Blood Pressure

Aka: Blood Pressure, BP Examination, Korotkoff Sound

1. See Also
   1. Hypertension
   2. Hypertension Criteria
   3. Pediatric Vital Signs
2. Preparation: Positioning of Blood Pressure Cuff
   1. Cuff applied directly over skin (not through clothes)
      1. Clothes artificially raises Blood Pressure
   2. Center inflatable Bladder over brachial artery
   3. Position lower cuff border 2.5 cm above antecubital
   4. Patient's arm slightly flexed at elbow
   5. Position stethoscope bell over brachial artery
3. Equipment: Blood Pressure cuff size
   1. Poor cuff fit results in inaccurate Blood Pressure
      1. Undersized cuff artificially raises Blood Pressure
      2. Oversized cuff artificially lowers Blood Pressure
   2. Pediatric Cuff size
      1. Minimum Cuff Width
         1. Width >2/3 length of upper arm
         2. Width >40% of arm circumference
      2. Minimum Cuff length
         1. Bladder nearly encircles arm
         2. Bladder length 80-100% of circumference
   3. Adult Cuff size
      1. Cuff Width: 40% of limb's circumference
      2. Cuff Length: Bladder at 80% of limb's circumference
      3. Indications for large cuff or thigh cuff
         1. Upper arm circumference >34 cm
      4. Indications for Forearm cuff (with radial palpation)
         1. Upper arm circumference >50 cm
4. Technique: BP measurement
   1. Wait 5 minutes of rest before checking Blood Pressure
   2. Check Blood Pressure in right arm, while seated
   3. Take Blood Pressure at heart level
   4. Inflate cuff rapidly to level above suspected SBP
   5. Deflate cuff slowly at a rate of 2-3 mmHg per second
   6. Listen for auditory vibrations from artery (Korotkoff)
      1. Systolic Blood Pressure: Onset of consecutive sounds
      2. Diastolic Blood Pressure: Disappearance of sounds
5. Technique: Obtain Multiple Blood Pressure measurements
   1. Validation of abnormal readings
      1. Recheck Blood Pressure twice more at same visit
   2. Aortic Coarctation
      1. Left and right arm, and one lower extremity
   3. Orthostatic Hypotension
      1. Check Blood Pressure and Pulse, Supine and Standing
6. Interpretation
   1. See Hypertension Criteria
   2. See Hypotension
7. Interpretation: Children
   1. See Pediatric Vital Signs
   2. Formulas for Systolic Blood Pressure estimate (for over age 1 year)
      1. Median SBP = 90 mmHg + (2 x Age in years)
      2. Minimum SBP = 70 mmHg + (2 x Age in years)
   3. Rough estimate for Systolic Blood Pressure (SBP)
      1. Typical systolic Blood Pressure
         1. Infant: 80
         2. Preschool: 90
         3. Adolescent: 100
      2. Minimal systolic Blood Pressure
         1. Infant: >60
         2. Toddler >70
         3. Preschool >75
         4. School-age: >80
         5. Teen >90
   4. Term Newborn (3 kg)
      1. Age 12 hours: 50-70 / 25-45
      2. Age 96 hours: 60-90 / 20-60
      3. Age 7 days: 74 +/- 22 mmHg (Systolic BP)
      4. Age 42 days: 96 +/- 20 mmHg (Systolic BP)
   5. Infant (6 months old)
      1. Blood Pressure: 87-105 / 53-66
   6. Toddler (2 years old)
      1. Blood Pressure: 95-105/53-66
   7. School age (7 years old)
      1. Blood Pressure: 97-112 / 57-71
   8. Adolescent (15 years old)
      1. Blood Pressure: 112-128 / 66-80