Hemostasis, surgical bleeding, and transfusion

Question 1

T/F: The synthesis of prostacyclin (PGI2) and nitric oxide (NO) is largely responsible for the antiplatelet properties of the intact endothelium.

Answer 1

True; Both of these substances inhibit platelet aggregation, and NO also inhibits platelet adhesion. The vasodilation induced by NO also helps to prevent clot formation by promoting low-turbulence blood flow.

Question 2

T/F: The vasoconstriction induced by NO helps to prevent clot formation by promoting low-turbulence blood flow.

Answer 2

False; NO induces vasodilation, which does reduce turbulence.

Question 3

T/F: Platelet aggregation and adhesion are up-regulated by enzymes on the endothelial surface that degrade adenosine diphosphate (ADP).

Answer 3

False: Platelet aggregation and adhesion are prevented by enzymes on the endothelial surface that degrade adenosine diphosphate (ADP).

Question 4

T/F: The electropositive charges on endothelium and platelets physically prevent adhesion.

Answer 4

False; The electronegative charges on endothelium and platelets physically prevent adhesion.

Question 5

T/F: Endogenous heparin-like substances are present on the endothelial surface, contributing substantially to anticoagulation.

Answer 5

True

Question 6

_______________ act as cofactors for antithrombin, which inactivates thrombin and coagulation factors ___, ____, _____, and ____.

Answer 6

Glycosaminoglycans; VIIa, IXa, Xa, and XIa.

Question 7

T/F: When vessel injury occurs, endothelial cells can express tissue factor (TF) and downregulate expression of thrombomodulin, becoming procoagulant.

Answer 7

True

Question 8

T/F: Activated endothelial cells release von Willebrand factor (vWF) from the Weibel-Palade bodies, promoting platelet adhesion.

Answer 8

True

Question 9

Platelets contain _______ _________, ____________ and lysosomes, which store the majority of platelet proteins needed for the initiation of coagulation.

Answer 9

dense granules; α-granules; lysosomes

Question 10

The ____________ are the largest and most prevalent storage granules, comprising the majority of the storage capacity of platelets.

Answer 10

α-granules

Question 11

____________ contain a number of proteins involved in platelet aggregation and cohesion, including fibrinogen, factor V (FV), factor VIII (FVIII), fibronectin, vWF, platelet-derived growth factor (PDGF), and platelet factor 4.

Answer 11

α-granules

Question 12

What is “stored” in dense granules?

Answer 12

Dense granules store calcium, ADP, adenosine triphosphate (ATP), and serotonin.

Question 13

What is the strongest stimulant for the release of the contents of the dense granules?

Answer 13

Thrombin

Question 14

T/F: Platelet lysosomes contain predominantly acid hydrolases, responsible for degradation of unwanted cellular debris after complete activation of fibrin formation.

Answer 14

True

Question 15

T/F: Platelet adhesion is mediated by expression of P-selectin on the activated endothelium and by the platelet receptor GPIbα, which attaches to vWF.

Answer 15

True

Question 16

T/F: Thrombin, collagen, ADP, and thromboxane A2 promote platelet activation.

Answer 16

True

Question 17

After the platelet plug bridges the gap between endothelial cells, ___________, produced by neighboring healthy endothelial cells, prevents unwanted expansion of platelet aggregates by decreasing further ADP release.

Answer 17

prostacyclin (PGI2)

Question 18

The __________ pathway, or “contact activation” pathway, is initiated by the activation of factor ______ and subsequently factor ___ through the exposure of blood to a negatively charged surface.

Answer 18

intrinsic; factor XII (FXII); XI

Question 19

T/F: Contact proteins such as high-molecular-weight kininogen (HMWK) and prekallikrein interact with FVII to accelerate its activation.

Answer 19

False; Contact proteins such as high-molecular-weight kininogen (HMWK) and prekallikrein interact with FXII to acclerate its activation. The activation of factor VII is by TF present in fibroblasts or other tissue factor–bearing cells.

Question 20

What catalyzes the activation of factor IX by factor XIa?

Answer 20

calcium

Question 21

What catalyzes the binding of factor IXa to procoagulant VIIIa?

Answer 21

calcium

Question 22

What steps in the coagulation cascade are facilitated by calcium?

Answer 22

(intrinsic)
The activation of factor IX by factor XIa.
The binding of factor IXa to procoagulant VIIIa.

(common)
The convertion of prothrombin (factor II) to thrombin (IIa) by factor X.
The stabilization of the fibrin clot by cross-linking strands of fibrin monomer by factor XIIIa .

Question 23

The ________ pathway is initiated by the activation of factor VII by TF present in fibroblasts or other tissue factor–bearing cells.

Answer 23

extrinsic

Question 24

Which of the following is not one of the three overlapping phases of the cell-based model of coagulation?

1. amplification
2. fibrinolysis
3. initiation
4. propagation

Answer 24

fibrinolysis

Question 25

T/F: Simultaneous activation of the fibrinolytic system with activation of coagulation is responsible for prevention of excessive fibrin deposition and restoration of nutrient blood flow to affected tissues.

Answer 25

True

Question 26

Fibrinolysis, in conjunction with _____________ released by surrounding healthy endothelial cells, inhibits unwanted expansion of the fibrin clot.

Answer 26

prostacyclin (PGI2)

Question 27

___________, an inactive zymogen produced primarily in the kidney and liver, is the principal component of the fibrinolytic system.

Answer 27

Plasminogen

Question 28

How is plasminogen converted to plasmin?

Answer 28

Plasminogen activators such as tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) convert plasminogen to plasmin.
The activation of the intrinsic pathway also activates plasminogen conversion to plasmin, through the action of kallikrein.

Question 29

What is the role of plasmin in the fibrinolytic system?

Answer 29

Plasmin degrades fibrinogen and fibrin into soluble fibrin(ogen) degradation products (FDPs).
Plasmin also inactivates other members of the coagulation cascade, such as factors Va and VIIIa, and actively degrades prekallikrein and HMWK. Through these mechanisms, plasmin not only degrades fibrin(ogen) but also downregulates coagulation.

Question 30

What are the products of fibrin(ogen) degradation?

Answer 30

The products of fibrinogen or fibrin degradation are the FDPs designated fragment X, fragment Y, and fragments D and E.
Plasmin degradation of cross-linked fibrin results in the D-dimer fibrin degradation product.

Question 31

What does an increase in D-dimers indicate?

Answer 31

increased fibrin production (and degradation) or liver dysfunction (these fragments are removed by mononuclear phagocytes in the liver).

Question 32

What are the principal inhibitors of coagulation (proteins that enzymatically bind with coagulation factors to form inactive complexes)?

Answer 32

The principal inhibitors of coagulation are antithrombin, heparin, protein C, protein S, and tissue factor pathway inhibitor (TFPI).

Question 33

Where are platelets formed?

Answer 33

megakaryocytes in bone marrow and in the lungs.

Question 34

This serine protease inhibitor is responsible for modulation of clot formation and is responsible for 70% to 80% of thrombin inhibition
in the coagulation system.

Answer 34

Antithrombin (AT); AT is a glycoprotein produced in the liver and in endothelial cells that binds aggressively to thrombin.

Question 35

T/F: A stable thrombin-antithrombin (TAT) complex is removed by the reticuloendothelial system.

Answer 35

True

Question 36

T/F: The cofactor heparin alters the arginine site of AT and dramatically increases its ability to interact with thrombin.

Answer 36

True; Heparin is a highly sulfated glycosaminoglycan, ranging in molecular weight from 3 to 30 kDa. It is produced primarily in mast cells located in the lung, liver, kidney, heart, and gastrointestinal tract. Heparin causes a conformational change in AT, which increases the activity of AT 1000-fold.

Question 37

Where is heparin produced in the body?

Answer 37

It is produced primarily in mast cells located in the lung, liver, kidney, heart, and gastrointestinal tract.

Question 38

Heparin releases ____ _____ ________ _________ from endothelial cells, thereby liberating one of the most effective inhibitors of the factor VIIa-TF complex.

Answer 38

tissue factor pathway inhibitor (TFPI)

Question 39

T/F: Protein C is a vitamin C–dependent zymogen with primary inhibitory action on factors Va and VIIIa.

Answer 39

False; Protein C is a vitamin K–dependent zymogen with primary inhibitory action on factors Va and VIIIa.

Question 40

Protein C is activated by __________________ complexes. This reaction is potentiated by the endothelial protein C receptor, which is located mainly in ______ vessels.

Answer 40

thrombomodulin-thrombin; large

Question 41

When activated protein C is released into circulation, it associates with protein S and is able to inactivate which factors?

Answer 41

factors Va and VIIa.

Question 42

T/F: Activated protein C is also profibrinolytic, since it inhibits plasminogen activator inhibitor-1 (PAI-1) and indirectly inhibits thrombin-activatable fibrinolysis inhibitor (TAFI) as a result of thrombin inhibition.

Answer 42

True

Question 43

Tissue factor pathway inhibitor (TFPI) is a group of lipoprotein-bound proteins produced primarily by ________ and _____________ cells.

Answer 43

platelets; endothelial

Question 44

T/F: In the presence of calcium, tissue factor pathway inhibitor (TFPI) inhibits factor VIIa-TF activation of factor X, thereby
dramatically decreasing the primary cellular initiator of coagulation.

Answer 44

True

Question 45

What is the importance of calcium in the thrombomodulin–protein C–protein S pathway during the inhibition of coagulation?

Answer 45

In the presence of calcium, tissue factor pathway inhibitor (TFPI) inhibits factor VIIa-TF activation of factor X, thereby
dramatically decreasing the primary cellular initiator of coagulation.

Question 46

T/F: PAI is present in endothelial cells and is stored in dense-granules of platelets.

Answer 46

False: plasminogen activator inhibitor (PAI) is present in endothelial cells and is stored in α-granules of platelets

Question 47

What is the principal regulator of plasminogen?

Answer 47

plasminogen activator inhibitor (PAI) is the principal regulator of plasminogen through inhibitory effects on tissue plasminogen activator (tPA), which is a plasminogen activator.

Question 48

What is the main physiologic inhibitor of plasmin?

Answer 48

The main physiologic inhibitor of plasmin is α-2-antiplasmin. An alternative inhibitor of plasmin, α-2-macroglobulin, may inhibit plasmin in a limited fashion, particularly if α-2-antiplasmin is overwhelmed.

Question 49

T/F: Another inhibitor of fibrinolysis, thrombin-activatable fibrinolysis inhibitor (TAFI), is activated by thrombin, the thrombin-thrombomodulin complex, and plasmin. As a negative-feedback mechanism, plasmin can also activate TAFI.

Answer 49

True

Question 50

Template bleeding time (TBT) is a platelet function test; it will be prolonged with ___________, ____________, and lack of vWF, and it may also be prolonged in cases of vasculitis.

Answer 50

thrombocytopenia; thrombocytopathia

Question 51

Name 3 platelet function tests.

Answer 51

1. Template bleeding time (TBT)
2. platelet aggregation studies
3. platelet function analysis (PFA-100)

Question 52

During this coagulation test platelet-poor plasma is mixed with thromboplastin and calcium, and time to clot formation is measured.

Answer 52

Prothrombin time

Question 53

Prothrombin time (PT) measures the function of the _________ and __________ coagulation pathways

Answer 53

extrinsic and common

Question 54

What conditions can result in a prolonged PT?

Answer 54

Deficiencies in FV, FVII, FX, prothrombin, and fibrinogen can result in prolonged PT.

Question 55

Activated partial thromboplastin time (APTT) measures the function of the _________ and __________ coagulation pathways

Answer 55

intrinsic and common

Question 56

The coagulation test is performed by adding an activating agent to platelet-poor plasma in a glass tube containing phospholipid emulsion and calcium.

Answer 56

Activated partial thromboplastin time (APTT)

Question 57

What conditions can result in a prolonged APTT?

Answer 57

Deficiencies of FXII, FXI, FX, FIX, FVIII, FV, prothrombin, and fibrinogen can result in prolonged APTT.

Question 58

T/F: Prolonged PT or APTT may be associated with body cavity bleeding, significant hematuria, or hematochezia.

Answer 58

True

Question 59

This test measures the time required for whole blood to clot after contact with diatomaceous earth.

Answer 59

Activated clotting time (ACT)

Question 60

Activated clotting time (ACT) simulates the _____________ and _____________ coagulation pathways.

Answer 60

Intrinsic and common

Question 61

What conditions can result in a prolonged ACT?

Answer 61

The ACT will be prolonged with deficiencies of FVIII, FIX, prothrombin, and fibrinogen.

Question 62

T/F: ACT is more sensitive than APTT for coagulation factor deficiencies.

Answer 62

False; ACT has the advantage of being a rapid, patient-side test; however, ACT is less sensitive than APTT for coagulation factor deficiencies.

Question 63

Increased D-dimer levels indicate increased _____________ or inability to clear the products from the circulation.

Answer 63

fibrinolysis; The D-dimer assay is specific for plasmin degradation of fibrin, as opposed to FDPs, which indicate degradation of either fibrin or fibrinogen.

Question 64

T/F: Severe inflammation can cause increases in coagulation, decreases in anticoagulation, and inhibition of fibrinolysis, resulting in a procoagulant state.

Answer 64

True

Question 65

T/F: Endotoxin and proinflammatory cytokines can activate platelets and induce the release of vWF from endothelium.

Answer 65

True

Question 66

T/F: AT and protein C have pro-inflammatory effects.

Answer 66

False; AT and protein C have anti-inflammatory effects.

Question 67

What is the mechanism of action of heparin?

Answer 67

Heparin increases the activity of AT, thereby inhibiting thrombin and factor Xa.

Question 68

T/F: Low-molecular-weight heparin (LMWH) has greater inhibition of FXa, dose-dependent clearance, and a longer half-life than unfractionated heparin (UFH).

Answer 68

True

Question 69

T/F: In horses, administration of Low-molecular-weight heparin (LMWH) has been associated with prolonged APTT and decreased packed cell volume (PCV).

Answer 69

False; In horses, administration of unfractionated heparin (UFH) has been associated with prolonged APTT and decreased packed cell volume (PCV); these side effects are not seen with administration of LMWH.

Question 70

Surgery of which of the following is not associated with significant risk for intraoperative and postoperative hemorrhage?

1. Sinuses
2. Gastrointestinal tract
3. Cranial reproductive tract
4. Spleen

Answer 70

Gastrointestinal tract

Question 71

______ _______ transfusion serves to restore blood volume as well as oxygen-carrying capacity for horses that have suffered acute blood loss.

Answer 71

Whole blood

Question 72

PCV may remain normal for up to _________ following acute hemorrhage because of the time required for fluid redistribution and the effects of splenic contraction.

Answer 72

12 hours

Question 73

Estimation of blood loss at surgery can be used to guide the decision to transfuse, with loss of greater than ______________________ generally requiring transfusion.

Answer 73

30% of blood volume or approximately 12 Liters of blood from a 500 kg horse.

Question 74

T/F: A rise in blood lactate concentration despite volume replacement with crystalloid or colloid fluids may indicate a need for blood transfusion.

Answer 74

True; A rise in blood lactate concentration despite volume replacement with crystalloid or colloid fluids may indicate continued tissue hypoxia and a need for blood transfusion.

Question 75

T/F: Allogenic transfused red blood cells maintain a longer increase in PCV than autologous transfused red blood cells.

Answer 75

False; Red blood cells from allogeneic transfusions do have a much shorter half-life than autologous red cells, so transfusion should still be considered a temporary measure to restore oxygen-carrying capacity, relying on the horse’s erythropoeitic response or resolution of underlying disease to provide long-term resolution. The life span of transfused autologous RBCs after 28 days of storage is approximately 30 days, compared to a 14-day half-life for fresh, crossmatched allogeneic blood.

Question 76

You have a 500 kg normovolemic anemic patient with a PCV of 14% and a donor with a PCV of 40%. How much whole blood is required to raise the patient’s PCV to 20%?

Answer 76

6L of whole blood;
Blood transfusion volume = body wt x 0.08 x [(desired PCV - actual PCV)/donor PCV]
= 500kg x 0.08 x [(20 - 14)/40]

Question 77

You have a 500 kg patient with total protein of 3.5 g/dL. How much plasma will you need to transfuse to attain a total protein of 5.0 g/dL? (assume donor has total protein of 7.0 g/dL)

Answer 77

4,821 mL (roughly 5 L);
Plasma transfusion volume = body wt x 45 mL/kg x [(desired TP - actual TP)/donor TP]
= 500kg x 45ml/kg x [(5.0 - 3.5)/7.0]

Question 78

T/F: Fresh whole blood can provide platelets at concentrations high enough to treat severe thrombocytopenia.

Answer 78

False; Fresh whole blood can also provide platelets, though generally not in concentrations high enough to treat severe thrombocytopenia. For patients with primary thrombocytopenia or thrombocytopathia, platelet concentrates can be given. Platelet concentrates can be obtained by plateletpheresis or by centrifugation using a slow-spin technique.

Question 79

T/F: Packed red blood cells (pRBCs) are indicated for normovolemic anemia, such as neonatal isoerythrolysis, erythropoietic failure, and chronic blood loss.

Answer 79

True; When pRBCs are not available, whole blood may be used for the same indications, although attention should be paid to the total volume given so that volume overload is avoided.

Question 80

Which of the following is not an indication for a plasma transfusion?

1. hypoalbuminemia
2. clotting factor deficiency
3. neonatal failure of passive transfer
4. neonatal isoerythrolysis

Answer 80

neonatal isoerythrolysis constitutes a normovolemic anemia (total protein is normally unaffected and NI generally indicates adequate passive transfer) which would be more appropriately treated with whole blood or packed RBCs.

Question 81

_________ and ______ _______ ________ contain immunoglobulins, coagulation factors (fibrinogen and factors II, VII, IX, X, XI, and XII), and cofactors (factors V and VIII), and the anticoagulant proteins _________, _________ __, and _________ __.

Answer 81

Fresh and fresh frozen plasma (FFP); antithrombin, protein C, and protein S

Question 82

T/F: Colloid support is generally recommended in patients with a total protein less than 4.0 g/dL, serum albumin concentration less than 2.0 g/dL, or colloid oncotic pressure less than 14 mm Hg.

Answer 82

True

Question 83

T/F: When plasma is not necessary for clotting factor replacement, a synthetic colloid such as hydroxyethyl starch (hetastarch) is preferred for volume expansion and more effective oncotic support.

Answer 83

True

Question 84

__________ is a hemoglobin-based oxygen-carrying solution that is indicated for treatment of anemia.

Answer 84

Oxyglobin

Question 85

The life span of transfused autologous RBCs after 28 days of storage is approximately ______, compared to a _____ half-life for fresh, crossmatched allogeneic blood.

Answer 85

30 days; 14-day

Question 86

T/F: Intraoperative or posthemorrhage cell salvage is also an option for autotransfusion.

Answer 86

True; RBC recovery can be performed with specialized cell salvage equipment, which washes and filters collected blood, but cell salvage can also be performed with simple anticoagulation and filtration.
The technique of cell salvage is limited to cases in which the salvaged blood is not in an area of infection or malignancy, unless specialized washing and filtering equipment is used.

Question 87

How soon after a transfusion can horses develop alloantibodies?

Answer 87

within 1 week of transfusion; however, a second blood transfusion may be performed safely within 2 to 3 days of the first transfusion without a blood crossmatch.

Question 88

The major crossmatch involves mixing the ______ washed red blood cells with the ________ serum, whereas the minor crossmatch involves mixing the recipient’s _________ with the donor’s __________.

Answer 88

donor’s; recipient’s; red cells; serum

Question 89

T/F: If the minor crossmatch is incompatible, but the major crossmatch is compatible, the transfusion can still be performed after washing the donor red blood cells.

Answer 89

True; The major crossmatch involves mixing the donor’s washed red blood cells with the recipient’s serum, whereas the minor crossmatch involves mixing the recipient’s red cells with the donor’s serum.

Question 90

T/F: Immunoglobulins and coagulation factor activity are well-maintained for at least 1 year in fresh frozen plasma.

Answer 90

False; Immunoglobulins are well-maintained for at least 1 year in FFP; however, coagulation factor activity may decrease after 2 to 4 months of storage.

Question 91

Up to ____ of RBCs lost into a body cavity (e.g., hemoperitoneum) are autotransfused back into circulation within ___ to ____ _____.

Answer 91

75%; 24 to 72 hours

Question 92

T/F: In cases of severe acute blood loss, between 25% to 50% of the estimated total blood lost should be replaced by transfusion.

Answer 92

True; In cases of acute blood loss, PCV is often not useful for estimates of volume to be transfused since it does not accurately reflect blood loss. Instead, estimates of blood loss and evaluation of clinical parameters are used to determine the volume of blood needed. From 25% to 50% of the total blood lost should be replaced by transfusion since much of the circulating volume will be replaced by fluid shifts.

Question 93

T/F: Volume of plasma for treatment of coagulopathy is often determined by clinical and clinicopathologic response. A starting point for treatment of coagulapathy is approximately 4 to 5 mL/kg plasma.

Answer 93

True

Question 94

This hemostatic agent binds well to tissue and exerts a hemostatic effect by swelling as it is soaked with blood. It can be soaked in thrombin to help promote coagulation directly. This product can potentiate infection, and its use should be avoided in contaminated wounds. It is absorbed over a period of 4 to 6 weeks.

Answer 94

Purified gelatin sponges (made from purified animal gelatin)

Question 95

______________________ is a chemically altered form of cellulose, which is particularly useful to control diffuse bleeding from broad surfaces.

Answer 95

Oxidized regenerated cellulose

Question 96

What are the mechanisms of action of Surgicel (oxidized regenerated cellulose)?

Answer 96

Surgicel has mechanical hemostatic effects as a result of swelling from blood absorption, and it activates coagulation on the collagen surface. Surgicel also acts as a caustic hemostatic agent because of its low pH. The low pH additionally confers antibacterial properties and therefore is preferred over gelatin foam for use in contaminated areas

Question 97

T/F: Surgicel can be soaked in thrombin to help promote coagulation directly.

Answer 97

False; Gelatin sponges can be soaked in thrombin to help promote coagulation directly. Surgicel should not be soaked in thrombin, because the biologic agents will be inactivated in the low-pH environment.

Question 98

T/F: The low pH of Surgicel may also lead to tissue inflammation and delayed wound healing.

Answer 98

True; The low pH may also lead to tissue inflammation and delayed wound healing, so any excess product should be removed from the surgical site.

Question 99

How quickly is Surgicel absorbed?

Answer 99

Surgicel is absorbed in 7 to 14 days, although residue from the material may persist for several months to years.

Question 100

These hemostatic agents are derived from bovine dermal collagen, and are available in fibrous (flour), sheet, and sponge forms.

Answer 100

Microfibrillar collagen agents (Avitene, Instat)

Question 101

How quickly are microfibrillar collagen agents (Avitene, Instat) absorbed?

Answer 101

8 to 10 weeks

Question 102

What is the mechanism of action for microfibrillar collagen agents (Avitene, Instat)?

Answer 102

Platelets adhere to the collagen and are activated, and the resultant platelet degranulation and aggregation lead to hemostasis. These products do not rely as much on their mechanical effect as does Gelfoam. They do bind tightly to the bleeding surface, so there is likely some mechanical blockage of injured vessels.

Question 103

T/F: Microfibrillar collagen is an appropriate hemostatic agent for use in patients with thrombocytopenia or with contaminated wounds.

Answer 103

False; Microfibrillar collagen relies on platelet adherence, degranulation. and aggregation to lead to hemostasis. It can also interfere with bacterial clearance and wound healing, and it is therefore recommended that it be removed from the surgical site before closure of the wound.

Question 104

These hemostatic agents have a porous surface that allows absorption of blood, thereby concentrating platelets and coagulation factors and reducing the time required for coagulation.

Answer 104

Microporous polysaccharide hemispheres (TraumaDex, chitosin)

Question 105

T/F: Microporous polysaccharide hemispheres (TraumaDex) is absorbable and does not appear to inhibit wound healing.

Answer 105

True

Question 106

_________ ____ is composed of beeswax and petroleum jelly and is used to control bleeding from bone surfaces.

Answer 106

Bone wax

Question 107

What is the mechanism of action of bone wax?

Answer 107

Bone wax mechanically stops blood flow from vessels in bone, and it does not have any biologic hemostatic effect.

Question 108

T/F: Bone wax is safe to use in long bone fractures and in contaminated wounds.

Answer 108

False; Bone wax inhibits bone healing, so it should not be used when fracture union is desired. It has also been shown to inhibit bacterial clearance from cancellous bone, and therefore it should not
be used in areas of bacterial contamination or infection.

Question 109

T/F: Bone wax has been reported to cause adverse effects such as allergic reaction, granulomatous reaction, and embolization.

Answer 109

True

Question 110

Name 5 common mechanical hemostatic agents.

Answer 110

1. Purified Gelatin Sponge
2. Oxidized regenerated cellulose (Surgicel)
3. Microfibrillar collagen agents (Avitene, Instat)
4. Microporous polysaccharide hemispheres (TraumaDex, chitosin)
5. Bone wax

Question 111

T/F: Fibrin sealants do not require that the patient have normal platelets or coagulation factors.

Answer 111

True; Fibrin sealants replicate the last stage of coagulation and do not require that the patient have normal platelets or coagulation factors.

Question 112

T/F: Fibrin sealants are biodegradable and have not been associated with tissue inflammation or foreign body reaction.

Answer 112

True

Question 113

These products are applied directly to the tissue and promote hemostasis by adhesion and formation of a fibrin clot, reducing the size of the open bleeding defect.

Answer 113

Fibrin-based sealants

Question 114

When would it be appropriate to apply topical hemostatic agents?

Answer 114

Topical hemostatic agents are needed for control of diffuse capillary bleeding from bone or parenchymal organs, such as liver or spleen.