Hemodynamics Flashcards
What are considered fluid flow?
- edema
- hyperemia & congestion
- hemostasis
- thrombosis
- embolism
What are considered vascular disorders?
- hypertension
- arteriosclerosis
- aneurysms
- ischemic heart disease
- anomalies of heart
What is edema?
increased hydrostatic pressure or decreased colloidal osmotic pressure increases fluid movement into tissues
What are the causes of edema?
- increased hydrostatic pressure
- reduced plasma osmotic pressure
- lymphatic obstruction
What are the types of edema?
- exudate: high protein content
- transudate: low protein content
- subcutaneous: below heart where hydrostatic pressure is high
- pulmonary: renal failure, CAD, inflammation
- brain: increased intracranial pressure causes abnormal herniation of brain tissue
What is hyperemia & congestion?
- both: increased blood volume in tissue
- hyperemia: active increase is blood volume
- congestion: passive increase blood volume; have cyanosis
What is hemostasis?
- maintaining blood; clot free state
- vasoconstriction & release endothelin
- glycoprotein 1B to adhere to ECM vWF
- promotes platelet aggregation=primary hemostasis
What occurs in platelet adhesion?
mediated by Gp1b platelet surface receptor to collagen bound vWF
What occurs in platelet activation & aggregation?
- confromational change
- secrete thromboxane A2
- platelet plug stability with fiubrin clot=secondary hemostasis
What occurs duing secondary hemostasis?
- release of tissue factor 3
- thrombin production
- fibrin clot
What occurs during antithrombotic counterregulaiton?
- counter regulatory mechanisms
- plasminogen activator & thrombomodulin
What are the key players in the endothelium pro-thrombotic process?
- tPAI
- vWF
- tissue factor 3 thromboplastin
What are the key players in the endothelium anti-thrombotic process?
- NO
- prostaglandin I2
- tPA
- thrombomodulin
- tissue factor inhibitor, heparin
What is the coagulation cascade?
- product is thrombin to drive fibrin clot
- co-factor: Ca++
- intrinsic & extrinsic pathways activate factor X
What is the fibrinolytic system?
- coagulation inhibited by activation of fibrinolytic apthway
- remodeling of fibrin clot
- driven by tPA
- serum plasmin inactivated by alpha 2-anti-plasmin
What are the roles of thrombin in hemostasis?
- platelet aggregation
- endothelial activation
- leukocyte activation
What are the chracteristics of hemorrhage?
- characterized by gross morphologic appearance
- can be internal or external
- bleeds into cavities-> hemothorax, hemopericardium, hemoperitoneum, hemathrosis (joints)
- petechiae= 1-2 mm
- purpura= 3-5 mm
What are ecchymoses and hematomas in hemorrhages?
- eccy: bruises >10mm caused by trauma
- hema: solid collections of coagulated blood
What are the 4 types of shock?
- cardiogenic: low cardiac output d/t myocardial pump failure
- hypovolemic: loss of blood or plasma reducing cardiac output
- anaphylactic: loss of blood/plasma reducing cardiac output d/t vasodilation
- septic: excessive vasodilation
What are the 3 abnormalities that contribute to thrombosis?
Virchow’s triad
* endothelial injury
* genetic/acquired conditions
* turbulent blood flow/stasis
What are thrombi?
- anywhere in vascular system
- arterial & cardiac -> endothelial injury
- mural: heart chambers & aorta
- arterial: grow in retrograde (opposite of flow)
- venous: develop at stasis; anti-retrograde (direction of flow)
What are the significances of thrombi?
- superficial venous thrombi: rarely embolize, painful, swelling
- deep vein thromboses: in larger leg veins, embolize to lungs
What are the types of systemic embolism?
- fat: from bone fracture
- amniotic fluid: during labor
- air: in some surgeries, nitrogen into bloodstream
- septic: live bacteria; in bacterial endocarditis
- athero: disruption of atherosclerotic plaque
What do infarction and ischemia lead to?
- infarction & ischemia -> coagulative necrosis
- iscehmic infarcts in CNS -> liquefactive necrosis
- restored by reperfusion
What are red & white infarcts?
- red: venous congestion, loose tissue with space for blood
- white: arterial in solid organs with end-arterial circulation; wedge shaped
What are the clinical impacts of infarction?
- anatomy of vascular supply
- hypoxemia
- rate of occlusion
- tissue susceptibility to ischemia
What is blood pressure?
- cardiac output & vascular resistance
- renal Na+ excretion/resorption
- caused by reduced renal Na or increased vascular resistance
What is arteriosclerosis?
- small arteries & arterioles in pts with hypertension or diabetes
- Monckeberg’s: dystrophic calcification of media; does not result in significant luminal narrowing
What is hyaline arteriosclerosis?
- diabetes
- thickened arterial walls by protein deposit
What is hyperplastic arteriosclerosis?
- SM cells in media of small arteries (onion like)
- fibrinoid necrosis
What are the constitutional & modifiable risk factors of atherosclerosis?
- constitutional: family genetics, age, male, obesity
- modifiable: lyperlipidemia, hypertension, smoking, obesity
What is the pathogensis of atherosclerosis?
- thick intimal layer depends on endothelial cell injury hemodynamic disturbance, lipids
- SM cells -> foam cells
- fatty streak -> early atherosclerotic deposition
- plaques enlarge -> obstruction to vascular flow
- hypoxia occurs
What are aneurysms?
- true: involve all 3 layers of vessel
- false: blood leaks completely out of artery or vein
What is an abdominal aortic aneurysm?
- b/w renal arteries & aortic bifurcation
- associated with atherosclerosis
- vascular occlusions, embolism, rupture, impingement
What is a thoracic aortic aneurysm?
- associated with hypertension & Marfan syndrome
- result fo compression of mediastinal structures
What are aortic aneurysms?
- intimal tear
- results in masive hemorrhage or cardiac tamponade
- double-barreled aorta
- end-organ infarction
What are the types of aortic dissections?
- type A: ascending aorta (brian damage)
- type B: descending aorta (brain function is ok)
What are the abnormalities of the heart?
- failure of heart pump -> ischemic heart disease
- shunted flow -> patent foramen ovale
- regurgitation/obstructed valve flow -> calcific aortic stenosis
- disorder of cardiac conduction -> arrythmias
What is ischemic heart disease?
- myocardial ischemia
- results from coronary artery blood flow
- common clincal syndromes: angina, heart attack, chronic ischemic heart disease
What is angina?
- recurrent, reversible myocardial ischemia
- stable: CP & SOB precipitated by exertion or nitroglycerin
- unstable: CP & SOB at rest; plaque change; can progress ot transmural heart attack
- PRinzmetal’s: uncommon; pain at rest d/t coronary vasospasm
What are the types of MI tissure injury?
- transmural (full wall thickness)
- subendocardial more susceptible to damage
What are the biomarkers of MI?
- creatin kinase-MB
- cardiac troponin
What is the patent foramen ovale?
- persistent right to left atrial flow
- hypoxemia
- increase risk of DVT
What is valvar heart disease?
- heart valves lack vasculature
- bacterial infection
What is calcific aortic valve stenosis?
- on older pts
- calcification
- left ventricular hypertrophy
What does a cardiac conduction require?
atrioventricular node, bundle of his, right & left branches
What are the stages of a basic ECG?
- P wave: polarization
- PR interval: conduction is normal
- QRS: depolarization
- ST: flat plateau
- T: repolarization
