Within-subject variability of differences between conventional and automated blood pressure measurements in pregnancy

Abstract

Within-subject variability of differences between conventional and automated blood pressure measurements in pregnancy Koenen, S.V.; Franx, A.; Oosting, J.; Bonsel, G.J.; Bruinse, H.W.; Visser, G.H.A. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractObjective: To determine whether measured differences between standard mercury sphygmomanometry and the SpaceLabs 90207 ambulatory blood pressure monitor in pregnant women remain constant during 24 h measurements. Study design: Repeated comparisons between standard mercury sphygmomanometry and Spacelabs 90207 were performed at nine predetermined time points during 24 h ambulatory blood pressure measurements in a group of ten pregnant women with various pregnancy complications, including hypertension. Individual and group differences between standard mercury sphygmomanometry and SpaceLabs 90207 were calculated for each time point. Friedman's ANOVA was used to test stability of differences across time. Results: Mean group differences (standard deviation) between mercury sphygmomanometry and the SpaceLabs 90207 were 22 (6) mmHg and 3 (7) mmHg for systolic and diastolic pressure respectively. For systolic pressure the differences between time points were not statistically significant. Although a statistical significant trend was found for diastolic pressure differences (P,0.05), none of the contrasts between any pair of time points reached statistical significance. For both systolic and diastolic pressure the minimal and maximal difference lay at least 10 mmHg apart in seven patients. Conclusions: Despite standardisation and training, a substantial within-subject variability of the pressure difference between observers and SpaceLabs was found in this heterogeneous group of women. However, a systematic time-related effect on this pressure difference could not be demonstrated. The pressure difference between both methods cannot be estimated with great precision. This is a serious impediment for the clinical interpretation of automated or ambulatory blood pressure data.

Accuracy of Blood Pressure Measurement Devices in Pregnancy

“…The Spacelabs 90207 ambulatory BP monitor was tested most often (N=10 articles). 28, 37, 39, 46, 52, 53, 58, 64-66 The majority of devices (N=23) examined used the oscillometric method, and the remainder of devices (N=5) used the auscultatory method. Of the 41 included articles, 31 used a standard validation protocol or a modification of one (Tables 1 to 3): 1 used the AAMI protocol, 27 used the BHS (7 used the 1990 version and 2 used a modification of it, and 18 utilized the 1993 version), 3 used the ESH-IP (2 used the 2002 version and 1 used the 2010 version).…”

“…Among the 16 studies, 2 had no protocol violations, 26, 59 3 had at least one minor violation, 36, 53, 64 2 had at least one major violation, 37 and 7 had major and minor violations. 38, 39, 46, 58, 65, 66 Of the 5 ambulatory devices, 3 (BP Lab, Spacelabs 90207, Welch Allyn QuietTrak) passed at least one standard validation protocol. The Disetronic Profilomat 39 and Oxford Medilog 38 each failed one standard validation protocol.…”

Comparison of the BPLab® sphygmomanometer for ambulatory blood pressure monitoring with mercury sphygmomanometry in pregnant women: validation study according to the British Hypertension Society protocol

“…However articles have discussed some of the limitations of the use of this protocol for the study of ABPM devices, and these should be noted. 17 , 18 …”