Neil Atkins

In the last 30 years, several organizations, such as the US Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society, the European Society of Hypertension (ESH) Working Group on Blood Pressure (BP) Monitoring and the International Organization for Standardization (ISO) have developed protocols for clinical validation of BP measuring devices. However, it is recognized that science, as well as patients, consumers and manufacturers would be best served if all BP measuring devices were assessed for accuracy according to an agreed single validation protocol that had global acceptance. Therefore, an international initiative was taken by AAMI, ESH and ISO experts who agreed to develop a universal standard for device validation. This statement presents the key aspects of a validation procedure, which were agreed by the AAMI, ESH and ISO representatives as the basis for a single universal validation protocol. As soon as the AAMI/ESH/ISO standard is fully developed, this will be regarded as the single universal standard and will replace all other previous standards/protocols.

In the past 30 years, several organizations, such as the US Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society, the European Society of Hypertension (ESH) Working Group on Blood Pressure (BP) Monitoring, and the International Organization for Standardization (ISO), have developed protocols for clinical validation of BP measuring devices. However, it is recognized that science, as well as patients, consumers, and manufacturers, would be best served if all BP measuring devices were assessed for accuracy according to an agreed single validation protocol that had global acceptance. Therefore, an international initiative was taken by the AAMI, ESH, and ISO experts who agreed to develop a universal standard for device validation. This statement presents the key aspects of a validation procedure, which were agreed by the AAMI, ESH, and ISO representatives as the basis for a single universal validation protocol. As soon as the AAMI/ESH/ISO standard is fully developed, this will be regarded as the single universal standard and will replace all other previous standards/protocols.

This study describes the development of a new digital sphygmocorder (DS-II), which allows the digital recording and playback of the Korotkoff sounds, together with cuff pressure waveform, and its performance in a pilot validation study. A condenser microphone and stethoscope head detect Korotkoff sounds and an electronic chip, dedicated to audio-signal processing, is used to record high-quality sounds. Systolic and diastolic blood pressure (SBP/DBP) are determined from the recorded signals with an automatic beat detection algorithm that displays the cuff pressure at each beat on the monitor. Recordings of Korotkoff sounds, with the cuff pressure waveforms, and the simultaneous on-site assessments of SBP/DBP were performed during 100 measurements in 10 individuals. The observers reassessed the recorded signals to verify their accuracy and differences were calculated. The features of the high-fidelity DS-II, the technical specifications and the assessment procedures utilizing the playback software are described. Interobserver absolute differences (mean±SD) in measurements were 0.7±1.1/1.3±1.3 mmHg (SBP/DBP) with a mercury sphygmomanometer and 0.3±0.9/0.8±1.2 mmHg with the DS-II. The absolute DS-II mercury sphygmomanometer differences were 1.3±1.9/1.5±1.3 mmHg (SBP/DBP). The high-fidelity DS-II device presents satisfactory agreement with simultaneous measurements of blood pressure with a mercury sphygmomanometer. The device will be a valuable methodology for validating new blood pressure measurement technologies and devices.

Objective: The wide use of blood pressure (BP) measuring devices in most countries has led to an increasing interest in performing validation studies, aiming to ensure the accuracy of BP measurement and thereby the precise evaluation and effective management of hypertension. This analysis investigated the current status regarding the implementation of established protocols for the validation of BP monitors. Design and method: Studies reporting validation data of BP monitors in the period 2010–14 using the European Society of Hypertension International Protocol (ESH-IP), the British Society of Hypertension protocol (BHS), or the US Association for the Advancement of Medical Instrumentation / International Organization for Standardizationprotocol (AAMI/ISO) were identified from PubMed and the Dabl Educational Trust (DET) website. For devices evaluated in more than one studies, each study was considered independently. Results: A total of 111 validation studies evaluating 102 devices were identified (87 for home use, 31 office and 10 for ambulatory use; some for more than one uses. The number of studies reported in 2010/11/12/13/14 were 32/29/12/15/23 respectively. Solely oscillometric devices were tested in 93.7% of the studies and upper arm monitors in 85.6%. Children/adolescents were included in 7.2% of the studies, pregnancy with preeclampsia in 2.7% and patients with chronic nephropathy in 0.9%. 43.2% were conducted in Europe, 39.6% in Asia and 10.8% in the USA. The ESH-IP protocol was used in 83.9% of the studies, the BHS in 17.1% and the AAMI/ISO in 10.8%. Finally, 94.3% of the studies were reported to pass the validation protocol. Conclusions: These findings suggest that: (i) there is continuing interest worldwide for the validation of BP monitors using established protocols; (ii) the ESH-IP remains the preferred protocol; (iii) there are relatively few validation studies in special populations; (iv) there seems to be a publication bias with negative studies not being published.

Objective Since 2002 when the European Society of Hypertension International Protocol (ESH-IP) was published it has become the preferred protocol for validating blood pressure monitors worldwide. In 2010, a revised version of the ESH-IP with more stringent criteria was published. This study assesses the impact of applying the revised ESH-IP criteria. Methods A systematic literature review of ESH-IP studies reported between 2002 and 2010 was conducted. The impact of applying the ESH-IP 2010 criteria retrospectively on the data reported in these studies was investigated. The performance of the oscillometric devices in the last decade was also investigated on the basis of the ESH-IP criteria. Results Among 119 published studies, 112 with sufficient data were analyzed. According to ESH-IP 2002, the test device failed in 19 studies, whereas by applying the ESH-IP 2010 criteria in 28 additional studies increased the failure rate from 17 to 42%. Of these 28 studies, in 20 (71%) the test device failed at part 1 (accuracy per measurement) and in 22 (79%) at part 2 (accuracy per subject). Most of the failures involved the ‘5 mmHg or less’ criterion. In the last decade there has been a consistent trend toward improved performance of oscillometric devices assessed on the basis of the ESH-IP criteria. Conclusion This retrospective analysis shows that the stricter revised ESH-IP 2010 criteria will noticeably increase the failure rate of devices being validated. Oscillometric devices are becoming more accurate, and the revised ESH-IP by acknowledging this trend will allow more accurate devices to enter the market.

The management of high blood pressure (BP) is particularly inadequate in low-income countries, where the unavailability of a reliable, durable, and affordable BP-measurement device is a major obstacle to accurate diagnosis. Recognizing this, a World Health Organization committee was established to correct this deficiency by influencing manufacturers to produce a device according to predetermined criteria and to demonstrate the suitability of the device for low resource settings. A device, which fulfilled stipulated criteria in being inexpensive, semiautomated, and solar powered, was validated according to the International Protocol of the European Society of Hypertension; it was then subjected to field testing in 716 subjects from 2 centers in Uganda and 1 in Zambia. The Omron HEM-SOLAR having previously fulfilled accuracy criteria of the International Protocol for both systolic blood pressure (SBP) and diastolic blood pressure (DBP), fulfilled criteria for SBP, but not for DBP, when revalidated. In field testing, average SBPs and DBPs were 120.5±21.6/74.6±13.8 mm Hg and 122.3±21.8/71.2±14.0 mm Hg, respectively, with the auscultatory technique and the Omron HEM-SOLAR, respectively. Between-device agreement in defining SBP was 93.7%. The Omron HEM-SOLAR was favored over the mercury sphygmomanometer by both patients and investigators. In summary, considering the accuracy, robustness, relatively low cost, operational simplicity, and advantages such as solar power, the Omron HEM-SOLAR is likely to be a valuable device for improving BP measurement in low-resource settings with nonphysician health workers.

Ambulatory blood pressure measurement (ABPM) is being used increasingly in clinical practice. One previous study has shown that there can be considerable variance between expert observers in the interpretation of ABPM data. The purpose of this study was to show whether computer-generated reports with the dablABPM system would provide more consistency in the interpretation of data than reports from expert observers. Twenty-six international experts in hypertension were invited to participate and 17 agreed to do so. Twelve ABPMs generated by the Spacelabs device that were considered representative of the patterns likely to be seen in practice were sent to each participant for reporting. The corresponding dabl reports with an automatic interpretation were generated according to the European Society of Hypertension guideline for comparison with the observer reports. Each of the observer-interpreted Spacelabs reports for the 12 ABPM patterns were coded, analysed and compared with the automatically interpreted dablABPM reports. Both sets of data were analysed for interobserver variability, observer v dablABPM consistency and the time taken for observer reportage. The main analysis determined issues of definite disagreement, namely the presence or absence of nocturnal dipping. Further analysis determined the presence or absence of white-coat phenomena and the severity of hypertension. Incorrect diagnoses were made in 13 instances. White-coat hypertension and white-coat effect, although obvious in many instances, were not identified in five ABPMs; the severity of hypertension was not reported in four ABPMs; the severity of nocturnal hypertension was not diagnosed in one ABPM by nine experts and isolated diastolic hypertension was not identified by six experts in two ABPMs. This study provides evidence to show that observer variance in reporting ABPMs is common even among experts and that computer-generated interpretative reports of ABPM data improve the diagnostic decisions based on the data generated by 24-h blood pressure recording.

To perform a systematic review of validation studies of blood pressure measuring devices done using the European Society of Hypertension International Protocol (ESH-IP) since its publication in 2002. Major aspects of ESH-IP studies are described. A review of the ESH-IP performance, problems and violations in its application, and the effect of applying several more stringent validation criteria in an ESH-IP revision is carried out. From January 2002 to June 2009, 104 validation studies had been conducted using the ESH-IP, 36 using the British Hypertension Society protocol and 28 using the US Association for the Advancement of Medical Instrumentation protocol. Among 78 studies reported up to June 2008, in 66 (85%) the tested device has passed the ESH-IP. In 19 validations a modification of the ESH-IP was performed to adapt for specific study needs (population or device). Protocol violations of the ESH-IP were identified in 23 studies (eight major violations). A test of several arbitrarily chosen changes in the ESH-IP validation criteria applied in the published studies showed the phase 2.1 criterion (BP differences < or =15 mmHg) and the phase 2.2 criteria to be the more stringent. The ESH-IP has succeeded in expanding the validation procedure worldwide by three to four-fold compared with the period before its publication. There is a need for protocol revision aiming to address issues that appeared in published studies, prevent protocol violations, and ensure complete data reporting. Standardization of the ESH-IP validation studies' report and application of more stringent criteria should be considered.