Chapter 18 Surgical Hemostasis

Question 1

What vessels can you NOT ligate in cats

Answer 1

Both common carotid arteries or both jugular veins

Question 2

Which renal vein can be ligated in dogs

Answer 2

Only the left renal vein in the dog can be ligated.

Question 3

How long can the abdominal aorta be ligated

Answer 3

30 minutes

Question 4

How long can the descending thoracic aorta be ligated

Answer 4

5-10 minutes

Question 5

Which vessels are ligated during the Pringle maneuver and how long can they be ligated for

Answer 5

Hepatic artery, protein vein, and common bile duct

10-15 minutes

Question 6

How long can the splenic artery and vein be ligated

Answer 6

15-20 minutes

Question 7

How long can the renal artery and vein be ligated

Answer 7

10 minutes

Question 8

Whats the maximum time a tourniquet should be used and why

Answer 8

1.5-2 hours
Corresponds to the point at which muscle ATP stores are depleted
Microvascular damage occurs after 2 hours

Question 9

T/F: Exsanguination of the limb before tourniquet application is not recommended in the presence of malignant neoplasia

Answer 9

True

Question 10

What are the 3 types of hemostatic agents

Answer 10

Mechanical hemostatic agents
Active hemostatic agents
Hemostatic sealants

Question 11

Name 5 mechanical hemostatic agents

Answer 11

Gelatin, bovine collagen, cellulose, polysaccharide spheres, and bone wax

Question 12

What is gelatins MOA, does it promote plt aggregation, and how is it reabsorbed

Answer 12

Provides matrix for fibrin strand formation and clot is stabilized on the matrix
Does not promote platelet aggregation
Reabsorbed by granulomatous inflammation with ingrowth of fibroblasts

Question 13

Bovine collagen MOA, absorption, efficacy

Answer 13

Enhances platelet aggregation
Absorbed by fibroblast remodeling in 8-10 weeks
Collagen more effective than gelatin

Question 14

Cellulose MOA, disadvantage, advantage, and reabsorption rate

Answer 14

Forms dense gelatinous clot
Acidic environment denatures blood proteins stimulating hemostasis
Disadvantage: acidic environment inactivates thrombin - not as good as other hemostatic agents
Advantage: Bactericidal against gram positive and negative bacteria due to low pH
Reabsorbed in 2-6 weeks

Question 15

Polysaccharide spores origin, MOA, and absorption

Answer 15

Plant derived starch
Spheres stimulate platelet response
Metabolized in 24-48 hours by endogenous amylase

Question 16

Name two active hemostatic agents

Answer 16

Thrombin and alginates

Question 17

Thrombin MOA

Answer 17

Uses normal clotting cascade*
Converts fibrinogen into fibrin creating a clot

Question 18

Cellulose and thrombin

Answer 18

Thrombin cannot be combined with cellulose since acidic environment will inactivate thrombin

Question 19

Alginates MOA and origin

Answer 19

Seaweed derived protein
Calcium ions released activating clotting cascade

Question 20

Name two hemostatic sealants

Answer 20

Fibrin and synthetic sealants

Question 21

Benefit of hemostatic sealants

Answer 21

Independent of patients clotting ability

Question 22

The hemostatic sealant- Fibrin Moa

Answer 22

Independent on patients clotting ability
Provide thrombin and fibrinogen
From human plasma

Question 23

How is fibrin formed

Answer 23

Common pathway -> fX activated into fXa
[fXa + fVa] —> activates prothrombin (fII) to thrombin (fIIa) —> cleaves fibrinogen into fibrin