Ambulatory blood pressure monitor

From IDWiki

Definition

  • Blood pressure monitor worn for 24h while the patient completes usual daily activities

Indication

  • Gold standard for diagnosing hypertension
  • Rule out white coat hypertension or masked hypertension
  • Evaluate borderline hypertension with evidence of end-organ damage
  • Evaluate labile/paroxysmal or orthostatic hypotension
  • Evaluate symptoms potentially caused by BP fluctuations, such as orthostasis
  • Follow response to antihypertensives

Procedure

  • Use non-dominant arm unless dominant arm is 10+ mmHg higher
  • Patient should keep event diary
  • Adjust settings to correspond to bedtime and waking time
  • Have them stop and stand still, if possible, while it is taking its reading
  • They should go about normal activities, but not exercise

Interpretation

  • Daytime average of 135/85 or 24h average of 130/80 is comparable to an office measurement of 140/90
  • A decrease of 10-20% from day to night average is normal
  • Steps
    • Check quality; should have 21 daytime readings, 7 nighttime readings, and at least 2 per hour
    • Check overall, daytime, and nighttime averages to ensure targets are met
    • Check nighttime dipping
    • Check heart rate
  • White coat hypertension: if hypertensive for first few readings then returns to normal
  • Masked hypertension: normal office BP but elevated
  • Dysautonomia: loss of normal day-night variation, with high blood pressure when sleeping supine
    • E.g. Parkinsonism