Hemostasis/Coagulopathies (Self-Made) Flashcards
What is primary hemostasis?
Platelet plug formation
What factors are contained within the alpha granule of a platelet?
- PDGF
- Transforming growth factor Beta
- Fibrinogen
- VWF
- PF4
- Factor V
Where can vWF be found?
- Endothelial cells
- Platelets
What are the primary functions of vWF?
- Binding to endothelium to promote platelet adhesion.
- Plasma carrier for Factor VIII, preventing its degradation.
- Binds to exposed collagen.
How does the extrinsic pathway of coagulation work?
7 => 10 => 5 => 2 => 1
How does the intrinsic pathway of coagulation work?
12 => 11 => 9 & 8 => 10 => 5 => 2 => 1
What is the driving force to convert prothrombin?
Prothrombin activator, which is Factor 10.
If I am vitamin K deficient, what factors/proteins are affected?
2, 7, 9, 10, protein C & S
What demograpic is especially susceptible to Vit K deficiency?
Newborns
What are the two ways the intrinsic pathway can be triggered for coagulation?
- Trauma to the blood vessels themselves.
- Exposure of blood to collagen.
What kind of chronic organ disease would impair blood coagulation? Why?
Liver disease, since prothrombin is manufactured by the liver.
Also affects fibrinogen production.
What is the most abundant coagulation protein?
Fibrinogen
What does heparin act on?
Anti-thrombin III
AT3 inactivates thrombin & 10a (Primary)
Also inactivates 9a & 11a (secondary)
AKA intrinsic pathway inhibition
What does a D-dimer measure?
The degradation products created from breakdown of fibrin by plasmin.
What does the protein C&S complex primarily inhibit?
Thrombin and 8a.
What compound inhibits coagulation of blood products?
Sodium citrate
What antibodies does a person with AB blood have? A blood?
AB: no antibodies present.
A: anti-B antibodies present.
Does Rh+ mean it has antigens or antibodies?
Antigens.
Why is a type and screen ordered? What is its function?
- Determines the receipient’s ABO and Rh phenotype. (Type)
- Identifies any antibodies that may directed against other antigens (Screen)
When is a cross-match not ordered? What is it?
Not ordered in emergency settings due to the time it takes.
Mixes donor blood with receipient blood to ensure a match.
Checks agglutination.
A patient presents to the ER with acute blood loss due to a 5cm laceration on their arm. The bleeding is controlled via applied pressure. They are mildly hypotensive, and CBC reveals a Hgb of 8.5. The patient has no other symptoms currently. Should they be transfused PRBCs? Why or why not?
No.
Given the lack of any other symptoms (esp. lack of CV symptoms) and her Hgb of 8.5, she is not indicated to require a PRBC transfusion.
If she was still having an ongoing bleed that was not stopping, PRBCs should be considered to stabilize her hemodynamically.
A patient presents to the ER with acute blood loss due to a 5cm laceration on their arm. The bleeding is not controlled via applied pressure. They are mildly hypotensive at the moment, and CBC reveals a Hgb of 7.5. The patient has no other symptoms currently. She is transfused 1 unit PRBCs, but during the transfusion, she begins to feel very chilly and starts itching her leg. Her temperature goes up to 38.3F from a baseline of 37C. What is the next step in her management?
Stop the transfusion, report it to the blood bank, and administer tylenol to bring her fever down.
Always stop transfusion if an acute reaction is suspected.
What is the benefit of whole blood transfusion and the primary reason it is not used commonly?
It offers the greatest oxygen affinity within its RBCs.
However, it is difficult to store due to RBCs requiring a temperature that platelets and clotting factors become degraded in.
A patient requires a unit of PRBCs for transfusion. They are noted to be immunodeficient and have a history of GVHD. What modification should be made to their PRBC transfusion order?
Irradiation of PRBCs.
What blood type is a universal receipient for plasma?
O blood type can receive any plasma from any blood type.
Plasma only has antibodies.
What is the chief advantange of cryoprecipitate over FFP?
Smaller volume overall, but high concentrations of vWF, F8, F13, and fibrinogen
For a patient with a platelet count of 140k, what would prompt us to transfuse them?
Ongoing bleeding + platelet dysfunction (disease or drug-induced)
What can reverse heparin?
Protamine sulfate.
How does DDAVP/Desmopressin work?
Increases plasma levels of vWF, F8, and tPA, shortening aPTT and bleeding time.
When is topical thrombin contraindicated?
- Known sensitivity to bovine products
- Massive bleeding
- Large vessel bleeds
A patient is admitted to the hospital with a hx of ESRD on dialysis. The hospitalist wants you to order an anticoagulant for them. What would be the best option for a parenteral anticoagulant?
Unfractionated heparin, which is cleared hepatically.
What hypersensitivty reaction type is heparin induced thrombocytopenia?
Type 2 antibody-mediated.
What risk factors are associated with HIT?
- Use of UFH in surgical patients
- Females
What is the classic presentation of HIT?
- A drop of platelet count > 50% from baseline or new onset thrombocytopenia 5-10 days after beginning heparin.
- Acute systemic reactions
- Necrotic skin lesion at heparin injection site.
After HIT is suspected, what steps should be taken?
- STOP heparin.
- Confirm HIT via HIPA, serotonin release assay, and Heparin-PF4 Ab ELISA.
- Switch to argatroban if AC still required.
What are the primary differences between UFH and LMWH?
- UFH is hepatically cleared; LMWH is renally cleared.
- UFH has broad activity and binds to 10a directly; LWMH has far higher inhibition of 10a by AT3 binding.
- LWMH can be given SC in the abdominal wall.
- LWMH must be monitored via anti-F10 levels, not aPTT.
If a patient is pregnant and requires AC, what is the best medication?
LMWH