Chapter 16 Flashcards
Cardiac Output (CO)
CO = SV (Stroke Volume) x HR (heart rate)
End- diastolic volume
- the preload
- amount of blood returned to the heart
Systemic Vascular Resistance (SVR or afterload)
- determined by the radius of arteries and the degree of vessel compliance
- SVR = BP/CO
Blood Pressure (BP)
BP = CO x SVR
Hypertension
- increases morbidity and mortality associated with heart disease, kidney disease, peripheral vascular disease, and stroke
- Is determined by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure
- is classified as a higher than usual Diastolic and/or Systolic blood pressure
Prehypertension
- a range of pressures between normal and stage 1 hypertension in an effort to initiate interventions early enough to prevent or deter progression of the disease process
Numbers the classify Hypertension
Normal: SBP < 120 and DBP < 80
Prehyp: SBP 120-139 and DBP 80-89
Stage 1 Hyp: SBP 140-159 and DBP 90-99
Stage 2 Hyp: SBP >or= 160 and DBP >or+ 100
Primary Hypertension
- also called essential hypertension
- is an idiopathic disorder
- most common form
- Systolic BP: major risk factor of CV disease
Subtypes of Primary Hypertension
Isolated systolic: SBP >or= 140 while DBP < 90
Isolated Diastolic: DBP >or= 90 while SBP < 140
Combined: Both exceed hypertension levels
Nonmodifiable risk factors of Primary Hypertension
- family history
- age
- ethnicity/genetics
Modifiable Risk Factors of Primary Hypertension
- diet/weight
- Metabolic issues
- high blood glucose levels/diabetes
- high cholesterol
- alc and cigs
Outcomes of Primary Hypertension
- sometimes called the silent killer as damage to organs is done before diagnosis
- Results in end-organ damage
Treatment of Primary Hypertension
- lifestyle changes such as weight loss and exercise, decrease in sodium intake, moderation of alcohol
- Drug therapy but will affect heart rate, SVR, and/or SV
Secondary Hypertension
- hypertension attributed to a specific identifiable pathology or condition
- most common in infants and preschoolers
- most common cause is renal disease and coarctation of the aorta
- other causes are obstructive sleep apnea
- Adult secondary can be attributed to : Renal artery stenosis, Pheochromocytoma, Pregnancy, Obesity/sleep apnea, and Hyperaldosteronism
Hypertensive Emergency
- a sudden increase in either both SBP or DBP with evidence of end organ damage
- treated with rapid but controlled reduction of blood pressure using parenteral antihypertensive agents under close monitoring (ICU)
Hypertensive Urgency
- similar blood pressure elevation without evidence of end organ damage
- treated with oral medications to bring blood pressure under control over 24-48 hrs
Orthostatic (postural) Hypotension
- an extreme response to the change from supine to upright position; activation of the short term control mechanisms is slow or inadequate
- causes a decrease in SBP (>or= 20 or >or=10 in 3min) when moving to an upright position
- excessive increase in heart rate may also be diagnostic (20-30 BPM)
- results in dizziness(presinkapy), blurred vision, confusion, and possible syncope
Orthostatic Hypotension may be the result of
- problem with vasomotor or baroreceptor responese
- adverse effect of drug therapy
- arterial stiffness
- volume depletion
- secondary disease process
- Vasovagal reaction
- cardiac dysrhythmias
Treatment for Orthostatic Hypotension
- review medical history
- slow positional changes
- avoid high temps
- avoind large carbs/heavy metals
- squatting /bending forward or crossing legs at onset can reduce effects
- elastic compression stockings, abdominal binders, elevate head of bed
- increase salt and fluid intake
Renin-Angiotensin-aldosterone system (RAAS)
- important regulator of BP
- juxtaglomerular cells when stimulated by low arterial pressure release renin which activates angiotensinogen to angiotensin I
- Angiotensin I when in contact with ACE activates angiotensin II, a potent vasoconstrictor and stimulates release of aldosterone
- Aldosterone, a hormone, causes reabsorption of sodium and water passively follows
Monitoring Blood Pressure (measurement)
- components of monitoring include SBP, DBP,, SV, SVR, and Mean Arterial Pressure (MAP)
- ## there are both direct and indirect methods
Mean Arterial Pressure (MAP)
the calculated average pressure within the circulatory system throughout the cardiac cycle
- MAP = (2 x DBP) + SBP/ 3
Direct BP Monitoring
- requires an intraarterial catheter and specialized equipment to transduce arterial fluid pulsations into electrical signals (waveforms)
- catheder placed in radial artery
- most accurate method
Indirect BP Monitoring
- commonly measuredd via the brachial artery using a stethoscope and sphugmomanometer or automated oscillometric system
- Auscultation of Korotkoff sounds (SBP is onset of Korotkoff sounds) (DBP is disappearance of Korotkoff sounds)
