Blood Pressure Flashcards
What is blood pressure?
Is the lateral force on the walls of an artery by the pulsing blood under pressure from the heart.
What is systolic and diastolic pressure?
Systolic: The peak maximum pressure when ejection occurs is systolic blood pressure.
Diastolic: When the ventricles relax, the blood remaining in the arteries exerts a minimum or diastolic pressure.
What is the difference between systolic and diastolic pressure?
Pulse Pressure
What is cardiac output?
Cardiac output is the volume of blood pumped by the heart during 1 minute. The blood pressure depends on the cardiac output and peripheral vascular resistance (BP = CO x R)
What is peripheral resistance?
the resistance to blood flow determined by the tone of vascular musculature (smooth muscle in lumen wall) and diameter of blood vessels. The smaller the lumen the greater the peripheral resistance to blood flow. As resistance rises, arterial blood pressure rises. As vessels dilate and resistance falls, blood pressure drops.
What is Blood Volume?
The volume of blood exerts pressure against the arterial walls. Normally blood volume remains constant. However, if the volume rises (for example from an uncontrolled intravenous input) the pressure rises. With haemorrhage or dehydration blood pressure falls.
What effect does viscosity have on blood pressure?
The viscosity of blood affects the ease with which blood flows through small vessels. The heart must contract more forcefully to move the viscous blood through the circulatory system (which increases blood pressure).
What effect does elasticity have on blood pressure?
Normally arterial walls are elastic and easily distensible; distensibility prevents wide fluctuations in blood pressure. With arteriosclerosis the vessel walls lose their elasticity and are replaced by fibrous tissue that cannot stretch well causing greater resistance and systemic pressure rises. Systolic pressure is more significantly elevated than diastolic as a result of reduced arterial elasticity.
What are five factors that influence blood pressure?
a. Age: Blood pressure increases throughout the lifespan. Systolic blood pressure rises with decreased vessel elasticity.
b. Stress: Stress results in sympathetic stimulation (releasing cortisol and adrenaline) which increases heart rate, cardiac output, peripheral vascular resistance and ultimately blood pressure.
c. Medications: Some medication can directly or indirectly affect blood pressure such as anti-hypertensives (diuretics, beta-blockers, vasodilators, calcium channel blockers and ACE inhibitors) and narcotics)
d. Diurnal variation: Blood pressure varies over the 24 hour day. Typically it is lowest in the morning and afternoon, and peaks in late afternoon or evening. (Blood pressure rises during REM sleep as well).
e. Gender: After puberty males tend to have higher blood pressure. After menopause, women tend to have higher levels of blood pressure.
How would hypertension get diagnosed?
An average of two or more diastolic readings on at least two subsequent visits of 90 mmHg or higher.
What is the physiology of hypertension?
Hypertension is associated with the thickening and loss of elasticity in the arterial walls. Peripheral vascular resistance increases within thick and inelastic vessels. As a result, blood flow to vital organs such as the heart, brain and kidneys decreases.
What are five factors linked to hypertension?
a. Obesity
b. Cigarette smoking
c. Heavy alcohol consumption
d. High sodium intake
e. Sedentary lifestyle and continued exposure to stress
What is the criteria for being diagnosed with hypotension?
When systolic blood pressure falls to 90 mmHg or below.
What is the physiology of hypotension?
Hypotension occurs because of the dilation of the arteries in the vascular bed, the loss of a substantial amount of blood volume (e.g. haemorrhage), or the failure of the heart muscle to pump adequately (e.g. myocardial infarction). Hypotension associated with pallor, skin mottling, clamminess, confusion, increased heart rate or decreased urine output is life-threatening.
When does orthostatic hypotension occur and how would you assess it?
Orthostatic hypotension occurs when a person with normal blood pressure develops symptoms and low blood pressure when rising to an upright position
It would be assessed by Obtaining blood pressure and pulse with the patient supine, sitting and standing. Consider safety when sitting and standing patient. Assess for dizziness, weakness or light-headedness.
