Quiz 10 Flashcards
Do platelets have a nucleus?
no- they cannot reproduce
What does a TEG measure?
process of clot formation over time
What are the physiologic effects of a pneumoperitoneum?
bradycardia (can pretreat with glyco), CO2 absorption, decreased ventilatory ability
What is factor 4?
calcium
Platelets are mostly inactive until?
vessel injury
What receptors are on platelets?
GPIIb-IIIa, thrombin, TxA2, ADP, and GPIb
Where are platelets formed? What is the normal value and what is their normal lifespan?
megakaryocytes in bone marrow; 150-300k, 8-12 days
What is on the external membrane of platelets? What do they do?
glycoproteins- repelled by healthy endothelium, adheres to injured endothelium, collagen and fibrinogen
phospholipids- substrate for prostaglandin synthesis (produces thromboxane A2 which activates platelets)
What does the severity of thalessemia depend on ?
number of gene deletions
What is normal fibrinogen levels?
150-350 mg/dL
What is factor 13?
fibrin stabilizing factor
What does thrombin time measure? What is normal?
fibrinogen-to-fibrin reaction (8-12 seconds)
What is factor 2?
prothrombin
What does D dimer measure? What is normal?
degradation products secondary to fibrinolysis- <500 mg/ml
When is the extrinsic pathway activated?
when coagulation is initiated outside intravascular space
What are the 4 steps of hemostasis?
1) vascular spasm
2) formation of platelet plug (primary hemostasis)
3) coagulation and formation of fibrin (secondary hemostasis)
4) fibrinolysis when the clot is no longer needed
What is factor 1?
fibrinogen
What is factor 12?
Hageman factor
What are some complications that may occur during the establishment of a pneumoperitoneum?
vascular injury (venous bleeding might show up late due to tamponade from pneumoperitoneum), gas embolism, visceral injury, pneumo, subQ emphysema
If somebody just has sickle cell trait, when might sickling occur in terms of PaO2?
<20 mmHg
Why should you be conservative with your fluids if the patient is in Trendelenberg?
excess fluid can cause facial and airway edema, may increase IOP (blindness)
What is factor 5?
labile factor
Why is CO2 the gas used for laparascopic surgery?
inexpensive, does not support combustion, readily absorbed from the vascular system, and readily excreted by the pulmonary system
What do you give Dani if she ever comes in as a trauma?
platelets
At what platelet level do patients have a surgical risk? what about spontaneous bleeding?
<50k surgical risk, <20k spontaneous bleeding
When is the intrinsic pathway activated?
when coagulation is initiated inside intravascular space
What is factor 10?
Stuart-Prower factor
What are some drugs that decrease bleeding?
Amicar, TXA, DDAVP, protamine, Vitamin K
What does aPTT measure and what is normal?
intrinsic and common pathway disorders; 25-32 seconds
If somebody has sickle cell anemia, when might sickling occur in terms of PaO2?
30-40 mmHg
What factors are in the final common pathway?
5, 10, 1, 2, 13 (the FCP can be purchased at the five and dime for 1 or 2 dollars on the 13th of the month)
What is the mnemonic for coagulation factors?
foolish people try climbing long slopes after christmas some people have fallen
What is factor 7?
stable factor
What is factor 3?
tissue factor
What do platelets work in conjunction with in the coagulation cascade?
plasma proteins
What is factor 9?
Christmas factor
What is an example of fibrinolytics? Does it increase or decrease bleeding?
increases bleeding- tPa, streptokinase
What are the 3 lines of defense that are impaired for GERD to develop?
LES barrier impairment, decreased clearance of refluxed materials from esophagus, decreased esophageal mucosal resistance
What factors are in the extrinsic pathway?
3, 7 (you can buy the extrinsic pathway for 37 cents)
What are some drugs that lower LES tone?
alpha adrenergic agonists, anticholinergics, beta adrenergic agonists, CCBs, diazepam, dopamine, meperidine, nitrates and other vasodilators, estrogens/progesterones, prostaglandins, theophylline
What is factor 11?
plasma thromboplastin antecedent
What are some examples of antiplatelet drugs? Do they increase or decrease bleeding?
increase bleeding- ADP receptor inhibitors (clopidogrel), GpIIb/IIIa receptor antagonists (abciximab), COX 1-2 inhibitors (ASA, NSAIDs)
What does ACT measure? What is normal?
ability to clot- 80-150 seconds
What occurs during adhesion?
vWF emerges from endothelin, GIb receptors emerge from platelets and attach to vWF (attracts platelets), and vWF makes platelets sticky
What occurs during activation?
platelet undergoes conformational change (swells and becomes oval/irregular), glycoproteins IIb/IIIa project themselves outward on platelet and link other platelets to form plug
What should you do before extubating a patient who has been in Trendelenberg position?
Ensure there is an air leak after deflating the cuff- evaluates for airway edema
What are the 3 types of vWD?
type 1- reduced vWF
type 2- abnormal vWF
type 3- complete absence of vWF
What should you keep Hct in somebody with sickle cell disease?
30-35%
What are some triggers for sickle cell crisis?
pain, hypothermia, hypoxemia, acidosis, dehydration
What lab values evaluate the extrinsinc and common pathway? What is normal?
INR (1.5-2.5 seconds) and PT (12-13 seconds)
How much must factor decrease by before PT and aPTT is prolonged?
30%
What is normal fibrinogen degradation products?
<10 mcg/mL
What is on the inside of the platelet and what do they do? (7 things)
actin and myosin (contracts platelet to form plug), thrombosthenin (contraction), ADP (activation and aggregation), calcium (multiple functions), fibrin stabilizing factor (crosslinks fibrin), serotonin (activates nearby platelets), growth factor (helps repair damaged vessel walls)
What factors are in the intrinsic pathway?
12, 11, 9, 8 (if you can’t buy the intrinsic pathway for $12, you can buy it for 11.98)
What are some things that can lower LES tone?
food bolus, LMA, pregnancy, certain drugs
What do plateletes produce?
thrombin
What are s/s of a gas embolism? How do you treat?
hypotension, dysrhythmia, hypoxia, pulmonary edema, mill wheel murmur;
d/c insufflation and release pneumoperitoneum, 100% FiO2, L lateral decubitus, central line to aspirate air bubble
What occurs during aggregation?
platelets release granules to promote procoagulant activity which forms unstable clot (primary plug is enough for hemostasis if injury is minute)
What is factor 8?
antihemophilic factor
What clears platelets?
macrophages in the reticuloendothelium system and the spleen
What are some examples of anticoagulants? Do they increase or decrease bleeding?
increase bleeding- heparins, thrombin inhibitors (argatroban), factor 10 inhibitors, Vit K antagonists (warfarin)
What is the open vs closed technique for establishing a pneumoperitoneum?
open- Hasson technique with incision
closed- Veress needle
Why might you have decreased urinary output in laparoscopic procedures? Should you give them fluid?
compression of kidneys and IVC, increased levels of ADH; no
What normally inhibits platelet function?
prostaglandin I2 and nitric oxide secreted by the endothelium
What is the difference between sickle cell trait and having sickle cell anemia?
sickle cell trait is heterozygous (AS genes) where both HbgA and S is present- asymptomatic
sickle cell anemia is homozygous (SS genes) where majority of Hgb is S
