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Flashcards in Hemostasis Deck (57):
1

What is hemostasis?

spontaneous physiological defense mechanism to stop hemorrhage

2

What does hemostasis depend on?

vascular, extravascular and intravascular factors

3

What is the end product of hemostasis?

an effective thrombus

4

What is surgical hemostasis used for?

used to augment, faility or bypass physiological clotting

5

What is the goal of surgical hemostasis?

to reduce blood loss and resultant complications

6

What are 4 issues with surgical bleeding?

1. obscures surgical field, reducing accuracy and efficiency
2. blood on field, gloves, drapes, instruments is ideal medium for bacterial growth
3. extravated blood has negative effects on body
4. severe or prolonged hemorrhage may result in shock, hypoxemia, death

7

What are the problems caused by extravasated blood in the body?

1. irritates tissues
2. prevents coaptation of wound edges
3. delays healing
4. encourages infection
5. promotes intraabdominal adhesions

8

What is primary hemorrhage?

occurs immediately after disruption of blood vessels
occurs during surgical dissection

9

How do you minimize primary hemorrhage?

know anatomy--ligate vessels
traverse one tissue plane at a time
apply tension in tissue handling?

10

What is delayed hemorrhage?

(intermediate) within 24 hours of injury
(secondary) >24 hours of injury

11

What is delayed hemorrhage often caused by?

often caused by ineffective treatment of primary hemorrhage
1. slipped ligatures
2. necrosis of ligated or cauterised vessels

12

What is the use of hemostatic forceps?

can be used to clamp vessels that will not be repaired. crushing the vessel stops hemorrhage and damages vessel wall, activating clotting.
only for small vessels

13

What hemostatic forcep is used for a wound?

1. smallest forceps capable of achieving hemostasis
2. curved hemostats improve visibility

14

How do you apply hemostatic forceps to stop bleeding?

1. grip in dominant hand with wide based tripod grip
2. small superficial bleeders point the tip towards the vessels
3. for deep bleeders, large vessels or pedicles apply hemostasis with convex surface facing end of vessel

15

How do you apply hemostatic forceps to stop bleeding?

1. grip in dominant hand with wide based tripod grip
2. small superficial bleeders point the tip towards the vessels
3. for deep bleeders, large vessels or pedicles apply hemostasis with convex surface facing end of vessel
4. for large vessels use jaw rather than tip
5. for large pedicles clamped with a carmalt or similar to minimize slippage

16

What are the most secure methods for hemostasis?

vascular clips and ligatures

17

What is an advantage of vascular clips and ligatures?

they are less likely to slip than a clot is to be dislodged

18

What is a disadvantage of vascular clips and ligatures?

foreign material is left in the wound

19

How do you apply vascular clips?

1. dissect vessel free from the surrounding tissue
2. diameter of vessel between 1/3-2/3 the length of the clip
3. apply several mm from cut end of vessel
4. clip artery and vein separately

20

What are the advantages of vascular clips?

1. can be placed more rapidly than ligatures
2. good for poorly accessible locations

21

What is a disadvantage of vascular clips?

more likely to be dislodged during surgical manipulation

22

What is the most commonly used method of hemostasis?

ligatures

23

What are the advantages of ligatures?

1. more secure than hemostatic clips
2. better suited for occlusion of multiple vessels and vascular pedicles
3. for large vessels the increased security outweighs the application time

24

What is a disadvantage of ligature?

take longer to apply

25

What is a disadvantage of ligature?

take longer to apply

26

What is the advantage of a square knot (ligature)

least likely to loosen (unless half hitch)

27

What is the advantage of surgeon knot?

used for large pedicles if cannot adequately tighten a square knot (apply square knot over top)

28

What material should not be used with a surgeon's knot?

chromic gut because friction causes fraying at the knot

29

What are two ways you can tie ligatures?

hand or instrument ties

30

What is recommended for large vessels with regards to applying ligatures?

use double ligatures

31

What are tansfixation ligatures less prone to?

slippage

32

What suture size should be used for ligatures?

3-0 for isolated vessels, maximum 0 for pedicles

33

Why should ligatures be adequately tightened?

because inadequate tightening leads to bulky and less secure knotes

34

What should be the tail length of ligatures for synthetic sutures?

3-4mm

35

What is cautery performed on?

arteries up to 1mm and veins up to 2mm

36

What is used for cautery?

radiofrequency from an electrosurgical unit

37

How does cautery work?

heat is produced by tissue resistance to current, electrical energy is absorbed and converted to thermal energy

38

What is a monopolar cautery?

there if flow from handpeice through the patient to a ground plate
the current enters a small volume of tissue and exits a large volume of tissue to avoid burns

39

What can monpolar cautery do besides cut?

coagulate

40

What are two ways you can apply monopolar cautery?

1. directly onto a vessel
2. indirectly onto forceps holding the vessel (less collateral damage)

41

What must you remember when usingmonopolar cautery?

1. only contact at point of coagulation
2. use minimum intensity and time necessary
3. dry first
4. there is a risk of distant burns if take alternative path to ground plate
5. need dry area

42

What are the featuers of bipolar cautery?

1. the current passes between arms when the tips are ~1mm apart
2. no need for ground plate
3. need electrolyte fluid between tips
4. if tips touch the current shorts--no coagulation

43

What are the advantages of bipolar cautery?

1. less current needed
2. less risk of injury to surrounding tissue
3. no pathway of burns of distant tissues
4. works well in wet field
5. useful for fine vessels needing precise coagulation

44

What are the advantages of bipolar cautery?

1. less current needed
2. less risk of injury to surrounding tissue
3. no pathway of burns of distant tissues
4. works well in wet field
5. useful for fine vessels needing precise coagulation

45

What is an advantage of cautery?

properly used it provides rapid definitive hemostasis

46

What is a disadvantage of cautery

less secure ligation

47

improper use of cautery can cause what?

1. secondary hemorrhage
2. severe burns
3. delayed wound healing
4. increased infection rates
5. fires and explosions

48

What is ligasure?

bipolar vessel sealing device

49

How does ligasure work?

The machine measures the bioimpedence of the current through the tissue and adjusts the current to seal the vessels
proteins denatured and reforms into a sealed end

50

Where/when can ligasure be used?

1. on vessels up to 7mm
2. with laparascopy, thoracoscopy

51

What is a topical hemostatic agent?

gelfoam

52

What are topical hemostatic agents (e.g. gelfoam) used for?

diffuse low level bleeding that is not amenable to other methods of hemostasis (cancellous bone, liver biopsy)

53

What are 4 types of topical hemostatic agents?

1. fibrin adhesives
2. oxidised cellulose
3. microfibrillar collagen sponges
4. gelatin sponges

54

What can topical hemostatic agents be combined with?

thrombin

55

Why should you use the minimum amount of topical hemostatic agents?

because they can potentiate infection

56

What is bone wax used for?

1. to control bleeding form cancellous bone especially in neurological surgery, mandible

57

Why must you only use bone wax in clean wounds

because it persists from several years and impedes clearance of bacteria