Ambulatory BP monitoring

Ambulatory BP monitoring

It is well known that blood pressure of an individual can vary widely at various times of the day. There is also a so called “white coat effect” in which blood pressure is elevated when recorded in the medical setting. Ambulatory BP monitoring and home monitoring are two methods which have been developed to assess the ‘true’ blood pressure in an ideal setting.  A blood pressure cuff applied over the arm is connected by tubings to the inflation and recording device kept in a belt pouch. The device can be programmed to measure blood pressure at varying intervals like 15 or 30 minutes throughout the day and night.

The subject is asked to avoid movements of the arm while the cuff inflation and deflation are going on. The readings can be analyzed by a computer software to get average blood pressure, diurnal rhythm of blood pressure variation and the blood pressure variability. The average blood pressure determines the possible target organ damage better than the clinic measured blood pressure.

Dip in pressures during sleep is used to classify individuals into dippers, extreme dippers, non dippers and reverse dippers. Dip = (1-Systolic BP during sleep/Systolic BP while awake), expressed as a percentage. Negative value indicates reverse dipper. Values less than 10 percent are considered in the non-dipper range, while 10-20% range constitutes the dippers and more than 20% constitute the extreme dippers. The morning surge in blood pressure has been linked to cardiovascular events and stroke.