Hypertension Flashcards
Hypertension Epidemiology
HTN is the leading risk factor for CVD mortality (13% of global deaths)
Leading cause of CVD worldwide
“Silent killer” often asymptomatic even at extremes
Only about 50% of people with HTN are compliant with medications
Physiologic Factors Influencing Blood Pressure
Cardiac output
Peripheral vascular resistance
Volume of circulating blood
Viscosity of blood
Elasticity of vessels
Poiseuille’s
Law flow rate
Q= (3.14 or pie)*P*r^4/ 8nl Q= flow rate P= pressure r=radius n= fluid viscosity l= length radius has the biggest effect on flow rate
Poiseuille’s
Law resistance
R= 8nl/ (3.14 or pie)*r^4 R= resistance
Regulation of Blood Pressure
Fast
Baroreceptor (Aortic Arch and Carotid Sinuses)
Regulation of Blood Pressure
slow
Renin-Angiotensin System (Kidneys)
Natriureticpeptides (Atrial natriuretic peptide
and Brain natriuretic peptide) (Heart)
Renin
is an enzyme that is released into the circulation by the kidneys.
Renin is stimulated by
Sympathetic nerve activation (acting through β1-adrenoceptors)
Renal artery hypotension (caused by systemic hypotension or renal artery stenosis)
Decreased sodium delivery to the distal tubules of the kidney.
Essential hypertension
(cause unknown) accounts for 95-99% of cases
Interaction between environmental factors and genetics.
Secondary hypertension
(1-5%)** of cases
Result of some sudden biochemical or mechanical pathology, potentially reversible.
Normal blood pressure
<120/<80
Elevated blood pressure
120-129/<80
Hypertension stage 1
130-139/80-89
Hypertension stage 2
> 140/<90
Hypertension crisis
> 180/>120
SPRINT trial
targeting a systolic blood pressure of less than 120 mm Hg, as compared with less than 140 mm Hg (the previous JNC guidelines), resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause
JNC 8 Guidelines
pharmacologic treatment should be initiated when blood pressure is 150/90 mm Hg or higher in adults 60 years and older, or 140/90 mm Hg or higher in adults younger than 60 years.
Pulse Pressure
Pulse pressure (PP=SBP-DBP) is normally ~40-60mmHg Might be a better predictor of CV risk than systolic blood pressure
Low pulse pressure
<40mmHg may indicate pulse narrowing
Elevated pulse pressure
> 60mmHg PP associated with higher CVD morbidity and mortality rates
Hypotension
Systolic blood pressure <90mmHg OR Diastolic <60 mmHg
Mean Pressure <70mmHg
<60mmHg concerning for shock
Causes of hypotension
Depletion of blood volume (hemorrhage, dehydration)
Cardiogenic insufficiency
Acute Myocardial Infarction
Anti-Hypertensive Medications
Concerns with hypotension
Generally only concerning if present with signs or symptoms or in patients with preexisting medical (i.e., heart disease)
Signs and symptoms of hypotension
dizziness, fainting, cold and sweaty skin, fatigue, blurred vision, or nausea.
Issues with Brachial Blood Pressures
Brachial BP may not accurately reflect central pressure
A lot of cuffs underestimate systolic and over estimate diastolic
Static/Rest BP is only a snap shot, doesn’t reflect response to load
Common Errors To Avoid when measuring BP
Full Bladder Unsupported back Unsupported feet Crossed legs Cuff over clothing Unsupported arm Patient talking
Normal Cardiovascular Response to Exercise
Cardiac output increases in proportion to oxygen consumption
Substantial increases in heart rate
Modest increases in stroke volume (SV).
High sympathetic nervous system (SNS) activity during exercise:
Withdrawal of baroreceptor mediated and vagal control
Increase SA node firing rate
Increases HR (chronotropic effect), SV (inotropic effect)
Increases vascular constriction (alpha receptors)
Increases venous return slightly due to reduced venous compliance
Small increase in Q (~7 L/min)
BP response during exercise
SBP: ~10mmHg increase per change in workload (1MET)
DBP: Minimal Increase (<10mmHg), none or slight decrease
BP response steeper with UE activities compared to LE activities
Heart Rate Response during exercise
~10bpm increase per change in workload
Normal Recovery heart rate
Heart Rate
Recovery >12bpm within 1min,
Resting levels 2-3min
Normal Recover Blood Pressure
Approximately 10mmHg decrease Systolic within 1min,
After 3 minutes Systolic should decrease to <90% of peak exercise values
Return to normal in approximately 5-6min post
Resistance Training blood pressure
Resistance training (RT) elicits a more pronounced pressure response BP increases to max values (due to load of weight) are encountered during the concentric lifting phase.
Eccentric Loading/Exercise
Improves strength comparable to concentric training.
May increase muscle soreness more than concentric training
Lower perceived exertion, systemic vascular resistance, oxygen consumption, Cardiac Index, peak SBP and HR at similar workloads to concentric.
Post Exercise Hypotension (PEH)
The presence of a prolonged decrease in resting blood pressure in the minutes and hours following acute exercise.
The magnitude of PEH
has been found to be dose-dependent
Higher intensity exercise results in greater reductions in BP post exercise
Hypertensive response
(SBP) >220mmHg for men; >190mmHg for women.
(DBP) >10 mmHg or >90 mmHg
Exercise and HTN adverse events
Vigorous exercise increases the risk of a cardiovascular event during or soon after exertion in both young subjects with inherited cardiovascular disease and adults with undiagnosed or diagnosed congenital heart disease
The relative risk of cardiac arrest was greater during exercise than at rest for all levels of habitual physical activity
Pain and Hemodynamics
Acute pain has been shown to result in tachycardia and elevated blood pressure in experimental models. However, the research on this is limited
Experimental Pain and Blood Pressure
SBP has been shown to increase by 15-25mmHg to experimental pain.
DBP has been shown to increase by by 10-20mmHg
Experimental Pain and Heart Rate
Pain evoked a 7% rise in HR after only 15 seconds and an additional 4% rise in HR to elicit a total of 11% rise in HR after 120 seconds, mean 8.87 beats/min increase.
Higher HR increase (>20%) was associated with mod-high pain level (≥50/100)
Chronic Pain and Hemodynamics
Higher (HR) than healthy subjects at baseline and to painful stimuli
Lower parasympathetic and increased sympathetic activity
Chronic pain intensity is a significant predictor of hypertensive status independent age, race/ethnicity, and family history.
Screening Recommendations in PT
At least take resting vitals on each patient
>140/90 proceed with usual care
Contact PCP
Monitor closely
> 160/100mmHg Hold resistance exercise, consider aerobic exercise
Contact PCP
Monitor closely
> 180/120mmHg; Hold Exam
Examine for organ damage
Contact PCP
Consider contacting EMS
