26 Cardiovascular Adaptation Flashcards
What are the 4 types of circulatory shock?
1) hypovolemic
2) distributive (Low TPVR, sepsis, anaphylaxis)
3) cardiogenic (low CO, MI, valvular disfunction)
4) obstructive (cardiac tamponade, P. embolism)
What is heart failure?
failure of the heart to pump enough blood to satisfy the needs of the body at normal filling pressures. It can be left or right sided.
What are some common causes of heart failure?
MI
chronic hypertension
valvular heart disease
AV shunts
what is circulatory shock?
a state of inadequate tissue perfusion and oxygenation that is not always associated with hypotension.
Why is central blood volume important?
central blood volume correlates with measurements of right atrial pressures and cardiac preload.
What does hemorrhage do the the cardiac function curve?
It makes you slide downward on the same slope. Recall that decreasing preload does the same thing, so these are the same.
What are some factors that restore BP and CO?
increasing TPVR
increasing HR
increasing contractility
increasing central blood volume
what is the function of cardiopulmonary vagal afferents?
To sense decreases in cardiac filling pressures
what is the function of arterial baroreceptors?
to sense decreases in arterial BP
If there is a decrease in afferents from the baroreceptors and cardiopulmonary vagal receptors, what happens?
There is an increase in SNA, and decrease in paraSNA.
There is also a release of vasopressin, epi, & norepi.
What is the Bezold Jarisch reflex?
overcompensation of the body that results in inhibition of SNA, activation of paraSNA, and worsening of hypotension. (Usually occurs with hemorrhage)
what releases renin and why?
1) juxtaglomerular cells in the kidney in response to low blood flow
2) SNA
What does renin do?
increases the formation of angiotensin I from angiotensinogen. Ace then converts angiotensin I to angiotensin II with release of aldosterone.
what does contractility do to the cardiac function curve?
it shifts it up and to the left leading to increased SV and CO without increasing preload.
T/F An increase in contractility results in decreased preload?
true because more is being pumped out.
what is the effect of increasing SNA to the veins?
decreased venous compliance and increased central blood volume.
what does decreasing venous compliance do to the cardiac function curve?
Nothing, but it shifts the vascular function curve because it increases the preload. Said another way, it slides up the cardiac function curve.
T/F Increasing TPVR improves cardiac function?
False. Although it does not improve cardiac function (CO), it does maintain arterial BP which is essential for perfusion.
What is systolic heart failure?
heart failure with reduced left ventricular ejection fraction.
What is diastolic heart failure?
heart failure with a normal ejection fraction.
what does contractility do to the cardiac function curve?
left shift with increased contractility
right shift with decreased contractility
Where do you find Beta1 receptors? what activates them and what do they do?
Found on the heart
activated by SNA, and increases contractility
what is the effect of SNA on alpha-adrenergic receptors on the arterioles?
vascoconstriction
what are some potential side effects associated with SNA on the venous system?
Decreased compliance will help to return blood to the heart, but this can cause problems such as:
ascites
lower extremity edema
liver congestion
what affect will a diuretic have on the heart?
decreases preload, but also decreases afterload.
How do you treat a hemorrhage?
1) stop source of bleeding
2) restore blood volume
3) increase arterial BP
4) Bring everything into balance again (CO, Acid base balance, temperature, etc.)
T/F To much SNA, norepi, Ang II, and aldosterone becomes maladaptive?
True.
How do you treat heart failure?
Vasodilator therapy
Diuretics
Angiotensin II and aldosterone antagonists
