Blood Pressure Monitoring Device Research Articles

Screening for hypertension in adults - the use of tonometric blood pressure monitoring.

Arterial hypertension increases the risk of developing cardiovascular disease. Reliable screening tools for diagnosing hypertension are important to ensure correct risk stratification of subjects. In this study, we aimed to analyse if a wrist-worn device using a tonometric technique for measuring of 24-hour blood pressure could be used to diagnose hypertension and non-dipping. A conventional device using oscillometric measurements was used as golden standard. Secondary aim was to compare the degree of discomfort related to monitoring with the two devices. In 89 subjects with a history of normal blood pressure and naive to ambulatory BP monitoring (ABPM), 24-hour ABPM was measured simultaneously with A&D TM2430 (oscillometric technique) and BPro (tonometric technique). When comparing measurements from the two devices, we found that the tonometric device misclassified 46% of hypertensive subjects and 69% of non-dippers. The tonometric device measured significantly lower systolic 24-hour and daytime blood pressure. The subjects reported less discomfort related to the tonometric than the oscillometric device. Despite less discomfort related to usage of the tonometric device for 24-hour blood pressure monitoring compared to an oscillometric device, misclassification of hypertension and non-dipping makes the tonometric device inappropriate as a screening instrument.

B3X: a novel efficient algorithm for accurate automated auscultatory blood pressure estimation

Objective. The auscultatory technique is still considered the most accurate method for non-invasive blood pressure (NIBP) measurement, although its reliability depends on operator’s skills. Various methods for automated Korotkoff sounds analysis have been proposed for reliable estimation of systolic (SBP) and diastolic (DBP) blood pressures. To this aim, very complex methodologies have been presented, including some based on artificial intelligence (AI). This study proposes a relatively simple methodology, named B3X, to estimate SBP and DBP by processing Korotkoff sounds recordings acquired during an auscultatory NIBP measurement. Approach. The beat-by-beat change in morphology of adjacent Korotkoff sounds is evaluated via their cross-correlation. The time series of the beat-by-beat cross-correlation and its first derivative are analyzed to locate the timings of SBP and DBP values. Extensive tests were performed on a public database of 350 annotated measurements, and the performance was evaluated according to the BHS, AAMI/ANSI, and International Organization for Standardization (ISO) quality standards. Main results. The proposed approach achieved ‘A’ scores for SBP and DBP in the BHS grading system, and passed the quality tests of AAMI/ANSI and ISO standards. The B3X algorithm outperformed two well-established algorithms for oscillometric NIBP measurement in both SBP and DBP estimation. It also outperformed four AI-based algorithms in DBP estimation, while providing comparable performance for SBP, at the cost of a much lower computational burden. The full code of the B3X algorithm is provided in a public repository. Significance. The very good performances ensured by the proposed B3X algorithm, at a low computational cost and without the need for parameter training, support its direct implementation into clinical blood pressure (BP) monitoring devices. The results of this study pave the way for solving/overcoming the trade-off between the accuracy of the auscultatory technique and the objectivity of oscillatory measurements, by bringing an automated auscultatory BP measurement method in clinical practice.

Abstract P323: Going Beyond Spot 30-minute Nocturnal Blood Pressure (bp) Check With The Continuous Nocturnal Bp Monitoring

Background: Ambulatory Blood Pressure Monitoring (ABPM) is useful to determine nocturnal BP. However, the major limitation is the spot-check nature. The main objective of the study is to compare the nocturnal blood pressure (BP) results derived from continuous nocturnal (beat-to-beat) finger cuff BP monitoring device (CNBPM) based on pulse decomposition analysis and from conventional arm cuff-based ABPM. Methods: We prospectively enrolled 17 subjects from the community. Each subject underwent 1 day of standard 24-hour ABPM. On a second day, the subjects underwent continuous BP monitoring at nighttime only. Systolic BPs (BP hereafter) 12 AM - 6 AM constituted nocturnal BP. We compared the maximum nocturnal BP from ABPM with that from CNBPM. For paired comparison, we matched every 30-minute nocturnal BPs by ABPM, with the corresponding 30 min-averaged nocturnal BPs from CNBPM. Using these data points, we also examined nocturnal dipping by both methods. For continuous BP dipping calculation, we used late night and early AM BP recording (outside 12 AM-6 AM window) derived from continuous BP monitoring. Non-dipping was defined by < 10% BP reduction at nighttime. Results: All enrolled subjects recorded both ABPM and CNBPM. Maximum nocturnal BP was lower by ABPM than by CNBPM ( M 71.28, SD 8.65 vs. M 96.11, SD 13.74), p<0.0001). Paired comparison of every 30 min nocturnal BP yielded a lower nocturnal BP by ABPM than CNBPM (113.65 mmHg (18.31) vs. 113.43 (SD 27.32), p = 0.978). The mean absolute dipping was similar between ABPM and CNBPM (13.2% (7) and 9.5 (10.6), p=NS) respectively. Among 8 subjects with normal dipping, 9 subjects were categorized as non-dipping by CNBPM. Among 11 subjects who had normal dipping by ABPM, 6 subjects met non-dipping by ABPM. CNBPM was better tolerated than ABPM according to subjects. Conclusion: This study demonstrates that the clusters of BP variability overnight may be missed by a spot-check nocturnal BP measurement by ABPM. There was bias toward the underestimation of BP by ABPM when compared to CNBPM. Further studies should determine a subset of high-risk patients who may benefit from using CNBPM for accurate nocturnal BP monitoring.

Abstract P369: The Role Of Primary Cilia In The Pathogenesis And Therapy Of Hypertension In Polycystic Kidney Disease.

Primary cilia are sensory organelles, extending from the surface of vascular endothelialcells. Primary cilia dysfunctions have been linked to numerous genetic disorders,including polycystic kidney disease (PKD). Although PKD is characterized by fluid-filledcystic kidneys, cardiovascular complications such as hypertension (HTN) are the leadingcause of death in PKD patients. We demonstrated that primary cilia sense and transmitexternal mechanical stimuli such as fluid shear stress into internal biochemical reactionssuch as the release of nitric oxide (NO). This idea has only been investigated in ECs invitro . However, the importance of the vascular primary cilia in the long-term regulationof BP has not been investigated. NO-induced vasodilation is also produced in response tostimulation of eNOS by muscarinic acetylcholine receptor 3 (AChM3R) activation byacetylcholine (ACh). Using immunofluorescence staining, we generated new andsurprising data showing that AChM3R, and its signaling components, PIP2 are localizedto primary cilia and can modulate cilia function. We hypothesize that primary ciliacontribute to BP regulation in PKD through AChM3R. We showed that both, selective(cevimeline) and non-selective (ACh, CCh) activation of AChM3R led to an increase incilia length and cilia sensory function in terms of p-eNOS expression. We also generatedendothelial-specific ( Tie2Cre and VECre ) AChM3R KO mouse lines, in which AChM3R was deleted from the vascular endothelia. These mice developed high BP, as measured bytail cuff and telemetry blood pressure monitoring devices, associated with attenuated NOproduction and impaired vascular relaxation in response to ACh stimulation. Thesestudies demonstrated the physiological significance of primary cilia-derived NO in thelong-term control of vascular hemodynamics.

Accuracy of oscillometric-based blood pressure monitoring devices: impact of pulse volume, arrhythmia, and respiratory artifact.

An oscillometric waveform (OMW) envelope-based blood pressure (BP) monitoring device is widely used to monitor blood pressure and prevent hypertension and adverse cardiovascular events. At present, all primary care physicians and clinicians widely recommend oscillometric-based BP devices. The consumer selects the device based on their own decision, without knowing whether the device is validated or not, resulting in over- or under-treatment of hypertension. It is imperative that each device must comply with international protocols. In this study, we have investigated the accuracy of inflation and deflation-based oscillometric BP monitoring devices in the case of sinus rhythm (SR). Since different health conditions of the patient affect the oscillometric waveform, which can affect the device's accuracy, in such cases, many BP monitors are skeptical of succeeding in the norms of international protocols. Therefore, this study also aims to calculate the accuracy of these devices in various health conditions and measure the effect of pulse volume, arrhythmia, and respiratory artifact on it using a non-invasive blood pressure (NIBP) simulator. We found that the oscillometric BP devices failed to measure the correct blood pressure in several clinical conditions.

Evaluation of stroke volume estimation during orthostatic stress: the utility of Modelflow.

Advanced blood pressure monitoring devices contain algorithms that permit estimation of stroke volume (SV). Modelflow (Finapres Medical Systems) is one common method to non-invasively estimate beat-to-beat SV. However, Modelflow accuracy during profound reductions in SV is unclear. We aimed to compare SV estimation by Modelflow and echocardiography, at rest and during orthostatic challenge. We tested 13 individuals (age 24 ± 2 years; 7 female) using combined head-up tilt and graded lower body negative pressure, continued until presyncope. SV was derived by both Modelflow and echocardiography on multiple occasions while supine, during orthostatic stress, and at presyncope. SV index (SVI) was determined by normalising SV for body surface area. Bias and limits of agreement were determined using Bland-Altman analyses. Two one-sided tests (TOST) examined equivalency. Across all timepoints, Modelflow estimates of SV (73.2 ± 1.6 ml) were strongly correlated with echocardiography estimates (66.1 ± 1.3 ml) (r = 0.56, P < 0.001) with a bias of +7.1 ± 21.1 ml. Bias across all timepoints was further improved when SV was indexed (+3.6 ± 12.0 ml.m -2 ). Likewise, when assessing responses relative to baseline, Modelflow estimates of SV (-23.4 ± 1.4%) were strongly correlated with echocardiography estimates (-19.2 ± 1.3%) (r = 0.76, P < 0.001), with minimal bias (-4.2 ± 13.1%). TOST testing revealed equivalency to within 15% of the clinical standard for SV and SVI, both expressed as absolute values and relative to baseline. Modelflow can be used to track changes in SV during profound orthostatic stress, with accuracy enhanced with correction relative to baseline values or body size. These data support the use of Modelflow estimates of SV for autonomic function testing.

Reply to 'Inadequate study designs for the evaluation of blood pressure monitoring devices and their potential misleading conclusions'.

Reply to 'Inadequate study designs for the evaluation of blood pressure monitoring devices and their potential misleading conclusions'.

Inadequate study designs for the evaluation of blood pressure monitoring devices and their potential misleading conclusions.

Inadequate study designs for the evaluation of blood pressure monitoring devices and their potential misleading conclusions.

PPG Signals-Based Blood-Pressure Estimation Using Grid Search in Hyperparameter Optimization of CNN-LSTM.

Researchers commonly use continuous noninvasive blood-pressure measurement (cNIBP) based on photoplethysmography (PPG) signals to monitor blood pressure conveniently. However, the performance of the system still needs to be improved. Accuracy and precision in blood-pressure measurements are critical factors in diagnosing and managing patients' health conditions. Therefore, we propose a convolutional long short-term memory neural network (CNN-LSTM) with grid search ability, which provides a robust blood-pressure estimation system by extracting meaningful information from PPG signals and reducing the complexity of hyperparameter optimization in the proposed model. The multiparameter intelligent monitoring for intensive care III (MIMIC III) dataset obtained PPG and arterial-blood-pressure (ABP) signals. We obtained 75,226 signal segments, with 60,180 signals allocated for training data, 12,030 signals allocated for the validation set, and 15,045 signals allocated for the test data. During training, we applied five-fold cross-validation with a grid-search method to select the best model and determine the optimal hyperparameter settings. The optimized configuration of the CNN-LSTM layers consisted of five convolutional layers, one long short-term memory (LSTM) layer, and two fully connected layers for blood-pressure estimation. This study successfully achieved good accuracy in assessing both systolic blood pressure (SBP) and diastolic blood pressure (DBP) by calculating the standard deviation (SD) and the mean absolute error (MAE), resulting in values of 7.89 ± 3.79 and 5.34 ± 2.89 mmHg, respectively. The optimal configuration of the CNN-LSTM provided satisfactory performance according to the standards set by the British Hypertension Society (BHS), the Association for the Advancement of Medical Instrumentation (AAMI), and the Institute of Electrical and Electronics Engineers (IEEE) for blood-pressure monitoring devices.

Patent landscape review of non-invasive medical sensors for continuous monitoring of blood pressure and their validation in critical care practice.

Continuous non-invasive monitoring of blood pressure is one of the main factors in ensuring the safety of the patient's condition in anesthesiology, intensive care, surgery, and other areas of medicine. The purpose of this work was to analyze the current patent situation and identify directions and trends in the application of non-invasive medical sensors for continuous blood pressure monitoring, with a focus on clinical experience in critical care and validation thereof. The research results reflect data collected up to September 30, 2022. Patent databases, Google Scholar, the Lens database, Pubmed, Scopus databases were used to search for patent and clinical information. An analysis of the patent landscape indicates a significant increase in interest in the development of non-invasive devices for continuous blood pressure monitoring and their implementation in medical practice, especially in the last 10 years. The key players in the intellectual property market are the following companies: Cnsystems Medizintechnik; Sotera Wireless INC; Tensys Medical INC; Healthstats Int Pte LTD; Edwards Lifesciences Corp, among others. Systematization of data from validation and clinical studies in critical care practice on patients with various pathological conditions and ages, including children and newborns, revealed that a number of non-invasive medical sensor technologies are quite accurate and comparable to the "gold standard" continuous invasive blood pressure monitoring. They are approved by the FDA for medical applications and certified according to ISO 81060-2, ISO 81060-3, and ISO/TS 81060-5. Unregistered and uncertified medical sensors require further clinical trials. Non-invasive medical sensors for continuous blood pressure monitoring do not replace, but complement, existing methods of regular blood pressure measurement, and it is expected to see more of these technologies broadly implemented in the practice in the near future.

Cuff Size Variation Across Manufacturers of Home Blood Pressure Devices: A Current Patient Dilemma.

The American Heart Association (AHA) recommends cuff sizes of blood pressure (BP) monitoring devices based on patient arm circumference, which is critical for accurate BP measurement. This study aimed to assess cuff size variation across validated BP devices and to examine the degree of alignment with the AHA recommendations. Data on home BP devices were obtained from the US BP Validated Device Listing website and listed cuff sizes were compared against AHA recommendations: small adult (22-26 cm), adult (27-34 cm), large (35-44 cm), and extra-large (XL) (45-52 cm). There were 42 home validated BP devices from 13 manufacturers, and none offered cuffs that were aligned with the AHA recommendations. Over half of the devices (22, 52.4%) were compatible with only a broad-range cuff, generally excluding arm sizes larger than 44 cm. Only 5 devices from 4 manufacturers offered a cuff labeled "XL," and of these, only 3 devices had sizes that covered the AHA XL range. Terminology lacked consistency with manufacturers using: different labels to describe the same-sized cuffs (e.g., 22-42 cm was labeled "integrated," "standard," "adult," "large," and "wide range"); the same labels to describe differently sized cuffs (e.g., cuffs labeled "large" were sized 22-42 cm, 32-38 cm, 32-42 cm, 36-45 cm). Manufacturers of US home BP devices employ inconsistent terminologies and thresholds for cuff sizes, and sizes were not aligned with AHA recommendations. This lack of standardization could pose challenges for clinicians and patients attempting to select a properly sized cuff to support hypertension diagnosis and management.

A Hemodynamic Pulse Wave Simulator Designed for Calibration of Local Pulse Wave Velocities Measurement for Cuffless Techniques.

Devices for cuffless blood pressure (BP) measurement have become increasingly widespread in recent years. Non-invasive continuous BP monitor (BPM) devices can diagnose potential hypertensive patients at an early stage; however, these cuffless BPMs require more reliable pulse wave simulation equipment and verification methods. Therefore, we propose a device to simulate human pulse wave signals that can test the accuracy of cuffless BPM devices using pulse wave velocity (PWV). We design and develop a simulator capable of simulating human pulse waves comprising an electromechanical system to simulate the circulatory system and an arm model-embedded arterial phantom. These parts form a pulse wave simulator with hemodynamic characteristics. We use a cuffless device for measuring local PWV as the device under test to measure the PWV of the pulse wave simulator. We then use a hemodynamic model to fit the cuffless BPM and pulse wave simulator results; this model can rapidly calibrate the cuffless BPM's hemodynamic measurement performance. We first used multiple linear regression (MLR) to generate a cuffless BPM calibration model and then investigated differences between the measured PWV with and without MLR model calibration. The mean absolute error of the studied cuffless BPM without the MLR model is 0.77 m/s, which improves to 0.06 m/s when using the model for calibration. The measurement error of the cuffless BPM at BPs of 100-180 mmHg is 1.7-5.99 mmHg before calibration, which decreases to 0.14-0.48 mmHg after calibration. This study proposes a design of a pulse wave simulator based on hemodynamic characteristics and provides a standard performance verification method for cuffless BPMs that requires only MLR modeling on the cuffless BPM and pulse wave simulator. The pulse wave simulator proposed in this study can be used to quantitively assess the performance of cuffless BPMs. The proposed pulse wave simulator is suitable for mass production for the verification of cuffless BPMs. As cuffless BPMs become increasingly widespread, this study can provide performance testing standards for cuffless devices.

DIFFERENTIAL DETERMINANTS OF AMBULATORY VS. HOME MORNING BLOOD PRESSURE MEASURED BY A SINGLE MULTISENSOR BLOOD PRESSURE MONITORING DEVICE: THE HI-JAMP STUDY BASELINE DATA

Objective: Out-of-office blood pressure (BP) monitoring using ambulatory BP (ABP) monitoring (ABPM) and home BP (HBP) monitoring (HBPM) is recommended for hypertension management. However, BP level measured by ABPM and HBPM may not be consistent even when evaluated the same time-window, morning. This study investigated the determinants of the difference between ABP and HBP in the morning time measured by a multisensor BP monitoring device equipped with a high-sensitivity actigraph and a thermometer. Design and method: Medicated hypertension patients enrolled in the Home-Activity ICT-based Japan Ambulatory Blood Pressure Monitoring Prospective (HI-JAMP) Study consecutively underwent office BP monitoring, 24-h ABPM (with 30-min intervals), and 5-day HBPM (twice each morning and evening) using the same multisensor BP monitoring device (TM-2441; A&amp;D Company, Tokyo). Morning ABP (average of 4 readings within 2-h after waking) and morning HBP (average of HBP readings measured in the morning over a HBPM period) were compared. In addition, this device recorded the wearer's fine-scale physical movement during a 24-h ABPM period and stored temperature data at the time of each BP measurement. Hourly averages of physical activity and temperatures at the time of HBPM (i.e., room temperature) were used for the analysis. Results: Among 2322 patients (males 53.2%, 69.2±11.5 years, average office systolic BP [SBP] 132.8±18.8 mmHg), morning home SBP was 2.4 mmHg higher than morning ambulatory SBP with standard deviation of 15.9 mmHg (ABP &lt; HBP). In a multivariable analysis including conventional risk factors, older age and larger number of antihypertensive agents were significantly associated with [HBP &gt; ABP], while history of cardiovascular disease (CVD) was significantly associated with [ABP &gt; HBP]. In the analysis additionally including physical activity in the morning and room temperature at the morning HBP measurement, higher activity level was significantly contributed to [ABP &gt; HBP] and lower room temperature was significantly contributed to [HBP &gt; ABP]. Conclusions: In treated hypertensive patients, HBPM is recommended especially if the patient is older, taking multiple antihypertensive agents, or living in an environment with lower room temperatures in the winter, while ABPM is recommended if the patient has a history of CVD.

Nighttime home blood pressure lowering effect of esaxerenone in patients with uncontrolled nocturnal hypertension: the EARLY-NH study

There is limited evidence on the blood pressure (BP)-lowering effect of esaxerenone on home BP, including nighttime BP. Using two newly developed nocturnal home BP monitoring devices (brachial and wrist), this multicenter, open-label, prospective study investigated the nighttime home BP-lowering effect of esaxerenone in patients with uncontrolled nocturnal hypertension being treated with an angiotensin receptor blocker (ARB) or calcium-channel blocker (CCB). In total, 101 patients were enrolled. During the 12-week study period, change in nighttime home systolic/diastolic BP from baseline to end of treatment measured by the brachial device was −12.9/−5.4 mmHg in the total population and −16.2/−6.6 and −10.0/−4.4 mmHg in the ARB and CCB subcohorts, respectively (all p < 0.001). For the wrist device, the change was −11.7/−5.4 mmHg in the total population and −14.6/−6.2 and −8.3/−4.5 mmHg in each subcohort, respectively (all p < 0.001). Similar significant reductions were shown for morning and bedtime home BP and office BP. Urinary albumin-to-creatinine ratio, N-terminal pro-brain natriuretic peptide, and cardio-ankle vascular index improved in the total population and each subcohort. Incidences of treatment-emergent adverse events (TEAEs) and drug-related TEAEs were 38.6% and 16.8%, respectively; most were mild or moderate. The most frequent drug-related TEAEs were associated with serum potassium elevation (hyperkalemia, 9.9%; blood potassium increased, 3.0%); however, no new safety concerns were raised. Esaxerenone was effective in lowering nighttime home BP as well as morning and bedtime home BP and office BP, safe, and showed organ-protective effects in patients with uncontrolled nocturnal hypertension. Caution is warranted regarding elevated serum potassium levels.This study investigated the effect of esaxerenone on nighttime home BP and organ damage (UACR and NT-proBNP) in patients with uncontrolled nocturnal hypertension despite treatment with an ARB or CCB. Our results show that safe 24-h BP control and organ protection are possible with esaxerenone.

Clinical Validation of Wearable Piezoelectric Blood Pressure Sensor for Continuous Health Monitoring.

Wearable blood pressure sensors have recently attracted attention as healthcare devices for continuous non-invasive arterial pressure (CNAP) monitoring. However, the accuracy of wearable blood pressure (BP) monitoring devices has been controversial due to the low signal quality of sensors, the absence of an accurate transfer function to convert the sensor signals into BP values, and the lack of clinical validation regarding measurement precision. Here, we report a wearable piezoelectric blood pressure sensor (WPBPS), which achieved a high normalized sensitivity (0.062 kPa-1 ), fast response time (23ms) for CNAP monitoring. The transfer function of a linear regression model was designed, offering a simple solution to convert the flexible piezoelectric sensor signals into BP values. In order to verify the measurement accuracy of WPBPS, clinical trials were performed on 35 subjects aged from 20s to 80s after screening. The mean difference between the WPBPS and a commercial sphygmomanometer of 175 BP data pairs was -0.89 ± 6.19mmHg and -0.32 ± 5.28mmHg for systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. By building a WPBPS-embedded wristwatch, we demonstrated the potentially promising use of a convenient, portable continuous BP monitoring system for cardiovascular disease diagnosis in this study. This article is protected by copyright. All rights reserved.

Continuous Non-Invasive Blood Pressure Measurement Using 60 GHz-Radar-A Feasibility Study.

Blood pressure monitoring is of paramount importance in the assessment of a human's cardiovascular health. The state-of-the-art method remains the usage of an upper-arm cuff sphygmomanometer. However, this device suffers from severe limitations-it only provides a static blood pressure value pair, is incapable of capturing blood pressure variations over time, is inaccurate, and causes discomfort upon use. This work presents a radar-based approach that utilizes the movement of the skin due to artery pulsation to extract pressure waves. From those waves, a set of 21 features was collected and used-together with the calibration parameters of age, gender, height, and weight-as input for a neural network-based regression model. After collecting data from 55 subjects from radar and a blood pressure reference device, we trained 126 networks to analyze the developed approach's predictive power. As a result, a very shallow network with just two hidden layers produced a systolic error of 9.2±8.3 mmHg (mean error ± standard deviation) and a diastolic error of 7.7±5.7 mmHg. While the trained model did not reach the requirements of the AAMI and BHS blood pressure measuring standards, optimizing network performance was not the goal of the proposed work. Still, the approach has displayed great potential in capturing blood pressure variation with the proposed features. The presented approach therefore shows great potential to be incorporated into wearable devices for continuous blood pressure monitoring for home use or screening applications, after improving this approach even further.

Method-comparison study between a watch-like sensor and a cuff-based device for 24-h ambulatory blood pressure monitoring

The use of 24-h ambulatory blood pressure monitoring (ABPM) has been continuously increasing over the last decades. However, cuff-based devices may cause discomfort, particularly at night, leading to potentially non-representative blood pressure (BP) values. We investigated the feasibility of a cuff-less BP monitoring solution in 67 subjects undergoing conventional 24-h ABPM. A watch-like optical sensor was attached at the upper arm or wrist at the contralateral side of the cuff. Systolic (SBP) and diastolic BP (DBP) values were estimated from the measured optical signals by pulse wave analysis. Average 24-h, daytime and nighttime BP values were compared between the conventional monitor and the cuff-less sensor. The differences between both methods—expressed as mean ± standard deviation (95% limits of agreement)—were of − 1.8 ± 6.2 mmHg (− 13.9, 10.3) on SBP and − 2.3 ± 5.4 mmHg (− 13.0, 8.3) on DBP for 24-h averages, of − 1.5 ± 6.6 mmHg (− 14.4, 11.4) on SBP and − 1.8 ± 5.9 mmHg (− 13.4, 9.9) on DBP for daytime averages, and of 0.4 ± 7.5 mmHg (− 14.4, 15.1) on SBP and − 1.3 ± 6.8 mmHg (− 14.7, 12.0) on DBP for nighttime averages. These results encouragingly suggest that cuff-less 24-h ABPM may soon become a clinical possibility.

53. Clinical Uses of Cuffless Blood Pressure Monitoring Devices Using Photoplethysmography as A Promising Ambulatory Telemonitoring Tool: A Systematic Review and Meta-Analysis

Introduction: As check-ups in healthcare facilities are much arduous during the pandemic including blood pressure (BP) control, an alternative is urgently needed to replace the use of disturbing cuff-based office and ambulatory BP monitoring (BPM) devices. With the advancement of telemedicine, real-time checking and reporting of blood pressure may be potentially achieved using photoplethysmography (PPG) technology in cuffless devices. Therefore, this study evaluated the accuracy of these devices compared to the cuff-based BPM devices. Methods: This systematic review and meta-analysis was conducted based on the PRISMA 2020 guideline through multiple databases using Rayyan according to the prearranged inclusion and exclusion criteria, yielding six clinical studies to be included in the final review and analysis. Results: Overall fixed-effect meta-analysis of all studies (total of 319 subjects) presented small differences between cuffless and cuff-based devices, showing promising accuracy according to the current medical instrumentation guideline both in measuring systolic BP (SMD: 0.23 mmHg [95% CI: 0.07–0.39], p = 0.004; I2 = 0%, p = 0.55) and diastolic BP (SMD: 0.27 mmHg [95% CI: 0.11–0.43], p = 0.0007; I2 = 39%, p = 0.14). Discussion: PPG itself is a noninvasive technology, consisting of an infrared-emitting light source and a photodetector to measure the blood-reflected light intensity. Despite its ease in equipment, it measures BP accurately without being influenced by various positions and activities. Moreover, the data can be accessed real-time by both users and healthcare providers. Conclusion: In summary, cuffless PPG BPM devices have the potential in becoming a telemonitoring device for ambulatory patients for its accuracy. Its presence may be the answer to current restriction towards healthcare access during the COVID-19 pandemic. Therefore, in order to further confirm our findings, more clinical studies with various settings are encouraged to be held.

Blood pressure estimation and its recalibration assessment using wrist cuff blood pressure monitor.

The rapid evolution of wearable technology in healthcare sectors has created the opportunity for people to measure their blood pressure (BP) using a smartwatch at any time during their daily activities. Several commercially-available wearable devices have recently been equipped with a BP monitoring feature. However, concerns about recalibration remain. Pulse transit time (PTT)-based estimation is required for initial calibration, followed by periodic recalibration. Recalibration using arm-cuff BP monitors is not practical during everyday activities. In this study, we investigated recalibration using PTT-based BP monitoring aided by a deep neural network (DNN) and validated the performance achieved with more practical wrist-cuff BP monitors. The PTT-based prediction produced a mean absolute error (MAE) of 4.746 ± 1.529 mmHg for systolic blood pressure (SBP) and 3.448 ± 0.608 mmHg for diastolic blood pressure (DBP) when tested with an arm-cuff monitor employing recalibration. Recalibration clearly improved the performance of both DNN and conventional linear regression approaches. We established that the periodic recalibration performed by a wrist-worn BP monitor could be as accurate as that obtained with an arm-worn monitor, confirming the suitability of wrist-worn devices for everyday use. This is the first study to establish the potential of wrist-cuff BP monitors as a means to calibrate BP monitoring devices that can reliably substitute for arm-cuff BP monitors. With the use of wrist-cuff BP monitoring devices, continuous BP estimation, as well as frequent calibrations to ensure accurate BP monitoring, are now feasible.

An Ultra‐Sensitive Flexible Resistive Sensor with Double Strain Layer and Crack Inspired by the Physical Structure of Human Epidermis: Design, Fabrication, and Cuffless Blood Pressure Monitoring Application

AbstractThe cuffless blood pressure (BP) monitoring device has attracted much attention because of its comfortable and real‐time monitoring. Inspired by the physical structure of the human epidermis, an ultra‐sensitive flexible resistive sensor with a double strain layer and crack structure is prepared by screen printing in this study. The strain material of the sensor is mainly prepared by blending Poly(3,4‐ethylenedioxythiophene) :poly(styrenesulfonate) (PEDOT:PSS) with waterborne polyurethane and reduced graphene oxide. The sensor exhibits a high gauge factor (GF, ≈1682), fast response (≈48 ms), and long‐term stability (&gt; 2000 cycles) at low strain (≈0–5%). The sensor is placed on the human radial artery and can accurately measure the pulse wave. The features of the pulse wave are automatically extracted using a convolutional neural network. Then the features are corrected using a long short‐term memory neural network, and the current BP value is predicted using a fully connected network layer. The BP result meets the A‐level standards of the Association for the Advancement of Medical Instrumentation and the British Hypertension Society. This study provides an efficient device and method for continuous and non‐invasive BP monitoring.