Diagnostic Tests

Computed tomography (CT) and magnetic resonance imaging help rule out other causes of your patient’s severe headache, such as a CVA. Imaging may reveal areas of hemorrhage ranging in size from pinpoint to massive.

A lumbar puncture is contraindicated because of the patient’s high ICP. Introducing a needle into the central canal of his spinal cord would cause cerebrospinal fluid (CSF) to gush, and the sudden and dramatic decrease in CSF could force delicate brain tissue to herniate into the spinal canal, resulting in immediate death

Usually, a physician prescribes an antihypertensive drug to rapidly reduce ICP and arterial blood pressure and to maintain diastolic blood pressure at about 100 mm Hg. The drugs used to treat hypertensive encephalopathy include vasodilators, beta-blockers, and osmotic diuretics. Most commonly, a physician prescribes the vasodilator nitroprusside. Vasodilators relax vascular smooth muscle, which reduces peripheral artery and vein dilation. Beta-blockers may be used to reduce vascular resistance.

The physician may prescribe mannitol, an osmotic diuretic, if the patient already shows signs and symptoms of cerebral edema. Although osmotic diuretics reduce ICP, they’re contraindicated in patients with active cerebral bleeding. The adverse effects of osmotic diuretics-confusion, convulsions, dizziness, disorientation, headache, rebound increased ICP, and syncope-can mimic a worsening neurologic condition .

Although rapidly reducing your patient’s blood pressure will dramatically improve the symptoms of hypertensive encephalopathy, he’ll require continued close monitoring in an ICU.

Many types of diuretics are used to mobilize edematous fluid, reduce pulmonary vein pressure, and reduce preload. Usually, a physician first prescribes a thiazide diuretic. These drugs reduce hypertension and treat edema by inhibiting sodium reabsorption in the distal renal tubule and promoting sodium and water excretion. If your patient has pulmonary edema, his physician also may prescribe morphine to reduce preload and control anxiety.By acting on the loop of Henle, loop diuretics also promote sodium and water excretion. With thiazide or loop diuretics, the patient may need potassium supplements. Or the physician may prescribe potassium sparing diuretics if the patient is prone to hypokalemia.

The only class of drugs that improves survival in patients with heart failure, vasodilators reduce systemic vascular resistance and pulmonary and peripheral vein pressures, increase left ventricular stroke volume and CO, and enhance myocardial function by reducing myocardial oxygen demand. Sodium nitroprusside, a potent vasodilator, commonly is administered for acute heart failure.

A physician also may prescribe an ACE inhibitor. These drugs prevent the conversion of angiotensin I to angiotensin II, thus increasing CO by reducing systemic vascular resistance.

If the physician has prescribed an antihypertensive drug to control hypertension, administer the drug, as ordered, and monitor your patient’s blood pressure. During the acute phase of an aortic aneurysm, monitor the patient for rupture, which would cause him to progress into shock quickly. Assess him for rapidly declining blood pressure, changes in level of consciousness, cool and clammy skin, and decreasing urine output. Monitor his respiratory rate; it may increase to compensate for decreased circulating oxygenated blood, weakened pulses, and tachycardia.

If your patient undergoes surgery for an aortic aneurysm, focus on maintaining cardiopulmonary and renal function and graft patency postoperatively. Also, monitor him for complications of surgery, such as CVA, renal failure, MI, respiratory insufficiency, and neurologic dysfunction.

To assess cardiopulmonary status, monitor his vital signs, ECG, serum electrolyte levels, and ABG measurements. Assess all peripheral pulses and compare the pulse, warmth, and color in his arms. Monitor his central venous pressure (CVP) readings and treat him for low blood volume as needed. Perform neurologic checks every 30 to 60 minutes, assessing his level of consciousness, pupillary reaction to light, arm and leg movement, and hand grasps.

A thrombus or plaque that breaks loose from the aorta may impair renal perfusion. Hypotension also can reduce renal perfusion. So monitor your patient’s blood pressure and CVP and administer fluids and volume expanders to ensure adequate renal perfusion. Monitor his urine output. Report an output of less than 30 ml/hour for 2 consecutive hours. Also, assess his serum BUN and creatinine levels for adequate renal function.

To assess graft patency, palpate the peripheral pulses distal to the graft. Immediately report to the surgeon a decreased or absent pulse accompanied by cool, mottled skin.

Protect graft patency by preventing hypotension and hypertension. Treat hypotension, which promotes thrombosis, with I.V. fluids, volume expanders, or blood products, as prescribed. Treat hypertension, which puts stress on the graft suture lines, with the prescribed diuretic or other antihypertensive drug.

To monitor your patient for graft infection, check his temperature and WBC count every 4 hours. Observe the operative site for signs of local infection, such as redness, warmth, edema, and purulent drainage. Administer a broad-spectrum antibiotic, as ordered, and encourage coughing and deep breathing.

After surgery, your patient is at risk for paralyticileus resulting from bowel manipulation, anesthesia, pain medication, and immobility. Auscultate his abdomen for the return of bowel sounds. Monitor him for flatus and record his gastric output. Reposition him every 2 hours and encourage earlyambulation.

More Medical Tips

Before your patient undergoes surgery, explain the procedure and outline what he can expect in the ICU, including cardiac, CVP, and pulmonary pressure monitoring and LV. fluid administration. Also, tell him that he may need an arterial line, indwelling urinary catheter, and endotracheal tube.

After his surgery, explain that frequent assessment of vital signs and peripheral pulses is necessary to determine graft patency. Explain the need for early ambulation to prevent complications. Instruct him on coughing, deep breathing, and splinting the incision. Have him perform return demonstrations.

Whether your hypertensive patient had surgery or was successfully treated with drug therapy, he may be prescribed one or more anti hypertensive drugs. Before he goes home, teach him the name of any prescribed drug and its dosage and therapeutic and adverse effects. Instruct him to take his blood pressure at home, and demonstrate how to take a pulse.

Discuss the signs and symptoms of a recurring aneurysm. Stress the need for him to promptly call his physician if signs or symptoms recur.

You can derive two measurements from a patient’s systolic and diastolic blood pressures. These measurements can help in detecting conditions related to a patient’s high blood pressure and in understanding the hemodynamic factors that affect blood pressure. One such measurement, pulse pressure, is the difference between the systolic and diastolic pressures. For instance, if a patient’s blood pressure is 120/80 mm Hg, his pulse pressure is 40 mm Hg. Normally, a patient’s pulse pressure is 30 to 40 mm Hg.

Pulse pressure reflects stroke volume (SV), ejection velocity, systemic vascular resistance, and CO. An increased or widened pulse pressure, such as in a patient with a blood pressure of 160/40 mm Hg, signifies increased SV, which could result from the following conditions:

• high blood pressure
• sinus bradycardia
• complete heart block
• aortic regurgitation
• anxiety
• exercise
• catecholamine production
• arteriosclerosis of the large arteries and aorta.

Increases in pulse pressure reduce a patient’s systemic vascular resistance and may appear when a patient has a fever, is in a hot environment, or has been exercising.

A decreased pulse pressure can be caused by factors such as:

• heart failure, which causes reduced ejection velocity
• hypovolemia
• shock.

A patient’s MAP is the average pressure in the arteries throughout the cardiac cycle as influenced by CO and vascular resistance. This pressure varies in different parts of the body, from about 100 mm Hg in the aorta and large arteries to about 0 mm Hg at the end of the vena caval system.

To calculate a patient’s MAP, use the following formula:

MAP = diastolic pressure + Y3 pulse pressure Using this equation, a patient whose blood pressure is 120/80 mm Hg and pulse pressure is 40 mm Hg would have a MAP of 93.2 mm Hg.

Normally, a patient’s MAP ranges from 70 to 100 mm Hg. An increased MAP occurs with primary hypertension, arterial disease, and epinephrine release, and a decreased MAP can indicate decreased vascular resistance, cardiac failure, or hypovolemia.

The current system for classifying blood pressure in people over age 18 defines normal and high normal blood pressure and four categories of increasingly severe hypertension . A patient who has a reading of 130/85 mm Hg or less and who doesn’t take antihypertensive drugs has normal blood pressure. However, a patient in this category still has some cardiovascular risk unless his blood pressure is less than 120/80 mm Hg. If a patient has unusually low readings, he should be evaluated further.

A patient in the high normal category has a systolic reading between 130 and 139 mm Hg and a diastolic reading between 85 and 89 mm Hg. A patient in this category has an increased risk of developing hypertension and should frequently have his blood pressure monitored. He should also be counseled on lifestyle changes that can reduce his blood pressure.

The four stages of hypertension indicate a patient’s increased risk of developing hypertension ­related complications or diseases such as a cerebrovascular accident (CVA), cardiovascular disease, and renal disease.

All stages of hypertension require treatment, though the specific treatment will vary. If left untreated, hypertension results in damage to organs such as the brain, heart, and kidneys. When noting the stage of a patient’s hypertension, you should also identify any organ disease and additional risk factors. For example, a patient with a blood pressure of 142/94 mm Hg and left ventricular hypertrophy plus diabetes should be classified as having stage 1 hypertension with organ disease (left ventricular hypertrophy) and a major risk factor (diabetes).

If a patient’s systolic and diastolic blood pressures fall into two different categories, he should be classified based on the more severe pressure reading. For example, 160/92 mm Hg should be classified as stage 2 hypertension based on the systolic pressure reading. However, a reading of 205/125 mm Hg should be classified as stage 4 hypertension based on the diastolic reading.

Stages 1 and 2 hypertension

Patients with stage 1 (mild) hypertension have systolic blood pressure readings of 140 to 159 mm Hg and diastolic blood pressure readings of 90 to 99 mm Hg. Stage 2 (moderate) hypertensive patients have systolic blood pressure readings between 160 and 179 mm Hg and diastolic readings between 100 and 109 mm Hg. Of the four stages of hypertension, stage 1 is the most common in adults.

The typical treatment of stages 1 and 2 hypertension involves lifestyle modification and, initially, a single antihypertensive drug, such as a diuretic or a beta-blocker. Some physicians may with­hold drugs from patients with diastolic pressures in the 90 to 94 mm Hg range. However, such patients should be examined in 3 to 6 months to determine if their blood pressure has risen or if they’ve experienced cardiac and vascular changes.

Stages 3 and 4 hypertension

A patient with stage 3 (severe) hypertension has a systolic blood pressure reading between 180 and 209 mm Hg and a diastolic blood pressure reading between 110 and 119 mm Hg. And the patient with stage 4 (very severe) hypertension has a systolic blood pressure reading of 210 mm Hg or more and a diastolic reading of 120 mm Hg or more.

Treatment of stages 3 and 4 hypertension also includes lifestyle modification. However, the patient may also need a second or third antihypertensive drug .

Usually, the early grades of hypertensive retinopathy go undetected. A patient may have no significant signs or symptoms to report nor any apparent reason to seek medical attention.

However, as his diastolic blood pressure remains elevated in grades III and IV, retinal lesions may produce blurred vision and scotomata (blind gaps in his visual field). Papilledema or hemorrhage in the macula can result in blindness.

Diagnostic Tests

A physician uses an ophthalmoscopic examination to diagnose hypertensive retinopathy. This examination is used to detect constricted retinal vessels in grades I and II retinopathy and to detect hemorrhages, yellow exudates, and papilledema in grades III and IV retinopathy.

If the patient has papilledema, the ophthalmo­scopic examination will reveal engorged, tortuous retinal veins, flame-shaped retinal hemorrhages in the superficial nerve fiber layer, and round hemorrhages in the deeper nerve layers.

By interfering with calcium ion influx across the cell membrane, calcium channel blockers inhibit calcium-dependent contraction of vascular smooth muscle. This decreases total peripheral vascular resistance and after load, which reduces blood pressure.Calcium channel blockers include diltiazem hydrochloride, felodipine, nicardipine, nifedipine, and verapamil.

Indications and Contraindications

Physicians commonly prescribe these drugs to treat patients with angina pectoris. However, several oral forms are used to treat vasospasm and mild to moderate hypertension. Parenteral forms are used to treat hypertension, atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. But sustained-release nifedipine is only used to treat hypertension.

Use calcium channel blockers cautiously in patients with heart failure, hypotension, hepatic injury, and renal disease. Do not administer a calcium channel blocker to patients with sick sinus syndrome, second-degree or third-degree heart block, hypotension, acute MI, or pulmonary congestion. Do not administer verapamil to patients with cardiogenic shock or severe heart failure, and administer it cautiously to patients taking beta-blockers.

Adverse Effects and Interactions

The most serious adverse effects of calcium channel blockers include cardiovascular changes such as hypotension, arrhythmias, and worsened eart failure. Other common effects include headache, dizziness, flushing, weakness, and persistent peripheral edema. Your patient may also experience nausea, vomiting, diarrhoea, muscle fatigue, cramps, worsened angina, skin eruptions, photosensitivity, pruritus, nasal congestion, and mood changes.

Calcium channel blockers can interact with beta-blockers, causing heart block and heart failure. When diltiazem is taken with cimetidine, its effect increases. And when it’s administered with cimetidine or ranitidine, felodipine levels increase. Nicardipine increases the effects of digitalis glycosides, neuromuscular blockers, and theophylline. And when nifedipine is administered in combination with theophylline, beta­blockers, other antihypertensives, or digitalis glycosides, it increases their effects.

Quinidine decreases the effects of nifedipine. The hypotensive effects of verapamil increase when the drug is given with prazosin and quinidine. Verapamil also decreases the effects of lithium and increases the blood levels of digoxin, theophylline, cyclosporine, and carbamazepine. Verapamil is incompatible with albumin, amphotericin B, ampicillin, dobutamine, hydralazine, mezlocillin, nafcillin, oxacillin, and sodium bicarbonate.

Direct vasodilators act on arteries and veins. They dilate arteriolar smooth muscle by direct relaxation, reducing systolic and diastolic blood pressure while increasing heart rate and CO.Direct vasodilators include diazoxide, hydralazine hydrochloride, minoxidil, and nitroprusside.

Indications and Contraindications

A physician prescribes diazoxide and nitroprusside to treat patients in hypertensive crisis when an urgent decrease in diastolic blood pressure is needed. Oral hydralazine is used to treat patients with primary hypertension; parenteral hydralazine is used in patients with severe primary hypertension and heart failure. Minoxidil is prescribed when severe hypertension is unresponsive to other therapy.

Don’t administer hydralazine to patients with CAD or rheumatic heart disease. Do not use minoxidil in patients with acute MI, dissecting aortic aneurysm, or pheochromocytoma. And do not administer nitroprusside to patients with compensatory hypertension.

Don’t use diazoxide in patients with hypersensitivity to thiazides or sulfonamide or in patients whose hypertension is caused by coarctation of the aorta, dissecting aortic aneurysm, atrioventricular shunt, or pheochromocytoma. And use it cautiously in patients with tachycardia, fluid and electrolyte imbalances, or impaired cerebral or cardiac circulation.

Adverse Effects and Interactions

Direct vasodilators commonly produce adverse effects related to reflex activation of the sympathetic nervous system, such as palpitations, angina, tachycardia, ECG changes, edema, rash, breast tenderness, fatigue, and headache. Severe pericardial effusions can develop. And alkaline phosphatase, BUN, and creatinine levels may increase.

Diazoxide commonly causes headache, anorexia, nausea, and diaphoresis. It can also cause excessive hypotension, and in diabetic patients, it may cause hyperglycemia. If more serious effects occur, such as rash, urticaria, polyneuritis, GI hemorrhage, anemia, and pancytopenia, diazoxide should be discontinued.

Hydralazine commonly causes headache, diarrhea, constipation, dizziness, orthostatic hypotension, facial flushing, shortness of breath, nasal congestion, urinary hesitancy, edema, tremors, and muscle cramps. It may also cause impotence.

Minoxidil commonly produces hair growth on the face, arms, and back. It also causes reflex tachycardia and fluid retention. When minoxidil is taken with guanethidine, orthostatic hypotension can occur.

Nitroprusside causes headache, dizziness, nausea, vomiting, abdominal pain, and thiocyanate or cyanide toxicity . Severe hypotension occurs when nitroprusside is administered with ganglionic blockers, volatile liquid anesthetics, halothane, enflurane, and circulatory depressants. Nitroprusside is incompatible with any drug in syringe or solution.

When diazoxide is administered with a thiazide diuretic, another antihypertensive drug, warfarin, guanethidine, or a sympathomimetic, its effects increase. It’s incompatible with other drugs in a syringe or solution. Hyperglycemia and hyperuricemia can result when diazoxide is combined with thiazides and other diuretics. The effects of both diazoxide and sulfonylureas decrease when the drugs are given together.

When hydralazine is used with epinephrine or norepinephrine, tachycardia and angina increase. Hydralazine increases the effects of beta-blockers. And it is incompatible with aminophylline, ampicillin, edetate calcium disodium, chlorothiazide, ethacrynic acid, hydrocortisone, mephentermine, methohexital sodium, nitroglycerin, phenobarbital, verapamil, fructose 10%, dextrose 10%, and lactated Ringer’s solution.

If your patient has hypertensive retinopathy, a physician may prescribe an antihypertensive drug to regulate his diastolic blood pressure-typically, a beta-blocker or diuretic. If other drugs or disorders contraindicate these antihypertensive drugs. the physician will prescribe another one, such as an ACE inhibitor. Controlling the patient’s blood pressure may reduce or eliminate the signs and symptoms of retinopathy. However, if he has experienced optic nerve ischemia, he may have a permanent loss of vision.

Complementary Therapies

Stress reduction and management help reduce blood pressure. Therefore, you should urge your patient to identify the stressors in his life and help him develop and implement methods to cope with them.

Relaxation techniques-exercises that reduce stress by decreasing sympathetic nervous system activity-can reduce blood pressure. In combination with drug therapy, these techniques have even been effectively used for patients with severe hypertension. Relaxation techniques include yoga, meditation, physical relaxation, and physical exercise.

Psychotherapy has also been used successfully as a method of lowering blood pressure. It helps patients deal with anxiety and constructively handle hostile and aggressive impulses. Counseling can also help increase patient compliance with the prescribed drug regimen.

Another therapy, biofeedback, uses specialized equipment to give the patient feedback about his bodily processes. The patient learns to achieve relaxation by self-regulating the autonomic nervous system. Biofeedback can decrease blood pressure; however, the long-term effects of biofeed­back and its success in controlling hypertension aren’t known.

Normally, hypertensive patients have a systolic blood pressure of 140 mm Hg or higher or a diastolic pressure of 90 mm Hg or higher on at least two separate occasions. However, even in healthy people, blood pressure fluctuates depending on the time of day and the activities they’ve been performing, so assessing hypertension requires several blood pressure measurements.Obtain at least one reading in both arms with the patient sitting, lying, and standing. A difference of 5 to 10 mm Hg between the arms is normal, but if the difference is more than 10 mm Hg, the patient may have arterial compression or obstruction on the side with the lower pressure.

If a hypertensive patient’s diastolic pressure increases when he stands up from a supine position, he may have primary hypertension. However, if his diastolic pressure decreases when he stands (and he’s not taking an antihypertensive drug), he may have secondary hypertension.

Take at least two measurements separated by at least 2 minutes. If the readings from the same arm vary by more than 5 mm Hg, recheck your technique and take additional readings until you obtain two that are similar. In particular, confirm a high reading with at least two subsequent readings. This helps to rule out white-coat syndrome­elevated blood pressure in response to the stress of having a health care professional take the reading. White-coat syndrome occurs about 20% of the time. Several other factors also can influence the accuracy of blood pressure readings.

Placing the cuff improperly or using a wrong­sized cuff may result in inaccurate readings. For example, using a regular adult cuff on an obese patient may give an incorrectly high reading .

You can use either a mercury or aneroid manometer. But remember that aneroid manometers require monthly calibration to ensure their accuracy.

Patient Preparation

To prepare the patient for blood pressure measurement, make sure you have him remain seated quietly, in a comfortable environment, for at least 5 minutes. Free his arm from clothing by either roIling up the sleeve or having him remove his long-sleeved shirt and offering him a patient gown, if necessary. Then place the arm in a comfortable position. Make sure his arm doesn’t have an AV fistula for dialysis, scarring from brachial artery cut­downs, or lymphedema, which may follow axillary node dissection and radiation therapy.

Palpate for the brachial pulse to make sure it’s present. Before applying the cuff, make sure the brachial artery, located at the crease of the antecubital fossa, is positioned at heart level. If the patient is sitting, a table that reaches just above his waist is usually sufficient. If the patient is standing, support his arm at midchest level. The reading can be falsely elevated if he expends effort keeping his arm up.

Nursing Considerations

If using a mercury manometer, position the gauge vertically with the meniscus at eye level. If using a calibrated aneroid manometer, turn the gauge so that it faces you. Place the cuff on the patient’s arm by centering the inflatable bladder over the brachial artery. Securely fasten the lower border of the cuff about 2.5 cm above the antecubital crease.

Falsely low blood pressure readings commonly occur when the cuff isn’t inflated high enough. To prevent this, first estimate the patient’s systolic blood pressure. Then add 30 mm Hg to this estimated pressure. This number will be the target for subsequent inflations; using it should prevent errors caused by an auscultatory gap. After obtaining the target number, deflate the cuff completely and wait a few minutes before taking an actual measurement .

To obtain the patient’s blood pressure measurement, place the bell of the stethoscope lightly over his brachial artery. The full rim should be in contact with his arm to create an air seal. Remember, the bell of the stethoscope will allow you to hear low-pitched Korotkoff sounds better than the diaphragm will.

Inflate the bladder quickly to the target level. Then deflate it at a rate of 3 mm Hg per second. As the pressure decreases, note the patient’s systolic pressure as the level at which you hear the sounds of at least two consecutive beats.

While continuing to release the pressure in the bladder, listen for the Korotkoff sounds to become muffled and then disappear. Note this level as the patient’s diastolic pressure. Usually, the points where the sounds are muffled and where the sounds disappear differ by only a few mm Hg. However, if the difference is more than 10 mm Hg, record both numbers along with the systolic pressure-for example, you might record a patient’s blood pressure as 160/90/72.

After the sounds have disappeared, continue listening while the pressure decreases another 10 to 20 mm Hg. Then rapidly deflate the cuff to zero.

If the sounds are difficult to hear, have your patient raise his arm and then open and close his hand five to ten times. Quickly inflate the cuff with his arm raised, then lower it and take a reading. This maneuver should help intensify the Korotkoff sounds.

You may also measure blood pressure in a patient’s leg, particularly if you’re trying to detec coarctation of the aorta. Wrap a thigh cuff around his thigh and place the stethoscope bell in the popliteal space. Then obtain the blood pressure measurement just as you would in the arm. If the systolic pressure in the leg is more than 20 mm Hg lower than the brachial systolic pressure, the patient probably has an arterial occlusion.

Another simple technique-the cold pressor test-can be used to enhance blood pressure measurement and help identify the severity of hypertension.

Recognizing Korotkoff Sounds

To accurately assess your patient’s systolic and diastolic blood pressure readings, you need to recognize the variations in the sounds you hear. After you inflate the blood pressure cuff and begin releasing air from it, you’ll hear the first of the five Korotkoff sounds described below. In this example, the blood pressure reading is 140/90 mm Hg.

Phase 1 (systolic blood pressure) A sharp thump, and then tapping.

Phase 2 A murmuring or swishing sound

Phase 3 The murmuring disappears, and sounds increase in intensity and clarity.

Phase 4 (first diastolic blood pressure) A softer blowing sound that fades.

Phase 5 (second diastolic blood pressure) The sounds disappear