Chapter 37

1. Chapter 37 Hypertension

2. Learning Objectives • Define hypertension. • Explain the physiology of blood pressure regulation. • Discuss the risk factors, signs and symptoms, diagnosis, treatment, and complications of hypertension. • Identify the nursing considerations when administering selected antihypertensive drugs. • List the data to be collected for the nursing assessment of a person with known or suspected hypertension. • Identify the nursing diagnoses, goals, and outcome criteria for the patient with hypertension. • Describe the nursing interventions for the patient with hypertension.

3. Definitions The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure Normal blood pressure Systolic: <120 mm Hg; diastolic <80 mm Hg Prehypertension Systolic pressures between 120 and 139; diastolic pressures between 80 and 89 Stage 1 and stage 2 hypertension See Table 37-1

4. Types of Hypertension Primary hypertension 90% to 95% of all cases of hypertension Its cause is unknown Secondary hypertension Caused by underlying factors, such as kidney disease, certain arterial conditions, some drugs, and occasionally pregnancy

5. Anatomy and Physiology of Blood Pressure Regulation Cardiac output The volume of blood pumped by the heart in a specific period (usually 1 minute) Determined by strength, rate, and rhythm of the contraction of the left ventricle and the blood volume

6. Anatomy and Physiology of Blood Pressure Regulation Peripheral vascular resistance Force in the blood vessels that left ventricle must overcome to eject blood from the heart Resistance to blood flow determined by diameter of the blood vessels and blood viscosity (thickness) Increased peripheral vascular resistance: the most prominent characteristic of hypertension

7. Anatomy and Physiology of Blood Pressure Regulation Diameter of blood vessels regulated by the vasomotor center Sympathetic nervous system tracts from the medulla extend down the spinal cord to the thoracic and abdominal regions Stimulation of sympathetic nervous system causes release of the hormones norepinephrine and epinephrine

8. Anatomy and Physiology of Blood Pressure Regulation Norepinephrine and epinephrine (catecholamines) are vasoconstrictors: cause blood vessels to constrict, making diameter smaller By constricting blood vessels, norepinephrine increases peripheral vascular resistance and raises blood pressure Epinephrine constricts blood vessels and increases the force of cardiac contraction, causing blood pressure to rise

9. Anatomy and Physiology of Blood Pressure Regulation Vasoconstriction decreases blood flow to the kidneys, which then release renin Renin leads to the formation of angiotensin, another potent vasoconstrictor Angiotensin stimulates the adrenal cortex to secrete aldosterone, a hormone that promotes sodium and water retention This results in an increased blood volume Vasoconstriction, cardiac stimulation, and retention of fluid all contribute to hypertension

10. Figure 37-1

11. Age-Related Changes Affecting Blood Pressure Atherosclerotic changes reduce the elasticity of the arteries, causing decrease in cardiac output and increase in peripheral vascular resistance Pulse pressure (the difference between the systolic and diastolic pressures) widens in response to a decreased ability of the aorta to distend

12. Primary (Essential) Hypertension

13. Risk Factors Dyslipidemia Atherosclerosis Diabetes mellitus Tobacco use Age >55 years for men or age >65 years for women Family history Father or brother with heart disease before age 55; mother or sister with heart disease before age 65 Sedentary lifestyle Obesity

14. Signs and Symptoms Occipital headaches that are more severe on arising Lightheadedness Epistaxis If hypertension has damaged blood vessels in the heart, kidneys, eyes, or brain, patient may have symptoms of impaired function of those organs

15. Figure 37-2

16. Complications Heart Coronary artery disease develops in patients with hypertension two to three times more frequently than in people with normal blood pressures Kidneys Narrowing of the renal arteries may decrease renal function and lead to chronic renal failure

17. Complications Brain Prolonged hypertension constricts and damages cerebral arteries, putting patient at risk for transient ischemic attacks and cerebrovascular accidents Eyes Damage to eyes may include narrowing of the retinal arterioles, retinal hemorrhages, and papilledema; may lead to blindness

18. Diagnostic Tests and Procedures Confirmed by repeated findings of average pressures equal to or greater than 140/90 Ambulatory blood pressure monitors Physician collects data about patient’s lifestyle, other cardiovascular risk factors, and other medical diagnoses Electrocardiogram Blood studies include glucose, hematocrit, potassium, calcium, creatinine, and a lipid profile Chest radiograph

19. Medical Treatment Lifestyle modifications Weight reduction Smoking cessation Sodium and alcohol restriction Exercise Relaxation techniques

20. Medical Treatment Pharmacologic therapy Specific antihypertensive drugs Diuretics Beta-adrenergic receptor blockers Calcium antagonists Angiotensin-converting enzyme (ACE) inhibitors (or ACEIs) Angiotensin II receptor antagonists (ARBs) Central adrenergic blockers Alpha-adrenergic receptor blockers Direct vasodilators

21. Figure 37-3

22. Medical Treatment Pharmacologic therapy Nursing implications Administering the drugs to inpatients Monitoring for therapeutic and adverse effects Teaching patients about their drugs

23. Secondary Hypertension Has a specific known cause and is less common than primary hypertension Causes Renal disease Excess secretion of adrenal hormones Narrowing of the aorta Increased intracranial pressure Some drugs such as vasoconstrictors

24. Nursing Care of the Patient with Hypertension

25. Assessment Periodic blood pressure checks detect new or unknown hypertensive people; provide data to evaluate effect of therapy in hypertensive people Complete history and physical examination by the registered nurse The LVN may be involved in initial blood pressure screenings and monitoring, and provides important data to evaluate treatment effectiveness

26. Health History Explore past medical for hypertension or renal, cardiac, or endocrine disorders Date and readings of the last blood pressure measurement Ask about pregnancy and about hormone replacement therapy Current medications, including over-the-counter drugs

27. Health History Family health history: hypertension, myocardial infarction, or cerebrovascular accidents Body systems for signs and symptoms, particularly headaches, epistaxis, dizziness, visual disturbances, dyspnea, angina, nocturia Data about the patient’s usual functioning may detect some risk factors for hypertension Occupation, exercise and activity, sleep and rest, nutrition, interpersonal relationships, and stressors

28. Physical Examination General appearance; note obvious distress Measure height and weight and vital signs Patient should be seated in a chair with feet on the floor and arm resting at the level of the heart The proper cuff size is essential Multiple readings should be taken Blood pressure assessed in both arms in the supine, sitting, and standing positions

29. Interventions: Ineffective Therapeutic Regimen Management Diet therapy goals Maintain ideal body weight; prevent fluid retention Exercise Walking is highly recommended: increases cardiovascular functioning, burns calories, relieves stress, and promotes a sense of well-being

30. Interventions: Ineffective Therapeutic Regimen Management Stress management Help patients identify stressors in their lives and explore ways to reduce them Drug therapy Review the name, dosage, purpose, and side effects of any prescribed medications

31. Interventions Risk for Injury Orthostatic hypotension Sudden drop in systolic blood pressure, usually 20 mm Hg, when going from lying or sitting to a standing position Monitor for lightheadedness, dizziness, syncope Sedation Advise if drowsiness is likely so activities requiring alertness can be avoided during times of peak drug effect Taking medications at bedtime to promote sleep

32. Interventions Ineffective Coping If depression a side effect of an antihypertensive, consult physician to substitute another drug Sexual Dysfunction Decreased libido, inability to achieve an erection, or delayed ejaculation Advise physician so an alternative medication or other intervention can be considered

33. Older Patients Response to drug therapy more difficult to predict; side effects are more common Orthostatic hypotension and sedation problematic for the older person, who is prone to fall and suffer serious injuries Depression also must be taken very seriously because it lowers motivation, impairs quality of life, and can lead to suicide

34. Hypertensive Emergencies A life-threatening medical emergency Severe headache, blurred vision, nausea, restlessness, and confusion Elevated diastolic blood pressure (130 mm Hg or more); the heart and respiratory rates are increased May result from having stopped taking antihypertensive drugs

35. Hypertensive Emergencies Causes: malignant hypertension, hypertensive encephalopathy, eclampsia, pheochromocytoma (adrenal tumor), cerebrovascular accident Without treatment, the patient in hypertensive crisis may incur cardiac and renal damage Death may ensue as a result of a cerebrovascular accident, renal failure, or cardiac failure

36. Medical Diagnosis Assessment in the ED reveals elevated blood pressure, pulse, and respiratory rate Retinal hemorrhage or papilledema, or both, observed in fundus (back, interior portion) of eye Physician may order blood drawn for arterial blood gases, CBC, electrolytes, blood urea nitrogen, creatinine, and cardiac enzymes Chest radiograph may be requested Direct blood pressure monitoring through an arterial catheter preferred

37. Medical Treatment The goal of drug therapy is to rapidly reduce the pressure to a non–life-threatening level and then to bring it slowly within normal range Diuretics and potent vasodilators Fenoldopam Nitroglycerin Diazoxide Hydralazine Phentolamine Labetalol Nitroprusside

38. Medical Treatment An intravenous line is usually established because many drugs are given by that route Oral options for the management of hypertensive crisis include captopril, clonidine, and nifedipine See Box 37-3, p. 728

39. Nursing Care of the Patient in Hypertensive Crisis

40. Assessment Frequently check blood pressure, pulse, respiration, and level of consciousness Some drugs are given in intravenous fluids, requiring continuous monitoring and adjustment Careful record of fluid intake and output Nausea and vomiting may indicate an impending seizure or coma

41. Interventions Administer prescribed drugs Vital signs before and after each dose Monitor cardiac and renal function Start and maintain intravenous therapy Administer oxygen as ordered Comfort the patient

42. Interventions Take appropriate safety measures if the patient shows signs of seizure activity or a decreasing level of consciousness Once patient’s condition improves, it is important to explain how to manage hypertension and prevent future crises