12: Hemostasis - Bennett

Question 1

how should anatomical dissection be done?

Answer 1

identification of tissue planes and the use of atraumatic technique

Question 2

preferred type of hemostasis

Answer 2

• pneumatic thigh cuffs
• causes pain due to high pressure and will require general or spinal anesthesia
• ankle can be used with all forms of anesthia or not sedated, but causes higher incidence of complicaitons

Question 3

what mmHg should not be exceeded with thigh cuffs?

Answer 3

500 mmHg

ankle should not exceed 250

Question 4

what is exsanguination?

Answer 4

• elevation of extremity before elevating the cuff pressure
• 45 degrees 3 min, 60 degrees 2 min
• or use esmarch or ace wrap up to cuff level

Question 5

contraindications to using pneumatic cuffs

Answer 5

• infection
• malignancy
• thrombo-embolic disease
• prior endovascular procedure

Question 6

proper inflation of cuff

Answer 6

• approx. 100 mgHg above systolic for ankle

- approx 200 mmHg above systolic for thigh

Question 7

max time for torniquet or pneumatic cuff

Answer 7

• 2-3 hours
• breathing times 5-10 min
• ideally max torniquet time 1.5 hrs with 5-10 min reperfusion interval allowed for complete cellular recovery

Question 8

physiological changes with tourniquet use

Answer 8

• increasing acidity
• decrease oxygen partial pressures
• increase carbon dioxide

Question 9

mimics natural catecholamines that bind to alpha adrenergic receptors

Answer 9

vasoconstrictors

Question 10

describe the use of epinephrine with hemostasis

Answer 10

• Reduces vascularity locally
• Permits a higher allowable dose of local
• Increases the duration of the block

permissible concentration: 1:100,000-200,000

Question 11

evithrom

Answer 11

• topical thrombin
• bovine origin
• clots fibrinogen of blood
• rate of coagulation dependent upon concentration
• 500 units will clot 5 ml in less than 1 sec

Question 12

gelfoam

Answer 12

• purified animal protein
• mechanical matrix promotes clotting and its a physical barrier
• absorbs many times its own weight in blood
• absorbed in 4-6 weeks

Question 13

avitene

Answer 13

• microfibrillar collagen
• attracts platelets
• may be used in pts undergoing heparin and aspirin therapy *

Question 14

surgicel

Answer 14

• oxidized regenerated cellulos
• absorbed
• hemostasis based on physical properties - binds to bleeding areas to coagulate vessels, compreses ara
• bactericidal properties**

Question 15

floseal

Answer 15

• combo of tow hemostatic agents [acts at beginning of coagulation cascade to promote contact activation; acts at end of coagulation cascade to facilitate fibrin formation]
• stops bleeding within 2 minutes
• effective on soft tissue and bone

Question 16

human thromin

Answer 16

evicel

Question 17

bone wax

Answer 17

• refined bees wax
• physical barrier
• inhibits bone healing