Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Coagulation > Clotting Times > Flashcards

Clotting Times Flashcards

1
Q

what is activated clotting times?

A

length of time required for whole blood to clot when exposed to an activate particle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the particles that blood is exposed to in ACT

A

kaolin
celite
glass
other negatively charged surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the activator for the ACT test

A

celite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

contact activating is used for which factor

A

F12

Hagemann

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are ACTs used for (3)

A
  • assess the status of the pt’s overall hemostatic mechanism
  • monitor the anticoagulant effect of various drugs used to modify the ability of a pt’s blood to form a clot
  • determine the pt’s hemostatic status following reversal of heparin with protamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

historically, ACT are used to

A

manage heparin anticoagulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

minimum standard of care for heparin management is based on

A

the Lee and White test tube based procedure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

First activated whole blood clotting time was described by who

A

Hattersley (1966)

  • activate factor XII
  • used to accelerate clot formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

ACT testing is required when….

A

CPB

minimum standard of care for monitoring anticoagulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

ACTs performed when (regarding in surgery).

A
  • prior to bypass (baseline)
  • every 20 to 30 minutes on bypass
  • following reversal with protamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ACTS are also performed (outside of surgery)

A
  • ECMO: done every 2-4 hrs
  • ICU/CCU: every 4-6 hrs during therapeutic heparinization
  • IR
  • VAD
  • hemodialysis
  • cardiac catheterization: following anticoagulant admin and prior to pulling the sheath
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the earliest activator used for ACT test

A

Celite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is prolonged ACT results caused by?

A
  • factor deficiency: congenital and acquired
  • hemodilution (CPB)
  • rapid consumption of clotting factors (DIC)
  • warfarin (Coumadin)
  • heparin
  • hypothermia
  • very low platelet count (need platelets to make a clot)
  • abnormal platelet function/platelet inhibitors (aspirin, plavix)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is normal ACT result

A

80-120

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what can cause shortened ACT results?

A
  • activation during sample collection: intro of tissue activator, venous access through a hematoma, slow syringe fill
  • delay in initiation of test following specimen collection: 60 sec for unanticoagulated sample, 120 sec for heparinized sample
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

i-Stat device for ACTs

A
  • synthetic substrate that reacts with thrombin

- does not measure clot formation

17
Q

what does heparinase ACT confirm

A

presence of heparin in a blood sample while performing HR-ACT

18
Q

what does heparinase ACT look at

A
  • presurgical assessment for presence of heparin
  • confirm heparin reversal following protamine
  • confirm heparin rebound
  • identify the presence of heparin in a pt with post-operative bleeding
19
Q

effect of CPB on hemostasis

A
  • HEMODILUTION
  • HYPOTHERMIA
  • factor 7/tissue factor activation
  • contact activation
  • kinin generation
  • complement activation & systemic inflammatory response
  • shear stress (platelet activation)
  • fibrinolysis
  • anticoagulation/reversal
20
Q

anticoagulant

A

ability to prolong coagulation

21
Q

antithrombotic

A

ability to inhibit thrombus formation

22
Q

detrimental effects of inadequate heparin dosing during CPB

A
  • activation of the coagulation proteins, platelets, and inflammatory system
  • generation of excess thrombin
  • increased post-operative bleeding
  • increased risk to patient associated with transfusion
23
Q

Heparin management with the HMS plus

A
  • heparin dose response (HDR)
  • heparin protamine titration (HPT)
  • high range ACT (HR-ACT)
24
Q

heparin dose response (HDR)

A
  • simultaneous evaluation of pt’s in-vitro response to multiple heparin doses
  • projects dose of heparin required to increase pt’s ACT to the user defined target
  • identify pt’s who are resistant to heparin
25
Q

if you have a HDR result of less than 80

A

resistance to heparin

26
Q

if you have a HDR more than 120

A

HIT?

27
Q

high slope in HDR means…

A

sensitivity

28
Q

mechanisms for heparin resistance

A
  • AT3 deficiency
  • IV nitroglycerine
  • elevated levels of heparin binding proteins
29
Q

congenital AT3 deficiency for heparin resistance is how common in population

A

rare <0.5%

30
Q

aquired AT3 deficiency for heparin resistance is how common in population comes from

A
  • pre-operative heparin
  • renal failure
  • liver disease
  • increased consumption
  • during CPB
31
Q

pediatric AT3 deficiency for heparin resistance has what characteristics

A
  • decreased AT3 synthesis

- higher RBC mass

32
Q

how do you get IV nitroglycerine heparin resistance

A

high dose with levels of >350 ug/min

33
Q

elevated levels of what heparin binding proteins can be a mechanism for heparin resistance

A
  • PF4
  • extracellular proteins
  • growth factors
  • enzymes
  • factor VIII/vWF
34
Q

what does an HMS plus HR-ACT tell us

A
  • global picture of patient’s function coagulation status
  • accepted test to indicate heparin effect
  • information regarding individual patient response to heparin
35
Q

what are some limitations of ACT during CPB

A
  • not specific to heparin (hemodilution, hypothermia, congenital deficiencies, lupus anticoagulant)
  • insufficient for determining protamine dose
  • questionable as sole indicator of heparin reversal
36
Q

what does HMS plus heparin protamine test (HPT) tell us

A
  • heparin concentration (specific and quantitative)
  • maintain constant heparin concentration
  • basis for determining appropriate protamine dose
  • quantitative verification of heparin neutralization
37
Q

if there is too much protamine, what will you see in the ACT level?

A

rise of ACT level

38
Q

results of good anticoagulation management (8)

A
  • minimize thrombin generation
  • preserve clotting factors
  • reduced platelet activation
  • decrease post-op bleeding
  • decrease blood product utilization
  • fewer surgical reps
  • fewer complications
  • improved pt outcomes
39
Q

anticoagulation management is part of a multimodality approach to (3)

A
  • minimize peri-operative blood transfusion
  • improve outcomes in cardiac surgery
  • STS/SCA guidelines

Coagulation (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions