Blood Pressure Agents Flashcards
What is angiotensin-converting enzyme responsible for?
converting angiotensin I to angiotensin II in the lungs
What is the MOA of ACE inhibitors?
blocks ACE, which prevents the vasoconstriction and aldosterone release related to angiotensin II
What are angiotensin II receptors?
specific receptors found in blood vessels and in the adrenal gland that react with angiotensin II to cause vasoconstriction and release of aldosterone
What are baroreceptors?
Pressure receptors located in the arch of the aorta and in the carotid artery that respond to changes in blood pressure and influence the medulla to stimulate the sympathetic system to increase or decrease blood pressure
What is the cardiovascular center and where is it located?
area of the medulla at which stimulation will activate the sympathetic nervous sytem to increase blood pressure and heart rate
What is essential hypertension?
sustained blood pressure above normal limits with no discernible underlying cause
What is peripheral resistance?
the force that resists the flow of blood through the vessels, mostly determined by the arterioles, which contract to increase resistance; important in determining overall blood pressure
What is the ultimate goal of the Renin-Angiotensin System?
The RAAS system causes vasoconstriction and Na2+ and H2O retention which results in an increase in BP.
Increased BP and increased blood volume with increase perfusion to the kidney.
How does HTN affect the RAAS system?
In the case of HTN, there is a miscommunication. The increased BP results in vasoconstriction so the kidneys don’t get as much pressure as they want so they release Renin and activate RAAS so they can try to get more blood.
BUT, it has the opposite effect b/c now we have vasoconstriction that decrease reduces blood flow further, which activates the RAAS again.
What is shock?
Severe hypotension that can lead to accumulation of waste products and cell death
What is stroke volume?
the amount of blood pumped out of the left ventricle with each beat
SV = end diastolic vol - end systolic vol
important in determining BP
What is the formula for BP?
HR X SV
Hypertension raises a patient’s risk for CAD. Explain the pathophysiology behind this risk.
HTN is due to increased peripheral resistance. This resistance causes thickening of the heart muscle. When it gets too thick, the heart cannot contract completely anymore, which causes hypertrophy, or enlargement of the heart. This causes congestive heart failure (CHF) and CAD.
List 4 conditions related to untreated HTN:
CAD and Cardiac Death
Stroke
Renal Failure
Loss of Vision
What is the nurse’s job concerning HTN and the patient?
Our job is to educate the patient about the risks of untreated HTN. Often patients see no symptoms of HTN and they don’t enjoy the lifestyle changes needed and adverse effects of the drugs, so they don’t want to continue. We need to teach them and be truthful.
List 5 things that increase BP
High levels of psychological stress
Exposure to high-frequency noise
High-salt diet (leads to fluid retention)
Lack of rest (physiological stress)
Genetic predisposition
Which blood pressure agents can we use with children?
Mild diuretics - monitor glucose and electrolytes
Calcium Channel Blockers
Beta-Blockers - Adverse effects are possible, so not the first choice
Childhood hypertension is usually ______________.
secondary to a primary disease process.
What are the signs of high BP?
HA
Vision Changes
Nosebleeds
Ringing in the ear
Why is dehydration a complication of HTN?
It can cause hypotension.
It can cause hypertension. The brain releases vasopressin as a result of dehydration, which vasoconstricts vessels, increasing BP.
Also, when dehydrated, the kidneys decrease urine formation which causes the capillaries in the heart and brain to constrict, which increases BP.
The combo of vasopressin and kidney changes causes serious kidney damage and renal disease.
How do blood pressure agents affect pregnancy and lactation? Which ones can we give?
Drugs enter breastmilk and can cause serious adverse effects, so we need to find an alternative to breastmilk.
IF benefits outweigh the risk, LABETALOL may be used in pregnancy.
For older adults, we start _____ and go ________. Why?
low
slow
Because the elderly are more susceptible to toxic effects. Also, the metabolism has slowed and there may be underlying conditions that effect metabolism and excretion.