24-hour Ambulatory Blood Pressure Measurements

Abstract

Ambulatory Blood Pressure Monitoring (ABPM) is now recognised as the gold standard method for measuring a patient’s BP. The process involves wearing a portable blood pressure monitor which inflates an upper arm cuff to determine BP at regular intervals over a complete 24 h period. The value of this measurement is that it provides an estimate of the diurnal changes in blood pressure while the patient undergoes their normal daily activities and importantly measurements are made during sleep. Measurement of BP in the physician’s office provide only a small sample of measurement of the patient’s BP and can be subject to higher readings due to the presence of the physician which is known as a “white coat effect”. Alternatively in some cases BP can be lower than normal in the doctor’s office particularly in subjects where normal activities are stressful resulting in hypertension. Such patients are known as “masked” hypertensives. Thus ABPM provides a much more reliable estimate of the patient’s true BP and avoids much of the misdiagnosis that can occur in subjects with either “whitecoat hypertension” or “masked hypertension” [33]. Nevertheless clinic BP assessments by the physician will continue to remain as an important screening tool.