Hypertension: Nursing Care Management and Study Guide

Hypertension is the silent killer for a reason: most patients have no symptoms until an organ is already damaged. On the floor your job is accurate, repeated blood pressure measurement, watching for target-organ damage (heart, brain, kidneys, eyes), and driving adherence to medication and lifestyle change.

What is Hypertension?

Hypertension is a systolic blood pressure greater than 140 mmHg and a diastolic pressure greater than 90 mmHg, based on the average of two or more accurate measurements taken at two or more visits. That definition comes from the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.

Classification

In 2017 the American College of Cardiology and American Heart Association revised their guidelines. The previous thresholds were 140/90 mm Hg for younger people and 150/80 mm Hg for those ages 65 and older. The current categories: normal is less than 120 and less than 80 mmHg; elevated is 120 to 129 systolic with less than 80 diastolic; stage 1 is 130 to 139 systolic or 80 to 89 diastolic; stage 2 is 140 or higher systolic or 90 or higher diastolic.

Pathophysiology

Each heartbeat transfers pressure to the blood, which then exerts pressure against the vessel walls. Hypertension is multifactorial. Excess sodium intake drives renal sodium retention, expanding fluid volume and raising preload and contractility. Obesity produces hyperinsulinemia and structural hypertrophy, increasing peripheral vascular resistance. Genetic alteration of the cell membrane causes functional constriction, which also raises peripheral vascular resistance.

Epidemiology

About 31% of US adults have hypertension. African-Americans carry the highest prevalence at 37%. Of all people with hypertension, 90% to 95% have primary hypertension from an unidentified cause, and the remaining 5% to 10% have secondary hypertension from an identified cause. The "silent killer" label holds: 24% of people with pressures exceeding 140/90 mmHg were unaware their blood pressure was elevated.

Causes

Increased sympathetic nervous system activity follows dysfunction of the autonomic nervous system. Increased renal reabsorption of sodium, chloride, and water reflects a genetic variation in how the kidneys handle sodium. Increased renin-angiotensin-aldosterone system activity expands extracellular fluid volume and raises systemic vascular resistance. Damage to the vascular endothelium reduces arteriolar vasodilation.

Clinical Manifestations

Most patients are asymptomatic at first, and physical exam may reveal nothing but the elevated pressure, so recognize it early. Constricted vessels limit oxygen delivery to the brain, producing headache and dizziness. Chest pain follows decreased oxygen, and blurred vision occurs later when the vessels of the eye constrict enough to block oxygen-carrying red cells.

Prevention

Prevention rests on a healthy lifestyle. Maintain normal body weight. Adopt the DASH diet, rich in fruits, vegetables, and low-fat dairy. Hold dietary sodium to no more than 2.4 g per day. Do regular aerobic activity for 30 minutes three times a week. Limit alcohol to no more than 2 drinks per day in men and one drink in women and lighter-weight people.

Complications

Untreated hypertension damages multiple organs. The heart pumps against high pressure until the muscle weakens, producing heart failure. Vessel constriction cuts oxygen to the myocardium and can cause MI. Ineffective perfusion of the eye impairs vision, and constricted renal vessels lead to renal failure.

Assessment and Diagnostic Findings

Assessment

Take a full health history, perform a physical exam, examine the retinas for organ damage, and draw labs to check for target-organ damage.

Diagnostic Tests

Urinalysis checks urine sodium concentration through specific gravity and may show blood, protein, white cells, or glucose suggesting renal dysfunction or diabetes. Blood chemistry (sodium, potassium, creatinine, fasting glucose, total and HDL cholesterol) gauges sodium and lipid load. A 12-lead ECG rules out cardiovascular damage and may show an enlarged heart, strain patterns, or conduction disturbances; a broad, notched P wave is one of the earliest signs of hypertensive heart disease. Echocardiography assesses left ventricular hypertrophy. Creatinine clearance, BUN, and creatinine evaluate renal perfusion and function and may be reduced with renal damage. Renin level shows how the RAAS is coping and is elevated in renovascular and malignant hypertension and salt-wasting disorders.

Hemoglobin and hematocrit gauge the cell-to-fluid relationship (viscosity) and flag hypercoagulability or anemia. Glucose may show hyperglycemia, since diabetes precipitates hypertension. Serum potassium may reveal hypokalemia from primary aldosteronism or diuretic therapy. Serum calcium imbalance can contribute. A lipid panel (total lipids, HDL, LDL, cholesterol, triglycerides, phospholipids) flags atheromatous plaque risk. Thyroid studies catch hyperthyroidism. Serum or urine aldosterone assesses primary aldosteronism. Urine VMA, a catecholamine metabolite, is elevated with pheochromocytoma; a 24-hour urine VMA may be done if hypertension is intermittent. Uric acid is a risk marker. Urine steroids may indicate hyperadrenalism, pheochromocytoma, pituitary dysfunction, or Cushing's syndrome. IVP identifies causes of secondary hypertension such as renal parenchymal disease or calculi. Kidney and renography nuclear scan evaluates renal status, and excretory urography may reveal renal atrophy from chronic disease. Chest x-ray may show valve calcification, aortic notching, or cardiac enlargement, and CT assesses for cerebral tumor, CVA, encephalopathy, or pheochromocytoma.

Medical Management

The goal is to prevent complications and death by keeping arterial pressure at or below 130/80 mmHg. Antihypertensives lower peripheral resistance, blood volume, or the strength and rate of myocardial contraction. For uncomplicated hypertension, start with diuretics and beta blockers at low doses; if pressure still exceeds 140/90 mmHg, raise the dose gradually. Thiazide diuretics lower blood volume, renal blood flow, and cardiac output. ARBs competitively inhibit aldosterone binding. Beta blockers block the sympathetic nervous system for a slower rate and lower pressure. ACE inhibitors block conversion of angiotensin I to angiotensin II and lower peripheral resistance. For stage 1, a thiazide diuretic is recommended for most, with an ACE inhibitor, aldosterone receptor blocker, beta blocker, or calcium channel blocker considered. Stage 2 usually uses a two-drug combination, typically a thiazide diuretic plus an ACE inhibitor, beta blocker, or calcium channel blocker.

Nursing Management

Nursing Assessment

Monitor blood pressure at frequent, routinely scheduled intervals. If the patient is on antihypertensives, assess pressure to judge effectiveness and detect change. Take a complete history for signs of target-organ damage and note the rate, rhythm, and character of the apical and peripheral pulses.

Diagnosis

Common diagnoses include deficient knowledge about the link between treatment and disease control, noncompliance with the regimen related to medication side effects, risk for activity intolerance related to an oxygen supply-demand imbalance, and risk-prone health behavior related to required lifestyle change.

Nursing Care Plan and Goals

Goals: understanding of the disease and treatment, participation in self-care, absence of complications, blood pressure within acceptable limits, prevention of cardiovascular and systemic complications, and a discharge plan in place.

Nursing Priorities

Maintain and enhance cardiovascular function, prevent complications, provide information about the disease and treatment, and support active patient control of the condition.

Nursing Interventions

Refer the patient to a dietitian for a plan to improve nutrient intake or lose weight. Encourage restriction of sodium and fat, more fruits and vegetables, regular physical activity, limited alcohol, and no tobacco, and help the patient adopt and stick to an appropriate exercise regimen.

Evaluation

Expected outcomes: blood pressure maintained at less than 140/90 mmHg with lifestyle changes, medication, or both; no angina, palpitations, or visual changes; stable BUN and serum creatinine; palpable peripheral pulses; adherence to diet, exercise, and medication with reported side effects; routine self-monitoring; abstinence from tobacco and alcohol; and no complications.

Discharge and Home Care Guidelines

Promote self-care and independence. Educate the patient on managing blood pressure, help set goal pressures, arrange social support, involve family in the education program, and provide written information on expected effects and side effects. Teach home blood pressure measurement and stress strict adherence to followup appointments.

Documentation Guidelines

Document the effect of behavior on the condition; the plan and the people involved; patient responses to interventions, teaching, and the action plan; progress toward outcomes; modifications to the plan; individual findings including any deviation from the prescribed plan; and the consequences of actions to date.