Automated Oscillometric Blood Pressure Measurement in Children

Recently, Eliasdottir and colleagues found low correlations between blood pressure (BP) measurements obtained with a hybrid (non-mercury) auscultatory device and an automated oscillometric device in a large sample of children.1 Based on these findings and other evidence, Dr J. Flynn argues in an accompanying commentary that “BP values obtained using oscillometric devices should not be used for the diagnosis of hypertension in children.”2 This study and the commentary raise several issues. First, the study compared two devices of questionable accuracy in children: the oscillometric device has not been validated in either adults or children1 and the auscultatory device has been validated in adults but not children. Unfortunately, a device validated in adults is not always accurate in children.3 For instance, while the Welch Allyn Vital Signs Office BP monitor has been clinically validated in adults,4 it has failed to be validated in children aged 5 to 15 years.5 Second, the auscultatory method is subject to observer error, prejudice, and bias. In the study by Eliasdottir and colleagues, the auscultatory measurements were obtained by a single observer, and no information was provided about the observer's training and performance. Third, none of the criteria of established validation protocols have been used to quantify the disagreement between the two devices.6 Finally, and more importantly, results for one oscillometric device cannot be extrapolated to another, notably because the measurement algorithm differs between devices. Therefore, one should not infer from the study by Eliasdottir and associates that the oscillometric method gives systematically biased BP estimates in children. Indeed, several oscillometric devices have been shown to give accurate estimates and fulfill the established validation criteria in children.5, 7 It is also important to recall that auscultatory non-mercury devices (eg, aneroid) are not free of potential systematic errors and need calibration at regular intervals. We agree with Dr J. Flynn that the diagnosis of hypertension in children is challenging and that the oscillometric method raises specific issues.2, 8 In particular, the fact that most automated devices have not been clinically validated in children is a major problem (for an updated list of clinically validated devices, including in children, see www.dableducational.org/). Hence, US and European guidelines recommend that BP elevation in children should be confirmed by auscultation.9, 10 Nevertheless, the oscillometric method has large potential for BP measurement in children. For instance, this method is used almost exclusively for ambulatory BP monitoring, a standard tool for the diagnosis of hypertension in children,10, 11 and increasingly so for home BP monitoring.12 The authors report no specific funding in relation to this research and have no conflict of interest to disclose.