Mod D Tech 14 Blood Pressures

Question 1

What is blood pressure?

Answer 1

Blood pressure is the force of blood against the walls of blood vessels

Recorded as two numbers:

Systolic

Diastolic

Question 2

Blood pressure Terminology

Answer 2

• Hypotension
• •Hypertension
• •Postural Hypotension
• •Pulse Pressure
• Mean Arterial Pressure

–MAP = Diastolic + 1/3 Pulse pressure

Question 3

average Blood pressures

Answer 3

Question 4

Factors involved in maintaining BP

Answer 4

• Cardiac output
• •Blood volume
• Peripheral resistance
• •Elasticity of the arteries
• •Viscosity
• •Venous return

ØMuscular contraction

ØSuction during inspiration

Question 5

Cardiac output

Answer 5

The volume of blood ejected from the left ventricle into the aorta each minute.

Cardiac Output (CO) = Stoke Volume (SV) x Heart Rate (HR)

In a typical resting adult male, cardiac output is CO

(4.9 l/min) = 70 x 70 = 4900ml/min

Question 6

Blood volume

Answer 6

• Blood pressure also depends on the total volume of blood in the cardiovascular system.
• Normal blood volume is approx 70ml/kg lean body mass in an adult and 80ml/kg in children
• Therefore 70ml/kg x 70kg = 4900ml
• It is usual to round this up to approx 5 litres

(can increase by up to 50% during pregnancy)

Question 7

Control of blood pressure

Answer 7

Short term regulation:

• Baroreflex mechanism
• Hormone

Long term regulation:

• Blood volume
• Hormones
• Kidney
• Microcirculation.

Question 8

Some factors that increase blood pressure

Answer 8

• Heredity
• Race
• Age
• Sedentary or inactive lifestyle
• Heavy alcohol consumption
• Obesity and overweight
• Stress

Question 9

Some factors that decrease blood pressure

Answer 9

• Abnormal heart rhythms
• •Alcohol
• •Antidepressants, such as amitriptyline
• Some allergic reactions
• •Calcium channel blockers
• •Nitrates

Question 10

How to obtain a Blood Pressure

Answer 10

• Relax patient
• Locate brachial pulse in antecubital fossa (ACF)
• Place correctly sized cuff
• Palpate radial pulse
• Inflate cuff
• Feel pulse disappear
• Place diaphragm of stethoscope on previously located brachial pulse in ACF
• Release pressure listen for sounds

Question 11

Pulse Pressure

Answer 11

Pulse pressure is the difference between Systole and Diastole e.g.

•BP = 120mmHg :- Pulse Pressure = ?

80mmHg

40mmHg