MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...

FM/UOJ
Experiment C 2
MEASUREMENT OF BLOOD PRESSURE
Blood pressure is the lateral pressure exerted by the blood on the artery wall at
the level of the heart. In experimental animals this can be measured by connecting a
manometer directly to the artery. The blood pressure of man is measured by an indirect
method; a measurable pressure is applied over the artery; the pressure required to
compress the artery is equal to the pressure. Measuring blood pressure is an accurate
and simple method of assessing the state of the circulatory system.
The main aim of this practical is to gain skill in measuring blood pressure
accurately
Instruments:
Sphygmomanometer and stethoscope.
Method:
Make sure that the subject (or patient) is comfortably seated or in bed and in a
relaxed condition. Remove cloths from the arm and apply the cuff.
Application of the cuff:
Blood pressure is generally recorded in the arm with the patient in sitting or
recumbent position. The artery over which the pressure is to be measured should be at
the level of the heart. The deflated compression cuff is applied evenly and snugly but
without constriction around the arm. The lower edge of the cuff should be about 2.5 cm
above the elbow joint. Make sure that the middle of the rubber bag is over the brachial
artery, in the medical aspect of the arm.
Palpatory method of measurement:
This method is based on the fact that the pulse wave is not conducted through
when the brachial artery is occluded. This happens when the external pressure (in the
cuff) is more than the maximum pressure in the artery.
First, locate and palpate the redial or brachial pulse. While feeling the pulse by
one hand, inflate the cuff by the other hand. Continue to increase the pressure for about
further 30 mm Hg after the disappearance of the pulsation. Deflate the cuff slowly
(about 2 or 3 mm Hg per second) until the pulse is felt again. The pressure at this
moment is equal to the systolic blood pressure.
Auscultatory method of measurement:
This method is based on sounds produced at the lower end of the partially
compressed artery due to turbulence. If the pressure in the cuff exceeds systolic
pressure the artery is closed and there will be no sound. If the pressure in the cuff is
below the diastolic pressure also there will be no sound because the artery is fully
opened and there is laminar flow. When the cuff pressure is between systolic and
Circulation
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