Ch.4 Hemostasis, Surgical Bleeding, Transfusions Flashcards
Absorption time of CoSeal (polyethylene glycol hydrogel)
30 days
To what extent does CoSeal (polyethylene glycol hydrogel) swell
Up to 4 times its volume
How does polyethylene glycol hydrogel (CoSeal) act
Polymerizes to form hydrogel acting directly as a barrier to blood flow.
Advantages of fibrin sealants
1- Do not require patient to have adequate platelets or coag factors
2- Biodegradable
3 - Have not been associated with tissue inflammation or FB rxn
How do fibrin sealants work
Replicate last stage of coagulation
Tisseel contains what
Thrombin and fibrinogen
Flowseal is an example of
A thrombin product
Disadvantages of bone wax
1- Non-absorbable
2 - Inhibits bacterial clearance
3 - Inhibits bone healing
4 - Allergic rxns
5 - Granulomatous rxns
6 - Embolization
Biologic hemostatic effect of bone wax?
None - mechanical
Advantages of polysaccharide hemostatic agents (TraumaDex, Arista)
Do not inhibit wound healing
What polysaccharide is used in hemostatic dressings such as HemCon
Chitosan
Absorption time for TraumaDex, Arista (polysaccharide hemostatic agents)
24-48hrs
Mechanism of hemostasis of polysaccharide hemostatic agents
Have a porous surface which allows absorption of blood - concentrating platelets, coag factors and reduces time for coag.
TraumaDex and Arista are examples of?
Polysaccharide hemostatic agents
Absorption time of microfibrillar collagen hemostatic agents
Should be removed from surgical site before closure of wound
Disadvantages of microfibrillar collagen hemostatic agents
(Avtene, Instat)
1-Allergic reactions - related to bovine origin
2-Interfere with bacterial clearance and wound healing
On which patients are microfibrillar collagen hemostatic agents (Avtene, Instat) less effective?
Patients with thrombocytopenia.
How do microfibrillar collagen hemostatic agents (Atvene, Instat) act?
1-Bind tightly to the bleeding surface - mechanical blockage.
2-Platelets adhere to the collagen and are activated the resultaning platelet degranulation and aggregation leads to hemostasis.
Absorption time of microfibrillar collagen hemostatic agents
8-10 weeks
Absorption time of surgicel (oxidized regenerated cellulose)
7-14 days however residue may persist for several months to years.
Disadvantages of using surgicel (oxidized regenerated cellulose)
1-Can’t be soaked in thrombin - the biologic agents will be inactivated in the low pH
2-Low pH may lead to tissue inflammation and delayed wound healing.
Advantage of Surgicel (Oxidized regenerated cellulose) over gelatin sponge?
Low ph confers antibacterial properties so can be used in contaminated areas.
How does oxidized regenerated cellulose (Surgical) elicit its hemostatic effects?
1-Swelling from blood absorption,
2-Activates coagulation on the collagen surface,
3-Caustic hemostatic agent due to low ph
Absorption time of gelatin sponge
4-6 weeks