Hypertension

• Circulatory system


  The system that circulates blood through the body

  
• Blood pressure


  The force exerted by the blood against the wall of the blood vessels
• Classification of hypertension


  • Primary hypertension (essential or idiopathic)
  • Secondary hypertension
• Primary hypertension


  • Elevated BP WITHOUT an identified cause
• Secondary hypertension


  • Elevated BP that is caused by another medical condition
• Risk factors for primary hypertension


  • Age
  • Drinking
  • Smoking
  • Diabetes
  • High cholesterol
  • High salt diet
  • Gender
  • Genetics
  • Obesity
  • Ethnicity
  • Healthy lifestyle choices
  • Socioeconomic status
  • Stress
• Causes of secondary hypertension

  • Cirrhosis
  • Narrowing of the aorta
  • Drugs
  • Pheochromocytoma
  • Cushing's
  • Thyroid disease
  • Brain tumors
  • Quadriplegia
  • Traumatic brain injury
  • Pregnancy induced hypertension
  • Renal disease
  • Sleep apnea
• Cardiac output (CO)


  The volume of blood being pumped by the heart by the right or left ventricle
• Systemic vascular resistance (SVR)


  The resistance to blood flow offered by all of the body's vessels with the exception of the lung
• Stroke volume (SV)


  Volume of blood pumped from the ventricle per beat
• Baroreceptors


  • Special receptors that detect changes in blood pressure
  • Decreases in BP will activate and decrease the receptor causing the HR to increase in order to restore BP levels
  • Increases in BP will activate and cause the HR to decrease
• Renin-angiotensin-aldosterone system (RAAS)


  1. Decreased blood flow to the kidneys causes release of renin (vasoconstrictor)

  2. Renin causes release of angiotensin 1 which is another vasoconstrictor

  3. Angiotensin 1 causes release of angiotensin 2 which is a more potent vasoconstrictor

  4. Angiotensin 2 causes the adrenal glands to release aldosterone
• Blood pressure goals (JNC 8th)


  • <60 years old: SBP<140mmHg, DBP<90mmHg
  • >60 years old: SBP<150mmHg, DBP<90mmHg
  • CKD (any age/no DM): SBP<140mmHg, DBP<90mmHg
  • DM (any age/no CKD): SBP<140mmHg, DBP<90mmHg
• Black Americans


  • Have a higher death rate resulting from HTN than whites
  • Produce less renin and do not respond well to renin-inhibiting drugs
  • Calcium channel blockers and diuretics provide better BP control, especially with monotherapy
  • Have a higher risk of angioedema with ACE inhibitors than whites
• Hispanic Americans


  • Obstacles related to lack of treatment include low SES and educational status
  • Likely to work in occupations with no health benefits
  • Inability to achieve higher incomes attributes to lack of access of preventative health care
  • Language barriers and cultural beliefs/attitudes related to health may keep them from seeking care
• Hypertension


  The "silent killer" because patients are frequently not symptomatic until target organ disease occurs
• Possible signs of severe hypertension


  • Dizziness
  • Fatigue
  • Palpitations
  • Angina
  • Dyspnea
  • Headache
  • Nosebleed
• Presentation of target organ disease


  • Cardiac
  • Cerebrovascular
  • Peripheral vascular
  • Renal (Serum Creatinine ≥1.5 mg/dL, Proteinuria (≥1+))
  • Retinopathy
• Hypertension is a major risk factor for coronary artery disease
• Hypertension contributes to the development of atherosclerosis which disrupts the coronary endothelium
• Hypertrophy


  An enlargement of an organ or tissue from the increase in size of its cells
• Heart failure


  A chronic condition in which the heart doesn't pump blood as well as it should
• Goals of diagnostics


  • Rule out the causes of any secondary HTN
  • Evaluate the extent of any target organ disease
  • Determine the patient's cardiovascular risk
  • Establish baseline BP levels before initiating therapy
• Diagnostic tests


  • Health & Physical Assessment with history (including comprehensive eye exam)
  • Urinalysis
  • Basic metabolic profile
  • Complete blood count
  • Serum lipid profile
  • Serum uric acid
  • Serum calcium
  • Serum magnesium
  • 12 lead EKG
  • Echocardiogram
• Ambulatory blood pressure monitoring (ABPM)


  • The best method for diagnosing HTN
  • Noninvasive, fully automated system that measures BP at preset intervals over 24-hour period
• Blood pressure measurement


  1. Take BP in both arms to note any differences

  2. Use arm with highest BP and take at least two readings, a minimum of 1 minute apart

  3. Wait at least 1 minute before repeating the BP

  4. Use the arm with the higher reading for all subsequent readings
• Tips for accurate BP measurement


  • Use properly calibrated sphygmomanometer or electric device
  • Placement of BP cuff is important
  • Size of BP cuff is also important
  • Estimate SBP by palpating the radial pulse & inflating cuff till pulse disappears
  • Deflate cuff at 2-3 mmHg a second
• Orthostatic hypotension


  • BP & Pulse are measured with the client in the supine, sitting & standing positions within 1 to 2 min of repositioning
  • Hypotension is defined as: Decrease of 20mmHg or more in SBP, Decrease of 10mmHg or more in DBP, Increase of 20bpm or more in pulse from supine to standing
• Lifestyle modifications for hypertension


  • Weight reduction plan for overweight patients
  • Moderate physical exercise
  • DASH eating plan
  • Fish Oil & Omega 3 Fatty Acids
  • Reduction of sodium to <2300mg/day (or <1500mg/day for middle age/older, HTN, DM, CKD)
  • Moderation of alcohol consumption
  • Avoidance of tobacco products
  • Reducing psychosocial risk factors
• Antihypertensive drug classes


  • Diuretics
  • Adrenergic inhibitors
  • Alpha & Beta Adrenergic blockers
  • Direct Vasodilators
  • Angiotensin-Converting Enzyme Inhibitors
  • Angiotensin II Receptor Blockers
  • Calcium Channel Blockers
• Diuretics


  • Promote Na+ & H20 excretion, reduce plasma volume
  • Loops (furosemide) & Thiazides(HCTZ) can cause hypokalemia
  • Loops are potentially ototoxic
  • NSAIDs can decrease the diuretic & antihypertensive effects
  • Aldosterone Receptor Blockers (spironolactone) are K+ sparing (amiloride) can cause hyperkalemia
• Adrenergic inhibitors


  • Central Acting Alpha Adrenergic Agonist (clonidine)
  • Peripheral Acting Alpha Adrenergic Agonist (reserpine)
  • Alpha Adrenergic Blockers (doxazosin)
• Beta blockers


  • Cardioselective (atenolol, metoprolol, nebivolol)
  • Non Cardioselective (carteolol, nadolol, propranolol, timolol)
  • Mixed Alpha & Beta Blockers (carvedilol, labetalol)
• Direct vasodilators


  • Reduce SVR by dilating the vascular smooth muscle to decrease BP
  • Available in IV for HTN crisis, usually in ICU/CCU for close monitoring (nitroglycerin, sodium nitroprusside, hydralazine)
• ACE inhibitors


  Decrease vasoconstriction by preventing conversion of Angiotensin I into Angiotensin II (benazepril, captopril, lisinopril, ramipril, enalapril)
• Angiotensin II receptor blockers (ARBs)


  Prevent angiotensin II from binding to its receptors in the wall of the blood vessels, producing vasodilation & increased Na+ and water excretion (losartan, candesartan, irbesartan, valsartan)
• Calcium channel blockers


  Cause vasodilation by preventing the movement of extracellular Ca+ into the myocardial cells, causing relaxation of the smooth muscle
• Peripheral vasodilation


  Decreased heart rate
• Used in HTN Crisis


  Available in IV form
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