Categories of HTN Overview of Hypertension Normal SBP <120 and DBP <80 Pre-HTN- SBP 120-139 or DBP 80-89 Stage 1 SBP 140-159 or DBP 90-99 Stage 2 SBP >160 or DBP >100 Quick review of the Basics: What is Hypertension? Hypertension, or high blood pressure, is the chronic state of elevated pressure in the arteries. Physiology: Narrowing of vessels Fluid retention Both Under normal conditions: Autoregulation of blood pressure is done by release of: Endothelins (upward) Prostacyclin (downward, short term) Nitric oxide (longer term) Blood Pressure Measurement Seated, arm at level of the heart Cuff size and pressure Serial measurements White coat hypertension 3 Quick Review of the Basics Where can I put a blood pressure cuff? Choose the correct cuff size Extremity at heart level Use proper size cuff Different locations are not interchangeable with the upper arm. Forearm position the cuff midway between elbow and wrist. Calf- lower edge of cuff should be 2.5cm above the malleoli. Auscultate at: Dorsalis pedis pulse Posterior tibialis pulse Thigh lower thigh, 2-3cm above the popliteal fossa. Auscultate at: Popliteal pulse 5 Primary Types of Hypertension Essential hypertension No known cause Diagnosed by excluding secondary causes Progressive disease Incidence: 90-95% of hypertension diagnoses Secondary Hypertension caused by another medical issue, including: Kidney disease Thyroid disease Appears quickly controllable by treating underlying condition Incidence: 5-10% of hypertensive cases 6 1
Causes of Hypertension Chronic Kidney Disease Primary aldosteronism Renovascular disease Sleep apnea Drug induced or drug related Chronic steroid therapy Pheochromocytoma Coarctation of the aorta Thyroid or parathyroid disease Evaluation of Newly Diagnosed HTN History and Physical Medical History Lifestyle evaluation Labs CBC UA Electrolytes Target Organ Damage Cardiac Effects of HTN on Target Organs Heart Cardiovascular or peripheral vascular damage due to ischemia Leads to cardiomyopathy Heart failure Pulmonary edema Peripheral edema Endothelial damage:» stiff vessels ->» Increased SVR ->» Increased myocardial oxygen demands -> Increased ischemia Effects of HTN on Target Organs Effects of HTN on Target Organs Brain Stroke or TIA Chronic kidney disease Cause of hypertensive crisis AND Result of hypertensive crisis Increased Serum Creatinine Microscopic hematuria Proteinuria Oliguria or anuria Peripheral arterial disease Retinopathy Eye exam will reveal the extent of stenosis Narrowing of small arteries Small hemorrhages Swelling of the optic nerve Will reveal approximate BP level 2
Major Risk Factors Hypertension Cigarette Smoking Obesity (BMI>30%) Dyslipidemia Diabetes Mellitus Microalbumiuria or GFR <60 ml/min Age (>55 for men, >65 for women) Family history of premature cardiovascular disease Treatment Algorithm Normal BP Encourage Lifestyle changes Pre-hypertensive Lifestyle changes No drugs unless have risks such as diabetes or renal insufficiency Treatment Algorithm Stage 1 Thiazide diuretic. Consider ACE-I, ARB, BB, or CCB Stage 2 Two drug combo for most (diuretic and ACE-I, ARB, BB, or CCB) RAAS Renin Angiotensin system: Regulates BP & fluid balance 1. Kidney responds to hypotension by releasing Renin. 2. Angiotensinogen is released by the liver. 3. Renin interacts with Angiotensinogen, to create Angiotensin I. 4. Angiotensin I interacts with ACE, creating Angiotensin II Lifestyle Modifications Weight Reduction DASH Diet (see next slide) Decrease Sodium Physical Activity Limit Alcohol Smoking Cessation DASH (Dietary Approach to Stop Hypertension) Plan Rich in potassium and calcium Fruits and vegetables Low fat dairy products Whole grains Low sodium 3
Diuretics Diuretic Agents Possible mechanisms of action Extracellular Volume Vascular Resistance Cardiac Output May increase lipids, BUN, glucose Electrolyte effects Thiazides Hydrochlorothiazide Zaroxolyn Loop Diuretics Lasix Bumex K+ sparing Spironolactone Triamterene amiloride Beta Blockers Decrease C.O. by decreasing HR Inhibit renin release Decrease vasomotor activity Atenolol Metoprolol Nadolol Propranolol Alpha agonists and blockers Mechanism of action Decrease sympathetic outflow Decrease peripheral vascular resistance Aldomet Captopril Clonidine Minipress Combined Beta and Alpha Blockers Carvedilol Labetalol Direct vasodilators Dilation of arterioles Decreased peripheral vascular resistance Hydralazine Minoxidil 4
Calcium Channel Blockers Reduced vascular tone Decreased peripheral resistance Vasodilatation verapamil diltiazem nefedipine Vasodilatation Captopril Lisinopril Enalapril ACE Inhibitors Hypertensive Crisis Renal HTN Endocrine (pituitary or adrenal tumors) Drug Ingestion Tricyclics, MAO Inhibitors Cocaine, amphetamines Pregnancy Autonomic Dysreflexia Head trauma, stroke, cerebral hemorrhage Hypertensive Crisis Untreated or uncontrolled hypertension. Poor compliance with prescribed medication regimen Sudden discontinuation of antihypertensive medication Postoperative Hypertension Post-op Hypertension presentationtreatment goals Check first before medicating Pain Anxiety Full bladder Nausea/vomiting Hypovolemia Labile Hypertension Baroreceptor injury Relieve symptoms that may lead to intense discomfort Treatment is dependent on surgery type. Cardiac, vascular or carotid surgery: More aggressive reduction Abdominal, ortho surgery: Tolerate higher BP 29 PHARMACOLOGICAL THERAPY Goals: Controlled lowering of blood pressure No more than 20% in first hour Reduce MAP by 25% in 8 hours Relief of vasospasm elief of vasospasm May require concomitant use of vasoconstrictor to allow use of antispasmodic Dependent on level of crisis 30 5
Vasodilators Nipride Nitroglycerin Adrenergic Inhibitors Labetalol Esmolol IV Drugs Nitroprusside (Nipride) Drug Action Arterial and venous dilator Decreases peripheral vascular resistance Preload and afterload reducer Improves LV function Rapid action with short half-life Nursing Considerations Arterial line for continuous BP monitoring Metabolizes into cyanide Antidote: Sodium Thiosulfate Increased risk of cyanide toxicity with renal failure Light sensitive: Shield from light Nitroglycerin Drug Action Affects venous dilation Arterial dilation at high doses Decreases preload and/or afterload Response varies with patient s baseline pressure Vasodilates the pulmonary vascular bed. Nursing Considerations Headache Arterial dilation at 1 mcg/kg/min Glass bottle requires vented tubing Absorbed by some IV tubing: May have increased response to drug when tubing is saturated 6