CV Function in Pathology - Nordgren Flashcards
What is circulatory shock?
Generalized, severe reduction in blood supply to the body tissues.
- metabolic needs of tissues not met
- arterial pressure usually low
What are the primary disturbances that can account for cariogenic, hypovolemic, anaphylactic, septic, and neurogenic shock states?
- Severely depressed myocardial functional ability
- cardiogenic shock
- Grossly inadequate filling due to low mean circulatory filling pressure
- hypovolemic shock
- Profound systemic vasodilation
- anaphylatic shock
- septic shock
- neurogenic shock
What are the compensatory processes that may arise during various types of circulatory shock?
- Greatly increased sympathetic nerve activity
- pallor, cold/clammy skin, rapid HR, muscle weakness, venous restriction
- Abnormally low arterial pressure, reduced cerebral perfusion –> dizziness, confusion, LOC
- Rapid/shallow breathing –> increase VR (respiratory pump)
- Increased levels of epinephrine
- Reduced capillary hydrostatic pressure resulting from intense arteriolar constriction –> reabsorption
- Increased glycogenolysis in the liver (via Epi/NE)
What are the renal compensatory processes that may arise during various types of circulatory shock?
- Increased RENIN release →
- increased TPR via formation of angiotensin II (vasoconstriction)
- Increased circulating levels of ADH →
- increased TPR (fluid retention)
- Increased circulating levels of Aldosterone →
- Na+ & fluid retention
What are the decompensatory processes that may arise during shock and describe how these lead to irreversible shock states?
- Arteriolar vasoconstriction
- can lead to severely reduced perfusion of other tissues → possibly damage organs
- Bodily homeostasis deteriorates with prolonged reductions in organ flow
- adversely impacts CV system → further reduces flow
How may coronary artery disease lead to abnormal cardiac function?
- Atherosclerosis of the large coronary arteries leads to:
- permanently increased vascular resistance → reduced coronary flow
- arrhythmias
- heart failure
- MI
What is the difference between Progressive shock and Irreversible shock?
- Progressive:
- general CV situation progressively degenerates
- Irreversible:
- no intervention can halt the ultimate collapse of the CV system → DEATH
Define the term “heart failure”.
Depressed ventricular function due to myocardial damage, insufficient coronary flow, or anything that directly impairs mechanical performance.
What is the difference between systolic and diastolic failure?
- Systolic:
- Left ventricular EF <40% (reduced CO at any given filling pressure)
- Reduced myocyte function
- 1° disturbance = decreased CO → decreased arterial pressure
- cause edema & congestion
- Diastolic:
- stiffened heart during diastole
- increases in cardiac filling pressure do not produce normal increases in EDV
What are the short-term and long-term compensatory processes that accompany chronic systolic heart failure?
- Short-term:
- Increased sympathetic activity
- Rapid breathing
- Long-term:
- Rise in blood volume (renin release)→ increased mean circulatory filling pressure
- Fluid retention causes increased peripheral and central venous pressures
- cardiac dilation → increased myocardial O2 demand
What are the advantages and disadvantages of the fluid accumulation that accompanies systolic heart failure?
- Pro:
- ↑sympathetic activity (short-term) → ↑blood volume → ↑mean circulatory filling pressure
- ↑CO closer to normal and allows reduction of sympathetic activity
- when enough fluid has been retained, normal CO can be achieved with normal sympathetic nerve activity
- CON:
- fluid retention → ↑ peripheral and central venous pressure → chronically high EDV
- causes excessive cardiac dilation → impairs function due to ↑ total wall tension/stress required to generate adequate pressure
- increased myocardial O2 demand
- fluid retention → ↑ peripheral and central venous pressure → chronically high EDV
What is the difference between pulmonary and systemic arterial hypertension?
- Pulmonary:
- pulmonary artery pressure >20mmHg
- systemic edema, chest pain, fatigue
- linked to chronic hypoxia (COPD, cystic fibrosis)
- Systemic:
- elevation of mean systemic arterial pressure > 140/90 mmHg
- >20% of adult western world pop’n
- increased risk of CAD, MI, heart failure, stroke, etc.
- primary OR essential