blood pressure. blood pressure is the force of blood against the arterial walls. responsible for the...

Blood Pressure

• Blood pressure is the force of blood against the arterial walls.

• Responsible for the flow of blood.

• Blood pressure is the result of:

- The pumping action of the heart.

- Resistance of the blood vessels.

- Volume of blood.

Blood pressure also depends on:

• Distance from the heart.

Would B/P in the legs be lower or higher than in the arm?

Pumping Action of the Heart

• Systolic Phase-Systole• Ventricles Contract• Blood flows to the body

Pumping Action of the Heart

• Diastolic Phase – Diastole

• Heart relaxes

Blood Pressure is Elevated by:• Sex and age of the

patient.• Exercise, eating,

emotions• Stimulants• Obesity• Arteriorsclerosis• Diabetes• Pain• Heredity factors• Some drugs

Blood Pressure is lowered by:

• Fasting• Rest• Depressants• Weight loss• Loss of blood or shock• Diuretics

Blood Pressure is:

• Recorded as an improper fraction. 120/80• Numerator equals systolic pressure, the

first sound you will hear.• Denominator equals diastolic pressure, the

last sound you will hear.

Blood Pressure Sounds are:

• Auscultated through a stethoscope• Sounds are correlated with the readings

on a sphygmomanometer.• Blood pressure is recorded in milligrams of

mercury. (mm HG)

Blood Pressure Variations• Determine baseline

- From medical record

- From systolic palpated pressure• Hypertension – High blood pressure• Hypotension – Low blood pressure• Orthostatic hypotension – decrease in

B/P with position change from supine to erect.

Equipment

Stethoscope

Stethoscope

Aneroid Sphygmomanometer

Aneroid Sphygmomanometer

• Use the proper size cuff• Undersized cuff artificially raises blood

pressure • Oversized cuff artificially lowers blood

pressure

• The "ideal" cuff should have a bladder length that is 80% and a width that is at least 40% of arm circumference (a length-to-width ratio of 2:1).

Mercury Sphygmomanometer

Positioning for BP

• Ideally have the patient seated and their arm at heart level. Make sure that they do not have any tight clothing which may constrict their arm.

Locate the brachial pulse

• Palpate in the antecubital fossa for the point of maximal pulsation of the brachial

artery.

Positioning of Blood Pressure Cuff

• Cuff applied directly over skin (not through clothes) – Clothes artificially raises blood pressure

• Center inflatable bladder over brachial artery • Position lower cuff border 1 inch above antecubital

space

Estimation of systolic pressure

• The examiner should assess the estimated systolic pressure. To do this, palpate the patient’s radial pulse. Now inflate the cuff until you feel the exact point when the pulse disappears. The point on the manometer at this moment represents the estimated systolic pressure.

Assessment of systolic & diastolic pressure

• Place your stethoscope over the brachial artery area. Now inflatean extra 30mmHg worth of pressure above the estimate systolic pressure (e.g. if the estimate systolic pressure was 120mmHg – inflate the cuff to 150mmHg).

Korotkoff Sounds

• Now slowly release the pressure in the cuff by using the valve.

• The pressure should be reduced at a rate of 2-3mmHg per second. The point where consecutive tapping noises (i.e. Korotkoff

phase 1) occur you should read off the pressure on the manometer – i.e. the

systolic pressure.

• When the consecutive heart beat sounds finally disappear (i.e. Korotkoff phase 5), read off the measurement on the manometer. This represents

the diastolic pressure.

Trouble-shooting

• False high reading

- Cuff too small

- Cuff too loose

- Slow cuff release

- Column or dial not at eye level

- Anxiety or recent exercise

• False low reading

- Incorrect position of arm…be sure

to position at the level of the heart - Failure to notice auscultatory gap:

Sounds fade out for 10 to 15 mm Hg then return

– Inaudibility of low volume sounds

– Column or dial not at eye level

Blood pressure values

• Systolic normal range 90 – 140 mm Hg

• Diastolic normal range 60 – 90 mm Hg

• Pulse pressure: difference between

systolic & diastolic pressure,

approximately 40 mm Hg

• Blood pressure readings…

• Use same arm for

readings

• Do not take B/P on

arm with:• – An IV• – Paralysis• – Injury• – A – V shunt• – Edema