Chapter 32
Hypertension
KEY POINTS
NORMAL REGULATION OF BLOOD PRESSURE
1. Blood pressure (BP) is the force exerted by the blood against the walls of the blood vessel.
Maintaining tissue perfusion during activity and rest must be adequate.
2. Regulation of BP involves nervous, cardiovascular, endothelial, renal, and endocrine
functions.
HYPERTENSION
Classification of Hypertension
1. Hypertension, or high BP, is defined as either a persistent systolic BP (SBP) greater than or
equal to 130 mm Hg or a diastolic BP (DBP) greater than or equal to 80 mm Hg. If either the
SBP or DBP is outside of a normal range, the higher measurement will determine the
hypertension classification.
2. Hypertension is classified as follows:
• Elevated blood pressure is defined as an SBP between 120-129 mm Hg and a DBP < 80
mm Hg.
• Hypertension (Stage 1) is defined as an SBP between 130-139 mm Hg and a DBP between 8089 mm Hg.
• Hypertension (Stage 2) is defined as an SBP > 140 mm Hg and a DBP > 90 mm Hg.5
Etiology
• Primary (essential or idiopathic) hypertension is elevated BP without an identified cause. It
accounts for 90% to 95% of all cases of hypertension.
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• Secondary hypertension is elevated BP with a specific cause. It accounts for 5% to 10% of
hypertension in adults.
Pathophysiology of Primary Hypertension.
• The hemodynamic hallmark of hypertension is persistently increased systemic vascular
resistance (SVR).
• This persistent elevation in SVR may occur in several ways. Defects in any of the mechanisms
involved in the maintenance of normal BP, including sodium intake, the renin-angiotensinaldosterone mechanism, and sympathetic nervous system (SNS) stimulation, can result in the
development of hypertension.
• Defects in glucose, insulin, and lipoprotein metabolism are common in primary hypertension.
• Contributing factors to the development of hypertension include cardiovascular risk factors
combined with socioeconomic conditions and gender and ethnic differences.
• Endothelial dysfunction is a marker for CVD and primary hypertension.
Clinical Manifestations
• Often called the “silent killer” because it is often asymptomatic until it becomes severe
and target organ disease occurs.
• Target organ diseases occur in the heart (hypertensive heart disease), brain
(cerebrovascular disease), peripheral vessels (peripheral vascular disease), kidney
(nephrosclerosis), and eyes (retinopathy).
• It is one of the leading causes of end-stage renal disease, especially in Blacks.
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• Damage to retinal vessels indicates concurrent vessel damage in the heart, brain, and kidney.
Manifestations of severe retinal damage include blurring of vision, retinal hemorrhage, and loss
of vision.
• There is a direct relationship between hypertension and cardiovascular disease (CVD).
Hypertension is a major risk factor for coronary artery disease (CAD), stroke, and cerebral
atherosclerosis.
• Sustained high BP increases the cardiac workload and produces left ventricular hypertrophy
(LVH). Progressive LVH, especially in association with CAD, is associated with the
development of heart failure.
Diagnostic Studies
• Basic laboratory studies are done to (1) identify or rule out causes of secondary hypertension,
(2) evaluate target organ disease, (3) determine overall cardiovascular risk, or (4) establish
baseline levels before starting therapy.
• Routine urinalysis, BUN, serum creatinine, and creatinine clearance levels are used to screen
for renal involvement and to provide baseline information about kidney function.
• Lipid profiles provide information about risk factors that predispose to atherosclerosis and
cardiovascular disease.
• 12 lead ECG and echocardiography provide information about the heart status.
• Ambulatory BP monitoring (ABPM) measures the BP at preset intervals over a 24-hour period.
• Home BP Monitoring (HBPM) measures the BP at home to confirm hypertension diagnosis
and for titration of oral agents. HBPM should be done in conjunction with regular follow up
visits with the HCP.
Interprofessional Care
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• Target goals take into consideration both age and comorbidities when recommending
treatment options.
• Lifestyle modifications are directed toward reducing the patient's BP and overall
cardiovascular risk. The AHA’s “Life’s Simple 7” steps support ways to modify and
improve health. These are: (1) manage blood pressure, (2) control cholesterol, (3)
reduce blood sugar, (4) get active, (5) eat better, (6) lose weight, and (7) stop smoking.
Other modifications by the taskforce on hypertension address sodium restrictions and
alcohol intake.
Drug Therapy
• Drugs currently available for treating hypertension work by (1) decreasing the volume of
circulating blood and/or (2) reducing SVR.
• Diuretics promote sodium and water excretion, reduce plasma volume, and reduce the
vascular response to catecholamines.
• Adrenergic-inhibiting agents act by decreasing the SNS effects that increase BP.
Adrenergic inhibitors include drugs that work centrally on the vasomotor center and
peripherally to inhibit norepinephrine release or to block the adrenergic receptors on
blood vessels.
• Direct vasodilators decrease the BP by relaxing the vascular smooth muscle and
reducing SVR.
• Calcium channel blockers increase sodium excretion and cause arteriolar vasodilation
by preventing the movement of extracellular calcium into cells.
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• Angiotensin-converting enzyme (ACE) inhibitors prevent the conversion of
angiotensin I to angiotensin II and reduce angiotensin II (A-II)–mediated
vasoconstriction and sodium and water retention.
• A-II receptor blockers (ARBs) prevent angiotensin II from binding to its receptors in
the walls of the blood vessels.
• Most patients who are hypertensive will need 2 or more antihypertensive drugs to achieve
their BP goals.
• Side effects and adverse effects of antihypertensive therapy may be so severe or
undesirable that the patient does not adhere to therapy. Patient and caregiver teaching
related to drug therapy is needed to identify and minimize side effects and to cope with
therapeutic effects.
• Resistant hypertension is the failure to reach goal BP in patients who are adhering to full
doses of an appropriate 3-drug therapy regimen that includes a diuretic.
NURSING MANAGEMENT: PRIMARY HYPERTENSION
• The primary nursing responsibility for long-term management of hypertension is to help the
patient in reducing BP and adhering to the treatment plan.
• Nursing actions include evaluating therapeutic effectiveness, detecting and reporting any
adverse treatment effects, assessing and enhancing adherence, and patient and caregiver
teaching.
• Patient and caregiver teaching includes: (1) nutritional therapy, (2) drug therapy, (3) lifestyle
modification, and (4) home monitoring of BP.
Blood Pressure Measurement
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• Accurate BP measurements are critical. A key role of the nurse is to provide patient and
caregiver teaching about measuring BP at home.
• Orthostatic hypotension is defined as a decrease of 20 mm Hg or more in SBP, a decrease of 10
mm Hg or more in DBP, and/or an increase of 20 beats per min or more in pulse from supine to
standing.
• Orthostatic changes in BP and pulse should be measured in older adults, in patients taking
antihypertensive drugs, and in patients who report symptoms consistent with reduced BP upon
standing (e.g., light-headedness, dizziness, syncope).
GERONTOLOGIC CONSIDERATIONS: HYPERTENSION
• The prevalence of hypertension increases with age. The lifetime risk of developing
hypertension is around 90% for normotensive men and women over age 55.
• In some older people, there is a wide gap between the first Korotkoff sound and
subsequent beats (auscultatory gap). Failure to inflate the cuff high enough may result
in an inaccurate SBP.
• BP goals in people older than 65 years of age who live independently are no different for
other independent living adults under 65 years old. Adults over 65 who are not
independent with comorbidities should have drugs added and titrated using clinical
judgement and patient preference as the guide.
• Orthostatic hypotension often occurs in older adults because of impaired baroreceptor
reflex mechanisms, volume depletion, and chronic disease states, such as decreased
renal and hepatic function or electrolyte imbalance.
HYPERTENSIVE CRISIS
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• Hypertensive crisis is a term used to indicate either a hypertensive urgency or emergency.
Diagnosis is determined by the presence of target organ disease and the type of
treatment the patient will receive.
• Hypertensive urgency has no clinical evidence of target organ disease.
1. Hypertensive urgencies usually do not need IV drugs but can be managed with oral therapy.
2. A patient with hypertensive urgency who is not hospitalized should have outpatient follow-up
care within 24 hours.
• Hypertensive emergencies have evidence of target organ disease. It needs hospitalization with
intensive care monitoring and the IV administration of antihypertensive drugs, including
vasodilators, adrenergic inhibitors, ACE inhibitors, and/or calcium channel blockers. Drugs are
titrated based on the MAP.
• Regular, ongoing assessment (e.g., ECG monitoring, vital signs, urinary output, level of
consciousness, visual changes) is essential to evaluate the patient with severe hypertension.
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