16 Alterations in Blood Pressure Flashcards
Components of BP measurement
1 Systolic BP 2 Diastolic BP 3 SV is primary factor of systolic p 4 SVR is major determinant of diastolic p 5 Pure Pressure = sys-dias 6 Mean Arterial Pressure
Systolic Blood Pressure [SBP]
peak pressure during cardiac systole
-the squeezing of heart to pump
Diastolic Blood Pressure [DBP]
lowest pressure during cardiac diastole
- dilating/relaxing part of heart/refilling
- takes longer than systolic
SV
primary factor influencing systolic pressure
SVR
major determinant of diastolic pressure
Pulse pressure
systolic - diastolic
Mean Arterial Pressure [MAP]
calculated average pressure w/in circulatory system throughout the cardiac cycle
MAP=
{[2x dias.press]+sys.press}/3
Direct measurements of BP
- requires intraarterial catheter + specialized euipt to transduce arterial fluid pulsations into electrl sgnals.
- catherer commonly placed in RADIAL ARTERY
- most accurate method to measure BP
where is catheter usually placed to measure BP?
radial artery
Indirect measurement of BP
- commonly via brachial artery w stethoscope + sphygmomanometer or automated oscillometric systm
- requires careful technique for accuracy
- auscultation of korotkoff sounds
- white coat effect
- elderly auscultatory gap
Auscultation of Korotkoff Sounds
-indirect form of measurement of BP
SBP: onset of Korotkoff sounds
DBP: disappearance of Korotkoff sounds
Auscultatory Gap
- occurs in elderly
- period of absent Korotkoff sounds during manual measurement of BP
Cardiac Output [CO]
Q=strok vol x heart rate
vol of blood being pumped by heart
Preload
end-diastolic volume
-amount of blood returned to heart
Afterload
- systemic vascular resistance
- determined by radius of arteries + degree of vessel compliance
Sympathetic Nervous System [SNS] on BP
- short-term regulator of systemic blood pressure
- based on epinephrine + norepinephrine
parasympathetic nervous system on BP
slows heart
Renin-Angiotensin-Aldosterone System [RAAS]
-important long-term regulator of BP 1 low arterial pressure causes Juxtaglomerular cells to secrete Renin 2 Renin activates ANG to ANG I 3 ACE activated ANG I into II [PRELOAD] 4 ANG II stim release of ALDOSTERONE 5 reabsorption of Na + H2O> PRELOAD
Angiotensin II
- activated from Angiotensin I by ACE
- potent vasoconstrictor [AFTERLOAD]
- stimulates the release of Aldosterone in RAAS
Aldosterone
hormone that causes reabsorption of Na
- causes water to follow
- PRELOAD
- release of aldosterone is stimulated by Angiotensin II
Na + H2O retention causes…
increase in BLOOD VOLUME>
increase in BLOOD PRESSURE
what it the main outcome of RAAS?
pathway leads to INCREASE IN BLOOD PRESSURE
RAAS/long-term syst BP
REGULATION
-regulated by neural, hormonal, + renal
increase in xtracellular FLUID VOLUME [PRELOAD]
1 increase in CO + SVR
2 elevated BP
-causes kidneys to EXCRETE excess Na + fluid
increase in SERUM SODIUM LVL
1 increase osmolality
2 increase ADH secretion
-causes kidneys to REABSORB water + increase PRELOAD
Vasopressin [ADH]
- hormone made by hypothalamus
- stored in PIT gland
- causes kidney to conserve/reabsorb H2O
Atrial Natriuretic Peptides [ANP]
1 increases GLOMERULAR FILTRATION RATE >
2 increase in H2O + Na EXCRETION
3 results in decrease of PRELOAD
Normal Blood Pressure
SBP <120
DBP <80
PRE hypertension
SBP 120-139
DBP 80-89
Stage 1 Hypertension
SBP 140-159
DBP 90-99
Stage 2 Hypertension
SBP >160
DBP >100
Primary Hypertension
aka HIGH BLOOD PRESSURE aka silent killer bc organs are damaged before diagnosis is made [END-ORGAN DAMAGE]
-no clear cause
End-Organ Damage
1 renal failure, stroke, heart disease
2 damaged arterial sytm >atherosclerosis >cardiovasc disease
3 incr myocardial work > heart failure
4 glomerular damage > kidney failure
5 affects microcirculation of eyes
6 incr pressure in cerebral vasculature > hemorrhage
Primary Hypertension
subtypes
1 Isolated Systolic Hypertension
2 Isolated Diastolic Hypertension
3 Combined
Isolated Systolic Hypertension
SBP>140 [stage 1 hypertension+]
DBP<90 [normal - prehypertension]
Isolated Diastolic Hypertension
SBP<140 [normal - prehypertension]
DBP>90 [stage 1 hypertension+]
Combined Sys + Dias Hypertension
both exceed prehypertension levels
SBP>140
DBP>90
what determines the degree of hypertension?
the highest reading
Primary Hypertension
risk factors
- family history
- age
- ethnicity
- genetics
Primary Hypertension
modifiable risk factors
- diet
- sedentary lifestyle
- obesity/weight gain
- metabolic syndrome
- elevated blood glucose/diabetes
- elevated total cholesterol
- alcohol + smoking
Primary Hypertension
treatment
lifestyle modifications are first + most important prevention + treatment strategy
-drug therapy affects heart rate, SVR, + stroke volume
lifestyle modifications are first + most important prevention + treatment strategy for primary hypertension
- weight loss
- exercise
- DASH diet
- alcohol moderation
- decreased sodium intake
Secondary Hypertension
-attributed to specific identifiable pathology or condition
most common form of hypertension in infants + children
Secondary Hypertension
most common cause of childhood secondary hypertension
RENAL DISEASE + coarctation of the aorta [AORTIC NARROWING]
-other cause is obstructive sleep apnea
normal BP
120/80
