Hypertension: the silent killer
Leslie Mickles, RN, MSN
• Afflicts almost 1 billion people
worldwide and is a leading cause of
morbidity and mortality.
• More than 20% of Americans are
hypertensive, and one-third of these
Americans are not even aware they are
Blood Pressure Physiology
Pressure in cardiovascular system controlled by:
• Actual blood volume
•Total peripheral resistance:
• small arterioles are most important due to small
diameter and ability to constrict to the point of
almost stopping blood flow.
• Baroreceptor reflex
• Carotids and Aortic Arch
• Brainstem to the vasomotor centre (VMC)
• Activation of the sympathetic nervous system
• increased contractility of the heart (beta receptors)
• vasoconstriction of both the arterial and venous
side of the circulation (alpha receptors)
• Renin-angiotensin system (RAS)
• Aldosterone release
Renin Angiotensin Cycle
Tissue Stimulation Causes
Stimulation of these receptors in the heart produces a
more rapid heart rate as well as more forceful heart
Heart Muscle muscle contractions. Drugs that stimulate beta1
and Fatty Tissue
receptors may, therefore, be useful in the treatment of
clients with depressed cardiac function
Stimulation of the beta2 receptors in bronchial muscle
Smooth Muscle results in muscle relaxation, thereby increasing the
of the Peripheral diameter of the air channels and promoting improved
Vasculature and beta 2
gas exchange. Beta2 stimulants (agonists) are sometimes
used, therefore, to treat bronchial asthma or other
conditions marked by breathing difficulty.
When alpha1 (α1) receptors are stimulated, either by a
Peripheral Blood neurotransmitter or a drug, the smooth muscle
Vessels and associated with them contracts. This contraction may
Sphincters of GI
result in an increase in blood pressure due to
and GU Tracts
constriction of peripheral blood vessels.
These receptors seem to function as “controllers” of
Located on the neurotransmitter release by the presynaptic neuron.
Presynaptic alpha 2 Inhibition of tansmitter release causes hypotension,
Receptor Sites Stumulation
vasoconstriction vasodilation (b2)
iris dilation cardioacceleration (b1)
intestinal relaxation intestinal relaxation (b2)
uterus relaxation (b2)
bladder sphincter contraction bronchodilation (b2)
• Hypertension is a systolic BP >140 and
a Diastolic BP >90 based on the average
of two or more correct blood pressure
measurements taken during two or
more contacts with a health care
Types of Hypertension
• Primary (essential) Hypertension:
means the cause can not be identified
• Secondary Hypertension: cause can be
traced to some underlying disorder (e.g.
renal disease, tumor of the adrenal
• Drug induced
• Renal failure
• Primary aldosteronism
• Renovascular disease
• Thyroid and parathyroid disease
• Family history
• Excess Sodium intake
• Alcohol intake
• Elevated serum lipids
African Americans develop hypertension earlier in life, and
it is more severe at any decade of life. The estimated
prevalence of individuals with hypertension in the
population at large is as follows:
POPULATION MALES FEMALES
American Indians 26.8% 27.5%
African Americans 35.0% 34.2%
Anglo-Americans 24.4% 19.3%
Asian/Pacific Islanders 9.7% 8.4%
Cuban Americans 22.8% 15.5%
Mexican Americans 5.2% 22.0%
Puerto Ricans 15.6% 11.5%
(American Heart Association, 1999d)
Aging Effect on BP
• As one ages there is an accumulation of
atherosclerotic plaque in arteries.
• Arteries become less elastic.
• Since arteries are less elastic the arterial
pressure is elevated with the force of
blood being pumped out from the left
BP SBP DBP Lifestyle Meds
Class (mm Hg) (mm Hg) Mod
Normal <120 <80 Enc No meds
PreHTN 120-139 80-89 Yes No Meds
Stage I 140-159 90-99 Yes Thiazide
Stage II 160 100 Yes Two meds
Target Organs Damaged by
• Heart (Angina, MI, hypertrophy,
• Brain (TIA or Stroke)
• Eyes (loss of vision, retinopathy)
• Kidneys (chronic renal failure)
• Peripheral artery disease
• Retinal hemorrhages
• Visual changes
• Papilledema (swelling of the optic
• Heart failure, or chest pain
• Slurred speech, hemiparesis, weakness
– suggestive of TIA (temporary) or CVA
• Elevated BUN and Creatinine
• Identify underlying cause if possible
• Keep BP <140/90
• Stepped Care Approach
• Step I: Life style modifications: wt reduction, restrict
Na intake, stop smoking, reduce alcohol consumption,
reduce stress, increase exercise.
• Step II: One medication started, usually a diuretic, but
may be an ARB, ACE inhibitor or calcium channel
• Step III: If ineffective, change dose or class of
antihypertensive med or add a second medication.
• Step IV: Adjustment of previous dosages, and addition
of another antihypertensive med until desired control
of BP obtained. Note many medications come as a
fixed combination of drugs
• Hypertensive Emergency:
• A situation in which the BP must be
lowered immediately to halt damage to
• Hypertensive Urgency;
• situation in which BP must be lowered
with a few hours.
• Arterial line
• Intravenous medication – typically nipride
• May also use cardene, or IV vasotec
• Lower BP but with MDs parameters.
Typically not below 140/90 or you will
impede cerebral perfusion
• Supportive care for any symptomatology
• Managed with oral medication such as
• Fast acting loop diuretics (Lasix, Bumex)
• ACE inhibitors, ARBs, calcium channel
blockers, beta blockers
• Close monitoring of BP – A line or
Action Named because the work int eh loop of Henle. Block the
chloride pump in the ascending loop of Henle (where
normally 30% of all filtered Na is reabsorbed) decreasing Na
reabsorption and producing copious amounts of urine.
Naming Generic names tend to end in “…ide” i.e. furosemide (Lasix),
bumetanide (Bumex), torsemide (Demadex).
Indication Used in treatement of severe edema, acute pulmonary
edema, CHF or hypertension because they can precipitate the
lose of up to 20 lbs of water per day. Preferred diuretic for
rapid and extensive diuresis.
Contraindication Hypersensitivity, electrolyte imbalance, anuria, severe renal
failure, hepatic coma, pregnancy and lactation.
Adverse Effects Hypokalemia, alkalosis (due to lose of bicarb with urine),
hypotenison, dizziness, ototoxicity and even deafness,
hyperglycemia (with long term use), dehydration/
Nursing Teaching regarding daily weights, potassium replacement.
Considerations Report signs of hypotension or hypovolemia. Also monitor
BUN and creatinine to ensure not overly dehydrated.
Action Belong to the chemical class of drugs called sulfonamides.
They work by blocking the chlorides movement out of the
renal tubules (and thereby Na+ movement). Blocking the
chloride pump keeps the Na and Cl in the tubules for
excretion in the urine.
Naming Generic name tends to end in “….thiazide” i.e.
hydrochlorothiazide (Hydrodiuril), chlorothiazide (Diuril),
bendroflumethiazide, (Naturetin), hydroflumethiazide
(Saluron), methyclothiazide (Enduron)
Indication Monotherapy or adjunctive thearpy for hypertension. Also,
treatement of edema associated with CHF or with liver or
renal disease. Mild diuretics compared to loop diuretics.
Contraindication Hypersensitivity, fluid or electrolyte imbalance, renal and/or
liver disease. Pregnancy and lactation.
Adverse Effects GI upset, CNS complications, hypovolemia, hypokalemia,
Nursing Monitor fluid and electrolyte balance closely, especially for
Considerations hypokalemia. Hypokalemia may cause leg cramps and
cardiac arrhythmias. Also monitor BUN and creatinine to
ensure not overly dehydrated.
Potassium Sparing Diuretics
Action Potassium-sparing diuretics decrease sodium reabsorption at
collecting tubules, inducing diuresis; decrease activity of
aldosterone at collecting tubules.
Naming No common ending to their names. Include: amiloride
(Midamor), sprionolactone (Aldactone), and triamterene
Indication Particularly useful in treating hypertension and edema
associated with CHF in patients at high risk if hypokalemia
would develop (i.e. patients on digoxin). Drug of choice for
Contraindication Hypersensitivity, hyperkalemia, renal disease, or anuria.
Adverse Effects Hyperkalemia which can lead to lethargy, confusion, ataxia,
muscle cramps and cardiac arrhythmias.
Nursing Closely monitor fluid and electrolyte balance (especially K+).
Considerations Also monitor BUN and creatinine to ensure not overly
Action Liberates nitric oxide (-NO)spontaneously in solution and thus
causes arteriolar and venous dilitation.
Indication Nipride is indicated for immediate reduction of BP in
hypertensive crisis. Also utilized post-op to control blood
pressure and reduce bleeding (i.e. post craniotomy). Utilized to
reduce afterload and preload and thereby improving Cardiac
Output in CHF and Cardiogenic Shock.
Contraindication Hypersensitivity to nitroprusside or any component of the
formulation; treatment of compensatory hypertension (aortic
coarctation, arteriovenous shunting)
Adverse Effects Cyanide toxicity. Thiocynate levels > 100 mcg/ml may cause:
drowsiness, lethargy, nausea and vomiting and muscle
twitching progressing to convulsions and coma. High
concentrations suppress thyroid function
Nursing Light sensitive. Infusion bag must be covered to block light and
Considerations changed every 24 hours to prevent more rapid degredation to
thicynate. Monitor for manifestation of cyanide toxicity.