An outline of the revised British Hypertension Society protocol for the evaluation of blood pressure measuring devices

Validation of the Meditech ABPM-06 24-hour blood pressure monitoring system in a pediatric population according to International Organization for Standardization Protocol 81060-2:2018

OBJECTIVE

Ambulatory blood pressure monitoring (ABPM) devices play a crucial role in diagnosing hypertension, not only in adults but also in pediatric patients. ABPM-06, the latest oscillometric device from Meditech Ltd. (Budapest, Hungary), is the focus of this study. The objective was to validate the ABPM-06 device using the International Organization for Standardization (ISO) 81060-2 : 2018 standard.

METHODS

A total of 86 healthy patients, consisting of 34 males and 52 females, aged between 3 and 17 years, were enrolled in this study. During the ambulatory phase, a total of 50 patients were enrolled, with 35 patients falling within the 3- to 12-year-old age range and 15 patients aged between 12 and 17 years. Additionally, for the dynamic test, 36 patients were selected, comprising of 10 individuals aged 3-12 years and 26 patients aged 12-17 years. These patients were recruited from the outpatient clinics of the Department of Pediatrics at Albert Szent-Györgyi University in Szeged, Hungary. The validation process involved utilizing the same-arm sequence protocol, both in resting positions and during stress testing.

RESULTS

The ABPM-06 performed well in both clinical and ambulatory validations. In terms of validation criterion 1, the mean ± SD of the differences between the test device and reference blood pressure readings was -1.3 ± 3.5  mmHg for systolic and -0.1  ± 2.3 mmHg for diastolic, in children under the age of 12 years. For those over the age of 12 years, the mean ± SD of the differences was -2.8 ± 4.6 mmHg for systolic and -0.5 ± 2.7 mmHg for diastolic. Regarding the ambulatory validation, for children under 12 years old, the mean ± SD of the differences was -1.3  ± 3.5  mmHg for systolic and -0.1  ± 2.3  mmHg for diastolic. In the age group above 12 years, the mean ± SD of the differences was -2.8 ± 4.6 mmHg for systolic and -0.5 ± 2.7 mmHg for diastolic. Both tests successfully met the established criteria regarding the mean and SD values of the differences between the device readings and the observed SBP and DBP measurements.

CONCLUSION

The ABPM-06 oscillometric device fully adheres to the ISO 81060-2 : 2018 standard requirements for ABPM determination in the pediatric population (ages 3-17 years). Consequently, this ABPM device proves to be suitable for effectively managing hypertension in children and adolescents.

Comparison between visit-to-visit office and 24-h blood pressure variability in treated hypertensive patients

OBJECTIVES

In any treated hypertensive patient office blood pressure (BP) values may differ between visits and this variability (V) has an adverse prognostic impact. However, little information is available on visit-to-visit 24-h BPV.

METHODS

In 1114 hypertensives of the ELSA and PHYLLIS trials we compared visit-to-visit office and 24-h mean BPV by coefficient of variation (CV) of the mean systolic (S) and diastolic (D) BP obtained from yearly measurements during a 3-4 year treatment period. Visit-to-visit BPV during daytime and night-time were also compared.

RESULTS

Twenty-four-hour SBP-CV was about 20% less than office SBP-CV ( P  < 0.0001). SBP-CV was considerably greater for the night-time than for the daytime period (20%, P  < 0.0001). Results were similar for DBP and in males and females, older and younger patients, patients under different antihypertensive drugs or with different baseline or achieved BP values. In the group as a whole and in subgroups there was significant correlations between office and 24-h BP-CV but the correlation coefficients was weak, indicating that office SBP or DBP CV accounted for only about 1-4% of 24-h SBP or DBP-CV values.

CONCLUSION

Twenty-four-hour mean BP across visits is more stable than across visit office BP. Visit-to-visit office and 24-h BPV are significantly related to each other, but correlation coefficients are low, making visit-to-visit office BP variations poorly predictive of the concomitant 24-h BP variations and thus of on-treatment ambulatory BP stability.

Towards Non-Invasive and Continuous Blood Pressure Monitoring in Neonatal Intensive Care Using Artificial Intelligence: A Narrative Review

Preterm birth is a live birth that occurs before 37 completed weeks of pregnancy. Approximately 11% of babies are born preterm annually worldwide. Blood pressure (BP) monitoring is essential for managing the haemodynamic stability of preterm infants and impacts outcomes. However, current methods have many limitations associated, including invasive measurement, inaccuracies, and infection risk. In this narrative review, we find that artificial intelligence (AI) is a promising tool for the continuous measurement of BP in a neonatal cohort, based on data obtained from non-invasive sensors. Our findings highlight key sensing technologies, AI techniques, and model assessment metrics for BP sensing in the neonatal cohort. Moreover, our findings show that non-invasive BP monitoring leveraging AI has shown promise in adult cohorts but has not been broadly explored for neonatal cohorts. We conclude that there is a significant research opportunity in developing an innovative approach to provide a non-invasive alternative to existing continuous BP monitoring methods, which has the potential to improve outcomes for premature babies.

Accuracy of cuff-less, continuous, and non-invasive blood pressure measurement in 24-h ABPM in children aged 5-17

PURPOSE

Ambulatory, cuff-less blood pressure (BP) measurement devices are a promising trend to alleviate the strains of conventional, cuff-based BP determination. Cuff-less devices circumvent discomfort and nocturnal arousal reactions which can be triggered by cuff inflation from conventional, cuff-based ambulatory blood pressure measurement devices. Mitigating these discomforts is especially desirable when performing measurement in children. In this study we want to assess the clinical validity of a cuff-less BP measurement device for 24-h measurements in children and adolescents.

MATERIALS AND METHODS

We compared the simultaneously retrieved BP data of the cuff-less SOMNOtouch NIBP and the cuff-based Mobil-O-Graph in 24-h use in 90 children in the range from 5 to 17 years old.

RESULTS

A total of 1218 valid measurement pairs showed a mean deviation of 0.99 mmHg (limits of agreement: 21.44/-19.46) for systolic and 3.03 mmHg (limits of agreement: 24.37/-18.31) for diastolic BP values. Patient-specific difference of means was within 15 mmHg in 97.7% (systolic BP) and 93.2% (diastolic BP) patients. 25.6% of nocturnal cuff inflations led to determinable, BP-relevant arousal reactions.

CONCLUSIONS

The SOMNOtouch NIBP demonstrated little measurement deviation of mean BP compared to the cuff-based technique over a broad spectrum of 24-h, ambulatory BP measurements in children and adolescents. Cuff-less blood pressure measurement relieves the issue of nocturnal arousal reactions which are shown to be frequently induced by cuff-based measurements. Driven by these promising results, we encourage ongoing efforts to create enough evidence on cuff-less BP measurement to promote it into broad clinical application.

Accuracy and User Acceptability of 24-hour Ambulatory Blood Pressure Monitoring by a Prototype Cuffless Multi-Sensor Device Compared to a Conventional Oscillometric Device

OBJECTIVE

24-hour ambulatory blood pressure monitoring (24ABPM) is state of the art in out-of-office blood pressure (BP) monitoring. Due to discomfort and technical limitations related to cuff-based 24ABPM devices, methods for non-invasive and continuous estimation of BP without the need for a cuff have gained interest. The main aims of the present study were to compare accuracy of a pulse arrival time (PAT) based BP-model and user acceptability of a prototype cuffless multi-sensor device (cuffless device), developed by Aidee Health AS, with a conventional cuff-based oscillometric device (ReferenceBP) during 24ABPM.

METHODS

Ninety-five normotensive and hypertensive adults underwent simultaneous 24ABPM with the cuffless device on the chest and a conventional cuff-based oscillometric device on the non-dominant arm. PAT was calculated using the electrocardiogram (ECG) and photoplethysmography (PPG) sensors incorporated in the chest-worn device. The cuffless device recorded continuously, while ReferenceBP measurements were taken every 20 minutes during daytime and every 30 minutes during nighttime. Two-minute PAT-based BP predictions corresponding to the ReferenceBP measurements were compared with ReferenceBP measurements using paired t-tests, bias, and limits of agreement.

RESULTS

Mean (SD) of ReferenceBP compared to PAT-based daytime and nighttime systolic BP (SBP) were 129.7 (13.8) mmHg versus 133.6 (20.9) mmHg and 113.1 (16.5) mmHg versus 131.9 (23.4) mmHg. Ninety-five % limits of agreements were [-26.7, 34.6 mmHg] and [-20.9, 58.4 mmHg] for daytime and nighttime SBP respectively. The cuffless device was reported to be significantly more comfortable and less disturbing than the ReferenceBP device during 24ABPM.

CONCLUSIONS

In the present study, we demonstrated that a general PAT-based BP model had unsatisfactory agreement with ambulatory BP during 24ABPM, especially during nighttime. If sufficient accuracy can be achieved, cuffless BP devices have promising potential for clinical assessment of BP due to the opportunities provided by continuous BP measurements during real-life conditions and high user acceptability.

Associations of Estimated Pulse Wave Velocity with Body Mass Index and Waist Circumference among General Korean Adults

The correlation between body fat parameters and arterial stiffness is still under debate. This study aimed to examine the associations of body mass index (BMI) and waist circumference (WC) with estimated pulse wave velocity (ePWV). We utilized data from 14,228 subjects (mean age 53.4 ± 16.8 years; 56.9% were female) from the Korean National Health and Nutrition Examination Survey. The ePWV was calculated using a formula based on age and blood pressure. Simple linear correlation analyses revealed significant associations between both BMI and ePWV (r = 0.098; p < 0.001) and WC and ePWV (r = 0.291; p < 0.001), with a stronger correlation observed between WC and ePWV. Multiple linear regression analysis demonstrated that WC remained significantly associated with ePWV after adjusting for potential confounders (β = 0.020; p = 0.001). However, a statistically significant association was not found between BMI and ePWV (β = 0.011; p = 0.076). Multiple binary logistic regression analysis further indicated that both higher BMI and WC were independently associated with higher ePWV, but the association was more pronounced between WC and ePWV than between BMI and ePWV. These findings underscore a stronger correlation between visceral obesity (as indicated by WC) and arterial stiffness (as indicated by ePWV) compared to overall obesity (as indicated by BMI). This highlights the potential significance of abdominal obesity in assessing cardiovascular risk.

Standardized protocol of blood pressure measurement and quality control program for the Korea National Health and Nutrition Examination Survey

Accurate blood pressure (BP) measurement is crucial for hypertension detection and management. The Korea National Health and Nutrition Examination Survey (KNHANES) assesses the health of Koreans using representative cross-sectional data. BP measurements were historically done with mercury sphygmomanometers for participants aged ≥10 years. However, KNHANES transitioned to Greenlight 300TM (mercury-free auscultatory device) in 2020 for participants aged ≥6 years and used dual devices (Microlife WatchBP Office AFIB and Greenlight) in 2021-2022. To ensure consistency, KNHANES will adopt Microlife as the unified BP device with Greenlight for device validation from 2023. Under the new protocol, participants aged ≥6 years will have their BP measured three times at 30-second intervals after a 5-minute rest under ambient temperature (20-25℃) and noise ≤65 dB. The average of the 2nd and 3rd readings will be used as the representative BP value. The quality control (QC) program involves four trained examiners passing the "quality control and assurance of BP measurement program" three times annually, and undergoing "video monitoring of weekly calibration process" once a year. Additionally, the QC team will conduct "on-site evaluations of BP measurement" at mobile examination centers three times a year. A Five-Step QC process for BP devices was also developed. This document outlines the standardized BP measurement protocol and rigorous QC program in KNHANES, aiming to ensure accurate and reliable BP data for epidemiological research and public health policymaking in South Korea.

Validation of the Withings BPM Core Device for Self-Blood Pressure Measurements in General Population According to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization Universal Standard

Background

Most of the scientific societies recommend assessing the accuracy of electronic devices for blood pressure (BP) measurements using established validation protocol.

Objective

To determine the accuracy of the BP measurements using the Withings BPM Core device in the general population according to the "Universal Standard (ISO 81060-2:2018/AMD 1:2020)".

Methods

The Withings BPM Core is an oscillometric device measuring BP at the brachial level. The study was performed according to the "Universal Standard (ISO 81060-2:2018/AMD 1:2020) protocol" using the same-arm sequential BP measurement method. Subjects (n ≥ 85) fulfilling the age, gender, BP, and cuff distribution criteria of the protocol were included. Analysis was performed as required by the Universal protocol using Criterion 1 - differences between observers' mercury sphygmomanometer reference measurements and test device BP values (test versus reference) and their standard deviation (SD); and Criterion 2 - The SD of the mean BP differences between the test device and reference BP per subject.

Results

Eighty-six subjects were selected, 85 of whom were included. The mean BP differences between the simultaneous two observers' measurements were -0.2 ± 2.1 mmHg for systolic BP (SBP) and 0.3 ± 2.1 mmHg for diastolic BP (DBP). For validation criterion 1, the mean difference ± SD between the reference and device BP values was -0.6 ± 4.8 mmHg for SBP and 0.1 ± 3.7 mmHg for DBP (≤5 ± 8 mmHg for both SBP and DBP). For criterion 2, the SD of the mean BP differences between the test device and reference BP per subject was 3.2/2.6 mmHg for SBP and DBP (≤6.91/6.95 mmHg).

Conclusion

The results of this study showed that the Withings BPM Core oscillometric device for home BP measurement fulfilled the accuracy requirements of the (ISO 81060-2:2018/AMD 1:2020) Universal protocol in the general population.

Non-invasive blood pressure estimation combining deep neural networks with pre-training and partial fine-tuning

Objective. Daily blood pressure (BP) monitoring is essential since BP levels can reflect the functions of heart pumping and vasoconstriction. Although various neural network-based BP estimate approaches have been proposed, they have certain practical shortcomings, such as low estimation accuracy and poor model generalization. Based on the strategy of pre-training and partial fine-tuning, this work proposes a non-invasive method for BP estimation using the photoplethysmography (PPG) signal.Approach. To learn the PPG-BP relationship, the deep convolutional bidirectional recurrent neural network (DC-Bi-RNN) was pre-trained with data from the public medical information mark for intensive care (MIMIC III) database. A tiny quantity of data from the target subject was used to fine-tune the specific layers of the pre-trained model to learn more individual-specific information to achieve highly accurate BP estimation.Main results.The mean absolute error and the Pearson correlation coefficient (r) of the proposed algorithm are 3.21 mmHg and 0.919 for systolic BP, and 1.80 mmHg and 0.898 for diastolic BP (DBP). The experimental results show that our method outperforms other methods and meets the requirements of the Association for the Advancement of Medical Instrumentation standard, and received an A grade according to the British Hypertension Society standard.Significance.The proposed method applies the strategy of pre-training and partial fine-tuning to BP estimation and verifies its effectiveness in improving the accuracy of non-invasive BP estimation.

Home blood pressure monitoring: a position statement from the Korean Society of Hypertension Home Blood Pressure Forum

Home blood pressure measurement (HBPM) has the advantage of measuring blood pressure (BP) multiple times over a long period. HBPM effectively diagnoses stress-induced transient BP elevations (i.e., white coat hypertension), insufficient BP control throughout the day (i.e., masked hypertension), and even BP variability. In most cases, HBPM may increase self-awareness of BP, increasing the compliance of treatment. Cumulative evidence has reported better improved predictive values of HBPM in cardiovascular morbidity and mortality than office BP monitoring. In this position paper, the Korean Society of Hypertension Home Blood Pressure Forum provides comprehensive information and clinical importance on HBPM.

Mechanically Active Materials and Devices for Bio-Interfaced Pressure Sensors-A Review

Pressures generated by external forces or by internal body processes represent parameters of critical importance in diagnosing physiological health and in anticipating injuries. Examples span intracranial hypertension from traumatic brain injuries, high blood pressure from poor diet, pressure-induced skin ulcers from immobility, and edema from congestive heart failure. Pressures measured on the soft surfaces of vital organs or within internal cavities of the body can provide essential insights into patient status and progression. Challenges lie in the development of high-performance pressure sensors that can softly interface with biological tissues to enable safe monitoring for extended periods of time. This review focuses on recent advances in mechanically active materials and structural designs for classes of soft pressure sensors that have proven uses in these contexts. The discussions include applications of such sensors as implantable and wearable systems, with various unique capabilities in wireless continuous monitoring, minimally invasive deployment, natural degradation in biofluids, and/or multiplexed spatiotemporal mapping. A concluding section summarizes challenges and future opportunities for this growing field of materials and biomedical research.

Cuffless Blood Pressure Estimation Based on Monte Carlo Simulation Using Photoplethysmography Signals

Blood pressure measurements are one of the most routinely performed medical tests globally. Blood pressure is an important metric since it provides information that can be used to diagnose several vascular diseases. Conventional blood pressure measurement systems use cuff-based devices to measure the blood pressure, which may be uncomfortable and sometimes burdensome to the subjects. Therefore, in this study, we propose a cuffless blood pressure estimation model based on Monte Carlo simulation (MCS). We propose a heterogeneous finger model for the MCS at wavelengths of 905 nm and 940 nm. After recording the photon intensities from the MCS over a certain range of blood pressure values, the actual photoplethysmography (PPG) signals were used to estimate blood pressure. We used both publicly available and self-made datasets to evaluate the performance of the proposed model. In case of the publicly available dataset for transmission-type MCS, the mean absolute errors are 3.32 ± 6.03 mmHg for systolic blood pressure (SBP), 2.02 ± 2.64 mmHg for diastolic blood pressure (DBP), and 1.76 ± 2.8 mmHg for mean arterial pressure (MAP). The self-made dataset is used for both transmission- and reflection-type MCSs; its mean absolute errors are 2.54 ± 4.24 mmHg for SBP, 1.49 ± 2.82 mmHg for DBP, and 1.51 ± 2.41 mmHg for MAP in the transmission-type case as well as 3.35 ± 5.06 mmHg for SBP, 2.07 ± 2.83 mmHg for DBP, and 2.12 ± 2.83 mmHg for MAP in the reflection-type case. The estimated results of the SBP and DBP satisfy the requirements of the Association for the Advancement of Medical Instrumentation (AAMI) standards and are within Grade A according to the British Hypertension Society (BHS) standards. These results show that the proposed model is efficient for estimating blood pressures using fingertip PPG signals.

Community-based multiple screening for metabolic syndrome by innovative theory: A longitudinal study

The purpose of this research is to elucidate whether metabolic syndrome affects the rate of adoption of a new multiple cancer screening programme, based on the Diffusion of Innovation theory. The time to attend the screening programme, conducted in Keelung, Taiwan, within 10 years was assessed by innovativeness (innovators, early adaptors, early majority, late majority and laggard) using data from 79,303 residents, with the information on metabolic syndrome accrued from routine adult health check-ups. The median time of adopting the programme and the relative rates of early adoption by metabolic syndrome and its severity score were estimated. The results show that the estimated times to adopt the programme ranged from 3 months for innovators to 10 years for the laggard. The rate of early adoption was 34% higher for participants without metabolic syndrome than for those with the disease, and the gradient relationship of disease severity was noted. The adjusted median time to adopt innovativeness was 0.82 years earlier for participants who were disease-free than those with the disease. Meanwhile, the adjusted median time was wider by up to 2.25 years for those with severe disease. The study suggests that innovation should prioritise the potential risk of the metabolic syndrome population.

Home blood pressure monitors owned by participants in a large decentralised clinical trial in hypertension: the Treatment In Morning versus Evening (TIME) study

Various home blood pressure monitors (HBPMs) are available to the public for purchase but only some are validated against standardised protocols. This study aimed to assess whether HBPMs owned by participants taking part in a clinical trial were validated models. The TIME study is a decentralised randomised trial investigating the effect of antihypertensive medication dosing time on cardiovascular outcomes in adults with hypertension. No HBPMs were provided to participants in this trial but patients were asked to report if they already owned one. We identified the model of HBPM reported by participants, then cross-referenced this against lists of validated HBPMs produced by dabl Educational Trust and the British and Irish Hypertension Society (BIHS). Of 21,104 participants, 10,464 (49.6%) reported their model of HBPM. 7464 (71.3%) of these participants owned a monitor that could be identified from the participants' entry. Of these, 6066 (81.3%) participants owned a monitor listed as validated by either dabl (n = 5903) or BIHS (n = 5491). Some were listed as validated by both. 1398 (18.7%) participants owned an identifiable HBPM that lacked clear evidence of validation. 6963 (93.3%) participants owned an upper arm HBPM and 501 (6.7%) owned a wrist HBPM. Validated HBPMs had a higher median online retail price of £45.00 compared to £20.00 for HBPMs lacking clear evidence of validation. A significant number of participants own HBPMs lacking evidence of validation.

Metabolic syndrome in middle-aged and older women: A cross-sectional study

Objective:

This study aims to compare the prevalence of metabolic syndrome between different age groups of middle-aged and older women and to assess whether these differences are independent of potential covariates.

Methods:

Study conducted with 510 women divided into three age groups: 45–54, 55–64 and 65–74 years. Socioeconomic, reproductive and lifestyle variables were self-reported. We defined metabolic syndrome using the National Cholesterol Education Program Adult Treatment Panel III criteria (abdominal obesity, diabetes, reduced high-density lipoprotein, elevated triglycerides, and hypertension). Logistic regression assessed the association between age groups, and metabolic syndrome was adjusted for covariates (socioeconomic variables, age at menarche and at first childbirth, parity, menopausal status, physical activity variables and smoking).

Results:

Women aged 55–64 years presented higher prevalence of all metabolic syndrome criteria than the other groups, except for abdominal obesity, which was higher in the oldest group. In the fully adjusted analysis, the 55–64 years age group continues to exhibit significantly higher odds of presenting metabolic syndrome when compared to the youngest group (45–54 years) (OR = 2.257; 95% CI = 1.20:4.24). There was no statistical difference in the odds of presenting metabolic syndrome when comparing the oldest and the youngest groups (OR = 1.500; 95% CI = 0.85:2.65).

Conclusion:

The higher prevalence of metabolic syndrome among those aged 55–64 years may indicate that middle-aged women become unhealthy earlier in the life course and that many of them may die prematurely. This result highlights the importance of screening metabolic syndrome earlier in the midlife and the need for public health policies aimed at reducing adverse effects in later years.

Towards a portable-noninvasive blood pressure monitoring system utilizing the photoplethysmogram signal

Blood pressure (BP) responds instantly to the body's conditions, such as movements, diseases or infections, and sudden excitation. Therefore, BP monitoring is a standard clinical measurement and is considered one of the fundamental health signs that assist in predicting and diagnosing several cardiovascular diseases. The traditional BP techniques (i.e. the cuff-based methods) only provide intermittent measurements over a certain period. Additionally, they cause turbulence in the blood flow, impeding the continuous BP monitoring, especially in emergency cases. In this study, an instrumentation system is designed to estimate BP noninvasively by measuring the PPG signal utilizing the optical technique. The photoplethysmogram (PPG) signals were measured and processed for ≈ 450 cases with different clinical conditions and irrespective of their health condition. A total of 13 features of the PPG signal were used to estimate the systolic and diastolic blood pressure (SBP and DBP), utilizing several machine learning techniques. The experimental results showed that the designed system is able to effectively describe the complex-embedded relationship between the features of the PPG signal and BP (SBP and DBP) with high accuracy. The mean absolute error (MAE) ± standard deviation (SD) was 4.82 ± 3.49 mmHg for the SBP and 1.37 ± 1.65 mmHg for the DBP, with a mean error (ME) of ≈ 0 mmHg. The estimation results are consistent with the Association for the American National Standards of the Association for the Advancement of Medical Instrumentation (AAMI) and achieved Grade A in the British Hypertension Society (BHS) standards for the DBP and Grade B for the SBP. Such a study effectively contributes to the scientific efforts targeting the promotion of the practical application for providing a portable-noninvasive instrumentation system for BP monitoring purposes. Once the BP is determined with sufficient accuracy, it can be utilized further in the early prediction and classification of various arrhythmias such as hypertension, tachycardia, bradycardia, and atrial fibrillation (as the early detection can be a critical issue).

Continuous PPG-Based Blood Pressure Monitoring Using Multi-Linear Regression

In this work, we present a photoplethysmography-based blood pressure monitoring algorithm (PPG-BPM) that solely requires a photoplethysmography (PPG) signal. The technology is based on pulse wave analysis (PWA) of PPG signals retrieved from different body locations to continuously estimate the systolic blood pressure (SBP) and the diastolic blood pressure (DBP). The proposed algorithm extracts morphological features from the PPG signal and maps them to SBP and DBP values using a multiple linear regression (MLR) model. The performance of the algorithm is evaluated on the publicly available Multiparameter Intelligent Monitoring in Intensive Care (MIMIC I) database. We utilize 28 data-sets (records) from the MIMIC I database that contain both PPG and brachial arterial blood pressure (ABP) signals. The collected PPG and ABP signals are synchronized and divided into intervals of 30 seconds, called epochs. In total, we utilize 47153 \textit{clean} 30-second epochs for the performance analysis. Out of the 28 data-sets, we use only 2 data-sets (records 041 and 427 in the MIMIC I) with a total of 2677 \textit{clean} 30-second epochs to build the MLR model of the algorithm. For the SBP, a standard deviation of error (SDE) of 8.01 mmHg and a mean absolute error (MAE) of 6.10 mmHg between the arterial line and the PPG-based values are achieved, with a Pearson correlation coefficient r = 0.90, . For the DBP, an SDE of 6.22 mmHg and an MAE of 4.65 mmHg between the arterial line and the PPG-based values are achieved, with a Pearson correlation coefficient r = 0.85, . We also use a binary classifier for the BP values with the positives indicating SBP ≥ 130 mmHg and/or DBP ≥ 80 mmHg and the negatives indicating otherwise. The classifier results generated by the PPG-based SBP and DBP estimates achieve a sensitivity and a specificity of 79.11% and 92.37%, respectively.

Home Blood Pressure Monitoring Devices: Device Performance in an Alaska Native and American Indian Population

Objectives: Home blood pressure monitoring (HBPM) is an important component of blood pressure (BP) management. We assessed performance of two HBPM devices among Alaska Native and American Indian people (ANAIs). Methods: We measured BP using Omron BP786 arm cuff, Omron BP654 wrist cuff, and Baum aneroid sphygmomanometer in 100 ANAIs. Performance was assessed with intraclass correlation, paired t-tests, and calibration models. Results: Compared to sphygmomanometer, average BP was higher for wrist cuff (systolic = 4.8 mmHg and diastolic = 3.6 mmHg) and varied for arm cuff (systolic = -1.5 mmHg and diastolic = 2.5 mmHg). Calibration increased performance from grade B to A for arm cuff and from D to B for wrist cuff. Calibration increased false negatives and decreased false positives. Discussion: The arm HBPM device is more accurate than the wrist cuff among ANAIs with hypertension. Most patients are willing to use the arm cuff when accuracy is discussed.

A hybrid neural network for continuous and non-invasive estimation of blood pressure from raw electrocardiogram and photoplethysmogram waveforms

BACKGROUND AND OBJECTIVES

Continuous and non-invasive blood pressure monitoring would revolutionize healthcare. Currently, blood pressure (BP) can only be accurately monitored using obtrusive cuff-based devices or invasive intra-arterial monitoring. In this work, we propose a novel hybrid neural network for the accurate estimation of blood pressure (BP) using only non-invasive electrocardiogram (ECG) and photoplethysmogram (PPG) waveforms as inputs.

METHODS

This work proposes a hybrid neural network combines the feature detection abilities of temporal convolutional layers with the strong performance on sequential data offered by long short-term memory layers. Raw electrocardiogram and photoplethysmogram waveforms are concatenated and used as network inputs. The network was developed using the TensorFlow framework. Our scheme is analysed and compared to the literature in terms of well known standards set by the British Hypertension Society (BHS) and the Association for the Advancement of Medical Instrumentation (AAMI).

RESULTS

Our scheme achieves extremely low mean absolute errors (MAEs) of 4.41 mmHg for SBP, 2.91 mmHg for DBP, and 2.77 mmHg for MAP. A strong level of agreement between our scheme and the gold-standard intra-arterial monitoring is shown through Bland Altman and regression plots. Additionally, the standard for BP devices established by AAMI is met by our scheme. We also achieve a grade of 'A' based on the criteria outlined by the BHS protocol for BP devices.

CONCLUSIONS

Our CNN-LSTM network outperforms current state-of-the-art schemes for non-invasive BP measurement from PPG and ECG waveforms. These results provide an effective machine learning approach that could readily be implemented into non-invasive wearable devices for use in continuous clinical and at-home monitoring.

Combined deep CNN-LSTM network-based multitasking learning architecture for noninvasive continuous blood pressure estimation using difference in ECG-PPG features

The pulse arrival time (PAT), the difference between the R-peak time of electrocardiogram (ECG) signal and the systolic peak of photoplethysmography (PPG) signal, is an indicator that enables noninvasive and continuous blood pressure estimation. However, it is difficult to accurately measure PAT from ECG and PPG signals because they have inconsistent shapes owing to patient-specific physical characteristics, pathological conditions, and movements. Accordingly, complex preprocessing is required to estimate blood pressure based on PAT. In this paper, as an alternative solution, we propose a noninvasive continuous algorithm using the difference between ECG and PPG as a new feature that can include PAT information. The proposed algorithm is a deep CNN–LSTM-based multitasking machine learning model that outputs simultaneous prediction results of systolic (SBP) and diastolic blood pressures (DBP). We used a total of 48 patients on the PhysioNet website by splitting them into 38 patients for training and 10 patients for testing. The prediction accuracies of SBP and DBP were 0.0 ± 1.6 mmHg and 0.2 ± 1.3 mmHg, respectively. Even though the proposed model was assessed with only 10 patients, this result was satisfied with three guidelines, which are the BHS, AAMI, and IEEE standards for blood pressure measurement devices.

Comparing Intra-Arterial, Auscultatory, and Oscillometric Measurement Methods for Arterial Blood Pressure

AIM

This study aimed to compare the measurement results of arterial blood pressure obtained through intra-arterial, auscultatory, and oscillometric methods.

METHOD

This prospective and descriptive study was conducted with 180 patients hospitalized in the intensive care units of cardiovascular surgery and anesthesia. Arterial blood pressures of the patients in the study were measured with 3 methods, and the mean arterial pressure values obtained by each method were analyzed to find out whether they were different or consistent.

RESULTS

The average systolic blood pressure value using the intra-arterial method was found to be 125.47 ± 21.39 mm Hg, and the average of diastolic blood pressure measurement obtained using the oscillometric method was the highest (73.91 ± 10.62 mm Hg). The highest correlation was seen between the arterial BP measurements of the intra-arterial and auscultatory methods (systolic [0.96] and diastolic [0.90]). According to the British and Irish Hypertension Society protocol, a very good agreement between the diastolic blood pressure values and a good agreement between the systolic blood pressure values were obtained.

CONCLUSION

The measurement results obtained through the auscultatory method more consistent with the results obtained through the intra-arterial method compared with those obtained using the oscillometric method.

Diagnostics and monitoring tools for noncommunicable diseases: a missing component in the global response

A key component of any health system is the capacity to accurately diagnose individuals. One of the six building blocks of a health system as defined by the World Health Organization (WHO) includes diagnostic tools. The WHO’s Noncommunicable Disease Global Action Plan includes addressing the lack of diagnostics for noncommunicable diseases, through multi-stakeholder collaborations to develop new technologies that are affordable, safe, effective and quality controlled, and improving laboratory and diagnostic capacity and human resources. Many challenges exist beyond price and availability for the current tools included in the Package of Essential Noncommunicable Disease Interventions (PEN) for cardiovascular disease, diabetes and chronic respiratory diseases. These include temperature stability, adaptability to various settings (e.g. at high altitude), need for training in order to perform and interpret the test, the need for maintenance and calibration, and for Blood Glucose Meters non-compatible meters and test strips. To date the issues surrounding access to diagnostic and monitoring tools for noncommunicable diseases have not been addressed in much detail. The aim of this Commentary is to present the current landscape and challenges with regards to guidance from the WHO on diagnostic tools using the WHO REASSURED criteria, which define a set of key characteristics for diagnostic tests and tools. These criteria have been used for communicable diseases, but so far have not been used for noncommunicable diseases. Diagnostic tools have played an important role in addressing many communicable diseases, such as HIV, TB and neglected tropical diseases. Clearly more attention with regards to diagnostics for noncommunicable diseases as a key component of the health system is needed.

Reproducibility of Office and Out-of-Office Blood Pressure Measurements in Children: Implications for Clinical Practice and Research

This study aimed to evaluate the reproducibility of office (OBP), ambulatory (ABP), and home blood pressure (HBP) measurements in children and adolescents, and their implications in diagnosing hypertension in clinical practice and in pediatric hypertension research. Apparently healthy children and adolescents referred for suspected hypertension were included. Measurements of 2-visit OBP, 7-day HBP, and 24-hour ABP were performed twice, 1 to 6 months apart. Reproducibility was quantified using the SD of differences between repeated measurements. The sample size of clinical trials comparing the efficacy of antihypertensive drugs using each method was calculated. Fifty-eight individuals were analyzed (mean age, 13.0±2.9 years, 60.3% boys). The reproducibility of 24-hour ABP (SD of differences 5.7/4.5 systolic/diastolic) and HBP (5.9/5.0 mm Hg) were comparable and superior to that of visit-2 OBP (9.2/7.8) and awake (6.7/5.5) or asleep ABP (7.6/6.1). As a consequence, a parallel-group comparative trial aiming to detect a difference in the effect of 2 drugs of 10 mm Hg systolic BP, would require 36 participants when using OBP measurements, 14 using 24-hour ABP, and 15 using HBP (102/34/42 respectively for detecting a 5 mm Hg difference in diastolic BP). For a crossover design trial, the corresponding sample sizes are 9/3/4 for systolic BP and 26/9/11 for diastolic, respectively. These data suggest that in children and adolescents 24-hour ABP and 7-day HBP have similar reproducibility, superior to OBP and daytime or asleep ABP. These findings have major implications in diagnosing hypertension in children in clinical practice and in designing clinical research trials in pediatric hypertension.

An Evaluation of Biometric Monitoring Technologies for Vital Signs in the Era of COVID-19

The novel coronavirus disease 2019 (COVID-19) global pandemic has shifted how many patients receive outpatient care. Telehealth and remote monitoring have become more prevalent, and measurements taken in a patient's home using biometric monitoring technologies (BioMeTs) offer convenient opportunities to collect vital sign data. Healthcare providers may lack prior experience using BioMeTs in remote patient care, and, therefore, may be unfamiliar with the many versions of BioMeTs, novel data collection protocols, and context of the values collected. To make informed patient care decisions based on the biometric data collected remotely, it is important to understand the engineering solutions embedded in the products, data collection protocols, form factors (physical size and shape), data quality considerations, and availability of validation information. This article provides an overview of BioMeTs available for collecting vital signs (temperature, heart rate, blood pressure, oxygen saturation, and respiratory rate) and discusses the strengths and limitations of continuous monitoring. We provide considerations for remote data collection and sources of validation information to guide BioMeT use in the era of COVID-19 and beyond.

Tissue microarray (TMA) use in post mortem neuropathology

BACKGROUND

Tissue microarrays (TMAs), where each block (and thus section) contains multiple tissue cores from multiple blocks potentially allow more efficient use of tissue, reagents and time in neuropathology.

NEW METHOD

The relationship between data from TMA cores and whole sections was investigated using 'virtual' TMA cores. This involved quantitative assessments of microglial pathology in white matter lesions and motor neuron disease, alongside qualitative TDP-43 inclusion status in motor neuron disease cases. Following this, a protocol was developed for TMA construction.

RESULTS

For microglial pathology we found good concordance between virtual cores and whole sections for volume density using one 1.75 mm core (equivalent to a 2 mm core after accounting for peripheral tissue loss). More sophisticated microglial cell size and measures required two cores. Qualitative results of pTDP-43 pathology showed use of one 1.75 mm core gave a 100 % sensitivity and specificity within grey matter, and 88.3 % sensitivity and 100 % specificity within white matter. A method of producing the TMAs was suitable for immunohistochemistry both manually and by autostainer, with the minimal core loss from the microscope slide.

COMPARISON WITH EXISTING METHODS

TMAs have been used infrequently in post mortem neuropathology research. However, we believe TMAs give comparable tissue assessment results and can be constructed, sectioned and stained with relative ease.

CONCLUSIONS

We found TMAs could be used to assess both quantitative (microglial pathology) and qualitative pathology (TDP-43 proteinopathy) with greatly reduced quantities of tissue, time and reagents. These could be used for further work to improve data acquisition efficiency.

Low anthocyanin plum nectar does not impact cognition, blood pressure and gut microbiota in healthy older adults: A randomized crossover trial

Queen Garnet plum (QGP), known for its high levels of anthocyanins, is a hybrid of the Japanese plum developed in Queensland, Australia. Anthocyanins provide the red, blue, and purple pigments in plants with demonstrated beneficial health effects. This study hypothesized that low-dose anthocyanin QGP intake will have a significant positive effect on cognition, blood pressure, and gut microbiota in healthy older adults. A randomized crossover trial was conducted to determine the effect and within subject variance on cognition and 24 hr. ambulatory blood pressure in older adults without cognitive impairment following daily consumption of 200 mL low-dose anthocyanin (5 mg/100 g) QGP nectar (intervention) or raspberry cordial (control). Secondary outcomes included inflammatory markers (C-reactive protein), nerve growth factor (BDNF), and gut microbiota (16S rRNA gene sequencing). Twenty-eight participants (55+ years) were recruited. Each randomized treatment arm lasted for 8 weeks with a 4-week washout period. Cognition, blood pressure, and urine samples were measured at each visit (5 total) while blood and fecal samples were collected at baseline, 8 weeks, and 20 weeks. Repeated-measures ANOVA was used to analyze the data. Across the treatments, no significant difference was observed for the different domains of cognition, blood pressure, or anti-inflammatory biomarkers. No intervention effect was found for genera or class of gut microbes. Low anthocyanin nectar derived from the QGP did not have any significant effects on cognition, blood pressure, or gut microbiota in healthy older adults.

Blood Pressure Measurement Error in Children: Lessons in Measurement Reliability

BACKGROUND AND PURPOSE

Blood pressure measurement represents the pressure exerted during heart ejection and filling. There are several ways to measure blood pressure and a valid measure is essential. The purpose of this study was to evaluate the approach to noninvasive blood pressure measurement in children.

METHODS

Blood pressure measurements were taken using the automatic Phillips MP30 monitor and compared against Welch Allyn blood pressure cuffs with Medline manual sphygmomanometers.

RESULTS

A total of 492 measurements were taken on 82 subjects, and they demonstrated comparability between automatic and manual devices.

CONCLUSIONS

Although our study indicated acceptable agreement between automatic and manual blood pressure measurement, it also revealed measurement error remains a concern, with sample size, study protocol, training, and environment all playing a role.

Accuracy of blood-pressure monitors owned by patients with hypertension (ACCU-RATE study): a cross-sectional, observational study in central England

Background

Home blood-pressure (BP) monitoring is recommended in guidelines and is increasingly popular with patients and health professionals, but the accuracy of patients’ own monitors in real-world use is not known.

Aim

To assess the accuracy of home BP monitors used by people with hypertension, and to investigate factors affecting accuracy.

Design and setting

Cross-sectional, observational study in urban and suburban settings in central England.

Method

Patients (n = 6891) on the hypertension register at seven practices in the West Midlands, England, were surveyed to ascertain whether they owned a BP monitor and wanted it tested. Monitor accuracy was compared with a calibrated reference device at 50 mmHg intervals between 0–280/300 mmHg (static pressure test); a difference from the reference monitor of +/−3 mmHg at any interval was considered a failure. Cuff performance was also assessed. Results were analysed by frequency of use, length of time in service, make and model, monitor validation status, purchase price, and any previous testing.

Results

In total, 251 (76%, 95% confidence interval [95% CI] = 71 to 80%) of 331 tested devices passed all tests (monitors and cuffs), and 86% (CI] = 82 to 90%) passed the static pressure test; deficiencies were, primarily, because of monitors overestimating BP. A total of 40% of testable monitors were not validated. The pass rate on the static pressure test was greater in validated monitors (96%, 95% CI = 94 to 98%) versus unvalidated monitors (64%, 95% CI = 58 to 69%), those retailing for >£10 (90%, 95% CI = 86 to 94%), those retailing for ≤£10 (66%, 95% CI = 51 to 80%), those in use for ≤4 years (95%, 95% CI = 91 to 98%), and those in use for >4 years (74%, 95% CI = 67 to 82%). All in all, 12% of cuffs failed.

Conclusion

Patients’ own BP monitor failure rate was similar to that demonstrated in studies performed in professional settings, although cuff failure was more frequent. Clinicians can be confident of the accuracy of patients’ own BP monitors if the devices are validated and ≤4 years old.

Self-Measured Blood Pressure Monitoring at Home: A Joint Policy Statement From the American Heart Association and American Medical Association

The diagnosis and management of hypertension, a common cardiovascular risk factor among the general population, have been based primarily on the measurement of blood pressure (BP) in the office. BP may differ considerably when measured in the office and when measured outside of the office setting, and higher out-of-office BP is associated with increased cardiovascular risk independent of office BP. Self-measured BP monitoring, the measurement of BP by an individual outside of the office at home, is a validated approach for out-of-office BP measurement. Several national and international hypertension guidelines endorse self-measured BP monitoring. Indications include the diagnosis of white-coat hypertension and masked hypertension and the identification of white-coat effect and masked uncontrolled hypertension. Other indications include confirming the diagnosis of resistant hypertension and detecting morning hypertension. Validated self-measured BP monitoring devices that use the oscillometric method are preferred, and a standardized BP measurement and monitoring protocol should be followed. Evidence from meta-analyses of randomized trials indicates that self-measured BP monitoring is associated with a reduction in BP and improved BP control, and the benefits of self-measured BP monitoring are greatest when done along with cointerventions. The addition of self-measured BP monitoring to office BP monitoring is cost-effective compared with office BP monitoring alone or usual care among individuals with high office BP. The use of self-measured BP monitoring is commonly reported by both individuals and providers. Therefore, self-measured BP monitoring has high potential for improving the diagnosis and management of hypertension in the United States. Randomized controlled trials examining the impact of self-measured BP monitoring on cardiovascular outcomes are needed. To adequately address barriers to the implementation of self-measured BP monitoring, financial investment is needed in the following areas: improving education and training of individuals and providers, building health information technology capacity, incorporating self-measured BP readings into clinical performance measures, supporting cointerventions, and enhancing reimbursement.

Blood pressure measurement device selection in low-resource settings: Challenges, compromises, and routes to progress

High blood pressure (BP) is the single leading preventable cardiovascular disease (CVD) risk factor across the world. In order to decrease the global burden of CVD, broad hypertension screening programs that facilitate early hypertension diagnosis and treatment are essential. Accurate BP devices are a key element of hypertension control programs. With the overwhelming number of devices available now on the market, most of which have not been tested for accuracy, it can be challenging to select the optimal BP measurement device for clinical settings. This review details essential factors to consider when selecting a good-quality BP device, particularly for use in low-resource settings. Barriers to the procurement and use of good-quality devices are reviewed and practical solutions proposed.

An Automated Blood Pressure Display for Self-Measurement in Patients With Chronic Kidney Disease (iHealth Track): Device Validation Study

BACKGROUND

Hypertension is a global public health issue and is closely related to chronic kidney disorder (CKD). In people with CKD, strict monitoring of blood pressure is an important part of therapy.

OBJECTIVE

The aim of this research was to validate the iHealth Track blood pressure monitoring device for patients with CKD according to the European Society of Hypertension International Protocol 2010 (ESH-IP2).

METHODS

In total, 33 patients who received hemodialysis in Plasencia participated in the study. There were 9 successive measurements made, which conformed to the ESH-IP2. We calculated the differences between the standard reference device (Omron M3 Intellisense) and the test device (iHealth Track) for blood pressure and heart rate values. For 99 total comparisons of paired measurements, we classified differences into various categories (≤5 mmHg, ≤10 mmHg, and ≤15 mmHg for blood pressure; ≤3, ≤5, and ≤8 beats per minute for heart rate).

RESULTS

In 90 of 99 systolic blood pressure and 89 of 99 diastolic blood pressure comparisons between the devices, measurement differences were within 5 mmHg. In 81 of 99 heart rate comparisons between the devices, measurement differences were within 3 beats per minute. The mean differences between the test and reference standard measurements were 3.27 (SD 2.99) mmHg for systolic blood pressure, 3.59 (SD 4.55) mmHg for diastolic blood pressure, and 2.18 (SD 2.75) beats per minute for heart rate. We also observed that for both systolic and diastolic blood pressure, 31 of 33 participants had at least two of three comparisons between the devices with measurement differences less than 5 mmHg. For heart rate, 28 of 33 patients had at least two of three comparisons between the devices with measurement differences less than 3 beats per minute.

CONCLUSIONS

To our knowledge, this is the first study to show that iHealth Track meets the requirements of the ESH-IP2 in patients with CKD. Therefore, the iHealth Track is suitable for use in renal patients.

Ambulatory blood pressure monitoring over 24 h: A Latin American Society of Hypertension position paper-accessibility, clinical use and cost effectiveness of ABPM in Latin America in year 2020

Accurate office blood pressure measurement remains crucial in the diagnosis and management of hypertension worldwide, including Latin America (LA). Office blood pressure (OBP) measurement is still the leading technique in LA for screening and diagnosis of hypertension, monitoring of treatment, and long-term follow-up. Despite this, due to the increasing awareness of the limitations affecting OBP and to the accumulating evidence on the importance of ambulatory BP monitoring (ABPM), as a complement of OBP in the clinical approach to the hypertensive patient, a progressively greater attention has been paid worldwide to the information on daytime and nighttime BP patterns offered by 24-h ABPM in the diagnostic, prognostic, and therapeutic management of hypertension. In LA countries, most of the Scientific Societies of Hypertension and/or Cardiology have issued guidelines for hypertension care, and most of them include a special section on ABPM. Also, full guidelines on ABPM are available. However, despite the available evidence on the advantages of ABPM for the diagnosis and management of hypertension in LA, availability of ABPM is often restricted to cities with large population, and access to this technology by lower-income patients is sometimes limited by its excessive cost. The authors hope that this document might stimulate health authorities in each LA Country, as well as in other countries in the world, to regulate ABPM access and to widen the range of patients able to access the benefits of this technique.

Arm Dimensions of Patients with Obesity and Their Experiences with Blood Pressure Measurement: An Observational Study

OBJECTIVE

In patients with obesity, it was determined what proportion had an arm slant angle (SA) < 83° and which measure best predicted arm conicity. Patient experience with noninvasive blood pressure measurement was evaluated.

METHODS

Arm SA was calculated from arm measurements. Linear regression determined whether BMI, weight, or right midarm circumference (MAC) best predicted conicity. Patient experiences were evaluated by survey and conventional content analysis of free-text comments.

RESULTS

One hundred participants had a median (interquartile range; range) BMI of 44.1 (39.1-53.1; 31.1-80.8). Thirty-three (33%) had a right arm SA < 83°. Seven (7%) had a right MAC outside the recommended range. BMI, weight, and the right MAC showed low correlation with and explained little of the variation (with age and sex adjustment) in right arm SA (r = -0.29, -0.27, -0.31; P = 0.003, 0.007, 0.002; R² = 0.09, 0.08, 0.10). Forty-two (42%) reported noninvasive blood pressure measurement caused severe pain, and 30 (30%) reported skin damage. Themes identified in free-text responses were "problems with equipment," "feelings and experiences," and "concerns about accuracy."

CONCLUSIONS

Current equipment is inadequate for patients with obesity based on MAC and conicity. Pain and skin damage contributed to negative experiences of these patients.

Accuracy of Vital Signs Measurements by a Smartwatch and a Portable Health Device: Validation Study

Background

New consumer health devices are being developed to easily monitor multiple physiological parameters on a regular basis. Many of these vital sign measurement devices have yet to be formally studied in a clinical setting but have already spread widely throughout the consumer market.

Objective

The aim of this study was to investigate the accuracy and precision of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and oxygen saturation (SpO₂) measurements of 2 novel all-in-one monitoring devices, the BodiMetrics Performance Monitor and the Everlast smartwatch.

Methods

We enrolled 127 patients (>18 years) from the Thomas Jefferson University Hospital Preadmission Testing Center. SBP and HR were measured by both investigational devices. In addition, the Everlast watch was utilized to measure DBP, and the BodiMetrics Performance Monitor was utilized to measure SpO₂. After 5 min of quiet sitting, four hospital-grade standard and three investigational vital sign measurements were taken, with 60 seconds in between each measurement. The reference vital sign measurements were calculated by determining the average of the two standard measurements that bounded each investigational measurement. Using this method, we determined three comparison pairs for each investigational device in each subject. After excluding data from 42 individuals because of excessive variation in sequential standard measurements per prespecified dropping rules, data from 85 subjects were used for final analysis.

Results

Of 85 participants, 36 (42%) were women, and the mean age was 53 (SD 21) years. The accuracy guidelines were only met for the HR measurements in both devices. SBP measurements deviated 16.9 (SD 13.5) mm Hg and 5.3 (SD 4.7) mm Hg from the reference values for the Everlast and BodiMetrics devices, respectively. The mean absolute difference in DBP measurements for the Everlast smartwatch was 8.3 (SD 6.1) mm Hg. The mean absolute difference between BodiMetrics and reference SpO₂ measurements was 3.02%.

Conclusions

Both devices we investigated met accuracy guidelines for HR measurements, but they failed to meet the predefined accuracy guidelines for other vital sign measurements. Continued sale of consumer physiological monitors without prior validation and approval procedures is a public health concern.

Validation of an automated home blood pressure measurement device in oldest-old populations

Despite the wide use of automated devices for the self-measurement of home blood pressure (BP), no evidence is available regarding the accuracy of such devices in oldest-old populations. The aim of this study was to validate the accuracy of the automated oscillometric upper arm-cuff BP-monitoring device according to an international protocol in oldest-old individuals. In 35 participants aged over 85 years old, BP was measured on the same arm sequentially using a mercury sphygmomanometer (by two observers) and an Omron HEM-7080IC. The difference between the test device and observer measurements and associated factors were evaluated according to the International Organization for Standardization (ISO) 81060-2:2013 protocol. A total of 105 pairs (three pairs per participant) of the test device and observer BP measurements were obtained. The mean (±standard deviation: SD) differences in systolic BP (SBP) and diastolic BP (DBP) between the methods were -0.7 ± 7.1 and -1.1 ± 4.5 mmHg, respectively, and those for each participant were -0.7 ± 5.8 mmHg for SBP and -1.1 ± 4.1 mmHg for DBP; the device therefore fulfilled the requirements of the ISO protocol. In the multivariate analysis with the linear mixed model, the difference was associated with the cuff size for SBP and pulse pressure for DBP. The Omron HEM-7080IC passed the ISO requirements for oldest-old individuals aged 85 years or older. This device can be recommended for clinical and self/home use in oldest-old populations.

Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association

The accurate measurement of blood pressure (BP) is essential for the diagnosis and management of hypertension. This article provides an updated American Heart Association scientific statement on BP measurement in humans. In the office setting, many oscillometric devices have been validated that allow accurate BP measurement while reducing human errors associated with the auscultatory approach. Fully automated oscillometric devices capable of taking multiple readings even without an observer being present may provide a more accurate measurement of BP than auscultation. Studies have shown substantial differences in BP when measured outside versus in the office setting. Ambulatory BP monitoring is considered the reference standard for out-of-office BP assessment, with home BP monitoring being an alternative when ambulatory BP monitoring is not available or tolerated. Compared with their counterparts with sustained normotension (ie, nonhypertensive BP levels in and outside the office setting), it is unclear whether adults with white-coat hypertension (ie, hypertensive BP levels in the office but not outside the office) have increased cardiovascular disease risk, whereas those with masked hypertension (ie, hypertensive BP levels outside the office but not in the office) are at substantially increased risk. In addition, high nighttime BP on ambulatory BP monitoring is associated with increased cardiovascular disease risk. Both oscillometric and auscultatory methods are considered acceptable for measuring BP in children and adolescents. Regardless of the method used to measure BP, initial and ongoing training of technicians and healthcare providers and the use of validated and calibrated devices are critical for obtaining accurate BP measurements.

Validation of the single-cuff oscillometric blood pressure monitor InBody BPBIO320 for public use according to the 2010 European Society of Hypertension International Protocol

OBJECTIVE

The aim of this study was to assess the accuracy of the single-cuff oscillometric blood pressure (BP) monitor InBody BPBIO320 developed for self-measurement by adults in public spaces according to the 2010 European Society of Hypertension International Protocol (ESH-IP).

PARTICIPANTS AND METHODS

Adults were recruited to fulfill the ESH-IP requirements. The same-arm sequential BP measurement method was used.

RESULTS

A total of 38 participants were recruited and 33 were included in the analysis. The average difference between test and reference BP measurements was-0.4±5.3 (SD)/-0.5±4.6 mmHg (systolic/diastolic). The number of test-reference BP differences within 5, 10, and 15 mmHg was 73, 91, and 98 for systolic BP and 79, 93, and 99 for diastolic. The number of participants with at least two of their three BP differences within 5 mmHg was 28 for both systolic and diastolic BPs. The number of participants with none of their three BP differences within 5 mmHg was 1 for both systolic and diastolic BPs.

CONCLUSION

The InBody BPBIO320 device fulfilled the requirements of the ESH-IP validation protocol and can be recommended for clinical use in adults.

Validation of the TM-2441 ambulatory blood pressure measurement device according to the ISO 81060-2: 2013 standard

OBJECTIVE

The aim of this study was to validate the TM-2441 ambulatory blood pressure monitoring (ABPM) device using the ISO 81060-2:2013 standard.

PARTICIPANTS AND METHODS

Participants were healthy individuals aged more than 12 years who were recruited from among the outpatients and volunteers of Jichi Medical University (Tochigi, Japan). The same-arm sequence protocol (clinical validation) and the opposite-limb simultaneous method (ambulatory validation) from the ISO 81060-2:2013 standard were used.

RESULTS

One hundred and seven participants were enrolled; 85 participated in the clinical validation and 35 participated in the ambulatory validation (13 participants were included in both validation protocols). The TM-2441 device performed well against the standard in both the clinical and ambulatory validations; the mean and SD values for the differences between device and observed systolic and diastolic blood pressure values in both tests fulfilled criterion 1 and criterion 2 of the standard. The Bland-Altman plots did not show any systematic variation in the error.

CONCLUSION

The TM-2441 ABPM device was accurate and fulfilled all ISO 81060-2:2013 standard requirements for ABPM determination in adults. It is therefore suitable for use for ABPM in adults with hypertension.

Pulse transit time technique for cuffless unobtrusive blood pressure measurement: from theory to algorithm

Cuffless technique holds great promise to measure blood pressure (BP) in an unobtrusive way, improving diagnostics and monitoring of hypertension and its related cardiovascular diseases, and maximizing the independence and participation of individual. Pulse transit time (PTT) has been the most commonly employed techniques for cuffless BP estimation. Many studies have been conducted to explore its feasibility and validate its performance in the clinical settings. However, there is still issues and challenges ahead before its wide application. This review will investigate the understanding and development of the PTT technique in depth, with a focus on the physiological regulation of arterial BP, the relationship between PTT and BP, and the summaries of the PTT-based models for BP estimation.

Out of Office Blood Pressure Measurement in Pregnancy and the Postpartum Period

PURPOSE

Hypertensive disorders of pregnancy are increasing in prevalence and associated with significant maternal and perinatal morbidity and mortality.

RECENT FINDINGS

Increased emphasis has been placed recently on the use of out-of-office (i.e., home and ambulatory) blood pressure (BP) monitoring to diagnose and manage hypertension in the general population. Current guidelines offer limited recommendations on the use of out-of-office BP monitoring during pregnancy and postpartum. This review will discuss the recent literature on BP measurement outside of the office and its use for screening, diagnosis, and treatment in pregnancy and postpartum, and will illuminate areas for future research.

Radial Artery Tonometry to Monitor Blood Pressure and Hemodynamics in Ambulatory Left Ventricular Assist Device Patients in Comparison With Doppler Ultrasound and Transthoracic Echocardiography: A Pilot Study

Noninvasive measurements of blood pressure (BP) and cardiac output (CO) are crucial in the follow-up of continuous-flow left ventricular assist device (CF-LVAD) patients. For our pilot study, we sought to compare BP measurements between a tonometry blood pressure pulse analyzer (BPPA) (DMP-Life, DAEYOMEDI Co., Ltd., Gyeonggi-do, South Korea) and Doppler ultrasound in CF-LVAD patients, as well as to compare the BPPA estimated CO to LVAD calculated blood flow and to the patient's intrinsic CO estimated with transthoracic echocardiography (TTE). Ambulatory CF-LVAD patients (6 HeartMate, 26 HeartMate II), were included. According to TTE findings, patients were then subdivided in two groups: patients with an opening aortic valve (OAV) [n = 21] and those with an intermittent opening aortic valve (IOAV) [n = 11]. We found a very good correlation of systolic BP (SBP) measurements between the two methods, BPPA and Doppler ultrasound (r = 0.87, P < 0.0001). Bland-Altman plots for SBP revealed a low bias of -4.6 mm Hg and SD of ±4.7 mm Hg. In CF-LVAD patients with IOAV, the BPPA-CO had a good correlation with the LVAD-flow (r = 0.78, P < 0.0001), but in OAV patients, there was no correlation. After adding the patient's intrinsic CO, estimated from TTE in patients with OAV to the LVAD-flow, we found a very good correlation between the BPPA-CO and LVAD-flow + TTE-CO (r = 0.81, P = 0.002). Our study demonstrated that compared with the standard clinical method, Doppler ultrasound, the BPPA measured BP noninvasively with good accuracy and precision of agreement. In addition, tonometry BPPA provided further valuable information regarding the CF-LVAD patient's intrinsic CO.

Validation of the professional device for blood pressure measurement Microlife WatchBP Office in adults and children according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization standard

OBJECTIVE

To assess the accuracy of the professional oscillometric blood pressure (BP) monitor Microlife WatchBP Office in adults and children according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060-2:2013 standard.

METHODS

Adults and children (aged 3-12 years) were recruited to fulfil the age, sex, BP and cuff distribution criteria of the ANSI/AAMI/ISO standard using the same-arm sequential BP measurement method. Three cuffs of the test device were used for arm circumferences of 14-22, 22-32 and 32-42 cm.

RESULTS

A total of 115 participants were recruited and 88 were included in the analysis (51 adults and 37 children). For criterion 1, the mean±SD of the differences between the test device and reference BP was -1.0±7.0/-4.7±5.4 mmHg (systolic/diastolic). For criterion 2, the SD of the averaged BP differences between the test device and reference per participant was 5.15/4.77 mmHg (systolic/diastolic).

CONCLUSION

The professional Microlife WatchBP Office BP monitor fulfilled the requirements of the ANSI/AAMI/ISO validation standard for adults and children and can be recommended for clinical use.

Validation of the iHealth ambulatory blood pressure monitor in adults according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization standard

OBJECTIVE

To assess the accuracy of the iHealth oscillometric ambulatory blood pressure (BP) monitor in adults according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060-2:2013 standard.

METHODS

Adults were recruited to fulfil the age, sex, BP and cuff distribution criteria of the ANSI/AAMI/ISO standard using the same-arm sequential BP measurement method. Two cuffs of the test device were used for arm circumferences 22-34 and 30-42 cm.

RESULTS

A total of 100 individuals were recruited and 85 were included in the analysis. For validation criterion 1, the mean±SD of the differences between the test device and reference BP was -0.7±6.0/0.7±4.8 mmHg (systolic/diastolic). For criterion 2, the SD of the averaged BP differences between the test device and reference per participant was 4.72/3.97 mmHg (systolic/diastolic).

CONCLUSION

The iHealth ambulatory BP monitor fulfilled the requirements of the ANSI/AAMI/ISO validation standard in adults and can be recommended for clinical use.