Blood Pressure Measurement: A Century of Achievements and Improvements in the Year 2002

The modern era of hypertension research started about 100 years ago, when Riva-Rocci and Korotkoff described the non-invasive method for blood pressure measurement that is still in use today [1, 2]. Most devices for measuring blood pressure are dependent on the occlusion of an artery of an extremity with an in atable cuff and detection of the Korotkoff sounds or the use of oscillometry [3]. Although the method is old, new knowledge has improved the method through the years. Even in the beginning of the era of non-invasive blood pressure assessment, von Recklinghausen demonstrated in the adult arm that the narrow Riva-Rocci cuff gave measurements that were higher than those obtained with a 12-cm wide in atable bladder [4]. This started a centuryold controversy relating to the error that may be introduced to measurement of blood pressure by using a cuff with a bladder of inappropriate dimensions for the arm for which it is intended. O’Brien recently performed a detailed review of the literature dealing with this subject [5]. There is clear evidence that either too narrow or too short a bladder will cause overestimation of blood pressure [3, 5]. Moreover, there are suggestions that too wide or too long a bladder may cause underestimation of blood pressure. Errors introduced by too small a cuff may in clinical practice cause over-diagnosing of hypertension, whereas too large a cuff may lead to hypertensive subjects being diagnosed as normotensive. Thus, studies on correct methods for blood pressure measurement are of major importance in order to avoid unnecessary antihypertensive treatment of individuals who would not bene t from treatment, as well as not to withhold lifesaving therapy from truly hypertensive subjects. However, cuff size is not the only limitation or confounding factor of the century-old technique for blood pressure measurement. In high-noise situations, such as ambulatory environments or if the patient moves slightly, the current auscultatory blood pressure method may be unreliable. Often the method is impossible to use. By placing two microphones along the biceps muscle near the brachial artery under the occluding cuff, Sebald et al. have shown that a similar blood pressure pulse appears in the two microphones with a relative time delay [6]. The acoustic noise, on the other hand, appears in both microphones simultaneously. This narrowband auscultatory blood pressure measurement is one of many interesting aspects of blood pressure measurement that has appeared only during this year. In this issue of Blood Pressure, Overgaard Andersen and co-workers report, based on data from the Copenhagen City Heart Study, that important factors to consider when assessing blood pressure in large-scale epidemiological surveys are seasonal variation, body mass index, cholesterol level, smoking habits and diabetes [7]. When comparing blood pressure data in studies, it is important to control for these factors. Another interesting observation is reported in this issue of Blood Pressure by Bodegard and co-workers, who describe a new source of potential blood pressure measurement bias [8]. In an observational study in 2014 healthy Norwegian males aged 40–59 years, the authors found that men who were examined as number one in a row of two to four subjects each morning had higher systolic blood pressure and heart rate at rest. The increased higher blood pressure level and heart rate may re ect a stress reaction to being number one in a row of subjects to be examined. The  nding may be of both clinical and scienti c importance. The clinical signi cance of the pressor response triggered by blood pressure measurement itself or the so-called “white-coat effect”, is well known from the literature [9]. Earlier this year, Munakata et al. [10] studied 75 consecutive, never-before treated patients with essential hypertension. They found that the systolic blood pressure response triggered by the doctor’s presence correlated positively with the left ventricular mass index and negatively with the diastolic function, as determined by echocardiography. Stepwise multiple linear regression analysis showed that the shift in systolic blood pressure was an independent predictor of the left ventricular mass index in men and of the left ventricular diastolic function in women. This phenomenon is interesting in relation to the work of Celis and co-workers, also in this issue of Blood Pressure, who evaluated cardiovascular outcome in patients with “white-coat hypertension” and in patients with sustained hypertension who had previously participated in the Ambulatory Blood Pressure Monitoring and Treatment of Hypertension trial [11]. At entry, 326 BLOOD PRESSURE 2002; 11: 325±327