4Circulatory Systems in the Body 1. Coronary—supplies blood to heart muscle (can form collateral circulation)2. Cerebral—supplies blood to head3. Splanchnic—supplies blood to abdomen (exercise removes blood and food attracts blood to this area)4. Pulmonary—supplies blood to lungs (O2 and CO2 exchange)
5Measures of Heart Function 1. Beats or pulse2. BP systolic and diastolic3. ECG
6Determinants of Blood Pressure 1. Blood volume2. Vascular resistance to pressure3. Heart stroke volume
7Cardiac Output ■ Amount of blood pumped by heart (vol/min) ■ Stroke volume times heart rate
8Vascular Resistance ■ Viscosity of blood ■ Width of vessels—(constriction or dilation)—controlled by muscle tone in vessel walls
9Regulation of Blood Pressure 1. Sympathetic nervous system (SNS)—responds immediately; baroreceptors monitor BPVasomotor center in brainSNS innervated tissues contract or dilate vascular bed2. Renin-angiotensin system—retains Na and H2O to increase blood volume; constricts blood vessels; increases aldosterone3. Kidneys—respond to renin-angiotensin system; aldosterone and antidiuretic hormone (ADH) are sent out as needed
10Homeostatic Control of Blood Pressure Short term—Sympathetic nervous system—Vasoconstriction—VasodilationLong term—Fluid volume—Renin-angiotensin system
11Hypertension1. 90% HTN is essential HTN (cause unknown; perhaps prenatal impacts?)2. 10% HTN is secondary to other diseases3. HTN is a risk factor for MI, CVA, renal failure
12Renin-Angiotensin Cascade Redrawn from Guyton AC: Textbook of medical physiology, ed 8, Philadelphia, 1991, WB Saunders.
13Classification of Blood Pressure for Adults Ages 18 Years and Older From the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: Sixth Report (JNC VI), Arch Intern Med 157:2413, 1997.*Not taking antihypertensive drugs and not acutely ill. When systolic and diastolic blood pressures fall into different categories, the higher category should be selected to classify the individual’s blood pressure status. For example, 160/92 mm Hg should be classified as stage 2 hypertension, and 174/120 mm Hg should be classified as stage 3 hypertension. Isolated systolic hypertension is defined as systolic blood pressure 140 mm Hg or greater and diastolic blood pressure less than 90 mm Hg and staged appropriately (e.g., 170/82 mm Hg is defined as stage 2 isolated systolic hypertension). In addition to classifying stages of hypertension on the basis of average blood pressure levels, clinicians should specify presence or absence of target organ disease and additional risk factors. This specificity is important for risk classification and treatment.†Optimal blood pressure with respect to cardiovascular risk is less than 120/80 mm Hg. However, unusually low readings should be evaluated for clinical significance.‡Based on the average of two orr more readings taken at each of two or more visits after an initial screening.
14Treatment of Hypertension—Cause Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
15Treatment of Hypertension— Pathophysiology Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
16Treatment of Hypertension— Medical and Nutritional Therapy Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
17Risk Factors for Developing Hypertension (Adapted from National High Blood Pressure Education Program Working Group report on primary prevention of hypertension. Arch Intern Med 153:186, Copyright 1993, American Medical Association. Reprinted with permission.)
18Components of Cardiovascular Risk Stratification in Patients with Hypertension (From The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. sixth report (JNC VI). Arch Intern Med 157:2413, 1997.)
19Untreated or Uncontrolled Hypertension Leads to increasedWorkload on heartDamage to arteriesAtherosclerosisCoronary heart disease esp. CHFStrokesTransient ischemic attacks (TIAs)Kidney damageMicrovascular hemorrhages in brain and eye
20Medical Management of Hypertension Based on Risk High-normal BP and Stage 1 hypertension in low- or medium-risk group—Begin with trial of lifestyle modification for 6 to 12 monthsHigh-normal BP and Stage 1 hypertension in high-risk group—Begin with drug therapy in addition to lifestyle modificationStages 2 and 3 all risk groups
21Steps to Manage High Blood Pressure Weight management—If over 115% of ideal body weight, exercise and hypocaloric diet estimate 25 kcal/kg minus 500 to 1000kcal/daySalt restriction—6 g NaCl or 2400 mg Na/day
22Levels of Na Restriction g Na mEq Na DescriptionNo added saltMild to moderate restrictionStrict sodium restrictionSevere sodium restriction
23Response to Dietary RxSalt sensitive respond well to sodium restrictionMost respond to increased potassium in diet.1.1 to 3.3 g Na is safe1.9 to 5.6 g K is recommended to achieve ratio Na:K of 1, which is goalIf taking a potassium-wasting diuretic drug, increased potassium in diet is essential.Most respond to increased calcium (at least the RDA)—use the DASH diet protocol
24DASH Diet Works within 14 days Lowers BP quite well Includes more potassium, calcium, other nutrients
25DASH Diet —cont’d Pattern —7-8 whole grains —4-5 vegetables —4-5 fruits—2-3 low-fat or fat-free dairy products—6 oz or less meat/poultry/fish—4-5 servings nuts, beans, or legumes/week—2-3 servings fat (total kcal = 27% fat)
27Food Label Terms Sodium free, no sodium = <5 mg/serving Very low sodium = <35 mg/serving and per 100 g foodLow sodium = <140 mg/serving and per 100 g foodReduced sodium = 50% less than comparison food1
28Salt Substitutes Composition: KCl, CaCl, Al-Cl KCl can provide extra potassium for those taking diureticsKCl can be harmful if patient has renal insufficiency“Lite” salt contains sodiumSome spices and herbs are low in sodiumOthers are high in sodium2
31Lifestyle Modifications for Prevention of Hypertension Lose weight if overweightLimit alcoholIncrease physical activityDecrease sodium intakeKeep potassium intake at adequate levelsTake in adequate amounts of calcium and magnesiumDecrease intake of saturated fat and cholesterolStop smoking
32SummaryLifestyle modifications for prevention of hypertension—quite effective!Management of hypertension—very important to reduce risk of heart attack or stroke!