1. Hypertension
Definition: the force exerted by the blood against the walls of the bleed vessels
Adequate to maintain tissue perfusion during activity and rest
Arterial blood pressure: primary function of cardiac output and systemic vascular resistance

2. What is the effect on BP if SVR increased and CO remains constant?
Hypertension
Arterial BP = Cardiac Output (CO) x Systemic vascular resistance (SVR)
Cardiac Output = stroke volume x beats per min
Systemic vascular resistance = force opposing the movement of blood within the blood vessels
What is the effect on BP if SVR increased and CO remains constant?

3. Hypertension Mechanisms that Regulate BP
Sympathetic Nervous System
Vascular Endothelium
Renal System
Endocrine System

4. Hypertension Mechanisms that Regulate BP
Sympathetic Nervous System (SNS) – norepinephrine released from sympathetic nerve endings - to receptors alpha1, alpha2, beta 1 & beta2
Reacts within seconds
Increases Heart Rate - chronotropic
Increased cardiac contractility - inotropic
Produces widespread vasoconstriction in peripheral arterioles
Promotes release of renin from the kidney

5. Hypertension SNS Receptors Influencing B/P

6. Hypertension Mechanisms that Regulate BP
Sympathetic Nervous System (SNS)–
Sympathetic Vasomotor Center – located in the medulla – interacts with many areas of the brain to maintain BP within normal range under various conditions
Exercise – changes to meet oxygen demand
Postural Changes – peripheral vasoconstriction

7. Hypertension Mechanisms that Regulate BP
Sympathetic Nervous System (SNS) –
Baroreceptors: specialized nerve cells the carotid arteries and the aortic arch
Sensitive to BP changes:
Increase: Inhibits SNS – peripheral vessel dilation. Decreased heart rate, and decreased contractility of the heart + increased parasympathetic activity (vagus nerve) decreased heart rate
Decrease: Activates SNS – peripheral vessel constriction, increased heart rate, and increased contractility of the heart

8. Hypertension Mechanisms that Regulate BP
Vascular Endothelium
Single cell layer that lines the blood vessels
Produce vasoactive substances:
EDRF Endothelium-derive relaxing factor –
Helps maintain low arterial tone at rest
Inhibits growth of the smooth muscle layer
Inhibits platelet aggregation
Vasodilation – prostacyclin
Endothelin (ET) potent vasoconstrictor
Endothelial dysfunction may contribute to atherosclerosis & primary hypertension

9. Hypertension Mechanisms that Regulate BP
Renal System
Control Na+ excretion & extracellular fluid volume
Renal - Renin-angiotensin-aldosterone
Renin converts angiotensinogen to angiotensin I
Angiotensin-converting enzyme (ACE) converts I into angiotsensin II
Immediate: Vasoconstrictor – increased systemic vascular resistance
Prolonged: Stimulates the adrenal cortex to secret Aldosterone – Na+ and Water retention
Renal Medulla - Prostaglandins - vasodilator effect

10. Hypertension Renin-Angiotensin

11. Hypertension Renin-Angiotensin System

12. Hypertension Mechanisms that Regulate BP
Endocrine System
Stimulates the SNS with
Epinephrine – increases HR and contractility
Activates B2-adrenergic receptors in peripheral arterioles of skeletal muscle = vasodilation
Activates A1-adrenergic receptors in peripheral arterioles of skin and kidneys = vasoconstiction
Adrenal Cortex – Aldosterone – stimulates kidneys to retain Na+
Increased Na+ stimulates posterior pituitary – ADH – reabsorbs ECF/water

13. Hypertension Aldosterone Mechanism
Increased Aldosterone =
Increases sodium reabsorption =
Increases water reabsorption =
Increases blood volume =
Increases cardiac output

14. Hypertension Mechanisms that Regulate BP
Regulatory mechanisms in the health person function in response to the demands on the body
When Hypertension develops, one or more of these mechanisms are defective
Sympathetic Nervous System
Vascular Endothelium
Renal System
Endocrine System

15. Secondary Hypertension Pathophysiology
Specific cause of hypertension can be identified
5+% of adult hypertension
Causes:
Coarctation or congenital narrowing of the aorta
Renal disease – renal artery disease / parenchymal
Endocrine disorders: Pheochromocytoma, Cushing Syndrome, Hyperaldosteronism
Neurology disorders – brain tumors / head injury
Sleep apnea
Medications – sympathetic stimulants
Pregnancy-induced hypertension

16. Hypertension Pathophysiology
Primary (Essential) Hypertension:
Elevated BP without an identified cause
Accounts for 95% of all cases of hypertension
Cause – unknown
Contributing Factors: Increased SNS activity, overproduction of Na+ retaining hormones & vasoconstrictors, increased Na+ intake
Risk Factors: Modifiable

17. Primary Hypertension Pathophysiology
Heredity – interaction of genetic, environmental, and demographic factors
Water & Sodium Retention – 20% of pts with high Na+ diet develop HTN
Altered Renin-Angiotensin Mechanism – found in 20% of patients
Stress & Increased SNS Activity
Insulin Resistance & Hyperinsulinemia
Endothelial Cell Dysfunction

18. Hypertension Clinical Manifestation
Dx is made after multiple readings over several weeks
NIH/Joint Committee Definition:
Category Systolic Diastolic
Optimal <110 and < 80
Normal <120 and <85
High Normal or
Stage or
Stage or
Stage 3 =>180 or => 110

19. Primary Hypertension Risk Factors
Age
Alcohol
Cigarette Smoking
Diabetes Mellitus
Elevated serum lipids
Excess Na+ in diet
Gender
Family History
Obesity
Ethnicity
Sedentary Lifestyle
Socioeconomic
Stress

20. Primary Hypertension Clinical Manifestations
Target Organ Complications:
Myocardium – angina / left ventricular hypertrophy
Brain – TIA / CVA
Peripheral vascular – Peripheral pulse change
Kidney – renal failure Creatinine / Proteinuria
Eyes – Hemorrhages with or without papilledema

21. Primary Hypertension Clinical Manifestations
“Silent Killer” – asymptomatic and insidious
Severe HTN – fatigue, reduced activity tolerance, dyspnea, dizziness, palpitations, angina

22. Hypertension Medical Diagnosis
History and Physical Examination
Renal Function
Serum Creatinine & Urine Creatinine Clearance
Electrolytes – especially K+
Blood Glucose
Serum Lipids/EKG
Ambulatory BP Monitoring

23. Primary Hypertension Medical Management
Risk Stratification
Level of BP
Presence of Target Organ Disease
Other Risk Factors

24. Hypertension Medical Management Risk Stratification

25. Primary Hypertension Medical Management
Lifestyle modification
Nutritional therapy
Alcohol consumption
Physical activity
Tobacco avoidance
Stress management
Drug Therapy

26. Hypertension Nutrition

27. Hypertension Risk Factor Modification

28. Primary Hypertension Medical Management Stepped Approach
Lifestyle modification
Not at Goal BP
Drug Therapy
Substitute med / add a 2nd med/ increase dose
Continue adding / changing meds until control

29. Primary Hypertension Medical Management – Drug Therapy
Diuretics
Thiazide
Loop
K+ Sparing
Adrenergic Blockers/ Inhibitors
B-Adrenergic Blockers
Central Acting Adrenergic Antagonists
Peripheral Acting Adrenergic Antagonists
A-Adrenergic Blockers
Vasodilators
Angiotensin Inhibitors
Calcium Channel Blockers

30. Hypertension Medication - Diuretics

31. Hypertension Medication – Beta-blocking Agents

32. Hypertension Medication Calcium Channel Blockers

33. Hypertension Medication Alpha Agonists & Vasodilators

34. Hypertension Antihypertensive Drug Therapy

35. Primary Hypertension Lack of Responsiveness to Therapy
Nonadherence to Therapy
Drug-Related Causes
Associated conditions
Secondary Hypertension
Volume overload

36. Primary Hypertension Hypertensive Crisis
Definition: Severe & abrupt elevation of BP with diastolic > mm Hg.
Causes:
Nonadherence, renovascular changes, pre- eclampsia, eclampsia, Pheochromocytoma, Rebound from abruptly stopping beta blockers, head injury, necrotizing vasculitis, acute aortic dissection
Hypertensive Encephalopathy:
headache, N/V, confusion, obtunded, stuporous, seizures, blurred vision, transient blindness

37. Primary Hypertension Nursing Diagnoses
Assess: Cardiovascular status; adherence to therapy; family interaction; risk factor modification?
Nsg Action: Supportive & reality-based; Administer meds; referrals; diagnostic preps; ask questions;
supportive care during hospitalization for acute crisis
Pt/Family Education: Medications; risk factor modification; Community support

38. Hypertension Dynamics of Treatment

39. Primary Hypertension Case Study