[Comparative study of 24-hour ambulatory blood pressure monitors with standard zero and random zero...

The aim of the study was to evaluate the accuracy of the most widespread 24-hour ambulatory blood pressure monitor in Hungary. The test was based on simultaneous measurement on the same arm with the test device and standard zero or random zero sphygmomanometer in 100 patients. The difference between the blood pressure values measured by the test device and by the standard device was calculated in each case, and a relationship between this difference and the actual blood pressure of the patient was analysed. Actual blood pressure was considered as the average of the blood pressure measured by the test and that by the standard device. Regarding the diastolic values, the mean difference between the values obtained by the test device and the standard zero sphygmomanometer was -3.8 +/- 7.55 mm Hg (p > 0.05), and that between the test device and the random zero sphygmomanometer was -0.1 +/- 6.05 mm Hg (p > 0.05). This differences did not reach statistical significance. Regarding the systolic values, the difference showed significant positive correlation with the actual blood pressure level of the patient, meaning that at higher blood pressure values the difference between the data gained by the test and standard device is greater than at lower actual blood pressure levels. Finally, according to the criteria of the British Hypertension Society, our device could be graded "C" both for diastolic and systolic values against the standard zero sphygmomanometer, and "C" for systolic and "B" for diastolic blood pressure against the random zero sphygmomanometer.