Comparison of ambulatory blood pressure determinations using the Remler and Spacelabs devices

Ambulatory blood pressure recorded with the Spacelabs was compared with both Remler recordings and office blood pressures in 11 normotensive and 13 hypertensive volunteers. Analysis of 324 simultaneous measurements with Remler and Spacelabs showed very high correlation for systolic and for diastolic blood pressure. For systolic blood pressure, measurements with Spacelabs recorder were lower than those with the Remler recorder by a mean of 3.6 +/- 6.5 mmHg, principally in hypertensive subjects. Spacelabs measurements were also lower than Remler measurements for diastolic blood pressure by a mean of 5.3 +/- 6.6 mmHg principally in normotensive subjects. The averages of blood pressure variability (standard deviation as index) recorded by each device were identical. Mean systolic and diastolic blood pressure differed by more than 10 and 5 mmHg respectively between the two devices in 11 and 83% of the subjects. These individual discrepancies were unpredictable. Comparison of Spacelabs records with office blood pressure measured with a standard mercury manometer showed discrepancies of more than 10 mmHg for systolic blood pressure and more than 5 mmHg for diastolic blood pressure in 46 and 42% of the 24 subjects, respectively. These discrepancies could be due, in part, to different methods of blood pressure measurements. These data demonstrate that the Spacelabs apparatus provides records for a group, reasonably close to those obtained with the Remler over a wide range of blood pressure. For the management of hypertension, the advantages--as compared to physician's measurements--of ambulatory blood pressures recorded with indirect methods,need to be weighed, taking into consideration the difference between the ambulatory record and the office blood pressure measured with the same device.