Testing the accuracy of blood pressure monitoring devices in ambulatory conditions.

In recent years technological progress has improved the construction of ambulatory blood pressure monitoring devices. This has resulted in devices able to measure blood pressure continuously and non-invasively, and also in lighter, less noisy and more accurate intermittent blood pressure monitors. The accuracy of monitors, however, is still tested by taking blood pressure measurements at rest, and testing against intra-arterial blood pressure values, in true ambulatory conditions, is very seldom used. When evaluated by the latter approach, devices such as SpaceLabs 5300 and the Sandoz SPS 1558 recorders can be substantially inaccurate. Newer devices such as the SpaceLabs 90202 and 90207 are also somewhat inaccurate, particularly when diastolic blood pressure is considered. However, hour-to-hour changes in blood pressure obtained by the SpaceLabs 90202 and 90207 monitors are qualitatively and quantitatively similar to those obtained by invasive methods. This makes it possible to describe the 24-h blood pressure profile more accurately.