Blood pressure is the pressure of blood in the arteries and is measured using a sphygmomanometer. It can be measured noninvasively using the auscultatory or oscillometry methods by wrapping a blood pressure cuff around the upper arm and listening or feeling for sounds. The systolic pressure is when the first sound is heard and diastolic is when the sounds disappear. Invasive methods involve direct measurement using a cannula placed in an artery.

1. BLOOD PRESSURE
Chamika Wickramavansa [Group 5]
1st Year 2nd Semester
Kursk State Medical University

2. What is blood pressure?
• Blood pressure is the pressure of the blood in
the arteries as it is pumped around the body
by the heart. Blood pressure does not stay
the same all the time. It changes to meet
your body’s needs. It is affected by various
factors including body position, breathing,
emotional state, exercise and sleep.

3. Methods of blood
measurement
• Auscultatory method
• Palpatory method
• Oscillometry method
• Invasive method
• Noninvasive method
• Continuous noninvasive techniques (CNAP)

4. How to measure blood
pressure?
• Arterial pressure is most commonly measured
via a sphygmomanometer, which historically
used the height of a column of mercury to
reflect the circulating pressure. Blood pressure
values are generally reported in millimeters of
mercury (mm Hg)
• Measured by wrapping an inflatable pressure
cuff around patient’s upper arm. This cuff is part
of a machine called a sphygmomanometer. It
is best to measure blood pressure when you are
relaxed and sitting.

5. Steps of measuring blood
pressure
1. Patients arm should be supported, with
his/her upper arm at heart level, back
supported, legs uncrossed, and feet on the
floor. Your upper arm should be bare, with
sleeve comfortably rolled up.
2. Medical personnel should wrap the blood
pressure cuff snugly around your upper
arm. The lower edge of the cuff should be 1
inch above the bend of your elbow.

6. Steps of measuring blood
pressure
3. The cuff must be inflated quickly, either by
pumping the squeeze bulb or pushing a
button. Patient would feel tightness around
his/her arm.
4. Next, the valve of the cuff should opened
slightly, allowing the pressure to slowly fall.
5. As the pressure falls, the reading when the
sound of blood pulsing is first heard is
recorded. This is the systolic pressure.

7. Steps of measuring blood
pressure
5. As the air continues to be let out, the
sounds would disappear. The point at which
the sound disappears is recorded. This is the
diastolic pressure.
• Inflating the cuff too slowly or not high
enough may cause a false reading. If you
loosen the valve too much, you won't be
able to determine your blood pressure.

8. Palpatory method
1. The cuff of the
sphygmomanomet
er is wrapped firmly
around the right
arm above the
elbow. The lower
arm should be
resting on a table-
top or bench.Source – www.gehealthcare.com

9. Palpatory method
2. The radial pulse (the pulse at the radial artery in
the wrist) is palpated with the fingers of the left
hand. The number of beats in 30 seconds is
counted, and the heart rate in beats per
minute is recorded.
3. The valve on the inflating bulb of the
sphygmomanometer is turned fully closed. The
cuff is inflated slowly (10 mm Hg/sec) by
pumping the inflating bulb until the radial pulse
is no longer felt. The cuff is inflated further until
the pressure is about 30 mm Hg higher.

10. Palpatory method
4. The valve on the inflating bulb is opened
slightly by turning it in the counterclockwise
direction, allowing the pressure to drop
slowly by about 5 mm Hg/sec. At some
point, one will be able to feel the radial
pulse once again. The pressure indicated
on the gauge when the pulse reappears is
noted. This is the systolic pressure. Now the
pressure in the cuff is quickly released, so as
not to cause undue discomfort to the
patient.

11. Auscultatory method
• The brachial pulse is
palpated just above
the angle of the elbow
(the "antecubital
fossa").
• The diaphragm is
placed over the
brachial artery in the
space between the
bottom of the cuff and
the crease of the
elbow. At this point no
sounds should
be heard
Source - www.laerdal.com

12. Auscultatory method
• The cuff pressure is inflated quickly to a pressure
about 30 mm Hg higher than the systolic
pressure determined by the method of
palpation. Then the air is let out of the cuff at a
rate such that cuff pressure falls at a rate of
about 5 mm Hg/sec.
• At some point the personnel listening with the
stethoscope will begin to hear sounds with
each heartbeat. This point marks the systolic
pressure.
• The sounds are called “Korotkoff” sounds.

13. Auscultatory method
• As the pressure is lowered further, the
character of the Korotkoff sounds should
change. At some point, the sounds will
disappear.
• The pressure reading at this point gives the
diastolic pressure.

14. Oscillometry method
• The pulsations induced by the artery are
different: when the artery is compressed, no
pulsation is perceived by the device, then
when the pressure decreases in the cuff, the
artery starts to emit pulsations: the pressure
then measured on the device defines the
maximal blood pressure or systolic blood
pressure.

15. Oscillometry method
• During the pressure decrease in the cuff, the
oscillations will become increasingly
significant, until a maximum amplitude of
these oscillations defines the average blood
pressure.

16. Oscillometry method
• Then, the oscillations can still be seen during
the decrease of the pressure in the cuff, until
they disappear: the pressure then read on
the device defines the minimal blood
pressure or diastolic blood pressure.
• This method of measurement of the blood
pressure is the oscillometric method. It is very
often used in the automatic device for the
measurement of the blood pressure
because of its excellent reliability

17. Oscillometry method

18. Invasive method
• This technique involves direct measurement
of arterial pressure by placing a cannula
needle in an artery (usually radial, femoral,
dorsalis pedis or brachial).
• The cannula must be connected to a sterile,
fluid-filled system, which is connected to an
electronic patient monitor.
• The advantage of this system is that pressure
is constantly monitored beat-by-beat, and a
waveform (a graph of pressure against time)
can be displayed.

19. Invasive method
www.laerdal.com

20. Cannula needles

21. Blood measuring apparatus
Mercury sphygmomanometers
They measure blood pressure by observing the height of a column of mercury

22. Blood measuring apparatus
Aneroid sphygmomanometers (mechanical types with a dial) are in
common use; they require calibration checks, unlike mercury manometers.
Aneroid sphygmomanometers are considered safer than mercury based.

23. Thank You
• Reference – www.heart.org / www.wikipedia.com