HYPERTENSION (High blood pressure, HTN, HPN)

Definition

Chronic elevation in BP > 140/90

Etiology unknown in 90-95% of pts (essential hypertension)

Always consider a secondary correctable form of hypertension, especially in pts under age 30 or those who become hypertensive after 55.

Isolated systolic hypertension (systolic > 160, diastolic < 90) most common in elderly pts, due to reduced vascular compliance.

Hypertension is the most important modifiable risk factor for coronary heart disease, stroke, congestive heart failure, ESRD, and peripheral vascular disease.

Classifications

Labile HypertensionIntermittently elevated BPPersistent/Resistant hypertensionHypertension that does not respond to usual treatment One of the risk factors for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure.Even moderate elevation of blood pressure leads to shortened life expectancy.Malignant hypertensionIs severe, rapidly progressive elevation in BP that causes rapid onset of end organ complicationsWhite coat hypertensionIs elevation of BP only during clinic visits.

Hypertension can be classified either essential(primary) or secondary

Essential hypertension indicates that no specific medical cause can be found to explain a patients condition.

Secondary hypertension indicates that the high blood pressure is a result of another condition, such as kidney disease or tumors (pheochromocytoma and paraganglioma)

Etiologies of Secondary hypertension

Renal artery stenosisDue to either to atherosclerosis (older men) or fibromuscular dysplasia (young women)

Sudden onset of hypertension

Refractory to usual antihypertensive therapy

Abdominal bruit often audible

Mild hypokalemia may be present due to activation of the renin-angiotensin-aldosterone system

Renal Parenchymal Disease

Elevated serum creatinine and abnormal urinalysis, containing protein, cells

Coarctation of Aorta

Presents in children or young adults

Constriction is usually present in aorta at origin of left subclavian artery

Exam shows diminished, delayed femoral pulsations

Late systolic murmur loudest over the midback

Pheochromocytoma

A catecholamine-secreting tumor, typically of the adrenal medulla, that presents as paroxysmal or sustained hypertension in young to middle-aged pts.

Sudden episodes of headache, palpitations and profuse diaphoresis are common.

Hyperaldosteronism

Due to aldosterone-secreting adenoma or bilateral adrenal hyperplasia

Should be suspected when hypokalemia is present in a hypertensive pt off diuretic

Hypertensive CrisisThere are two types:

Hypertensive emergencies Represent severe hypertension with acute impairment of an organ system (eg. Central Nervous System, Cadiovascular system, Renal system)In these conditions, the BP should be lowered aggressively over minutes to hours

Hypertensive urgencyDefined as a severe elevation of BP, without evidence of progressive target organ dysfunction.These patients require BP control over several days to weeks

Risk Factors

Family History

Age

High salt-intake

Low potassium intake

Obesity

Excess alcohol consumption

Smoking

Stress

Signs and Symptoms

Headache (especially upon waking). This is the most characteristic sign.EpistaxisDizzinessTinnitusUnsteadinessBlurred visionDepressionNocturiaRetinopathy, papilledema (on fundoscopy)

Laboratory and Diagnostic Procedures

Seventh Joint National Committee Classification:

Hypertension Category Systolic (mmHg)Diastolic(mmHG) Normal < 120and < 80 Pre-hypertension120 139or 80 89 HypertensionStage 1 (mild)140 159or 90 99Stage 2 160or 100(moderate-severe)

Note: Take at least 2 readings on separate occasions to diagnose hypertension

II. Recommendations for Follow-up Based on Initial Set of Blood Pressure Measurements for Adults

Initial Blood Pressure ScreeningFollow-up Recommended

SystolicDiastolic

< 120and < 80Recheck in 2 years.

120 139or 80 89Advice healthy lifestyle and recheck in 1 year.

140 159or 90 99Confirm hypertension in 2 months.

160or 100Evaluate or refer to source of care within 1 month.

III. Recommended Laboratory tests:

CBC, Urinalysis, Potassium, FBS, Creatinine, Calcium, Total Cholesterol, HDL, LDL, Triglycerides,ECG, arterial line BP monitoring, CXR

CBC

Hematocrit is the most significant finding that is related to hypertension.

Low hematocrit (< 36%) can be related to volume overload after aggressive hydration causing dilution and hypertension.

High hematocrit (>46%) means that the patient is dehydrated.

Urinalysis

Specifically, the Specific gravity determines the hemodynamic condition of the patient.

Low specific gravity means more concentrated therefore dehydrated.

High specific gravity means more diluted therefore overhydrated which is more prone to hypertension.

Potassium Level

Because of the use of potassium wasting diuretics as treatment to hypertension, we need to monitor the Potassium level of the patient.

Prompts for hyperaldosteronism or renal artery stenosis

Take note that when withdrawing blood specimen for chem-labs, the nurse must withdraw blood slowly from the patient to prevent hemolysis of RBCs. Hemolysis results in the release of potassium into the serum component making the reading falsely high.

CreatinineTo monitor kidney functionRenal parenchymal disease

Total Cholesterol>200 mg/dL is high and considered as high risk for hypertension

HDL Normal is 30-60 mg/dL

LDLNormal is < 190 mg/dL

TryglyceridesNormal is

Arterial line

It is used for patients receiving more than small amounts of vasoactive drip to properly manage blood pressure.

It is also preferred in sick patients who are labile and whose BP is unstable.

Certain situations absolutely require an a-line for BP monitoring: any use of any dose of nipride, for example. This is a truly powerful drug it works very quickly, and your patient can rapidly get into all sorts of trouble unless youre monitoring BP continuously.

Also serves as a port for obtaining ABG for lab testing.

Nursing Considerations (A-line):

Before the procedure

Obtain informed consent.

Assess the patients status:Is he hypotensive?Is he anticoagulated?Which hand is the dominant hand of the patient?Is the patient agitated? Needs sedation?

Allens test

After the procedure

Assess every shift:Capillary refillDistal PulseFeel the warmth of the hand and note its color

Apply pressure and compress the site after withdrawing specimen

Watch out for complications:Compartment SyndromeHematoma formation

Using a-line to monitor blood pressure

Make sure the trasducer is in level with the heart (4th intercostal space, mid axillary line)

Make sure that there is no air in the line before hooking it up to the patient use the flusher to clear the bubbles out of the tubing.

Zero the line to negate the pressure applied by the heparinised flush.

Correlation of pressure readings with blood pressure cuff should be done periodically, if possible.

Medical Surgical Management

There is no known surgical treatment to essential (primary) hypertension. Surgical treatment is only applicable to secondary hypertension wherein the cause of the hypertension can be managed surgically.

Some Surgical Procedures:

Renal artery stent placement

Indicated for renal artery stenosis which hemodynamically compromises the patient.

Hypertension that is poorly controlled on adequate (two or three drugs) medical therapy.

Renal insufficiency

flash pulmonary edema

Stents are superior to balloons for both procedural success and long-term patency

Not an absolute cure for hypertension. However, most of the patients will benefit by improved blood pressure control and the need for fewer medications

The benefits of renal stent placement include reperfusion of ischemic kidneys, resulting in a reduction in the stimulus to renin production, which decreases angiotensin and aldosterone production, thereby decreasing peripheral arterial vasoconstriction and intravascular volume.

Improving renal perfusion enhances glomerular filtration, thus natriuresis.

Resection and end-to-end anastomosis coarctation of aorta

Malignant pheochromocytomas are treated by surgical incision of the tumor.

Total adrenalectomy is the procedure of choice for pheochromocytomas.

Total adrenalectomy if the hyperaldosteronism is caused by an adrenocortical adenoma.

Approach to treatment:

Rule out correctable and secondary causes of hypertension first.

These include drug-induced hypertension, thyroid and parathyroid disease, chronic kidney disease, renovascular disease, coarctation of the aorta, primary aldosteronism, chronic steroid therapy and Cushings syndrome, pheochromocytoma.

B. Encourage Lifestyle Change for Essential Hypetension

Stop smoking

Lose weight if overweight. Maintain body mass index of 18.5 24.9 kg/m2. For every 10 kg of weight loss, BP drops by approximately 5-20 mmHg.

Reduce sodium intake (

Healthy diet. Consume a diet rich in vegetables, fruits and low fat dietary products. Reduce dietary saturated fat and cholesterol intake for overall cardiovascular health. Reducing fat intake also helps reduce calorie intake, which is important for control of weight in type II diabetes.

Engage in regular aerobic exercise once BP is controlled. At least 30 minutes per day, most days of the week. Brisk walking is good exercise.

Limit alcohol intake to less than 1 oz/day of ethanol (24 oz beer, 8 oz wine, or 2 oz 80-proof whiskey)

Maintain adequate dietary potassium, calcium and magnesium intake.

Medical treatment:Choice of antihypertensive drugs based on Patient characteristics

Diabetic patients and those with chronic kidney disease: Use ACE-inhibitors or Angiotensin II antagonists to delay diabetic nephropathy

Young patients:Use beta-blockers unless contraindicated

Coronary Artery Disease (CAD) patients:Use beta-blockers, calcium channel-blockers. Avoid hydralazine(Apresoline) which is a direct vasodilator

Heart Failure Patients: Use ACE-inhibitors and/or diuretics. Generally avoid beta-blockers and calcium-antagonists.

Athletes: Avoid beta-blockers and diuretics

Broncho-pulmonary disease patients: Use verapamil and other calcium-antagonist. Avoid beta-blockers.

Peripheral Vascular Disease patients: Use calcium-antagonist(nifedipine), vasodilators, or ACE-inhibitors. Avoid beta-blockers.

Dyslipidemic patients: Avoid beta-blockers and diuretics.

End-stage Renal Disease (ESRD) patients:Use calcium-antagonists, diuretics and centrally-acting agents(clonidine, methyldopa). Caution on ACE-inhibitors.

For stroke patients: Use ACE-inhibitors and/or diuretics.

Elderly patients:Use diuretics. Generally use lower dosages. Be wary of pseudohypertension wherein the elevated BP is due to brachial artery atherosclerosis and not hypertension per se.

Treatment Goal and Guide:

For hypertensive patients with diabetes or renal disease, the target BP is < 130/80 mmHg. For other patients without cardiovascular risk factors, the BP goal is < 140/90 mmHg.

JNC VII recommends the use of thiazide-type diuretics as first line treatment unless with contraindications. Hydrochlorothiazide 25 mg tab is given at tab per day or Aldazide at tab per day. Giving lower doses of diuretics is safer because it minimizes electrolyte imbalance.

Management of Hypertensive Crisis

Hypertensive Emergency

The patient should be hospitalized for IV access, continous intra-arterial blood pressure monitoring, and electrocardiographic monitoring. Volume status and urine output should be monitoredRapid, uncontrolled reduction of blood pressure should be avoided because coma, stroke, MI, acute renal failure or death may result.The goal of initial therapy is to terminate ongoing target organ damage.The Mean arterial pressure (MAP) should be lowered not more than 20 - 25%, or to a diastolic blood pressure of 100 mmHg over 15 to 30 minutes.Blood pressure should be controlled over a few hours

Hypertensive Urgency

The initial goal in patients with severe asymptomatic hypertension should be a reduction in blood pressure to 160/110 over several hours with conventional oral therapy.If the patient is not volume depleted, furosemide (Lasix) is given in a dosage of 20 mg if renal function is normal, and higher if renal insufficiency is present.A calcium channel blocker (isradipine [DynaCirc], 5 mg or felodipine [Plendil], 5 mg) should be added. A dose of captopril (Capoten)(12.5 mg) can be added if the response is not adequate. This regimen should lower the blood pressure to a safe level over three to six hours and the patient can be discharged on a regimen of once-a-day medications.

Parenteral antihypertensive agents

Nitroprusside (Nipride)Nitroprusside is the drug of choice in almost all hypertensive emergencies (except myocardial ischemia or renal impairment). It dilates both arteries and veins, and it reduces afterload and preload. Onset of action is nearly instantaneous, and the effects disappear 1-2 minutes after discontinuation.The starting dosage is 0.25-0.5 mcg/kg/min by continuous infusion with a range of 0.25-8.0 mcg/kg/min. Titrate dose to gradually reduce blood pressure over minutes to hours.When treatment is prolonged or when renal insufficiency is present, the risk of cyanide and thiocyanate toxicity is increased. Signs of thiocyanate toxicity include disorientation, fatigue, hallucinations, nausea, toxic psychosis, and seizures.

Nitroglycerin

Nitroglycerin is the drug of choice for hypertensive emergencies with coronary ischemia. It should not be used with hypertensive encephalopathy because it increases intracranial pressure.Nitroglycerin increases venous capacitance, decreases venous return and left ventricular filling pressure. It has a rapid onset of action of 2-5 minutes. Tolerance may occur within 24-48 hours.The starting dose is 15 mcg IV bolus, then 5-10 mcg/min (50 mg in 250 mL D5W). Titrate by increasing the dose at 3- to 5-minute intervals.Generally doses >1.0 mcg/kg/min are required for afterload reduction (max 2.0 mcg/kg/hr). Monitor for methemoglobinemia.

Labetalol IV (Normodyne)

Labetalol is a good choice if BP elevation is associated with hyperadrenergic activity, aortic dissection, an aneurysm, or postoperative hypertension.

Labetalol is administered as 20 mg slow IV over 2 min. Additional doses of 20-80 mg may be administered q5-10min, then q3-4h prn or 0.5-2.0 mg/min IV infusion.

Labetalol is contraindicated in obstructive pulmonary disease, CHF, or heart block greater than first degree.

Enalaprilat IV (Vasotec)

Enalaprilat is an ACE-inhibitor with a rapid onset of action (15 min) and long duration of action (11 hours). It is ideal for patients with heart failure or accelerated-malignant hypertension.

Initial dose, 1.25 mg IVP (over 2-5 min) q6h, then increase up to 5 mg q6h. Reduce dose in azotemic patients.

Contraindicated in bilateral renal artery stenosis.

Esmolol (Brevibloc)

is a non-selective beta-blocker with a 1-2 min onset of action and short duration of 10 min. The dose is 500 mcg/kg/min x 1 min, then 50 mcg/kg/min; max 300 mcg/kg/min IV infusion.

Hydralazine

is a preload and afterload reducing agent. It is ideal in hypertension due to eclampsia.Reflex tachycardia is common. The dose is 20 mg IV/IM q4-6h.

Nicardipine (Cardene IV) is a calcium channel blocker. It is contraindicated in presence of CHF.Tachycardia and headache are common. The onset of action is 10 min, and the duration is 2-4 hours. The dose is 5 mg/hr continuous infusion, up to 15 mg/hr.

Fenoldopam (Corlopam) is a vasodilator. It may cause reflex tachycardia and headaches. The onset of action is 2-3 min, and the duration is 30 min. The dose is 0.01 mcg/kg/min IV infusion titrated, up to 0.3 mcg/kg/min.

Phentolamine (Regitine)

is an intravenous alphaadrenergic antagonist used in excess catecholamine states, such as pheochromocytomas, rebound hypertension due to withdrawal of clonidine, and drug ingestions. The dose is 2-5 mg IV every 5 to 10 minutes.

Trimethaphan (Arfonad)

is a ganglionic-blocking agent. It is useful in dissecting aortic aneurysm when beta-blockers are contraindicated; however, it is rarely used because most physicians are more familiar with nitroprusside. The dosage of trimethoprim is 0.3-3 mg/min IV infusion.

Oral and sublingual antihypertensive drugs

NifedipineHas a rapid onset of action, usually within 15 to 30 min.Initial dose should not exceed 10 mg to prevent sudden drop in blood pressure.

ClonidineFor urgent hypertensionUse the clonidine loading regimen initial dose of 0.2 mg followed by 0.1 mg every hour, for up to 5 hours, until diastolic blood pressure is reduced to below 110 mmHg or a total dose of 0.7 mg is reached.Side effects of sedation, dry mouth, and orthostatic hypotension

Nursing Interventions

Patient Teaching/Counselling Teaching about hypertensionTeaching about the risk factorsStress therapyLow sodium, low saturated fat dietAvoid stimulants (eg. Caffeine, alcohol, cigarette)Regular pattern of exerciseWeight reduction if obese

Teaching about medication

The most common side effects of diuretics are potassium depletion and orthostatic hypotensionThe most common side effect of the different antihypertensive drugs is orthostatic hypotensionTake antihypertensive medications at regular basisAssume sitting or lying position for few minutesChange position graduallyAvoid very warm bathAvoid prolonged sitting or standingAvoid alcoholic beverages

Lie down immediately if faintness, weakness, nausea and vomiting occur; put feet higher than head; flex thigh muscles and wiggle toes.Use caution when driving or operating heavy or dangerous machineryAvoid cheese, beer, or wine when taking a Monoamine oxidase inhibitor (e.g. pargyline). A severe reaction might occur, with a possibility or cerebral hemorrhage.Should hypotensive crisis occur, wrap legs firmly with ace bandages when ambulating. Ace bandage helps promote venous return.

Avoid tyramine-rich foods (proteins) as follows:Aged cheeseLiverBeerWineChocolateYogurtPickleSausageSoy sauce*these may cause hypertensive crisis

Preventing Non-compliance

Inform the client that absence of symptoms does not indicate control of BP.

Advise the client against abrupt withdrawal of medication; rebound hypertension may occur.

Device ways to facilitate remembering of taking medications(e.g. labeled containers)

Other Nursing Considerations

When giving medications measure the BP before and 5 min after drug administration.

Nitroprusside must be protected from light, and the solution changed every 12 hours.High dosages of Nitroprusside over several days require monitoring of serum thiocyanate level.

Nitroprusside toxicity is treated by administration of Hydroxocobalamin a vit B12 derivative.

A special non absorbing infusion set is require to avoid adherence of nitroglycerin to the plastic or polyvinyl chloride contained in most IV lines.

Possible Nursing Diagnosis and interventions

Risk for decreased cardiac output

Determine baseline vital signs/hemodynamic parameters including peripheral pulsesProvide quiet environment, cool room, decreased sensory stimuli, soothing colors and soft music.Encourage patient to restrict activity and rest in bed as much as possibleAdminister oxygen as necessaryAdminister antihypertensive medications as indicatedStart an IV if symptoms of malignant hypertension were present (encephalopathy, intracranial hemorrhage, severe chest pain, acute pulmonary edema)

Deficient knowledge regarding condition (hypertension), therapeutic regimen and potential complications

Identify Significant others also requiring informationDiscuss the condition of the client and how it can be managedState objectives in learners term to meet the learners needDiscuss the side effects of the medications and its considerations