Taking an accurate measurement of blood pressure in a clinical setting is an important prerequisite for making a diagnosis of hypertension. So why are doctors getting it wrong so much of the time?
A review of blood pressure measurement suggests that there are a number of factors which doctors need to take into account before they can get the measurements right.
Several factors can distort a BP reading by as much as 5 mmHg for instance, acute exposure to cold, recent ingestion of alcohol, incorrect arm position and an incorrect cuff size. The so called white coat effect fear caused by being in a clinical setting can raise BP by more than 20/10 mmHg in up to 40 per cent of patients.
All guidelines for measuring BP agree on the best way to proceed, yet not all doctors follow these guidelines.
However, say the reviewers, good technique is important because, for example, consistently underestimating diastolic pressure by 5 mmHg can result in almost two thirds of hypertensive individuals being denied antihypertensive treatment, which could prevent illness and even death (BMJ, 2001; 322: 908-11).