Methods for assessing blood pressure values in humans.

In clinical medicine and epidemiology, measurements of blood pressure largely rely upon the use of cuff inflation and Korotkoff sounds. Although still the most practical, this method has been recognized to have important limitations. This paper focuses on two limitations of the cuff method that have been found while recording 24-hour intraarterial blood pressure in free-living normotensive and hypertensive patients. First, the 24-hour blood pressure is characterized by large long- and short-term variabilities whose magnitudes vary according to the patient's basal blood pressure and age. This is likely to reduce the possibility that a few isolated cuff measurements are accurate and representative of the patient's average blood pressure. Second, during cuff blood pressure assessment by the doctor (and to a lesser degree by the nurse), the patient's blood pressure normally rises due to an alarm reaction, with a large peak within the first 4 minutes and a subsequent decline. The magnitude of the peak rise, as well as its large and unpredictable difference among subjects may be responsible for seriously and variably overestimating the blood pressure. A 10-minute wait from the beginning of the doctor's visit usually avoids this inconvenience. Finally, the paper briefly considers alternative methods to the cuff method, including invasive intraarterial 24-hour recording in ambulatory subjects, which provides a large amount of information but is impractical, and noninvasive automatic blood pressure devices, which offer a promising practical approach but must wait for technical validation.