NURS 251 Portage Study Guide 5

Two factors that determine a person's blood pressure - Cardiac Output and Systemic Vascular Resistance Cardiac output - amount of blood ejected from the heart's left ventricle in one minute (heart rate x stroke volume) SVR (systemic vascular resistance) - amount of resistance to blood flow Contributing factors to a patient's blood pressure - Cardiac Factors: heart rate, contractibility Circulating Volume: salt, alaosterone, hormones, and peripheral sympathetic receptors Hypertension Classification - Normotensive = 120/80 Prehypertensive = 120-139/80-89 Hypertensive = 140/90 Stage 1 = 140-159/90-99 Stage 2 = 160/100 How to take blood pressure - The instrument used is called a sphygmomanometer. The health care provider uses a blood pressure cuff to cut off the blood flow from the brachial artery. As they release the pressure in the cuff, using a stethoscope, they are listening for the first sound, called the Korotkoff sound, meaning there is no longer enough pressure to keep all the blood from flowing. This is the top number or systolic value of the patient's blood pressure. The provider continues to let air out of the cuff and eventually the sounds disappear, representing that the brachial artery is now completely open. This is known as the diastolic value or bottom number in a patient's blood pressure. Differentiate essential hypertension and secondary hypertension - -Essential hypertension (primary hypertension): cause of the increased blood pressure is unknown. -Secondary hypertension: elevated blood pressure is caused by another disease. peripheral resistance - resistance generated by the flow of blood through the arteries. When this happens, the kidney releases an enzyme called renin. Renin enzyme - leads to further vasoconstriction, water and sodium retention, and an increase in blood pressure What happens to the peripheral resistance during high blood pressure - there is an increased peripheral resistance which decreases blood supply to the kidney. Antihypertensive therapy - -goal is to decrease morbidity and mortality without decreasing quality of life Antihypertensive therapy should be started in patients - · 60+ if their blood pressure 150/90mm/Hg. · 59- or those with chronic kidney disease or diabetes used when the blood pressure 140/90mm/Hg. The four first line antihypertensives - -Thiazide diuretics -ACE-Inhibitors -ARBs -CCBs Thiazide Diuretics (mechanism of action & example) - - known as a low sodium diet - decreases plasma and extracellular fluid volumes which decreases preload and leads to a decrease in cardiac output and total peripheral resistance. - Hydrochlorothiazide ACE Inhibitors (mechanism of action & example) - - Prevent angiotensin I from being converted to angiotensin II. Angiotensin II is a potent vasoconstrictor. It also stimulates the reabsorption of water and sodium into the body. Both of these actions raise blood pressure. Therefore, by blocking, blood pressure is reduced. - Lisinopril (Prinivil) ARBs (mechanism of action & example) - - Block the binding of Angiotensin II to type 1 Angiotensin II receptors. This blocks vasoconstriction and the secretion of aldosterone. Aldosterone causes sodium and water to be reabsorbed into the body, which can raise BP. Therefore, by blocking this receptor, blood pressure is reduced. - Losartan (Cozzar) CCBs (mechanism of action & example) - - Blocks Calcium from binding to receptors which causes smooth muscles to relax, thereby preventing contraction - Amlodipine (Norvasc) Sites of action of major antihypertensive medications - the brain, heart, blood vessels, and kindeys Angina pectoris - chest pain that results when the heart does not get enough oxygen Key terms related to angina - -coronary artery disease -ischemia -myocardial infarction CAD - any one of the abnormal conditions that can affect the arteries of the heart and produce various pathologic effects especially a reduced supply of oxygen and nutrients to the heart. Arteries that deliver oxygen to the heart - coronary arteries Ischemia - is when there is damage to the tissues or cells because of lack of oxygen delivery.