This document discusses blood pressure measurement. It defines blood pressure as the pressure exerted by blood on artery walls. The history of blood pressure measurement is described, from early techniques in the 19th century to Korotkoff's method in 1905 which is still used today. Factors affecting blood pressure are explained. The document outlines Korotkoff sounds and their phases used to determine systolic and diastolic pressure. Methods of direct and indirect blood pressure measurement are presented, with the indirect cuff method being the most common. Proper cuff size and blood pressure reading procedure are described. Normal and abnormal blood pressure ranges are defined.

1. Practical 4
Blood Pressure Measurement
By; Dr. Waheed Ali
https://www.youtube.com/watch?v=lpvyCGPsVDU

2. What is Blood Pressure?
• The pressure that your blood exerts against your arteries as it is
pumped through your body by the heart
• The pressure in the arteries increases when the heart beats and
decreases while it is resting

3. History
• 19TH Century- Jules Herisson – Sphygmograph
• 1905, Dr. Nikolai Korotkoff (1874-1920), a Russian surgeon -a simple
and precise technique to measure arterial pressure.
• Korotkoff described four distinct phases of sounds: He failed to notice
only the muffled second sound, which was demonstrated a little later.

4. Factors Effecting Blood Pressure
Factors responsible for the peak systolic BP:
1. The peripheral arteriolar resistance
2. The distensibility of the arterial wall
3. The viscosity of the blood
4. The end-diastolic volume in the arterial system
Factors responsible for the diastolic BP:
1. Blood viscosity
2. Arterial distensibility
3. Peripheral resistance to flow
4. Length of the cardiac cycle

5. Korotkoff Sounds
• Sounds originate from a combination of turbulent blood flow
and oscillations of the arterial wall & classified as 5 phases:
• Phase I- Appearance of clear tapping sounds corresponding
to the appearance of a palpable pulse
• Phase II- Sounds become softer and longer
• Phase III- Sounds become crisper and louder
• Phase IV- Sounds become muffled and softer
• Phase V- Sounds disappear completely. Recorded as last
audible sound.
• Phase I corresponds to systolic pressure
• Phase V corresponds to diastolic pressure
• No clinical significance of phases II and III.

6. Blood Pressure Measurement- Methods
1. Direct Method
• Measuring BP is to insert a catheter directly into blood vessel
lumen.
• Use of electromanometer, a transducer that converts mechanical
energy into electric signal.
2. Indirect Methods
• Use a blood pressure cuff (sphygmomanometer).
• Noninvasive evaluation of arterial BP, a pneumatic cuff with a
mercury or aneroid manometer
• Most frequently used technique.

7. Measuring Blood Pressure
http://upload.wikimedia.org/wikipedia/commons/b/b9/CM-106.jpg
Pump
Inflates the cuff to stop
blood flow
Valve
Lets air out of the cuff,
allowing it to deflate
Dial
Used to read
blood pressure
Cuff
Used to temporarily
stop blood flow
The Sphygmomanometer
 The Sphygmomanometer is also
called a Blood Pressure Cuff
Cuff size:
An undersized cuff - falsely high readings, and
An oversized cuff - falsely low readings
The recommended cuff sizes are: for arm circumference
22 to 26 cm, 'small adult' cuff, 12 x 22 cm
27 to 34 cm, 'adult' cuff: 16 x 30 cm
35 to 44 cm, 'large adult' cuff: 16 x 36 cm
45 to 52 cm, 'adult thigh' cuff; 16 x 42

8. The Stethoscope
• A stethoscope allows you to hear your heart beat and your blood
flow
• When used with a sphygmomanometer, you can hear the blood
flow through your brachial artery, allowing you to measure your
blood pressure

9. Blood Pressure Measurement
- Procedure
1. Sit comfortably with arm supported at heart level
2. Snugly wrap the sphygmomanometer cuff around
the upper arm, one inch above the elbow
3. Place the stethoscope just above the crease of the
elbow
4. Pump the cuff to around 180-200 mmHg
5. While listening with the stethoscope, slowly open
the valve to let the pressure fall
• When you first hear the beat of the blood flow, that is the
systolic pressure
• When you last hear the beat of the blood flow, that is the
diastolic pressure

11. 120
80
Reading Blood Pressure
Systolic Pressure
Pressure in the arteries while the heart beats
Diastolic Pressure
Pressure in the arteries while the heart rests
Blood Pressure Is Measured In Mmhg,
And Given As A Fraction
1. Systolic Pressure: Systolic pressure is the maximum pressure exerted by the blood
against the arterial walls.
• It results when the ventricles contract ( systole )
2. Diastolic Pressure: Diastolic Pressure is the lowest pressure in the artery.
• It result when the ventricles are relaxed (diastole )

12. Variations in Blood Pressure
• Abnormally high blood pressure is called hypertension
• Any blood pressure reading greater than
140
90
is considered high.
• Hypertension is usually asymptomatic .
• Abnormally low blood pressure is called hypotension
• There is not a specific blood pressure value that is
considered ‘low.’
• Symptoms define whether blood pressure is too low:
 Dizziness
 Blurred vision
 Nausea
 Fatigue

13. Hypertension
• Caused by both hereditary and
behavioral factors
• Diabetes
• High-sodium diets
• Smoking
• Age
• Genetic factors
• No symptoms of high blood
pressure, but the consequences of
untreated hypertension can be severe:
• Heart disease
• Heart failure
• Kidney failure
• General heart/artery damage