drug therapy for hypertension Flashcards
what is the function of the cardiac cycle?
essential in delivery of O2 to myocardium and tissues
what are the two parts of the cardiac cycle?
systole and diastole
describe…
systole
-contraction of the ventricles of the heart that occurs between the first and second sounds of the cardiac cycle
-pushes blod out
describe…
diastole
-part of the cardiac sysle dutring which the heart refills with blood after emptying during systole
-relaxation, resting state
describe…
stroke volume
amount of blood ejected from the left ventricle with each contraction
preload, afterload, contractility
describe…
preload
-end diastolic volume
-the amount of blood left in the left ventricle
describe…
afterload
-resistance to left ventriclular ejection
-the work the heart muscle must overcome to eject blood
-effected by aortic pressure and vascular resistance
describe…
contractility
ability of heart muscle to contract
describe…
cardiac output
-amount of blood pumped by the heart each minute
- HR x SV = CO
heartrate x stroke volume = cardiac output
what is the process of the cardiac conduction pathway?
SA node -> AV node -> bundle of his -> right and left bundle -> purkinje fibers
the heart is an electrical conduction pathway
what is the process of the cardiac conduction pathway?
SA node -> AV node -> bundle of his -> right and left bundle -> purkinje fibers
the heart is an electrical conduction pathway
cardiac conduction pathway
describe the SA node
pacemaker of the heart, sets the pace for contraction
cardiac conduction pathway
describe the AV node
-receives message from SA node
-has the ability to slow or delay the conduction so the ventricles fill properly
cardiac conduction pathway
describe bundle of his
-receives message from AV node
-sends message to right and left bundle branches
cardiac conduction pathway
describe purkinje fibers
-gets message from bundle branches
-causes contraction of the ventricles
describe…
cardiac blood flow
-venous system brings deoxygenated blood back to the heart
-arterial system brings oxygenated blood out of the heart and to the body
what are the differences between the venous and arterial systems
think about pressures
-venous is a low pressure system with valves
-arterial is a high pressure system with no valves
describe…
coronary circulation
-arteries and veins that supply the heart muscle itself
-right and left coronary arteries branch off base of aorta
-receive blood during diastole
describe…
pulse pressure
-SBP minus DBP
-represents filling pressure of coronary arteries
describe…
electrocardiography
ECG/EKG
measurment tool used to evaluate conduction of the heart
includes P wave, PR inerval, QRS complex, ST segment, T wave
describe…
P wave
atrial depolarization (conduction of electrical umplse through the atria)
describe…
PR interval
tracks the atrial impulse through the AV node, buncle of HIS and right and left bundle branches
describe…
QRS complex
depolarization of ventricles
describe…
ST segment
-end of ventricular conduction/depolarization
-beginning of ventricular repolarization (rest)
describe…
T wave
ventricular recovery or repolarization
what are the three components of the physiological regulation of blood pressure
-vasomotor center
-emotions
-hormones
what are the components of the vasomotor center
-baroreceptors
-chemoreceptors
describe…
baroreceptors
what do they respond to?
respond to increase or decrease in pressure or stretch
describe…
chemoreceptors
what do they respond to?
respond to changes in oxygen, carbon dioxide, and pH
how can emotions effect blood pressure?
-anger or stress elevate BP
-depression or lethargy decrease BP
what hormones impact BP?
-antidiuretic hormone (ADH)
-renin-angiotensin-aldosterone system (RAAS)
where is ADH released from?
hypothalamus
describe…
ADH
-keeps fluids in the body
-secreted when electrolytes get concentrated
-secreted when BP is too low
-inhibited when BP is too high
released to increase BP and increase fluid volume
describe…
RAAS
-in response to low BP or in response to low fluid volume (low Na+), RAAS kicks in to compensate
-in place to regulate BP by bringing it up
how does RAAS work?
-causes increase in Na+ which increases fluid and BP
-causes decrease in K+
-causes vasoconstriction in arterioles which increases BP
name 3 factors that effect BP
-blood volume
-peripheral resistance/diameter of arterioles
-cardiac output
how can blood volume affect BP?
-fluid loss (dehydration, bleeding) can lower BP
-fluid retention can increase BP
describe how peripheral resistance/diameter of arteriales can impact BP
-SNS activity (activation can increase HR and vasoconstriction)
-renin and angiotensin 2 are released as the bodys response to BP change
-increase in blood viscosity increases BP
describe how cardiac output can impact BP
-stroke volume (preload, contractility, afterload)
-HR (SNS activity, PNS activity, epinephrine)
true or false?
hypertension increases the risk of cancer
false
HTN increases the risk of MI, CHF, cerebral infarction/hemorrhage, and renal disease
describe the autoregulation of blood flow
ability of the organ/body tissues to regulateown blood flow (heart, brain, kidneys)
why does autoregulation of blood flow occur
occurs primarily by nutritional needs of the tissues:
-lack of o2 (BP increases)
-cellula metabolism byproduct accumulation (CO2/lactic acid)
what are some important factors in BP regulation?
think of things that are released
-histamine
-bradykinin
-prostaglandins
what does histamine release do?
dilates the blood vessels and lowers BP
what does bradykinin release do?
causes vasodilation and lowers BP
bradykinin is a potent peptide
what does bradykinin release do?
causes vasodilation and lowers BP
bradykinin is a potent peptide
what are prostaglandins indcluded in?
vasodilators and vasoconstrictors
describe…
arterial blood pressure
force exerted on arterial walls by blood flow
what are the two main determinants of arterial blood pressure?
-cardiac output (sytolic pressure)
-peripheral vascular resistance (diastolic pressure)
how do yu determine cardiac output?
whats the formula?
CO = HR x SV
describe…
frank starlings law
the greater the volume of blood in the heart during diastole, the more forceful the cardiac contraction, the more blood the ventricle will pump (to a point)
what are some causes of hypotension?
frequent diarrhea, emesis, or diaphoresis
may result in dizzines or lightheadedness
describe the body’s response to hypotension
SNS stimulated -> adrenal medulla secretes epinephrine and norepinephrine -> angiotensin 2 and aldosterone are formed -> kidneys retain fluid and BP in increased
describe the body’s response to hypertension
increased renal secretion (increased urine output) -> fluid loss and decreased circulating volume -> decreased cardiac output -> decreased arterial blood pressure -> decreased blood pressure
define hypertension
-common, chronic disorder affecting approximately 50-60 mil adults in the U.S.
-persistently high BP (increase force in the arteries) that results from abnormalities in regulatory system
what BP values are considered hypertensive?
systolic greater than 140mmhg and diastolic greater than 90mmhg
what BP values are considered pre hypertensive
systolic 120-139 and diastolic 80-89
describe…
primary HTN
-HTN with no identifiable cause
-90-95% of known cases
describe…
secondary HTN
-results from identifiable cause
-may result from renal (renal artery stenosis), endocrine, CNS disorders, or from medications
why is HTN dangerous?
pts can be asymptomatic for years
what ae the risks of HTN?
-increases the risk of target organ damage
-MI, CHF, stroke, renal disease, retinal damage
-increased cardiac workload = myocardium hypertrophy = CHF
when is ADH released
released in response to increased blood osmolality (when blood gets thicker, usually in a dehydrated state)
what does ADH do to urine output?
decreases it
how does ADH affect Na+, H2O, and K+
-increases circulatin Na+ and H2O
-losss of K+ in the urine
what does ADH promote?
reabsorption of water by kidneys
what is another name for ADH?
vasopressin
what does ADH do to the vessels?
ADH is a potent vasoconstrictor
synthetic vasopressin is used to treat….
diabetes insipidus and hypotensive crisis
RAAS is used to…
increase blood pressure
please look at this stuff about the RAAS thingy
BP indicates blood pressure based on…
-average of >2 careful readings obtained on >2 occasions, as deatiled in DBP and SBP
SBP and DBP in category of…
normal
sbp: <120mmhg
and
dbp: <80mmhg
SBP and DBP in category of…
elevated
sbp: 120-129mmhg
and
dbp: <80mmhg
SBP and DBP in category of…
stage 1 hypertension
sbp: 130-139mmhg
or
dbp: 80-89mmhg
SBP and DBP in category of…
stage 2 hypertension
sbp: >140mmhg
or
dbp: >90mmhg
what is the goal BP of ppl over the age of 60
<150/90
what is the goal BP of ppl less than 60 with diabetes of all ages (no CKD) and ppl of all ages with CKD (with or without diabetes)
<140/90
if somebody consistently has BP <120/90 whatre you gonna do
promote optimal lifestyle habits and reasses in one year
if somebody consitently has BP 120-129/<80 whatre you gonna do
nonpharmacologic therapy and reassess in 3-6 months
if somebody consistently has BP 130-139/80-89 and has no estimated CVD risk whatre you gonna do
nonpharmacologic therapy
if somebody consistently has BP 130-139/80-89 and has estimated CVD risk whatre you gonna do
nonpharmacologic therapy and BP lowering meds
if somebody consistently has BP >140/90 whatre you gonna do
nonpharmacologic therapy and BP lowering meds
what are some nonpharmacologic management techniques of HTN
-stress management
-limit ETOH (male <2/day, women <1/day)
-reduce na+
-reduce fat and cholesterol
-increase fruit and veggies
-increase aerobic physical activity
-discontinue tobacco products
-maintain optimum weight
describe the HTN management guidelines
-factors to be considered (age, ethnicity, CV disorders)
-start med in lowest available dose
-change med groups instead of increasing the dose if first med is ineffective
-many pts require 2+ meds for adequate BP control
-meds are titrated and dispensed according to individual response
what are some antihypertensive drug class meds
-angiotensin-converting enzyme (ACE) inhibitors
-angiotensin II receptor blockers (ARBs)
-calcium channel blockers
-antiadrenergics
-direct vasodilators
-diuretics
what is the action of ACE inhibitors
inhibit the conversion of angiotensin I to angiotensin II
what are some examples of ACE inhibitors
and which is most common
-capropril
-enalapril
-lisinopril (most common)
-ramipril
what are some side effects of ACE inhibitors
-ACE cough
-orthostatic hypotension
-peptic ulcers, gastric irritation
-hyperkalemia (avoid K+ supplements, K+ salt substitutes, and K+ sparing diuretics)
-angioedema(swelling of mouth)
-acute renal failure (kidneys regulate K+)
-HA, dizziness
what are soe special instructions involved with ACE inhibtors
-take one hour before or two hours after meal (lisinopril you can take wihtout regard to food)
-take caution in patients with impaired renal function/CHF
-no potassium supplements
what black box warning is on all ACE inhibitors
pregnancy known to cause injury/death to fetus
what foods are high in K+
soooo not for pts taking ACE inhibitors
raisins, bananas, apricots, oranges, beans, potatos, carrots, and celery
describe the action of ARBs
(angiotensin II receptor blockers)
selectively bind to angiontensin II receptors in vascular smooth muscle and adrenal cortex
what are some examples of ARBs
-losartan
-valsartan
-olmesartan
what are some side effects of ARBs
-orthostatic hypotension
-HA, dizziness, diarrhea
-dry mouth
-angioedema
-acute renal failure (monitor CRT, BUN, and GFR)
-hyperkalemia (blocking the angiotensinogen II in the cascade)
what are some contraindications of ARBs
hepatic or renal failure impariment
describe how ARBs are dose dependent
-once daily for HTN tx
-twice daily for CHF (monitor K+)
what is the black box warning for all ARBs
pregnancy - known to cause injury/death to fetus
describe the action of calcium channel blockers
inhibit the movement of Ca+ across the membranes of mycardial and arterial muscle cells = decrease in HR and causes vasodilation of the peripheral vasculature
what are some examples of Ca+ channel blockers
-amlodipine
-diltiazem
-verapamil
-nicardipine
-nifedipine
what are some side effects of Ca+ channel blockers
-flushed skin, muscle cramps, peripheral edema
-HA, dizziness, hypotension
-impotence, sexual dysfunction
-hepatotoxicity
-angioedema
what are some contraindications of Ca+ channel blockers
hepatic/renal impairment, CHF/heart block, or pregnancy
what do Ca+ channel blockers interact with
macrolide antibiotics and grapefruit juice
what do antiadrenergic (sympatholytics) drugs do to the body?
inhibit SNS - decrease HR, decrease force of myocardial contraction, cardiac output and blood pressure
describe what alpha1 adrenergic receptor blockers do
dilate blood vessels and decrease peripheral vasular resistance (PVR)
what are some examples of alpha1 adrenergic receptor blockers
-doxazosin
-prazosin
-terazosin
name four antiadrenergic (sympatholytic) meds
-alpha1 adrenergic receptor blockers
-alpha2 receptor agonists
-beta adrenergic blockers
-alpha-beta adrenergic blockers
describe what alpha2 receptor agonists do
inhibit norepinephrine = have antiadrenergic effect = decreased CO, decreased HR, decreased PVR, decreased BP
what are some examples of alpha2 receptor agonists
-clonidine (super strong)
-methyldopa
-guanfacine
what are some side effects of alpha1 adrenergic receptor blockers and alpha2 receptor agonists
-first dose phenomenon orthostatic hypotension, palpitations, syncopal episodes
-start low first dose and increase slowly to prevent side side effects
-can have increase Na+/fluid retention (may need diuretic Rx as well)
describe how beta andrenergic blockers work
decrease HR, force of myocardial contraction, cardiac output, and renin release from the kidneys
what are some special characteristics of beta adrenergic blockers?
-first med for pts under 50 with cardio selective meds
-first choice in pts with asthma, PVD, or DM
-do not stop with med abruptly
-may cause erecetile dysfunction - men will stop or ot take it
-sometimes in hospital setting, perameters are set to hold the med if HR is not at certain numbers
what are some examples of beta adrenergic blockers?
-atenolol
-metoprolol
-propranolol
what are beta adrenergic blockers used for?
tx of:
-HTN
-dysrhythmias
-HF
-MI
-narrow angle glaucoma (eye drops)
what are some side effects of beta adenergic blockers?
-hypotension
-bradycardia
-dizziness
-use caution in pts with liver impairment
what is the black box warning on all beta adrenergic blockers?
for pt with CAD, dose must be titrated down prior to discontinuing med… if not there is high risk of rebound angina, ventricular dysrhythmias, and MI
describe alpha-beta adrenergic blockers
-achieve dual effect as a combination med
-dual action in one tablet
-also less side effects
what are some examples of alpha-beta adrenergic blockers
and which is most common
-carvedilol(most common)
-labetalol
describe how diruetics work
-reduction of blood volume through urinary excretion of H2O and electrolytes
which type of med is used as first line of treatment for mild-moderate HTN
diuretics
do they exact mechanisms of action of diuretics differ by the type?
yeppers
describe thiazide and thiazide-like diuretics
-block Na+ reabsorption
-increase K+ and H2O secretion
what is an example of thiazide and thiazide-like diuretics
hydrochlorothiazide (HCTZ)
describe potassium sparing diuretics
-excretion of Na+ and retantion of K+
-can increase effects of digoxin, monitor for hypekalemia in pts also taking ACE inhibitors or ARBs
most often used for pts with low K+ levels
what is an example of potassium sparing diuretics
spironolactone
(blocks aldosterone)
describe loop diuretics
-reabsorption of Na+ and Cl- in the loop of henle
-K+ wasting diuretic
-can increase digoxin levels and cause hypokalemia
ALWAYS MONITOR K+ LEVELS
what is an example of a loop diuretic
furosemide
hypertensive emergencies
episodes of severly elevated BP caused by…
-extension of malignant HTN
-cerebral hemorrhage
-dissecting aortic aneurysm
-renal diease
-etc
what are some sx of hypertensive emergencies
-severe HA
-N/V
-visual disturbances
-neurologic disturbances
-disorientation
-decreased level of consciousness
how do you treat hypertensive emergencies?
direct acting vasodilators
how do direct acting vasodilators work?
directly relax smooth muscles in the blood vessels = dilation and decreased peripheral vascular resistance
what are some examples of direct acting vasodilators
-hydralazine
-nitroprusside (IV only)
what are some nursing implications for anti hypertension treatments?
monitor for:
-bradycardia
-hypotension, orthostatic hypotension (falls risk)
-monitor I+O PRN
-heart healthy/low Na+ diet
-electrolyte
-telemetry
-herbal and dietary supplement use
-specialty populations
