Module 13 Hypertension Flashcards
Blood Pressure
- Force against artery walls
- Heart pumps blood through body
- Measured with sphygmomanometer
Hypertension
- Elevated arterial blood pressure
Accurate BP Measurement
- Seated for 5 minutes
- No caffeine/nicotine 30 mins prior
- Feet flat on floor
- Arm elevated to heart level
- Measure both arms 5 mins apart
Hypertension Diagnosis
- 3 blood pressure measurements
- Each 2 weeks apart
Systole
- Contraction of heart
- Top number
Diastole
- Heart fills with blood
- After contraction/ejection
- Bottom number
Prehypertension Range
- 120-139 systolic
- 80-89 diastolic
Stage 1 Hypertension
- 140-159 systolic
- 90-99 diastolic
Stage 2 Hypertension
- 160+ systolic
- 100+ diastolic
Primary Hypertension
- No known cause
- Majority of cases
- 90% of people over 55
Secondary Hypertension Causes
- Kidney disease
- Hyperthyroidism
- Pregnancy
- Erythropoietin
- Pheochromocytoma (adrenal tumour)
- Sleep apnea
- Contraceptive use
Hypertension Consequences
- Increased morbidity & mortality
- Myocardial infraction
- Kidney failure
- Stroke
- Retinal damage
BP Determinants
- Cardiac output x peripheral resistance
CO Determinants
- Heart rate, contractility
- Blood volume
- Venous return
Peripheral Resistance Determinants
- Arteriolar constriction
Blood Pressure Regulation
- Sympathetic NS
- Renin-angiotensin-aldosterone system (RAAS)
- Renal regulation
Sympathetic Nervous System (SYN)
- Fight/flight response
- Maintain homeostasis
- Baroreceptor reflex for BP regulation
Baroreceptors
- Aortic arch & carotid sinus
- Sense blood pressure
- Relay to brainstem
- Rapid response
Baroreceptor Reflex Low BP
- Brainstem sends impulses along SYN neurons
- Stimulate heart
- Increase CO
- Vasoconstriction (smooth muscle)
Baroreceptor Reflex High BP
- Decrease sympathetic activity
- Decrease CO
- Vasodilation
Renin-Angiotensin-Aldosterone System (RAAS)
- Protein hormones
- Blood pressure/volume regulation
- Electrolyte balance
- Long term response
RAAS Role
- Affects kidney & vascular smooth muscle
- Target of BP lowering drugs
RAAS Formation
- Angiotensinogen
- Renin
- Ang I (inactive)
- Ang converting enzyme (ACE)
- Ang II (active)
- Aldosterone/ADH
Renin
- Formation of Ang I from angiotensinogen
- Rate limiting step in Ang II formation
- Juxtaglomerular cells of kidney
Increase Renin Release
- Decrease blood volume
- Low blood pressure
- Beta 1 receptor stimulation (juxtaglomerular cells)
Angiotensin Converting Enzyme (ACE)
- Convert inactive Ang I to active Ang II
Angiotensin II Function
- Potent vasoconstrictor (bind to receptor)
- Stimulates aldosterone release from adrenal cortex
- ADH release from posterior pituitary
Aldosterone Function
- Acts on kidneys
- Increase Na+ retention
- Increase H2O retention
Antidiuretic Hormone (ADH) Function
- Also known as vasopressin
- Acts on kidneys
- Increase H2O retention
Renal Regulation of BP
- Decrease in BP causes increase in H2O retention
- Increase in H20 retention causes increase blood volume
- Increase blood volume causes increased CO
- Increased CO causes increase BP
Non-Drug Hypertension Treatment
- Decrease body weight
- Restriction of sodium intake
- Physical exercise
- Potassium supplementation
- DASH diet
- Smoking cessation
- Alcohol restriction
Mechanisms of Obesity causing Hypertension
- Increased insulin secretion
- Increased reabsorption of Na+
- Increased H20 absorption
- Higher blood volume
- Increase SYN activity
Sodium Intake Restriction
- Increased salt levels cause increase H2O reabsorption
- Increase in blood volume & pressure
- Kidney regulates salt, eliminating extra in urine
Physical Exercise
- Decrease fluid volume
- Decrease levels of plasma catecholamines (epinephrine)
- Pairs with sodium restriction & weight loss
Potassium Supplementation
- Inversely correlated with BP
- Decrease BP
- Increase Na+ excretion
- Decrease renin release
- Vasodilation
- Don’t mix with ACE inhibitors
DASH Diet
- 14 days for results
- Rich in fruits, vegetables
- Low fat dairy
- Lean meats
- Whole grains
Smoking Cessation
- Elevates BP
- No direct link in causing hypertension
- Risk for cardiovascular disease
Alcohol Restriction
- Excessive consumption increase BP
- Decrease medication response (antihypertensive)
- Less than 14 (men)/9 (women) drinks per week
Hypertension Medication SItes
- Vascular Smooth muscle
- RAAS
- Brainstem
- Heart
- Kidney
Vascular Smooth Muscle
- Ca+ channel blockers
- Thiazide diuretics
RAAS
- Beta blocker
- Renin inhibitors
- ACE inhibitors
- ARB
- Aldosterone receptor antagonists
Brainstem
- Alpha 2 antagonists
Heart
- Beta blockers
- Ca+ channel blockers
Kidney
- Thiazide diuretics
- Loop diuretics
- K+ sparing diuretics
Diuretics
- Blood Na+/Cl- reabsorption in nephron
- Prevent H2O reabsorption
- Promotes excretion of all
Loop Diuretics
- Largest BP decrease
- Blood Na+/Cl- reabsorption
- Ascending loop of henle
- Situations of rapid fluid loss
Conditions for Loop Diuretics
- Edema
- Severe hypertension
- Severe renal failure
Adverse Effects of Loop Diuretics
- Hypokalemia (K+ into blood)
- Hyponatremia
- Dehydration
- Hypotension
Thiazide Diuretics
- Most common treatment (work on own)
- Less diuresis than loop diuretics
Mechanisms of Thiazide Diuretics
- Block Na+/Cl- reabsorption in distal tubule
- Decrease vascular resistance
Adverse Effects of Thiazide Diuretics
- Hypokalemia
- Dehydration
- Hyponatremia
K+ Sparing & Aldosterone Antagonists
- Minimal BP lowering
- Use with other diuretic
- Don’t combine with ACE/renin inhibitors
- Inhibiting aldosterone receptors in collecting duct
- Increase Na+ excretion
- Increase K+ retention
Beta Blockers
- Blocking cardiac beta 1 receptors
- Blocking juxtaglomerular cell beta 1 receptors
- Suffix “olol”
Cardiac Beta Receptor 1 Block
- Catecholamines bind to cardiac beta receptors
- Decrease CO
- Decreases BP
Beta 1 Receptors on Juxtaglomerular Cells Block
- Decrease renin release
- Decreasing RAAS vasoconstriction
1st Gen Beta Blockers
- Non-selective blockade
- Inhibit beta 1 (heart & juxtaglomerular)
- Inhibit beta 2 (lung)
2nd Gen Beta Blockers
- Selective blockade of beta 1 receptors
Adverse Effects of Beta 1 Blockers
- Bradycardia
- Decrease CO
- Heart failure
- Hypertension/excitation (abrupt withdrawal)
Adverse Effects Non-Selective Beta Blockers
- Bronchoconstriction
- Hepatic & muscle glycogenolysis inhibition
Angiotensin Converting Enzyme Inhibitors (ACEI)
- Decrease Ang II production
- Inhibit bradykinin breakdown
- Suffix “pril”
Ang II Decrease
- Causes vasodilation
- Decease blood volume
- Reduces CO & peripheral resistance
Bradykinin Breakdown Inhibition
- Causes vasodilation
Adverse Effects of Ang II Decrease
- Hypotension (1st dose emphasis)
- Hyperkalemia
Adverse Effects of Bradykinin Increase
- Persistent cough
- Angioedema
Angiotensin Receptor Blockers (ARB)
- Block Ang II binding to AT1 receptor
- Cause vasodilation
- Decrease aldosterone release
- Increase Na+/H2O excretion
- Suffix “sartan”
ARB Adverse Effects
- Angioedema (less risk than ACEI)
- Hyperkalemia
Direct Renin Inhibitors (DRI)
- Bind to renin
- Block angiotensinogen to Ang I conversion
- Limit RAAS pathway
- Decrease BP
DRI Adverse Effects
- Hyperkalemia
- Persistent cough/angioedema (low)
- Diarrhea
Calcium Channel Blockers
- Block movement of Ca++ into cell
- Heart/smooth muscle cells
- Decrease contraction
Dihydropyridine Calcium Channel Blockers
- Decrease Ca++ into smooth muscle/arteries
- Vasodilation/relaxation
- Suffix “dipine”
- No action on heart
Adverse Effects of Dihydropyridine Blockers
- Flushing
- Dizziness
- Headache
- Peripheral edema
- Reflex tachycardia
- Rash
Non-Dihydropyridine Calcium Channel Blockers
- Block Ca++ in smooth muscle & heart
- Vasodilation of arteries
- Decrease CO
Adverse Effects of Non-Dihydropyridine Blockers
- Constipation
- Dizziness
- Flushing
- Headache
- Edema
- May compromise cardiac function
Centrally Acting Alpha 2 Agonists
- Bind & activate receptors in brainstem
- Decrease sympathetic activity in heart & vessels
- Decrease CO & peripheral resistance
Adverse Effects of Alpha 2 Agonists
- Drowsiness
- Dry mouth
- Hypertension (abrupt withdrawal)
Treatment Algorithms
- 140/90mmHg target BP
- 130/80mmHg target Bp for diabetes/kidney disease
- Slow disease progression by lowering BP
Prehypertension Algorithm
- Lifestyle modifications
- Thiazide diuretic
Stage 1/2 Hypertension Algorithm
- Lifestyle modification
- Thiazide diuretic
- Add ACEI, ARB, BB, CCB
Moderate Renal Disease/Diabetes Algorithm
- Lifestyle modifications
- Thiazide diuretic
- ACE/ARB
Severe Renal Disease Algorithm
- Lifestyle modification
- Loop diuretic
- ACE/ARC
