Blood Pressure
What is blood pressure?
Measurement of the pressure that the blood
exerts on the walls of the arteries during the
various stages of heart activity (or as the
heart contracts or relaxes)
BP is measured in mm of mercury- (mmHg)
BP is measured on an instrument called a
sphygmomanometer
sfig-mo-man-ometer
Measurements are read @ 2 points
Recorded as a fraction
Systolic 120 120/80 mm Hg
Diastolic 80
Systolic Pressure
Pressure that occurs in walls of arteries when
the left ventricle of the heart is contracting &
pushing blood into arteries
Normal reading is 120 mm Hg
Normal range 100-140 mm Hg
Recorded as first sound heard when listening
to BP
Diastolic pressure
Constant pressure that is in the walls of the
arteries when the left ventricle of the heart is
at rest or between contractions
Normal reading is 80 mm Hg
Normal range is 60-90 mm Hg
Noted as reading when sound stops or
becomes faint
Pulse Pressure
Difference between systolic & diastolic
pressure
Important indicator of health & arterial walls
Normal range is 30-50 mm Hg
Ex: 120/80 mm Hg = pulse pressure of 40
mm Hg
Hypertension
High blood pressure
> 140/90 mm Hg
Causes of ↑BP
1. stress
2. anxiety
3. obesity
4. high salt intake
5. aging
6. kidney disease
7. arteriosclerosis * If not tx can lead to CVA, kidney
disease, heart disease
Hypotension
Low blood pressure
< 100/60 mm Hg
Occurs with:
1. heart failure
2. dehydration
3. depression
4. severe burns
5. hemorrhage
6. shock
Orthostatic hypotension
Postural hypotension
Sudden drop in BP when pt moves from lying
to sitting or standing position
Caused by inability of blood vessels to react
quickly to change in position
S/S: lightheaded, dizzy, blurred vision
Factors that ↑ BP
Excitement, anxiety, nervousness
Stimulants
Exercise
Eating
Smoking
Factors that ↓ BP
Rest/sleep
Depressant drugs
Shock
Excess blood loss
fasting
sphygmomanometers
2 kinds
1. Mercury
-long column of mercury
-calibrated in MM of mercury
-each line represents 2 mm of Hg
-guage positioned at eye level
-when cuff deflated, needle must be
on zero
2. Aneroid
-round gauge
-calibrated in mm Hg
-each line represents 2 mm of Hg
Electronic sphygmomanometer
digital
AHA Recommendations
for measuring BP
1. Sit quietly for 5 minutes before taking BP
2. Two separate readings & averaged
3. Wait at least 30 sec between readings
Size & Placement of cuff
1. Too narrow or too wide cause inaccurate
readings
2. Width of cuff should be 20% wider then diameter of pt’s arm
3. Pt should be seated or lying
-forearm supported
-cuff area at heart level
4. Arm free of constricting clothing, apply cuff to bare arm
5. Centered over brachial artery
6. Lower edge of cuff at least 1-11/2 inch above antecubital area
Placement of diaphragm
1. Place diaphragm directly over brachial
artery
2. Hold securely but with little pressure
Placement of earpieces
Pointed forward for accurate sound