3. hypertension 3/13

Question 1

1. define hypertension:

2. what is the prevelance of HTN

Answer 1

1. a) primary (essential): bp of 140/90 independent of other causes
   b) secondary (remedial): htn due to another condition
2. # 1 cause of cardiovascular disease, 50 million americans aged 60 or greater; 25% of the population

Question 2

1. what is the best way to manage a hypertensive patient during anesthesia?
2. what about an elective surgery with a diastolic bp>110?

Answer 2

1. keep them where they live (preferrably less than 160/100).
2. diastolic >110; cancel procedure d/t cardiac, neurological and renal risk of complications

Question 3

artline during cardiac surgery:

1. why put one in (cardiac wise)?
2. what about patient positions?

Answer 3

1. to make sure the blood pressure will be maintained during bigger surgeries (especially persons with blood pressure risk-wide swings, chronic HTN, lots of blood loss or fluids).
2. patients that are prone or beach chair (for beach chair, put transducer near tragus of ear to see what brain perfusion pressure is).

Question 4

what is Systolic pressure?

Answer 4

• A wave of vascular distension from the stroke volume of each heart beat as blood is ejected into a closed system from the base of the aorta throughout the arterial system.
• Pulse waveform is not from the blood but from the forward pressure movement and its reflectance back toward the heart.
(In layman’s terms…High systolic blood pressure is when the heart’s contracting pressure is too high).

Question 5

what is Diastolic pressure?

Answer 5

• Indicates perfusion to tissue beds
• lateral pressure exerted by the blood on the walls of the vessels.
(In layman’s terms…High diastolic blood pressure is when the heart’s resting blood pressure is too high.)

Question 6

how to calculate Mean Arterial Pressure?

Answer 6

Mean arterial pressure = Diastolic pressure + (1/3 Systolic pressure – Diastolic Pressure) Or:
SBP+(DBPx2) divided by 3

Question 7

1. Hypertension is…?
2. how many americans over 50 y/o have HTN?
3. what percent of americans have HTN? how ,many know?

Answer 7

1. the #1 cause of cardiovascular disease; silent killer
2. 50 million Americans aged 60 and older have HTN
3. one in five Americans (1/5) have HTN but only one-third of those people even know

Question 8

Subsequent Hemodynamic effects of HTN

Answer 8

• Increased systemic vascular resistance
• Increased cardiac output
• Decreased intravascular volume
• Exaggerated endogenous and exogenous pressor response (because vessels are already narrowed).
• Edema

Question 9

Systemic effects of Chronic Uncontrolled HTN

Answer 9

• early arteriosclerosis leading to coronary artery disease
• increased afterload from chronic vasoconstriction→
- congestive heart failure
- LV hypertrophy, cardiomegally
- Peripheral vascular disease
• intracerebral occlusions or hemorrhage (CVA or TIAs)
• renal failure
• retinopathy

Question 10

1. Angiotensin Converting Enzyme (ACE) inhibitors and Angiotensin II blockers (ARBs)
2. what does this cause?
3. examples:

Answer 10

1. Prevent conversion of angiotensin I to II or block angiotensin II (recall: angiotensin II is a potent vasoconstrictor)
2. • Arteriolar dilation
   • Attenuation of SNS activity and release of NE
   • Reduction of aldosterone secretion (recall, aldosterone stimulates Na+ reabsorption)
   • May use ACE-diuretic combo tx
3. Ex. ACE inhibitor and HCTZ (end in “ide”—Aldactizide, Dipizide, Maxide)

Question 11

Adrenergic central alpha-2 agonists:

1. what do they do?
2. alpha 2 receptors exist pre or post synaptically?
3. examples:

Answer 11

1. Stimulate central alpha receptors which inhibit efferent sympathetic activity. Activation of these receptors inhibits the release of norepinephrine. This results in a decrease in peripheral vascular resistance.
2. Alpha2 receptors exist presynaptically.
3. Ex.Clonidine (Catapress), Methyldopa (Aldomet)

Question 12

Alpha 1 blockers:

1. what is the action?
2. examples:

Answer 12

1. These drugs block the effect of sympathetic nerves on blood vessels by binding to alpha-adrenoceptors located on the vascular smooth muscle. Most of these drugs act as competitive antagonists to the binding of norepinephrine that is released by sympathetic nerves synapsing on smooth muscle. Some alpha-blockers are non- competitive (e.g., phenoxybenzamine), which greatly prolongs their action.
2. medication classification group has the suffix of -sin (ex. prazonin, terazosin, doxazosin)
   Ex. Prazocin (Minipress),Terazoncin (Hytrin)
   Ex. Phenoxybenzamine-for tx of pheochromocytoma

Question 13

Beta blockers

Answer 13

Beta-blockers are drugs that bind to beta-adrenoceptors and thereby block the binding of norepinephrine and epinephrine to these receptors. This inhibits normal sympathetic effects that act through these receptors. Therefore, beta-blockers are sympatholytic drugs. Second generation beta-blockers are more cardioselective in that they are relatively selective for b1 adrenoceptors. third generation beta-blockers are drugs that also possess vasodilator actions through blockade of vascular alpha-adrenoceptors.

Question 14

Calcium antagonists

1. how do they work?
2. examples

Answer 14

1. Blocks calcium influx. These drugs primarily affect arterial resistance vessels, with only minimal effects on venous capacitance vessels.
   • Smooth muscle relaxation
   • Vasodilation
   • Reduced peripheral resistance; preserved CO
2. ex: Amlodipine (Norvasc), Felodipine (Plendil), Nicardipine, Diltiazem Verapamil