Blood pressure (OSCE)

Taking a Blood Pressure

General

• No:
  • smoking or caffeine x 30 mins
  • constrictive clothing

• Yes:
  • rest for ≥ 5 minutes
  • breathing normal and relaxed

• During recording: no talking and patient’s legs uncrossed

Equipment

• cuff size
  • bladder width > 40 % of arm circumference
  • length > 80% of arm circumference

Positioning

• Level: devices and columns at eye level, patient’s arm held at heart level

Placement

• lower edge of cuff ~ 3 cm above elbow crease
• bladder centered over brachial artery (palpate medial to biceps tendon)

Performance

• palpate radial pulse (note arrythmias)
• inflate cuff to ~ 30 mm Hg above palpable pulse
• drop the pressure by 2 mm Hg / second (prolonged filling will lead to venous congestion, making the sounds harder to hear)
• repeat after ≥ 2 minutes of standing to assess for orthostatic hypotension (drop in 20/10)

• for all patients on the first visit, take at least 2 readings separated by 2 minutes
  • if first 2 readings differ by > 5 mm Hg, another reading is indicated
  • Elevated readings should be confirmed on 3 readings

Pitfalls

• anxiety, pain
• arrhythmias
• wrong cuff size (too small overestimates, too large underestimates)
• Isolated office hypertension ('white coat' hypertension) (up to 25%)
• exercise

JNC-7 Classification

(criteria for adults > 17 and not taking antihypertensives)

• Optimal
• Normal < 120 SBP and < 80 DBP
• Prehypertension 120-139 SBP or 80-89 DBP
• Hypertension Stage 1 140-159 SBP or 90-99 DBP
• Hypertension Stage 2 >or=160 or >or=100

Other OSCE modules