Blood Pressure
Chapter 9
Blood Pressure (BP)
• The amount of pressure or tension
exerted on the arterial walls as blood
pulsates through them
–Systolic (SBP)
• Pressure exerted during the contraction phase
of the heartbeat
–Diastolic (DBP)
• Resting pressure on the arteries as the heart
relaxes
• BP is written as a fraction- SBP/DBP
BP values
• Measured in millimeters of mercury
–Systolic readings
• Between 100 and 140 mm Hg
–Diastolic readings
• Between 60 and 90 mm Hg
BP values
• Prehypertension
–Readings of 120-139/80-89
• Hypotension
–Leads to shock
–Example
• BP 60/34
• Symptoms
– Change in consciousness
– Increased heart rate and respirations
– Weak, thready pulse
– Pale, sweaty skin
Sites for BP
• Brachial
–Upper arm
–Most common
• Radial
–Infants
–Patients with large arms
Sites for BP
• Popliteal
• Thigh
–Used instead of arm
• Trauma, disease, medical treatments, recent
mastectomy
• Dorsalis pedis and posterior tibial
–Infants
Equipment for Measuring BP
• Sphygmomanometer
–BP cuff
• Stethoscope
Taking a BP reading
• Place the BP cuff on the extremity just
above the pulse site
• Place a stethoscope on the artery at the
pulse site
• Squeeze and release the bulb to push
air into the cuff
• Slowly release air from the cuff while
listening for sounds
–Take note of the reading when
• You first hear a sound
• When you last hear a sound
Types of Sphygmomanometer
• Mercury
–Calibrated glass cylinder containing
mercury
• Aneroid
–Calibrated dial with a needle
• Electronic
–Digital display (common in pharmacy
stores)