CLINICAL ACTIONS:

The AHA has released a statement on taking BP measurements, a topic also addressed in detail as part of the most recent ACC/AHA task force document. Appropriate preparation is vital to obtaining accurate BP measurements. Following recommended protocols when obtaining a BP measurement can improve accuracy

Prior to Obtaining BP Measurement

• Ask about the following when taking the family and personal history
  • Medication history (BP and non-BP meds)
    • If patient is on BP meds, is patient currently taking as prescribed
    • If not taking medications appropriately, identify barriers
• Discuss physical activity and diet
  • If either/both are limited, determine why
• Caffeine, exercise and smoking should be avoided at least 30 minutes before BP measurement  

When Obtaining BP Measurement

Ensuring the following will prevent artificial increase in BP levels

• Use correct cuff size
  • Bladder should encircle 80% of the arm
• Remove clothing covering cuff placement
• Place and support arm at heart level (atrium / mid-sternum)
• Ask patient to uncross legs
• Patient should sit on chair, feet on floor and back supported for > 5 min before taking pressure (not lying or sitting on an exam table)
• No talking while measurement is taken
• Have patient empty bladder

SYNOPSIS:

The new ACC/AHA taskforce guidelines have resulted in a change with respect to lowering the threshold for making the diagnosis of hypertension. However, accuracy in obtaining the measurements in critical for accurate management and treatment plan. The AHA has released a scientific statement (2019), maintaining that validated oscillometric devices allow accurate BP measurement in the outpatient setting, while reducing human errors associated with the auscultation. The AHA document further states that

Fully automated oscillometric devices capable of taking multiple readings even without an observer being present may provide a more accurate measurement of BP than auscultation

KEY POINTS:

Hypertension Definitions (ACC/AHA)

• Normal
  • Systolic <120 mmHg and diastolic <80 mmHg
• Elevated
  • Systolic 120 to 129 mmHg and diastolic <80 mmHg
• Hypertension
  • Stage 1: Systolic 130 to 139 mmHg or diastolic 80 to 89 mmHg
  • Stage 2: Systolic ≥140 mmHg or diastolic ≥90 mmHg
• ‘White Coat’ hypertension
  • Elevated BP in the office but not outside the office
  • Checking for ‘White Coat’ hypertension using either daytime Ambulatory Blood Pressure Monitoring (ABPM) or Home Blood Pressure Monitoring (HBPM) is “reasonable” if
    • Office SBP is >130 but <160 mm Hg or
    • Office diastolic BP (DBP) >80 but <100 mm Hg
• ‘Masked’ hypertension
  • Elevated BP out-of-office but not in-office
  • Checking for ‘masked’ hypertension with daytime ABPM or HBPM is “reasonable if”
    • Office SPB is 120 to 129 and DBP is <80
• Hypertensive emergency (formerly called ‘malignant hypertension’)
  • Severe hypertension: SBP ≥180 mmHg or DBP ≥120 mmHg
  • Consider this a medical emergency which may need ICU care
• Resistant hypertension
  • Uncontrolled BP despite treatment ≥3 antihypertensive agents (one of which is usually a diuretic)

Making the Diagnosis (ACC/AHA)

• Use an average based on ≥2 readings obtained on ≥2 occasions
• Out-of-office and self-monitoring can be used to
  • Confirm the diagnosis of hypertension
  • Titrate BP-lowering medication
  • Counsel via Telehealth
• Corresponding measurements
  • Office/clinic: 140/90
  • HBPM: 135/85
  • ABPM: 135/85
  • Night-time ABPM: 120/70
  • 24-hour ABPM: 130/80 mm Hg
• In adults with untreated systolic BP (SBP) >130 but <160 mm Hg or diastolic BP (DBP) >80 but <100 mm Hg, “it is reasonable” to screen for the presence of white coat hypertension using either
  • Daytime ABPM or HBPM

Note: The diagnosis of hypertension requires integration of HBPM or ABPM in addition to measurements made in the clinical setting

Learn More – Primary Sources:

Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults – A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

AHA | AMA: Target BP Tools

Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association

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