Technical possibilities and limits of indirect automatic twenty-four-hour blood pressure devices

Automatic 24-h indirect ambulatory monitoring of blood pressure and heart rate was performed in 758 patients. The blood pressure profiles of 1105 subjects were evaluated for 5 years using seven different monitors: Pill (Del Mar Avionics), PHYSIOPORT (Natic), Accutracker (Oxford), BDS (Medizintechnik), SL 5200, SL 90202 and SL 90207 (Spacelabs). The monitors were equipped with auscultatory and/or oscillometric devices, provided accurate readings and were repeatedly used up to eight times in some patients. Up to 100 data points per 24 h provided circadian blood pressure profiles for over 91% of the patients in clinical and non-clinical situations. Early identification of borderline hypertensives at risk and detailed information on the efficacy of different antihypertensive regimens may in part justify the high costs of the monitors. Although sleep disturbance continued in more than 24% of investigated patients, the new lighter, quieter monitors (e.g. SL 90207, 380 g) were well received by patients and nurses. In the future, simultaneous registration with 24-h ECG may help in identifying the effects of different antihypertensive therapies on blood pressure variability and rhythmicity of the heart rate.