Perfusion Flashcards
What is perfusion ?
process of transporting nutrients to the cells and surrounding tissues
What is the difference between central and tissue perfusion ?
- Central: perfusion to the heart muscle itself
- Tissue: peripheral perfusion
What is cardiac output ?
amount of blood pumped by each ventricle in 1 minute
What is blood pressure ?
force exerted by the blood against the walls of the blood vessels
What is blood pressure a measure of ?
cardiac output and systemic vascular resistance
What is systole ?
contraction of myocardium
- < 120 is good
What is diastole ?
relaxation of myocardium
- <80 is good
What is mean arterial pressure (MAP) ?
the average pressure within the arterial system that is felt by organs in the body
- goal MAP: >60 mmHG
What are the 3 functional ways to view cardiac activity ?
- electrical
- muscular
- vascular
What is the SA node ?
pacemaker of the heart
- electrical system starts here
- 60-100 bpm
What is the AV node ?
delays electrical signal
- 40-60 bpm
- further down the SA node the slower the HR
What is the Purkinje Fibers ?
deliver shock to both ventricles
- 20-40 bpm
What is the Frank-Sterling Law ?
the greater the contraction, the more force the blood is excreted out of the aorta
Where does the Left Coronary and Circumflex Artery supply blood to ?
to left atrium, left ventricle, interventricuar septum
Where does the Right Coronary Artery supply blood to ?
to right atrium, right ventricle, and posterior side of left ventricle
When does coronary circulation occur ?
during diastole
What is Systemic Vascular Resistance (SVR) ?
total peripheral resistance that your heart must overcome to provide adequate perfusion
What are the 3 factors that influence Systemic Vascular Resistance (SVR) ?
- vascular resistance
- blood viscosity
- turbulence
How does length affect vascular resistance ?
the longer the tube the more resistance
- usually static in pt’s
How does diameter affect vascular resistance ?
- the wider the diameter the less resistance
- the smaller the diameter the more resistance
What is viscosity ?
measure of a fluid’s resistance to flow
- high viscosity needs high pressure to move
Which types of conditions are those that affect blood viscosity ?
that involve Hct levels
- Ex. Polycythemia, DM
Why do pt’s with DM have thick blood ?
they have more glucose in their blood
What is turbulence ?
type of fluid flow that undergoes irregular fluctuations in speed
What assessment finding will indicate turbulence ?
a bruit
- can be caused by vessel changes (atherosclerotic plaque)
What are baroreceptors ?
stretch receptors located in aortic arch and carotid arteries
What happens when BP decreases ?
- increases: HR, contractility, vasoconstriction (alpha1 & beta1)
What happens when BP increases ?
parasympathetic activity increases
- parasympathetic will increase in order to decrease the BP
What does the Alpha 1 Adrenergic receptor do ?
- vasoconstriction
- increased peripheral resistance
- increased BP
What does the Alpha 2 Adrenergic receptor do ?
- inhibits: norepinephrine release, acetylcholine release, & insulin release
- vasodilation
- works in the brainstem which results in reduced sympathetic stimulation
What does the Beta 1 Adrenergic Receptor do ?
- tachycardia
- increased myocardial contractility
- increased release of renin
What does the Beta 2 Adrenergic Receptor do ?
- bronchodilation
- decreased peripheral resistance
What is the Renin Angiotensin Aldosterone System (RAAS) ?
how your kidneys, liver, and lungers affect your BP
- liver produces angiotensinogen and cholesterol
- kidneys produce renin
- lungs produce ACE
What does Angiotensin 2 cause ?
vasoconstriction of vessel
How does more or less water affect your BP ?
- more water causes higher BP since it has to circulate more of it
- less water causes lower BP since it has less to pump out and circulate
What is cholesterol ?
waxy, fat type substance that travels through the blood stream
What does cholesterol play a role in forming ?
- estrogen, testosterone
- cortisol
- vita. D
- bile acid
- cell membrane
What are lipoproteins ?
help transport fat around the body
- LDL is the major cholesterol carrier in the blood
What cholesterol is known as the “good cholesterol” ?
HDL
- people with high cholesterol have low HDL
What is hyperlipidemia ?
elevation of blood lipid levels
- Risk factors: lifestyle, genetic factors
What would be the 1st step for hyperlipidemia ?
have pt make lifestyle changes
- diet, exercise, alcohol consumption
- first step before we start pt on any meds
Why is HTN the “silent killer” ?
often no symptoms
What is hypertension ?
when systolic BP is greater than 130 mmHg or diastolic BP is greater then 80 mmHg for extended periods of time
- one of the most modifiable risk factors
What are some risk factors for primary HTN ?
- age
- alcohol
- cigarette smoking
- DM
- elevated serum lipids
- excess dietary sodium
- family history
- socioeconomic status
- stress
With older adults why are they at risk for HTN ?
- loss of elasticity in the large arteries (atherosclerosis)
- increase collagen and stiffness of the myocardium
- increased peripheral vascular resistance
- decreased renal function
What does primary HTN mean ?
idiopathic HTN
- can’t say that they have HTN because of a definitive answer
What does secondary HTN mean ?
can say that HTN is caused by a definitive answer
- tx is aimed at removing or treating the underlying cause
What are some potential symptoms of HTN ?
- headache
- blurry vision
- chest pain
- nose bleeds
- ringing in the ears
- dizzy
How does Sodium affect BP ?
sodium causes water in the body to last longer which causes an increase in BP
What is orthostatic hypotension ?
- decrease of 20mmHg or more in SBP or 10mmHg more in DBP
- increase in pulse of 20 bpm or more from supine to standing
What is Coronary Artery Disease ?
disease of the blood vessels where soft fatty deposits build up on the lining of the arteries and harden with age (atheroscletosis)
