Hypertension

Blood pressure is the force of blood exerted on the vessel walls. Systolic pressure is the pressure during the contraction phase of the heart and is evaluated as the top number of the blood pressure reading. Diastolic pressure is the pressure during the relaxation phase of the heart and is evaluated as the lower number of the blood pressure reading. A diagnosis of hypertension is made by a blood pressure value greater than 140/90 obtained on two separate occasions with the client sitting, standing, and lying. In clients with diabetes, a reading of 130/85 or higher is considered to be hypertension.

Accuracy of the BP reading depends on the correct selection of cuff size. The bladder of the blood pressure cuff size should be sufficient to encircle the arm or thigh. According to the American Heart Association, the bladder width should be approximately 40% of the circumference or 20% wider than the diameter of the midpoint of the extremity. A blood pressure cuff that’s too small yields a false high reading, whereas a blood pressure cuff that’s too large yields a false low reading.

Hypertension is classified as either primary or secondary. Primary hypertension, or essential hypertension, develops without apparent cause; secondary hypertension develops as a result of another illness or condition. Symptoms associated with secondary hypertension are improved by appropriate treatment of the contributing illness. Blood pressure fluctuates with exercise, stress, changes in position, and changes in blood volume. Medications such as oral contraceptives and bronchodilators can also cause elevations in blood pressure. Often the client with hypertension will have no symptoms at all or might complain of an early morning headache and fatigue. This silent killer, if left untreated, can lead to coronary disease, renal disease, strokes, and other life-threatening illnesses.

Management of hypertension includes a program of diet and exercise. If the client’s cholesterol level is elevated, a low-fat, low-cholesterol diet is ordered. The total serum cholesterol levels should be less than 200 mg/dl.

Medications Used to Treat Hypertension

Should diet and exercise prove unsuccessful in lowering the blood pressure, the doctor might decide to prescribe medications such as diuretics or antihypertensives. Table 13.1 includes drugs used to treat hypertension.

Table 13.1. Hypertension Drugs

Drug Category	Drug Types
Diuretics	Thiazide: Chlorothiazide (Diuril), hydrochlorothiazide (Esidrix, HydroDiuril) Loop diuretics: Furosemide (Lasix), ethacrynic acid (Edecrin) Potassium-sparing diuretics: Spironolactone (Aldactone), triamterone (Dyrenium)
Beta blockers	Propanolol (Inderal), atenolol (Tenormin), nadolol (Corgard), Carvedilol (Coreg)
Calcium channel blockers	Nifedipine (Procardia), verapamil (Calan), diltiazem hydrochloride (Cardizem)
Angiotensin converting enzyme inhibitors	Captopril (Capoten), enalpril (Vasotec), lisinopril (Zestril, Prinivil)
Angiotensin receptor blockers	Candesartan (Altacand), losartan (Cozaar), telmisartan (Micardis)

These drugs can be used alone or in conjunction with one another. Diuretics and vasodilators are often given in combination to lower blood pressure through diuresis and vasodilation. Hypertensive crisis exists when the diastolic blood pressure reaches 140. Malignant hypertension is managed with administration of IV Nitropress, nitroglycerine, Nipride, Lasix, and other potent vasodilators such as Procardia.