15) Blood Pressure Flashcards
What is blood pressure?
- Force exerted on artery walls by pulsing blood from the heart
- Blood flows from high pressure to low pressure areas
What is systemic/arterial blood pressure?
- Blood pressure in the arteries of the body
- Good indicator of cardiovascular health
What is systolic blood pressure?
- Peak maximum pressure when heart contracts
- Blood forced into aorta under high pressure
What is diastolic blood pressure?
- Minimal pressure exerted on artery walls
- When ventricles are relaxed
How is blood pressure measured?
- In millimeters of mercury (mmHg)
- Indicates height a column of mercury is raised
How is blood pressure recorded?
- Systolic reading over diastolic reading (e.g. 120/80)
What is pulse pressure?
- Difference between systolic and diastolic pressures
- For 120/80, pulse pressure is 40
Why is pulse pressure important?
- Potential indicator of cardiovascular disease
- Related to arterial compliance/stiffness
What factors influence arterial blood pressure?
- Cardiac output
- Peripheral vascular resistance
- Blood volume
- Blood viscosity
- Artery elasticity
Why is knowledge of hemodynamic variables important?
- Helps in assessing blood pressure alterations
How does cardiac output affect blood pressure?
- As cardiac output increases, more blood is pumped against artery walls
- This causes blood pressure to rise
- Cardiac output increases from increased heart rate, contractility, or blood volume
How does a rapid heart rate increase affect blood pressure?
- Decreases heart’s ability to fill properly
- Results in decreased blood pressure
What is peripheral vascular resistance?
- Resistance to blood flow determined by vessel diameter and tone
- Smaller lumen = greater resistance to flow
How does peripheral resistance affect blood pressure?
- As resistance rises, arterial blood pressure rises
- As vessels dilate and resistance falls, blood pressure decreases
How do arteries and arterioles regulate blood flow?
- Surrounded by smooth muscle that constricts/dilates
- Constriction decreases blood supply to that area
- Allows more blood to major organs requiring it
How does blood volume affect blood pressure?
- Most adults have ~5000 mL circulating blood volume
- Increased volume exerts more pressure on artery walls
- Decreased volume (hemorrhage, dehydration) reduces blood pressure
What is blood viscosity?
- Thickness/resistance of blood flow through vessels
- Determined by percentage of red blood cells (hematocrit)
- Higher hematocrit = more viscous blood = higher blood pressure
How does artery elasticity affect blood pressure?
- Elastic arteries accommodate pressure changes without fluctuations
- Reduced elasticity (arteriosclerosis) increases resistance
- Rigid arteries cannot expand for stroke volume = higher systolic pressure
How are hemodynamic factors interrelated?
- Each factor significantly impacts the others
- Reduced elasticity increases peripheral resistance
- Body compensates for changes to maintain stable pressure
What is the normal state of artery walls?
- Elastic and easily distensible
- Expand in diameter to accommodate pressure changes
- Prevents wide fluctuations in blood pressure
How do diseases like arteriosclerosis affect artery walls?
- Walls lose elasticity and become rigid
- Replaced by fibrous tissue that cannot stretch well
- Increases resistance to blood flow
How does reduced elasticity impact blood pressure?
- Vessels cannot expand for stroke volume
- Blood forced through rigid walls
- Systolic pressure significantly elevated
Why is a single blood pressure measurement inadequate?
- Blood pressure is not constant
- It changes from heartbeat to heartbeat
- Influenced by many factors
What should guide nursing interventions for blood pressure?
- Blood pressure trends over time
- Not just individual measurements
Why is understanding influencing factors important?
- Allows more accurate interpretation of readings
- Provides context for blood pressure values
How does blood pressure change in childhood?
- Increases during childhood
- Assessed based on age and body size
- Larger/taller children have higher BP for their age
What are normal BP ranges in children?
- 6-12 months: 80-100/55-65 mmHg
- 3-6 years: 95-110/60-75 mmHg
How does blood pressure change in adulthood?
- Tends to increase with advancing age
- Systolic BP and pulse pressure may rise due to artery stiffness
What are BP treatment targets in adults?
- Most adults: <140/90 mmHg
- Diabetes: <130/80 mmHg
- High normal BP requires annual monitoring
How does stress affect the body?
- Stimulates sympathetic nervous system
- Increases heart rate, cardiac output, peripheral resistance
- These changes raise blood pressure
What emotional states can increase blood pressure?
- Anxiety
- Fear
- Pain
- Other emotional stress
How much can anxiety raise blood pressure?
- Anxiety can raise blood pressure by up to 30 mmHg
Do patients with male or female genitalia have different baseline blood pressure levels?
- No clinically significant differences
- After puberty, those with male genitalia tend to have higher readings
What factors can increase hypertension risk in those with female genitalia?
- Pregnancy
- Birth control
- Menopause
After what age are those with female genitalia more likely to have higher blood pressure?
- After age 65
What is the diurnal rhythm of blood pressure?
- Daily peak and trough pattern
- Steep increase in the morning
- Peaks in late afternoon
- Decreases at night during rest
When is blood pressure highest during the day?
- Late afternoon
When is blood pressure lowest?
- At night during rest
What medications can lower blood pressure?
- Antihypertensive drugs
- Other cardiac medications
- Opioid analgesics
What can increase blood pressure?
- Vasoconstrictors
- Excess intravenous fluids
Why assess blood pressure before medication administration?
- Some medications directly or indirectly affect blood pressure
- Critical to have a baseline reading
For low risk patients, what BP level requires antihypertensive therapy initiation?
- SBP ≥ 160 mmHg
- DBP ≥ 100 mmHg
What are the BP treatment targets for low risk patients?
- SBP < 140 mmHg
- DBP < 90 mmHg
For high cardiovascular risk patients, what BP level requires therapy initiation?
- SBP ≥ 130 mmHg
What is the SBP treatment target for high CV risk patients?
- SBP < 120 mmHg
For patients with diabetes, what BP levels require antihypertensive therapy?
- SBP ≥ 130 mmHg
- DBP ≥ 80 mmHg
What are the BP treatment targets for diabetic patients?
- SBP < 130 mmHg
- DBP < 80 mmHg
For all other patients, what BP level requires therapy initiation?
- SBP ≥ 140 mmHg
- DBP ≥ 90 mmHg
What are the general BP treatment targets?
- SBP < 140 mmHg
- DBP < 90 mmHg
What do diuretics do?
- Reduce kidneys’ reabsorption of sodium and water
- Lower circulating fluid volume
How do β-blockers lower blood pressure?
- Block sympathetic nerve impulses
- Reduce heart rate and cardiac output
What is the mechanism of action for vasodilators?
- Act on arteriolar smooth muscle
- Cause relaxation and reduce peripheral resistance
How do calcium channel blockers reduce blood pressure?
- Cause systemic vasodilation
- Reduce peripheral vascular resistance
What do ACE inhibitors prevent?
- Block conversion of angiotensin I to angiotensin II
- Prevent vasoconstriction
- Reduce aldosterone and fluid retention
How do angiotensin II receptor blockers work?
- Block binding of angiotensin II
- Prevent vasoconstriction
How does exercise affect blood pressure?
- Blood pressure can be reduced for several hours after exercise
What happens to older adults’ blood pressure after eating?
- Often experience 5-10 mmHg drop about 1 hour after eating
How does activity affect blood pressure?
- Increased oxygen demand leads to increased blood pressure
Is obesity linked to hypertension?
- Yes, obesity is a factor in hypertension
How does smoking impact blood pressure?
- Causes vasoconstriction
- Blood pressure rises during smoking
- Returns to baseline 15 minutes after smoking stops
What is the most common blood pressure alteration?
- Hypertension
What are the effects of hypertension on arteries?
- Thickening of arterial walls
- Loss of elasticity in arterial walls
- Increased peripheral vascular resistance
How does hypertension impact the heart and blood flow?
- Heart must pump against greater resistance
- Decreased blood flow to vital organs like heart, brain, kidney
When should hypertension be diagnosed and treated immediately?
- If patient exhibits features of hypertensive urgency or emergency
What blood pressure readings indicate hypertension diagnosis via office measurement?
- MBP ≥180/110 mmHg
- AOBP 135-179/85-109 mmHg
- OBPM 140-179/90-109 mmHg
How is hypertension diagnosed via ambulatory monitoring?
- Mean SBP ≥135 or DBP ≥85 mmHg
- 24-hr mean SBP ≥130 or DBP ≥80 mmHg
When is home blood pressure monitoring (HBPM) used?
- If ambulatory monitoring is not tolerated or available
- Consists of 2 readings morning and evening for 7 days (28 total)
- Discard first day’s readings, average last 6 days
What home BP readings indicate hypertension diagnosis?
- Mean SBP ≥135 mmHg
- Mean DBP ≥85 mmHg
What should nurses do regarding BP measurement?
- Incorporate recommendations into practice
- Correctly interpret BP and minimize error
What is white coat hypertension?
- BP elevated during healthcare visits
- Patients more likely to develop true hypertension
What is masked hypertension?
- BP normal during healthcare visits
- BP elevated at home
What advice was given to M.J. regarding white coat hypertension?
- Monitor blood pressure at home
- Reduce sodium intake
- Exercise regularly
What lifestyle factors increase hypertension risk?
- Physical inactivity
- Poor diet low in fruits/veggies
- Overweight/obesity
- Diabetes
- Chronic kidney disease
What lifestyle changes help prevent/treat hypertension?
- Increase physical activity
- Weight reduction
- Moderate alcohol
- Eat healthier
- Relaxation therapies
- Quit smoking
What are the major risks associated with hypertension?
- Major risk factor for cardiovascular disease
- Number one risk factor for stroke
Who is at significant risk for developing hypertension and cardiovascular disease?
- People with a family history of hypertension
What type of disease is cardiovascular disease?
- A noncommunicable disease (NCD)
What blood pressure level indicates hypotension?
- Systolic blood pressure ≤ 90 mmHg
Is low blood pressure always abnormal?
- For most people, yes - it is associated with illness
- Some adults may have low BP normally
What causes hypotension?
- Dilation of arteries in vascular bed
- Substantial blood volume loss (e.g. hemorrhage)
- Failure of heart to pump adequately (e.g. myocardial infarction)
What symptoms indicate life-threatening hypotension?
- Pallor
- Skin mottling
- Clamminess
- Confusion
- Increased heart rate
- Decreased urine output
What should be done for life-threatening hypotension?
- Report to healthcare provider immediately
What risk factors contribute to most CVDs?
- Tobacco use
- Unhealthy diet and obesity
- Physical inactivity
- Harmful alcohol use
What is orthostatic/postural hypotension?
- Low blood pressure when rising to upright position
- Occurs in normotensive (normal BP) individuals
What happens in healthy individuals when standing?
- Blood vessels in legs constrict
- Prevents blood pooling due to gravity
- No symptoms felt
What happens in volume-depleted patients when standing?
- Blood pressure drops significantly
- Heart rate increases to compensate for low cardiac output
Who is at risk for orthostatic hypotension?
- Dehydrated patients
- Anemic patients
- Prolonged bed rest
- Recent blood loss
How is orthostatic hypotension assessed?
- BP and pulse taken supine, sitting, standing
- Readings 1-3 mins after position change
- Observe for symptoms like fainting, weakness
How should orthostatic BP be recorded?
- Note patient position with each reading
e.g. 140/80 supine, 132/72 sitting, 108/60 standing
Who should perform orthostatic measurements?
- Requires advanced nursing judgment
- Should not be delegated to unregulated providers
