Chapter 11 Cardiovascular function in pathological situation

Question 1

Pulmonary hypertension is called when mean pulmonary artery pressure is greater than **** mmHg

Answer 1

25mmHg

Question 2

True or False?

Treatment for systemic hypertension has a fairly good effect on pulmonary hypertension

Answer 2

Treatment of systemic hypertension have had little or no effect on the pulmonary bed.

Question 3

Explain the pharmacologic effect of phosphodiesterase-5 inhibitors such as sildenafil.

Answer 3

PDE5 inhibitors prevent cyclic GMP(guanosine monophosphate) breakdown, thus promoting the vasodilating effects of nitric oxide

Question 4

Once hypertension is established, what are changes in peripheral resistance, cardiac output and blood volume?

Answer 4

Total peripheral resistance Increases
Cardiac output and blood volume may be elevated during the early phase but usually normal after the hypertension is established.

Question 5

True or false?
The urinary output rate is influenced by arterial pressure.
So in the long tern, arterial pressure can stabilize only at the level that makes urinary output rate less than fluid intake rate

Answer 5

False

arterial pressure can stabilize only at the level that makes urinary output rate equal to fluid intake rate

Question 6

4 therapeutic strategies for treating systemic hypertension

Answer 6

1. restricting salt intake to reduce water retention
2. diuretic therapy - by inhibiting renal tubular salt reabsorption, urinary output rate for a given arterial pressure is increased. It would raise the renal function curve.
3. ACE inhibitors
   - blocking vasoconstrictor angiotensin II
4. alpha adrenergic receptor blockers (prazosin)
   - prevent the vasoconstriction from catecholamines
5. calcium channel blockers (amlodipine)
   - directly decrease vascular muscle tone

Question 7

Definition of shock

Answer 7

generalized, severe reduction in blood supply to the body tissue and the metabolic needs of the tissuse are not met

Question 8

Three cardiovascular crises that precipitate shock

Answer 8

1. depressed myocardial functional ability
2. decreased preload
3. decreased afterload

Question 9

Types of shock presented in Chapter 11

Answer 9

1. Cardiogenic shock
2. Hypovolemic shock
3. Anaphylactic shock (what mediators are involved in anaphylactic shock? 1. histamine, 2. prostaglandin, 3. leukotrine, 4. bradykinin
4. septic shock
5. Neurogenic shock

Question 10

What is the most common substance released into circulating blood by infective agents?

Answer 10

lipopolysaccharide (endotoxin) released by bacteria. This induces the formation of iNOS (inducible NO synthase from where? endothelium, vascular smooth muscle, and macrophages)

Question 11

What are the 2 things responsible for triggering medullary cardiovascular centers in respone to decreased mean arterial pressure?

Answer 11

1. decreased activity of arterial baroreceptors

2. cerebral ischemic response

Question 12

What is the main compensatory response from shock?

Answer 12

increases in sympathetic activity, decreased parasympathetic activity

Question 13

What are additional compensatory processes?

Answer 13

1. Rapid and shallow breathing (resp pump) to promote venous return
2. Increase renin release from kidney from sympathetic stimulation, AG2 vasoconstriction
3. Increased vasopressin from posterior pituitary gland
4. increased epi and NE from adrenal meculla
5. intense arteriolar constriction- reduced capillary hydrostatic pressure- promote fluid movement from the interstitial space into the vascular space
6. epi/NE induced glycogenolysis in the liver- release of glucose and a rise in blood/interstitial glucose level, rise in extracellular osmolarity by 20 mOsm, induced a shift of fluid from IC into EC space
   “autotransfusion” include number 5 and 7- increase 1 L into the vascular space in the first hour- decreased HCT in hemorrhagic shock, this extent of fluid shift may be limited by a reduction in colloid osmotic pressure

Question 14

What are the long term effects of hypovolemic states trigger fluid retention mechanism?

Answer 14

1. RAAS

2. ADH

Question 15

What are the stages of shock in this chapter

Answer 15

1. compensatory (inadequate perfusion to renal, hepatic, and GI)
2. decompensatory
3. progressive stage
4. irreversible stage

Question 16

What is positive feedback process?

Answer 16

Decompensatory mechanism: reduced arterial pressure leads to alteration that further decrease arterial pressure rather than correct it

Question 17

Treatment of coronary artery disease

Answer 17

1. nitrite (quick acting vasodilator)
2. beta-adrenergic blocking agents
3. calcium channel blockers