Hypertension Flashcards
(38 cards)
Review of the Circulatory System
- Right side of the heart pumps deoxygenated blood to the lungs to pick up oxygen and the oxygenated blood is returned to the left side of the heart where it is pumped away from the heart all the way through arteries, arterioles, and capillary bed
- In the capillary bed there’s gas exchange
- Once gases have been exchanged, there’s a return flow to the heart through the capillary bed, the venules, and veins
- Largest veins are superior and inferior vena cavas
- Largest artery is the aorta
?
Is the force of blood pushing against the artery walls as it flows through them (arterial pressure [AP])
Blood pressure
- High pressure over time may cause inflammation, fatty accumulation, & atherosclerosis
AP = CO x PVR
AP = Arterial Pressure
CO = Cardiac Output
PVR = Peripheral Vascular Resistance
CO = Heart Rate (HR) x Stroke Volume (SV)
?
Is the volume of blood expelled from the ventricles w/each beat (SV) multiplied by bpm (HR)
CO
?
Is the resistance to the flow of blood determined by the tone of the vascular musculature, the diameter of blood vessels; whether they are dilated or constricted will effect BP
PVR
An increase in CO or PVR will increase BP
CO = ? x ?
Heart rate, contractility
Blood volume
Venous blood return to heart
PVR
> Arterial constriction
HR x Stroke Volume
Mean arterial pressure (MAP)
MAP = DP + 1/3 (SP - DP)
- A minimum MAP of ___ mmHg is required to perfuse vital organs
60
Autoregulation of BP - Compensatory mechanisms to maintain homeostasis
- Sympathetic baroreceptors
- Regulation of fluid volume
- Renin-Angiotensin System, aldosterone
- Vascular autoregulation
- ?
Are pressure-sensitive nerve endings located in the aorta, left ventricle, and carotid sinus
Slow HR and dilate vessels when BP elevated; increase HR and constrict blood vessels when BP is low
Baroreceptors
__ receptors in blood vessels cause vasoconstriction - increases PR
Alpha
__ receptors in heart stimulate increase in HR - increase in CO
Beta
Beta
Respond to ___ (increase HR and decrease bronchospasm) and beta blockers (decrease HR)
> Increases rate and force of heart
> Relaxation of bronchial muscles
epinephrine
Alpha
Responds to ___
Causes increased PVR, dilation of pupils, contraction of pilomotor muscles (goose bumps)
norepinephrine
- Regulation of Fluid Volume
Excess sodium or water increases CO & BP
Kidneys will diurese the extra volume and sodium
If BP dropping, kidneys will reabsorb sodium and water to increase BP
- Renin-Angiotensin System
A) Decreased blood volume - the body senses a decreased BP
B) Decreased blood flow to kidney increases the release of renin from kidney which increases angiotensin I that’s released and converts to angiotensin II;
This increases renal and systemic blood vessel constriction, so blood vessel constriction will increase blood flow
- Two-fold, angiotensin II stimulates the release of aldosterone from the kidney which increases sodium and water retention (has to do with volume & increases BP as well)
- Vascular Autoregulation
- Intrinsic vessel dilation/constriction locally at certain organs (brain, heart, kidneys)
- Is a manifestation of local blood flow regulation
- Defined as the intrinsic ability of an organ to maintain a constant blood flow despite changes in perfusion pressure
- For example, if perfusion pressure is decreased to an organ (e.g., by partially occluding the arterial supply to the organ), blood flow initially falls, then returns towards normal levels over the next few min
- This autoregulatory response occurs in the absence of neural and hormonal influences and therefore is intrinsic to the organ
Categories of BP in Adults
It’s important to modify risk factors by implementing lifestyle changes prior to the individual becoming hypertensive and requiring implementation of rx’s
Treatment starts w/identification of risk factors and modifying them to optimize BP and decrease risk of long-term complications
Primary or essential HTN accounts for 90% of people w/HTN
Not caused by an existing health problem
Secondary HTN develops r/t another disease process
Primary or secondary HTN?
- Kidney disease / primary aldosteronism
- Pheochromocytoma / Cushing disease
- Coarctation of the aorta / brain tumors
- Encephalitis / Pregnancy
- Drugs/hormones: estrogen, glucocorticoids, mineralocorticoids, sympathomimetics
Secondary
Primary or secondary HTN?
- Fhx / African-American ethnicity
- Hyperlipidemia / smoking
- > 60 yrs age or post menopausal / excess caffeine, sodium, ETOH
- Overweight, obesity / sedentary lifestyle
- Low potassium, calcium, magnesium
Primary (essential)
Complications of Chronic HTN
- Blood vessel damage - atherosclerosis, PVD
- Coronary artery disease - MI
- Enlarged heart - CHF
- Cerebrovascular disease - CVA
- Kidney failure - dialysis/transplant
- Eyes - retinal hemorrhage/blindness
Target organ damage
- Sheering forces from the increased BP damage the intimal layers of the blood vessels causing edema & fibrin, fatty plaque accumulation followed by atherosclerosis
- Small vessels become narrow & blood flow lessens to particular “target” organs
- Vessels become less flexible and can occlude
> Heart, brain, eyes, kidneys; intermittent claudication of LE’s
Nursing Assessment
Complete history
- Social/habits
- Rx’s
- Sx’s (target organ involvement?)
Physical assessment
- CV assessment
- Lung sounds
- MS/neuro
- Vision, renal
Diagnostics
- Risk factor assessments - implement lifestyle modifications (i.e., smoking cessation)
- Urinalysis
- Inc albumin in the urine & GFR will decrease if there’s an issue w/the kidneys
- Blood chemistry
- Cholesterol, LDL/HDL, triglycerides
- Electrolytes (K+, Na+, Mg2+)
- Blood sugars
- CRP is released in acute inflammatory conditions & w/necrosis
- Homocysteine (an amino acid) increases risk of collagen & cardiovascular disorders
- 12-lead ECG
- Prior MI or cardiomegaly?
- Echo
- Would look at signs of cardiomegaly & CHF
- Fundoscopic exam
- Looks at the back of the eye to check for any leaking capillaries or other identifiable dyscrasias in the eye
