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
