Hypertension Blog

When your hypertensive patient begins an exercise program, teach him about the prescribed exercise. Monitor his exercise tolerance and continue to regularly measure his blood pressure.During your patient teaching, tell him to exercise at the same time every day. Instruct him to wear loose-fitting clothing and to wear shoes that properly support his feet. If his exercise consists of walking, tell him to walk at a comfortable pace on level ground. Also, urge him to carry identification and a list of the drugs he’s taking.

Hypertensive patients with other health problems may need special devices, such as braces or splints, to assist them in an exercise program. Assess your patient’s overall physical status and consult with a physical therapist or cardiac rehabilitation specialist for exercise suggestions.

To help your patient adapt his exercise program to his needs and tolerance level, advise him to measure his pulse rate before and immediately after he exercises. He can use his pulse as a guide to increasing or decreasing his activity. Also, tell him to assess himself after 5 minutes of exercise. He should feel warm, not hot and sweating.

Until the patient knows his exercise tolerance, he should exercise with someone else. Instruct him to stop exercising if he becomes extremely tired, short of breath, dizzy, or light-headed. If he develops chest pain, palpitations, or tingling, numbness, or pain in his arms or legs, he should stop exercising and contact his physician. Tell him to seek emergency care if any of these symptoms persists for more than 15 minutes after the exercise activity is stopped.

Review the key elements of the exercise program with your patient. Provide suggestions to help him comply with the plan and stress the importance of exercise for managing his hypertension. Encourage him to do exercises that he enjoys so that he’ll be more likely to do them regularly.

Advise your patient to set realistic goals and advance his exercise program at his own pace. To ensure compliance, suggest that he join a walking group such as one that walks in malls.

Monitor the success of your patient’s exercise program by checking his blood pressure and resting heart rate weekly. If his blood pressure decreases, emphasize the success of the exercise program to encourage continued compliance.

Aortic aneurysms-dilated segments of the aorta-are more common in men ages 50 to 70. Hypertension increases the risk of a patient developing an aortic aneurysm by accelerating atherosclerosis in peripheral blood vessels. If an aortic aneurysm is larger than 6 mm in diameter, it has a 50% chance of rupturing within a year.

Pathophysiology

An aortic aneurysm results from atherosclerotic plaque formation on the aorta’s walls. These plaques, consisting of lipids, cholesterol, fibrin, and other debris, cause degenerative changes in the aorta’s medial layer. The aorta loses elasticity and becomes weak. The pulsatile flow of the blood places additional stress on the weakened aorta, causing it to dilate, thus forming an aneurysm.

The growth rate of an aortic aneurysm can’t be determined, but the larger the aneurysm, the greater the risk of rupture. An aneurysm can form anywhere along the aorta. But the most common location is the abdominal aorta below the renal arteries. Typically, an abdominal aortic aneurysm involves the iliac arteries at the point of bifurcation.

Aneurysms are divided into two classifications: true aneurysms and false aneurysms. In a true aneurysm, at least one layer of the aorta remains intact. One-fourth of true aneurysms occur in the thoracic region and three-fourths occur in the abdominal region. A true aneurysm may be a fusiform or saccular dilation .

A false aneurysm is a disruption of all three layers of the aorta. This condition results in blood leakage into a contained area.

The rupture of an aortic aneurysm is a life­threatening complication. If the rupture causes bleeding into the retroperitoneal space, it may be stopped by compression from the nearby organs. Bleeding into the abdominal cavity is fatal.

Alcohol

When obtaining your patient’s health history, ask him how much alcohol he drinks. If appropriate, advise him to reduce his intake to less than 1 ounce per day.

The exact mechanism by which alcohol raises blood pressure isn’t known, but alcohol may increase renin or aldosterone release. Chronic alcohol abuse

can also increase blood cortisol levels, which can aggravate hypertension.

Alcohol consumption also affects weight reduction. Alcohol provides empty calories. Plus, one or two drinks a day can slow a person’s metabolism by as much as 25%. Drinking three or more alcoholic drinks a day also increases a person’s risk of hypertension.

Caffeine

By constricting the peripheral blood vessels, caffeine increases the heart rate and blood pressure. Therefore, you should encourage your hypertensive patient to reduce his intake of caffeinated beverages. Tell him that most drinks such as coffee, tea, and soda are now available in caffeine-free preparations. Also, teach him that many other products contain caffeine, including foods such as chocolate and over-the-counter (OTC) drugs used for the treatment of headaches.

Sodium

You should advise your patient to limit his sodium intake, especially if he’s sodium sensitive. Restricting sodium intake may reduce extracellular fluid and total circulating blood volume, thus decreasing the heart’s workload.

Sodium may interfere with the effectiveness of certain antihypertensive drugs. Thus, by limiting his sodium intake, the patient may be able to control his blood pressure with lower doses of antihypertensive drugs. And by using lower dosages, he will have less risk of developing adverse effects from the drugs.

Usually, sodium is restricted to 2 grams of sodium or 5 grams of salt per day. A patient can achieve this restriction by not adding table salt to food and by avoiding foods that are high in sodium.

Hypertension is a major modifiable risk factor for CAD. Normally, CAD takes years to develop, but hypertension accelerates the atherosclerotic process that causes CAD. Then, as CAD progresses, the resulting arterial narrowing worsens the hypertension.

Its Pathophysiology

In CAD, atherosclerotic plaques collect in the arteries. These deposits, which line the intimal layer, consist of cholesterol and lipids.

In a person with hypertension, the elevated blood pressure causes high shear stress, speeding the atherosclerotic process. As a result, the artery’s endothelial lining is injured. Then, platelets begin to accumulate at the site of the damage, resulting in a denuding injury.

Alternatively, hypertension can result when CAD causes a non denuding injury. After the endothelium is damaged, low-density lipoproteins (LDLs) and growth factor from platelets stimulate smooth-muscle proliferation and arterial-wall thickening. Smooth-muscle cells proliferate, trapping lipids. Over time, the lipids calcify and irritate the endothelium, causing platelets to adhere and aggregate. Thrombin is generated, and fibrin and thrombi form.

With denuding and nondenuding injuries, the thickened walls of atherosclerotic arteries lose their elasticity. Thus, the heart must beat harder to pump blood through the restricted vessels, increasing blood pressure even more .

At first, many patients with hypertension have no symptoms. As the disease progresses, some patients actually become accustomed to its symptoms-headaches, dizziness, and blurred vision­and view them as insignificant. Thus, diagnosing and treating hypertension may require a thorough patient assessment. This usually includes obtaining and interpreting a patient’s health history, performing a physical examination, taking blood pressure readings, and monitoring the results of diagnostic tests.You also may use your assessment skills to help identify someone who may develop hypertension. And you may use them to evaluate a patient who has just been diagnosed with hypertension, to monitor a hypertensive patient’s treatment, and to detect complications resulting from hypertension.

Echocardiography uses sound waves to evaluate the heart’s structure and function. In this test, a transducer is positioned on various areas of the chest. The transducer emits sound waves, which make contact with the heart and are then recorded on a monitor as moving images of it. Using this test, a physician can observe a patient’s systolic and diastolic function, calculate the sizes of the cardiac chambers, measure left ventricular wall thickness, and measure valve areas.An echocardiogram can accurately detect ischemia or left ventricular hypertrophy resulting from hypertension. On an echocardiogram, ischemic changes appear as wall-motion abnormalities. However, standard echocardiography may not detect ischemia of the left ventricle.

To detect such ischemia, a physician may order stress echocardiography. This test is performed immediately after the patient exercises. Patients who can’t exercise are tested by pharmacologic stress echocardiography. Dobutamine, an inotropic agent, is administered I.V. as the patient lies in bed. The examiner gradually increases the dose until the patient’s heart rate mimics an exercise heart rate. Then, echocardiography is performed to evaluate the heart wall for motion abnormalities.

Echocardiography also helps in evaluating a patient’s response to hypertensive therapy. For instance, calcium channel blockers can decrease left ventricular hypertrophy and the occurrence of arrhythmias; follow-up echocardiographic testing can verify this response to therapy.

Stress or pharmacologic stress echocardiograms are usually performed when cardiac isoenzymes have returned to normal 7 to 10 days after surgery or an acute ML And some patients then have these tests performed several months later so that the physician can evaluate therapy and progress.

Nursing Considerations

When preparing a patient for an echocardiogram, advise him that he may feel some discomfort during the test because the technician must place the transducer firmly between the ribs to enhance sound-wave transmission and diminish interference. Also, advise your patient that he’ll have to lie quietly for 30 to 45 minutes, depending on the technical quality of sound-wave transmission and the cardiac images.

Treatment usually begins in the emergency department and continues in the intensive care unit (ICU).The vasodilator of choice for emergency hypertension is sodium nitroprusside administered at 0.3 to 10 µg/kg/minute . By working directly on the vessels, this drug immediately lowers the patient’s blood pressure. After his blood pressure has been stabilized and he has begun taking an oral antihypertensive drug, sodium nitroprusside can be discontinued.

Several other antihypertensive drugs also are commonly used to treat emergency hypertension. Drugs with a short duration of action are preferred because hypotensive effects can be reversed quickly by reducing the dose or stopping the drug.

A physician prescribes the drug regimen based in part on the complications the patient has. Depending on the complication, a physician may need to prescribe a vasodilator other than nitroprusside (nitroglycerin, diazoxide, or hydralazine), an adrenergic blocker (phentolamine mesylate or labetalol), an ACE inhibitor (enalapril), a ganglionic blocker (trimethaphan), or a calcium channel blocker (nicardipine).

Nitroglycerin

Nitroglycerin dilates veins and arterioles. It also decreases preload and afterload. To treat emergency hypertension, you’ll administer nitroglycerin at a rate of 5 to 10 µg/ minute and increase the rate by 5 µg/minute every 3 to 5 minutes, as ordered. If the patient’s blood pressure doesn’t decrease by the time he’s receiving 20 µg/minute, increase the rate by 10 to 20 µg/minute, as prescribed, until the desired blood pressure is reached. Typically, nitroglycerin begins working in 5 minutes.

A patient receiving nitroglycerin may experience orthostatic hypotension, tachycardia, flushing, and headache. Also, he may develop a tolerance to the drug over time.

Diazoxide

Diazoxide dilates arteriolar smooth muscle. It’s administered to treat emergency hypertension in doses of 50 to 150 mg every 5 minutes as an I.V. bolus or 7.5 to 30 mg/minute as an I.V. infusion. Diazoxide begins working 1 to 5 minutes after administration.

A patient receiving diazoxide may experience nausea, vomiting, abdominal discomfort, hyperglycemia, tachycardia, hypotension, sodium retention, fluid retention, and angina. Diazoxide may exacerbate an MI, heart failure, and an aortic dissection. It also may trigger cerebral ischemia.

When administering diazoxide, don’t mix it with other drugs. Protect the drug from light. And inject it rapidly, in less than 30 seconds, to overcome protein binding.

During and after administration, monitor your patient’s blood glucose level. Also, monitor him for sodium and fluid retention. If he’s retaining sodium and fluid, he may need a diuretic.

Hydralazine

Typically, a physician prescribes hydralazine, which dilates arteriolar smooth muscle, for patients with renal insufficiency because it doesn’t compromise renal function. For emergency hypertension, the drug usually is administered as an I.V. bolus of 5 to 20 mg. It begins to work in 5 to 20 minutes.

A patient receiving hydralazine may experience tachycardia, palpitations, headache, fluid retention, nasal congestion, gastrointestinal (GO symptoms, angina, and an Ml. If the patient shows signs and symptoms of lupus-like syndrome, discontinue the drug.

Phentolamine Mesylate

A physician may prescribe phentolamine mesylate, an alpha-blocker, for emergency hypertension resulting from elevated catecholamine levels, clonidine withdrawal, and interactions between monoamine oxidase inhibitors and tyramine.

Phentolamine mesylate is administered as an I.V. bolus dose of 2.5 mg. You can also give a subsequent I.V. bolus of 5 mg, as ordered. Usually, the drug begins working within seconds.

A patient receiving phentolamine mesylate may experience tachycardia, dry mouth, flushing, nausea, vomiting, MI, arrhythmias, angina, and hypotension.

Labetalol

Labetalol, an alpha-blocker and beta-blocker, is prescribed for emergency hypertension resulting from elevated catecholamine levels and antihypertensive drug withdrawal. It’s prescribed for patients with emergency hypertension who have had an MI and for those with an aortic dissection. It also is prescribed for emergency hypertension in patients with renal failure because the drug doesn’t compromise renal perfusion.

For emergency hypertension, labetalol is administered as an I.V. infusion at a rate of 0.5 to 2 mg/minute or as an I.V. bolus in doses of 20 to 80 mg every 10 minutes. The maximum cumulative dose for the drug is 300 mg. Usually, it begins to work in 5 minutes.

A patient receiving labetalol may experience orthostatic hypotension, bronchospasm, nausea, vomiting, heart failure, and arrhythmias. When administering the drug, monitor the patient for heart failure and heart block.

Enalapril

Enalapril, which suppresses the renin-angiotensin­aldosterone system, is prescribed for emergency hypertension in I.V. doses of 0.625 to 1.25 mg over 5 minutes. You also can give it in subsequent 1.25 mg doses every 6 hours, as ordered. Usually, the drug begins to work in 5 to 15 minutes.

A patient receiving enalapril may experience proteinuria, renal failure, loss of taste, hyperkalemia, tachycardia, neutropenia, and agranu­locytosis. If the patient has hypovolemia or is taking a diuretic when enalapril is administered, he also may experience excessive hypotension.

Trimethaphan

Trimethaphan blocks transmission in the autonomic ganglia, exerting a direct peripheral vasodilator effect. A physician prescribes it for patients who have emergency hypertension and acute aortic dissection because it reduces blood pressure and reduces the sharpness of the pulse wave produced by ventricular contractions.

Trimethaphan is administered I.V. in 500 mg doses diluted in 500 ml of dextrose 5% in water or 0.9% normal saline solution and infused at a rate of 0.5 to 5 mg/minute. Then, it’s titrated until the desired blood pressure is reached. Usually, the drug begins to work in 1 to 2 minutes.

A patient receiving trimethaphan may experience intestinal and bladder paresis, blurred vision, dry mouth, respiratory arrest, orthostatic hypotension, paralytic ileus, and urticaria.

Nicardipine

Nicardipine, a calcium channel blocker, dilates the arterioles. It’s prescribed for emergency hypertension in patients with renal failure because it doesn’t compromise renal perfusion.

Nicardipine is administered by I.V. infusion at a rate of 5 to 15 mg/hour. Usually, it begins to work in 1 to 15 minutes.

A patient receiving nicardipine may experience tachycardia, nausea, vomiting, flushing, and headache. The drug is contraindicated in a patient who has aortic stenosis.

Instruct your patient in lifestyle modifications to manage his hypertension. Help him develop a diet plan to reduce his sodium intake and reduce his weight. Also, help him develop an exercise program.If the physician has prescribed an antihypertensive drug, teach your patient the name of the drug, its dosage, and its therapeutic and adverse effects. Explain the relationship between untreated hypertension and chronic complications, such as retinopathy.

Tell the patient that he’ll need regular ophthalmic examinations to detect and monitor retinal changes. Teach him the signs and symptoms of retinal detachment, such as dark irregular floaters, flashes of light, blurred vision, and a progressively enlarged dark area in his field of vision. Tell him to report any of these signs and symptoms to the physician immediately.

If your patient can’t care for himself because of vision limitations, he may require evaluation for home care assistance. If necessary, refer him to an occupational or physical therapist for suggestions on assistive devices and ways he can adapt his home to meet his needs.

Some More Facts

Focus on controlling your patient’s blood pressure. Administer an antihypertensive drug, as ordered. Also, instruct your patient in lifestyle modifications that can help control his hypertension, including limiting his sodium intake, losing weight, and exercising.

If your patient with hypertensive retinopathy is a pregnant woman, monitor her for signs and symptoms of eclampsia and worsening hypertension, which can cause retinal detachment from fluid leaking under the retina. Administer an antihypertensive drug, as ordered. When her hypertension is controlled, the retinal detachment may resolve.

Teach your patient about the various therapies that can work in conjunction with drug therapy and lifestyle modifications. If necessary, refer him to local community agencies for classes taught by qualified instructors. And advise him that patient participation in stress-reducing activities is an important adjunct to medical treatment.

Treating a patient with CAD involves risk-factor management, drug therapy, and, if needed, invasive procedures or surgery. Treatment has two goals -

• Reducing myocardial oxygen demand
• Increasing oxygen supply.

Invasive Procedures and Surgery

In severe cases of CAD, a patient may require an invasive procedure to relieve the signs and symptoms of the disease. Several procedures use a balloon-tip coronary artery catheter to restore blood flow to blocked coronary arteries by enlarging the arterial lumen.

The most common of these procedures is percutaneous trans luminal coronary angioplasty, which uses balloon inflation to clear arteries. Other procedures include intra-coronary stenting, atherectomy, and laser angioplasty.

A physician performs these procedures in a cardiac catheterization laboratory using coronary angiography to evaluate progress. He inserts a femoral artery sheath and threads a catheter with a balloon, rotor blade, or laser tip through the aorta into the affected coronary vessel.

When the procedure is complete, the physician removes the catheter but leaves the sheath in place for up to 8 hours. Most patients receive a heparin infusion during the procedure and for several hours afterward. Some require long-term anticoagulant therapy.

If the procedure fails to remove the blockage, the patient usually will need coronary artery by­pass grafting. This surgery involves bypassing the occluded artery with a graft from a saphenous vein or internal mammary artery. The graft is sutured to the aorta and anastomosed to the affected coronary artery.

Coronary Artery Bypass Grafting

If your patient is scheduled for coronary artery bypass grafting, thoroughly assess his cardiovascular status before the operation.

After the procedure, monitor your patient’s hemodynamic status. Maintain the patency of his chest tube (or tubes) and assess tube drainage. Also, observe the surgical wound for signs and symptoms of infection and provide routine wound care as necessary.

Monitor the patient’s fluid balance and serum electrolyte levels. Administer fluids, blood products, or vasoactive infusions, as ordered. Record his fluid intake and output and daily weights.

Monitor the patient’s breath sounds and chest X-ray results for signs of atelectasis. Help him increase his activity level gradually, following the guidelines of his cardiac rehabilitation program.

Coronary Artery Catheterization

lf your patient is scheduled for coronary artery catheterization, explain the procedure to him and answer any questions. Tell him that he’ll be awake during the procedure and that he may be asked to assist with catheter placement by taking deep breaths.

After the procedure, your patient’s arterial and venous sheaths may remain in place for up to 8 hours, if he has received a thrombolytic drug. Connect the sheaths to a heparin flush setup to maintain patency. Ask the patient about back pain, a possible indication of retroperitoneal bleeding from the sheath site. And frequently check the insertion site for signs of bleeding.

Instruct your patient to keep the affected leg straight and to stay in bed with the head of the bed at a 45-degree angle or less.

After the sheaths have been removed and hemostasis has been achieved, a pressure dressing will be applied. Frequently assess the circulation of the affected leg by checking its warmth, color, and distal pulses. Watch your patient for signs and symptoms of complications, such as chest pain, shortness of breath, and changes in mental status. Monitor his heart rate and rhythm carefully. Also, monitor him for angina, which could be caused by coronary vasospasm or reocclusion. Report any unusual findings to the physician.

Regular isotonic exercise-such as walking, jogging, and swimming-can help control blood pressure. Generally, hypertensive patients should participate in a moderate amount of exercise at regular intervals, rather than vigorous exercise at irregular intervals.The short-term benefits of exercise include stress reduction and appetite suppression. Over time, exercise promotes effective blood flow, increases oxygen consumption, and strengthens the cardiac muscle. With stronger muscle, the heart beats more efficiently. Also, blood flows more easily through the vessels and at a lower pressure, thereby reducing systolic blood pressure.

Isotonic exercises, which are recommended for hypertensive patients, don’t put unnecessary strain on the heart. However, isometric exercises such as weight lifting significantly raise blood pressure. And participating in isometric exercises increases a hypertensive patient’s risk of sustaining an acute myocardial infarction (MI) or cerebrovascular accident.

Isometric exercises are not recommended because they also increase muscle tension and demand more oxygen. In hypertensive patients, the heart contracts with greater force than normal, so blood flows through the vessels with greater force. Hypertension also causes the arterioles and capillaries to be rigid. Therefore, blood flow through these vessels to the muscles may not meet the increased oxygen demands of isometric exercise. As exercise tolerance decreases, the muscles cramp, and a hypertensive patient may faint from lack of oxygen to the tissues.

Exercise Plan

Patients with known cardiac disease or other health problems need a thorough examination, including stress testing monitored by electrocardiography (ECG) , before beginning an exercise plan. Also, the patient’s physician should approve the program.

Walking is the ideal exercise for the hypertensive patient. The amount of walking should be increased gradually to establish exercise tolerance and to reduce the effects of overexercise .