Measurements of blood pressure with various techniques in daily practice: uncertainty in diagnosing office hypertension with short-term in-hospital registration of blood pressure.

OBJECTIVE

To predict blood pressure outside the clinic from a short-term in-hospital registration for patients referred for ambulatory blood pressure monitoring (ABPM) with special attention to office hypertension.

PATIENTS AND METHODS

A series of measurements of blood pressure was performed by the same technician for 187 patients, 82% of whom were being administered antihypertensive therapy. She performed three mercury measurements of blood pressure (Hg stress 1) and then three manually started measurements with a semi-automatic device (Dinamap 1846SX; Dinamap stress) alternated with three manually started readings with a SpaceLabs 90207 monitor (SpaceLabs stress) on the contralateral non-dominant arm. The in-hospital session was continued with 15 automatic Dinamap registrations at 2 min intervals without the technician being present (Dinamap unstressed, five periods of three measurements averaged) before the patient left the hospital for 24h ABPM.

RESULTS

The percentages of patients with hypertension in the office (systolic blood pressure >/= 140 mmHg or diastolic blood pressure >/= 90 mmHg, or both) were 80% with Hg stress 1, 76% with Dinamap stress and 85.0% with SpaceLabs stress. Average diastolic SpaceLabs stress was 6.0+/-5.6 mmHg (significantly) higher than diastolic Dinamap stress, whereas the difference between systolic blood pressures was 0.2+/-10.0 mmHg. No further change in blood pressure occurred after the fourth period of Dinamap unstressed measurements. Office hypertension defined as SpaceLabs stress systolic blood pressure >/= 140 mmHg or diastolic blood pressure >/= 90 mmHg, or both, and SpaceLabs daytime systolic blood pressure < 135 mmHg and diastolic blood pressure < 85 mmHg was found in 21 individuals. Office hypertension defined with similar cut-off points in the comparison of Dinamap stress versus Dinamap unstressed period 5 was found in 29 cases, 10 of which overlapped with the definition SpaceLabs stress versus SpaceLabs daytime. The differences between Dinamap stress and Dinamap unstressed period 5 were significantly correlated to the changes of SpaceLabs stress and SpaceLabs daytime both for systolic (r =0.41) and for diastolic (r =0.32) blood pressures.

CONCLUSIONS

Measurements of blood pressure in the office with various techniques (mercury, Dinamap and SpaceLabs) are not equivalent. Office hypertension cannot be reliably predicted from a short-term semi-automatic in-hospital registration of blood pressure with a Dinamap device.