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 Hypertension• Intermittently elevated BPPersistent/Resistant hypertension• Hypertension 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 hypertension• Is severe, rapidly progressive elevation in BP that causes rapid onset of end organ complicationsWhite coat hypertension• Is 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 patient’s 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 stenosis•Due 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 urgency•Defined 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.•Epistaxis•Dizziness•Tinnitus•Unsteadiness•Blurred vision•Depression•Nocturia•Retinopathy, papilledema (on fundoscopy)

Laboratory and Laboratory and Diagnostic ProceduresDiagnostic Procedures

Seventh Joint National Committee Classification:

I. Hypertension Category Systolic (mmHg) Diastolic(mmHG)

Normal < 120 and < 80 Pre-hypertension 120 – 139 or 80 – 89 Hypertension

Stage 1 (mild) 140 – 159 or 90 – 99Stage 2 ≥ 160 or ≥ 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 Screening Follow-up Recommended

Systolic Diastolic

< 120 and < 80 Recheck in 2 years.

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

140 – 159 or 90 – 99 Confirm hypertension in 2 months.

≥ 160 or ≥ 100 Evaluate 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.

Creatinine•To monitor kidney function•Renal parenchymal disease

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

HDL •Normal is 30-60 mg/dL

LDL•Normal is < 190 mg/dL

Tryglycerides•Normal is <180 mg/dL

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 you’re 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 patient’s status:Is he hypotensive?Is he anticoagulated?Which hand is the dominant hand of the patient?Is the patient agitated? Needs sedation?

•Allen’s 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.

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

o Renal insufficiency

o “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:

A.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 Cushing’s syndrome, pheochromocytoma.

B. Encourage Lifestyle Change for Essential Hypetension

1. Stop smoking

2. 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.

3. Reduce sodium intake (<2 grams of sodium or approximately < 6 grams of sodium chloride).

4. 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.

5. 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.

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

7. Maintain adequate dietary potassium, calcium and magnesium intake.

Medical treatment:Choice of antihypertensive drugs based on

Patient characteristics

1.Diabetic patients and those with chronic kidney disease:

Use ACE-inhibitors or Angiotensin II antagonists to delay diabetic nephropathy

2.Young patients:Use beta-blockers unless contraindicated

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

direct vasodilator

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

5.Athletes: Avoid beta-blockers and diuretics

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

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

8.Dyslipidemic patients: Avoid beta-blockers and diuretics.

9.End-stage Renal Disease (ESRD) patients:Use calcium-antagonists, diuretics and

centrally-acting agents(clonidine, methyldopa). Caution on ACE-inhibitors.

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

11.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:

1. 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.

2. JNC VII recommends the use of thiazide-type diuretics as first line treatment unless with contraindications. Hydrochlorothiazide 25 mg tab is given at ½ tab per day or Aldazide at ½ 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 monitored•Rapid, 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

Nifedipine•Has 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.

Clonidine•For urgent hypertension•Use 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/Counsellingo Teaching about hypertensiono Teaching about the risk factorso Stress therapyo Low sodium, low saturated fat dieto Avoid stimulants (eg. Caffeine, alcohol, cigarette)o Regular pattern of exerciseo Weight reduction if obese

•Teaching about medication

oThe most common side effects of diuretics are potassium depletion and orthostatic hypotensionoThe most common side effect of the different antihypertensive drugs is orthostatic hypotensionoTake antihypertensive medications at regular basisoAssume sitting or lying position for few minutesoChange position graduallyoAvoid very warm bathoAvoid prolonged sitting or standingoAvoid 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 machinery

•Avoid 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.

oAvoid tyramine-rich foods (proteins) as follows:

Aged cheese Liver Beer Wine Chocolate Yogurt Pickle Sausage Soy sauce

*these may cause hypertensive crisis

•Preventing Non-compliance

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

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

o 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 pulses•Provide quiet environment, cool room, decreased sensory stimuli, soothing colors and soft music.•Encourage patient to restrict activity and rest in bed as much as possible•Administer oxygen as necessary•Administer antihypertensive medications as indicated•Start 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 information•Discuss the condition of the client and how it can be managed•State objectives in learner’s term to meet the learner’s need•Discuss the side effects of the medications and its considerations