caused by ruptured artery
-Bright red color
-Pulse flow
-May be steady if artery is deep
-Spontaneous hemostasis rare
-Life-threatening
-Hardest to control

Question 3

Venous hemorrhage

Answer 3

-Ruptured vein
-Rather dark red
-Steady profuse bleeding
-Spontaneous hemostasis possible
-Level of danger dependant on the diameter
-Potentially life-threatening

Question 4

Types of hemorrhage (4)

Answer 4

Arterial, venous, capillary, parenchymatous

Question 5

Capillary hemorrhage

Answer 5

-Ruptured capillaries
-Most common
-Mix of arterial and venous blood
-Trickle of blood (small drops)
-Spontaneous hemostasis likely
-Usually not life-threatening
-Easy to control

Question 6

Parenchymatous hemorrhage

Answer 6

-Injury of parenchymal organ, corpus cavernosum or cancellous bone
-Similar to capillary hemorrhage, bleeding more profuse
-Spontaneous hemostasis unlikely or time-consuming
-Potentially life-threatening

Question 7

Prognosis of blood loss

Answer 7

It is dependent on severity, rate(time), concurrent disorders etc. Blood loss leads to hypovolemic shock and to death when 1/2 - 2/3 of total volume is lost.

Question 7

Classification of hemorrhage

Answer 7

Blood volume is 7-9% of bw
1.Class I (minimal) 15%
HR, RR, BP normal, normal urine output, slightly anxious
2.Class II (mild) 15-30%
HR, RR higher, BP normal, oliguria, confused, cool extremities
3.Class III (moderate) 30-40%
HR, RR higher, BP lower, oliguria, lethargic, cool extremities
4.Class IV (severe) >40%
HR, RR high, BP low, anuria, lethargic, comatose, cold extremities, cyanosis

Question 8

Hemostasis definition

Answer 8

Complex process involving platelet activation and circulating clotting factors. Causes bleeding to stop from the damaged blood vessel. Physiological hemostasis and artificial hemostasis (temporary and definitive)

Question 9

How hemostasis happens (NEED TO KNOW WORD BY WORD)

Answer 9

Injury => vasoconstrictors released from endothelium (endothelin) => vasoconstriction at the site => aggregation and adhesion of platelets (plug formation) => Thromboplastin (combination of phospholipids and tissue factors) catalyzes the conversion of prothrombin (nonactive) to thrombin) => thrombin causes fibrinogen to polymerize => polymerized fibrin forms long strands of tough insoluble protein that are bound to the platelets => formation of hemostatic clot

Question 10

Provisional (temporary) artificial hemostasis

Answer 10

-Manual pressure
-Tamponade (Can lead to physiological hemostasis, ligation might be unnecessary)
-Pressure bandage
-Hemostats (forceps)
-Tourniquet (not so good in surgery)

Question 11

Definitive hemostasis (4)

Answer 11

Mechanical, physical, chemical, biological

Question 12

Mechanical hemostasis

Answer 12

Tamponade - Closure of blockade of a wound as if or by a tampon to stop bleeding (absorbent material, pressure); mild capillary or parenchymatous hemorrhage
Ligation - Placement of surgical suture (smallest material possible?) around a vessel; arterial or venous hemorrhage. Transfixation ligature around larger arteries

Question 13

Transfixation ligature

Answer 13

First to the blood vessel wall and after that around the vessel

Question 14

Physical hemostasis

Answer 14

1.Low local temperature => vasoconstriction
2.High temperature: electrocautery (monopolar and bipolar)

Question 15

Chemical hemostasis

Answer 15

1.Topical substances
-Bone wax (tamponade)
-Gelatin- and cellulose-based hemostatic products (clotting)
-Adrenalin (vasoconstriction)
2.Systemic treatment
-Ca
-Vitamin K
-Tranexamic acid (Cyclokapron)