Abstract
This study aimed to validate the accuracy of DBP-6279B, an automated inflationary oscillometric upper-arm blood pressure (BP) monitor, in the sitting position according to the AAMI/ESH/ISO (81060-2 : 2018 + Amd.1 : 2020) universal standard protocol. SBPs and DBPs were measured simultaneously on the same arm in 88 adults (female : male = 47 : 41) with a mean age of 56.85 years using a mercury sphygmomanometer (two observers) and a DBP-6279B device (one supervisor). The AAMI/ESH/ISO 81060-2 : 2018 and Amd.1 : 2020 universal standards for the validation of BP-measuring devices in adults and adolescents were followed. A total of 259 valid pairs of data were used in the analysis. According to Criterion 1, the mean difference of SBP between the test device (DBP-6279B) and the reference device (the mercury sphygmomanometer) was 0.75 mmHg, with a SD of 7.66 mmHg. The mean difference in DBP was 1.13 mmHg, with a SD of 6.14 mmHg. The mean difference of both SBP and DBP was less than 5 mmHg, and the SD was less than 8 mmHg, which met the requirements. According to Criterion 2, the mean difference of SBP between the test device and the reference device was 0.85 mmHg, and the SD was 6.56 mmHg, which was less than 6.88 mmHg and met the requirements. The mean difference in DBP was 1.27 mmHg, and the SD was 5.42 mmHg, which was less than 6.82 mmHg and met the requirements. DBP-6279B fulfilled the requirements of the AAMI/ESH/ISO universal standard (ISO 81060-2 : 2018 + Amd.1 : 2020); hence, it can be recommended for both clinical and self/home BP measurement in adults and adolescents.
Keywords: accuracy, blood pressure measurement, device, universal standard, validation
Introduction
As a basic public health strategy, monitoring blood pressure (BP) is important for the prevention and control of hypertension [1]. The accuracy of BP measurement devices is essential for monitoring BP. Some studies have shown that an overestimation of DBP by 5 mmHg will double the number of hypertensive patients (half of whom are misdiagnosed) while underestimating DBP by 5 mmHg will lead to a missed diagnosis in 2/3 hypertensive patients. There are multiple international protocols that provide standards to evaluate noninvasive BP-measuring devices for accuracy. In 2018, members of the The Association for the Advancement of Medical Instrumentation (AAMI), EuropeanSociety of Hypertension (ESH), and International Standard Organization (ISO) committees reached a consensus on an optimal validation standard, the AAMI/ESH/ISO universal standard (ISO 81060-2 : 2018) which is now considered the standard protocol for the validation of noninvasive BP-measuring devices [2–4]. An automated oscillometric upper-arm BP monitor, DBP-6279B (hereafter referred to as the test device), was developed and manufactured by JOYTECH Healthcare Co., Ltd., Hangzhou, China. It is a cuff device, and the cuff is inflated and BP is measured during inflation. This study aimed to validate its accuracy according to the AAMI/ESH/ISO 81060-2 : 2018 and Amd.1 : 2020 universal standard protocols, was conducted with the approval of the ethics committee of the Hebei General Hospital (Shijiazhuang, China).
Participants and methods
Participants were recruited from among outpatients at the Hebei General Hospital. Adults and adolescents who met the inclusion criteria and did not meet the exclusion criteria were selected for BP measurement using tests and reference devices [5,6]. The devices were tested on 90 participants according to the AAMI/ESH/ISO 81060-2 : 2018 and Amd.1 : 2020 criteria. Data for each participant’s sex, age, height, weight, arm circumference, history of antihypertensive treatment, and BP were collected.
The validation was performed in a quiet and comfortable environment, with the participants seated with their legs uncrossed and resting for at least 5 min before BP measurements. The arm was kept at the heart level with the back elbow, and forearm supported. The cuff for upper-arm circumferences 22.0–42.0 cm was applied on the bare arm. The validation was performed by two observers to determine the BP of each subject using a mercury sphygmomanometer (Jiangsu Yuyue Medical Equipment Co., Ltd., China), and a supervisor to record the determinations of the test device. Observers were trained on mercury BP measurements according to the Universal Standard. Each observer’s measurements were not visible to the other. The determination of the test device was not visible to the observers. The Korotkoff sound [fifth phase (K5)] was used by the observers to determine the reference DBP. If the Korotkoff sound [fifth phase (K5)] was not audible, the participant was excluded. If either observer detected a significantly irregular heart rhythm, the reading was excluded. Any pair of observers’ SBP value or DBP value with a difference greater than 4 mmHg (0.53 kPa) was excluded.
The same arm sequential method was applied. Two observers used a mercury sphygmomanometer to measure the BP. Interchanged cuffs and used the test device to measure the subjects’ BP. The first paired values were not used in the calculation of accuracy. Then two observers used the reference device to measure the subjects’ BP. The cuffs were interchanged and waited for at least 60 s, and the test device was used to measure the subjects’ BP. The cuffs were then interchanged and waited for at least 60 s. The reference device was then used to measure the subjects’ BP. The last two procedures were repeated until sufficient valid BP data were collected.
Analysis
Data were analyzed using SPSS for Windows, IBM according to the criteria described in the protocols. The difference between the mean observer values and the test values was calculated according to the protocol and was displayed as Bland–Altman plots against the mean of two values.
Results
A total of 90 subjects were enrolled, of whom two participants met the exclusion criteria, All measured data from the two excluded subjects (six sets in total) and the other five pairs of data (two reference DBP values differ by more than 8 mmHg) were excluded. In the end, there was a total of 259 sets of valid data. The 88 participants included 41 (46.6%) men and 47 (53.4%) women with a mean age of 56.85 ± 18.37 years (range:27–96 years) and a mean arm circumference of 31.10 ± 5.49 cm (range: 21.40–40.50 cm). The arm circumference was 22.0–27.0, 27.0–32.0, 32.0–37.0, 37.0–42.0, 22.0–24.5, and 39.5–42.0 cm in 21 (23.9%), 25(28.4%), 21 (23.9%), 20 (22.7%), 10 (11.4%) and 10 (11.4%) of the participants, respectively (Table 1). The BP distribution, based on the measurements of the reference device, fulfilled the protocol (Table 2), too.
Table 1.
Arm circumference distribution of subjects
| Variable | Descriptive statistics | Value |
|---|---|---|
| Range of arm circumference | 220 mm~270 mm | 21 (23.9%) |
| 270 mm~320 mm | 25 (28.4%) | |
| 320 mm~370 mm | 21 (23.9%) | |
| 370 mm~420 mm | 20 (22.7%) | |
| 220 mm~245 mm | 10 (11.4%) | |
| 395 mm~420 mm | 10 (11.4%) |
Table 2.
Blood pressure distribution of subjects
| Variable | Descriptive statistics | Value (%) |
|---|---|---|
| SBP | ≤100 mmHg | 10.66 |
| ≥160 mmHg | 5.19 | |
| ≥140 mmHg | 21.90 | |
| DBP | ≤60 mmHg | 6.92 |
| ≥100 mmHg | 7.49 | |
| ≥85 mmHg | 41.50 |
The results showed that the mean difference of SBP was 0.75 mmHg, with a SD of 7.66 mmHg; the mean difference of DBP was 1.13 mmHg, with a SD of 6.14 mmHg. The mean difference of both SBP and DBP was less than 5 mmHg, and the SD was less than 8 mmHg, which fulfilled the Criterion 1. Bland–Altman scatterplots of SBP and DBP differences between the test and reference devices are shown in Figs. 1 and 2.
Fig. 1.
Distribution diagram for difference value of SBP (mmHg) measured by the test device and the reference device (259 sets of data).
Fig. 2.
Distribution diagram for difference value of DBP (mmHg) measured by the test device and the reference device (259 sets of data).
As the Criterion 2 suggested, the mean difference of SBP was 0.85 mmHg, and the SD was 6.56 mmHg, which was less than 6.88 mmHg. The mean difference of DBP was 1.27 mmHg, and the SD was 5.42 mmHg, which was less than 6.82 mmHg. The Bland–Altman scatterplots are shown in Figs. 3 and 4.
Fig. 3.
Distribution diagram for difference value of SBP (mmHg) measured by the test device and the reference device (88 sets of data).
Fig. 4.
Distribution diagram for difference value of DBP (mmHg) measured by the test device and the reference device (88 sets of data).
Discussion
Generally, BP monitor uses an inflated cuff wrapped around the upper arm or wrist. The cuff was automatically inflated by using an internal pump in the device. SBP and DBP were measured using an oscillometric method and pressure sensor technology, respectively.
The accuracy of oscillometric devices is significantly affected by several factors such as arterial stiffness, heart rate, and cuff size [7–11]. A feature of the test device is BP measurement during the inflation phase. The cuff is slowly inflated while simultaneously sensing oscillations to determine the DBP and SBP. Once SBP was determined, the cuff deflated rapidly. Compared to the measurement during deflation, which causes an obvious sense of pressure, the measurement during inflation is less likely to affect patients’ psychology, and the measurement results are more accurate. The performance of additional functions of the DBP-6279B, such as pulse rate measurement, the alarm of incorrectly wrapping cuffs and the Bluetooth function, which helps to save and send measurement data to a smart device, worked well during the validation, making the devices becoming more reliable and accurate.
The results of the present study showed that DBP-6279B fulfilled the validation Criteria 1 and 2 of the AAMI/ESH/ISO 81060-2 : 2018 and Amd.1 : 2020 standard requirements for both SBP and DBP in adults and adolescents. According to Criterion 1, the mean difference of SBP between the test device and the reference device was 0.75 mmHg, with a SD of 7.66 mmHg. The mean difference in DBP was 1.13 mmHg, with an SD of 6.14 mmHg. The mean difference between SBP and DBP was less than 5 mm Hg, and the SD was less than 8 mm Hg. According to Criterion 2, the mean difference of SBP between the test device and the reference device was 0.85 mmHg, and the SD was 6.56 mmHg, which was less than 6.88 mmHg and met the requirements. The mean difference of DBP was 1.27 mmHg, and the SD was 5.42 mmHg, which was less than 6.82 mmHg. Above all, the DBP-6279B meet the requirements of universal standard.
The test device was easy to operate, and there was no working instability, abnormal shutdown, and other abnormal conditions. Our study had several limitations. The selected participants did not include children younger than 12 years, pregnant women, and individuals with cardiac arrhythmia or arm circumference beyond the cuff size.
Conclusion
In summary, DBP-6279B met the AAMI/ESH/ISO universal standard (ISO 81060-2 : 2018 + Amd.1 : 2020) requirements, and could therefore be recommended for both clinical and self/home BP measurements in adults and adolescents.
Acknowledgements
We would like to thank Wendong Gao and Jian Xu, who gave us some suggestions and help with the content related to the DBP-6279B device. This study was funded by the JOYTECH Healthcare Co., Ltd., Hangzhou, China, through the Hebei General Hospital Special Account for Research. The study design, participant recruitment, and data collection were completed independently by the investigators of the Hebei General Hospital, and the PI was Chief Physician G.L. B.D. conceived the idea of the manuscript. L.H. and J.Z. conducted the analysis. L.F. wrote the initial draft of the paper. All authors read and approved the final manuscript.
Conflicts of interest
There are no conflicts of interest.
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