Replacing the mercury manometer with an oscillometric device in a hypertension clinic: implications for clinical decision making.

Oscillometric devices are being widely used for ambulatory, home and office blood pressure (BP) measurement, and several of them have been validated using established protocols. This cross-sectional study assessed the impact on antihypertensive treatment decisions of replacing the mercury sphygmomanometer by a validated oscillometric device. Consecutive subjects attending a hypertension clinic had triplicate simultaneous same-arm BP measurements using a mercury sphygmomanometer and a validated professional oscillometric device. For each device, uncontrolled hypertension was defined as average BP ≥140/90 mm Hg (systolic/diastolic). A total of 5108 simultaneous BP measurements were obtained from 763 subjects in 1717 clinic visits. In 24% of all visits, the mercury and the oscillometric BP measurements led to different conclusion regarding the diagnosis of uncontrolled hypertension. In 4.9% of the visits, the diagnostic disagreement was considered as 'clinically important' (BP exceeding the diagnostic threshold by >5 mm Hg). These data suggest that the replacement of the mercury sphygmomanometer by a validated professional oscillometric device will result into different treatment decisions in about 5% of the cases. Therefore, and because of the known problems when using mercury devices and the auscultatory technique in clinical practise, the oscillometric devices are regarded as reliable alternatives to the mercury sphygmomanometer for office use.

Unreliable oscillometric blood pressure measurement: prevalence, repeatability and characteristics of the phenomenon.

Oscillometric devices are being widely used for ambulatory, home and office blood pressure (BP) measurement. However, even successfully validated oscillometric devices fail to provide accurate measurements in some patients. This study investigated the prevalence, the reproducibility and the characteristics of the phenomenon of unreliable oscillometric BP (UOBP) measurement. A total of 5070 BP measurements were obtained simultaneously (Y connector) using a professional oscillometric device (BpTRU) and a mercury sphygmomanometer in 755 patients (1706 visits). UOBP readings were defined as those with >10 mm Hg difference (systolic or diastolic) between the two methods. UOBP was found in 15% of systolic and 6.4% of diastolic BP measurements. In all, 18% of the participants had UOBP in their first but not their second visit, or the reverse. However, 49% of these participants had at least one more UOBP visit after their second visit within the study database. Patients with persistent UOBP were more likely to be female and had lower arm circumference. The systolic BP discrepancy between the two methods was associated with pulse pressure (r=0.41) and inversely with diastolic BP (r=0.40) and arm circumference (r=0.30), whereas the diastolic discrepancy with diastolic BP (r=0.61) and inversely with pulse pressure (r=0.32). There was a consistent significant trend for larger systolic BP discrepancy and smaller diastolic from the lower to the higher pulse pressure quintile (P<0.0001). A decreasing arm circumference was a significant predictor of persistent UOBP. These data suggest that the UOBP measurement is particularly common, not very reproducible and mainly affected by pulse pressure and arm circumference.