1. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 23 Disorders of Blood Pressure Regulation

2. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Arterial Blood Pressure (Definitions) Systolic pressure: pressure at the height of the pressure pulse Diastolic pressure: the lowest pressure Pulse pressure: the difference between systolic and diastolic pressure Mean arterial pressure: the average pressure in the arterial system during ventricular contraction and relaxation

3. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Arterial Blood Pressure Represents the pressure of the blood as it moves through the arterial system Cardiac output = HR x SV Vascular resistance (VR) Mean arterial pressure = CO x VR

4. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Mechanisms of Blood Pressure Regulation Short-term regulation: corrects temporary imbalances in blood pressure –Neural mechanisms –Humoral mechanisms Long-term regulation: controls the daily, weekly, and monthly regulation of blood pressure –Renal mechanism

5. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Factors Determining Systolic and Diastolic Blood Pressure Systolic pressure –The characteristics of the stroke volume being ejected from the heart –The ability of the aorta to stretch and accommodate the stroke volume Diastolic pressure –The energy stored in the aorta as its elastic fibers are stretched during systole –The resistance to the runoff of blood from the peripheral blood vessels

6. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Kortokoff Sounds Phase I: marked by the first tapping sound, which gradually increase in intensity Phase II: period in which a murmur or swishing sound is heard Phase III: period during which sounds are crisper and greater in intensity Phase IV: period marked by distinct abrupt muffling or by a soft blowing sound Phase V: point at which sounds disappear

7. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Factors Influencing Mean Arterial Blood Pressure Physical –Blood volume and the elastic properties of the blood vessels Physiologic factors –Cardiac output –Peripheral vascular resistance

8. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Which of the following does not directly affect arterial blood pressure? a.Heart rate b.Vascular resistance c.Venous constriction d.Blood volume

9. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer a.Heart rate b.Vascular resistance c.Venous constriction: Venous constriction will not affect arterial pressure, but the other factors will have immediate effects. d.Blood volume

10. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Joint National Committee on Detection, Evaluation, and Treatment of Hypertension Systolic pressure less than 120 mm Hg and a diastolic pressure of less than 80 mm Hg are normal. Systolic pressures between 120 and 139 mm Hg and diastolic pressures between 80 and 89 mm Hg are considered prehypertensive. A diagnosis of hypertension is made if the systolic blood pressure is 140 mm Hg or higher and the diastolic blood pressure is 90 mm Hg or higher. For adults with diabetes mellitus, the goal is BP less than 130/80 mm Hg

11. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Factors Affecting Hypertension Age –More common in younger men than younger women –More common in the elderly Race –More common in blacks than whites Socioeconomic group –More common in lower socioeconomic groups

12. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Categories of Hypertension Primary hypertension (essential hypertension) –Chronic elevation in blood pressure that occurs without evidence of other disease Secondary hypertension –Elevation of blood pressure that results from some other disorder, such as kidney disease Malignant hypertension –An accelerated form of hypertension Systolic hypertension –Systolic pressure of 140 mm Hg or greater and a diastolic pressure of less than 90 mm Hg

13. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Classifications of Essential Hypertension Systolic/diastolic hypertension –Both the systolic and diastolic pressures are elevated. Diastolic hypertension –The diastolic pressure is selectively elevated. Systolic hypertension –The systolic pressure is selectively elevated.

14. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Risk Factors for Hypertension Family history Age-related changes in blood pressure Race Insulin resistance and metabolic abnormalities Circadian variations Lifestyle factors

15. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Lifestyle Factors Contributing to Hypertension High salt intake Obesity Excess alcohol consumption Dietary intake of potassium, calcium, and magnesium Oral contraceptive drugs Stress

16. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Target Organ Damage Heart –Hypertrophy Brain –Dementia and cognitive impairment Peripheral vascular – Atherosclerosis Kidney –Nephrosclerosis Retinal complications

17. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Drugs Used in the Treatment of Hypertension Diuretics β-adrenergic–blocking drugs Angiotensin-converting enzyme (ACE) inhibitors Angiotensin II receptor blockers Calcium-channel–blocking drugs Central α 2 -adrenergic agonists α 1 -adrenergic receptor blockers Vasodilators

18. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Factors Affecting Treatment Strategies for Hypertension Lifestyle Demographics Motivation for adhering to the drug regimen Other disease conditions and therapies Potential for side effects

19. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Renal failure results in Na + and water retention. This results in hypertension. How would you classify this type of hypertension? a.Primary hypertension b.Secondary hypertension c.Malignant hypertension d.Systolic hypertension

20. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer a.Primary hypertension b.Secondary hypertension: Secondary hypertension accompanies an underlying disease. c.Malignant hypertension d.Systolic hypertension

21. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Most Common Causes of Secondary Hypertension Kidney disease (renovascular hypertension) Adrenal cortical disorders Pheochromocytoma Coarctation of the aorta Sleep apnea

22. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Types of Hypertension in Pregnancy Gestational hypertension Chronic hypertension Preeclampsia/eclampsia Preeclampsia superimposed on chronic hypertension

23. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Diagnosis and Treatment of Hypertension in Pregnancy Early prenatal care Refraining from alcohol and tobacco use Salt restriction Bed rest Carefully chosen antihypertensive medications

24. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins High Blood Pressure in Children and Adolescents Blood pressure norms for children are based on age, height, and gender-specific percentiles. Secondary hypertension is the most common form of high blood pressure in infants and children. –Kidney abnormalities –Coarctation of the aorta –Pheochromocytoma and adrenal cortical disorders In infants, hypertension is associated most commonly with high umbilical catheterization and renal artery obstruction caused by thrombosis.

25. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Orthostatic Hypotension Definition –An abnormal decrease in blood pressure on assumption of the upright position Causes –Decrease in venous return to the heart due to pooling of blood in lower part of body –Inadequate circulatory response to decreased cardiac output and a decrease in blood pressure

26. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Causes of Orthostatic Hypotension Conditions that decrease vascular volume –Dehydration Conditions that impair muscle pump function –Bed rest –Spinal cord injury

27. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Causes of Orthostatic Hypotension (cont.) Conditions that interfere with cardiovascular reflexes –Medications –Disorders of autonomic nervous system –Effects of aging on baroreflex function

28. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Common Causes of Orthostatic Hypotension Related to Hypovolemia Excessive use of diuretics Excessive diaphoresis Loss of gastrointestinal fluids through vomiting and diarrhea Loss of fluid volume associated with prolonged bed rest

29. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Complaints Associated With Orthostatic Intolerance Dizziness Visual changes Head and neck discomfort Poor concentration while standing Palpitations Tremor, anxiety Presyncope, and in some cases syncope

30. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Increased vascular compliance may contribute to which condition? a.Systolic hypertension b.Orthostatic hypotension c.Orthostatic hypertension d.Diastolic hypertension

31. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer a.Systolic hypertension b.Orthostatic hypotension: Orthostatic hypertension is the result of lower pressures, and increased compliance would decrease the vascular resistance and result in lower pressures. c.Orthostatic hypertension d.Diastolic hypertension