Cuffless Device Research Articles

Wearable cuffless blood pressure monitoring devices: a commentary.

Hypertension is a growing public challenge as a leading risk factor for cardiovascular disease and all-cause mortality. Reducing overall cardiovascular risk through early screening, initiation of treatment and ongoing monitoring remains a priority in the comprehensive management of hypertension and its complications. Community nurses are ideally positioned to play a crucial role in the early detection of hypertension and providing support for its management. Wearable cuffless devices have the potential for continuous remote blood pressure monitoring. However, there is not enough literature on the validity and usability of wearable cuffless blood pressure devices to justify their use in clinical practice. This commentary critically appraises a systematic review designed to assess the validity, features and clinical usability of wearable cuffless devices, and expands on its findings and their relevance to community nursing and future research.

A comparative study of ProRithm and standard monitoring techniques for non-invasive blood pressure measurement using photoplethysmography and electrocardiography signals through artificial intelligence/machine learning methods

Background: Multi-parameter monitoring devices are essential for providing real-time patient data, which is crucial for effective healthcare interventions. This clinical trial evaluated the accuracy of the ProRithm beat-to-beat cuffless device for arterial blood pressure monitoring, comparing it with a standard sphygmomanometer. Methods: This observational study included 30 subjects aged 18 and above. Systolic and diastolic blood pressure measurements from both the ProRithm device and the Philips Monitor were compared using statistical analysis. Results: The analysis revealed no statistically significant differences between the ProRithm device and the manual method. In comparison with manual measurements using a sphygmomanometer, the mean systolic blood pressure was 131.2 mmHg with ProRithm it was 129.3 mmHg. Similarly, with the manual method, while the mean diastolic blood pressure was 76.2 mmHg and with ProRithm it was 75.9 mmHg. Conclusions: This study indicates that portable, small-sized devices like ProRithm, which facilitate remote monitoring, are effective for real-time blood pressure assessment in clinical settings.

COMPARISON OF OFFICE-BASED BLOOD PRESSURE TO DAYTIME CUFFLESS BLOOD PRESSURE IN A POPULATION-BASED STUDY

Objective: The latest ESH 2023 guidelines still recommend the use of office blood pressure (BP) measurement for the diagnosis and the follow-up of arterial hypertension. Although cuffless (BP) devices are attractive for patients due their practicality and easy to use, they are not yet recommended by international guidelines. The aim of this project was to test the diagnostic performance of a cuffless device in the adult Swiss population. Design and method: This was a multicentric sub-study nested within a nationwide population-based survey on dietary salt intake in Switzerland. Blood pressure was measured 5 times with a validated oscillometric device (Omron HEM-907) on two separate visits according to a standardized protocol. Cuffless blood pressure using the Aktiia® bracelet was measured intermittently over 24 hours in between visits. The device was calibrated on the first visit using an independent oscillometric device. The average of the last four office BP at each visit was compared to the daytime average BP from the cuffless device with a Bland-Altman plot. Results: Of the 863 individuals included in the study, 511 (46% women, age: 48.6±15.8 years) had their BP taken with both devices. The median number of BP measurements with the cuffless device was 46(IQR 28-90)). Bland and Altman analysis revealed a difference of 0.015 (CI -0.734 to 0.763) in systolic BP and of 0.380 (CI -0.216 to 0.975) in diastolic BP (Figure 1). The agreement for the diagnosis of hypertension was 92.4% with a kappa of 0.61±0.04 for systolic BP and 94.7% with a kappa of 0.50±0.04. Conclusions: In this adult population-based study, the accuracy and the diagnostic performance of a cuffless device were promising. The differences may be secondary to either accuracy or to white coat/masked effect reflecting the different environments of BP measures.

EVALUATION OF A PROTOTYPE CUFFLESS MULTI-SENSOR DEVICE TO TRACK BLOOD PRESSURE CHANGES

Objective: Accurate measurements are essential if cuffless blood pressure (BP) devices are to be used in hypertension care. The aim of the present study was to evaluate the ability of a prototype cuffless device (XXXXX) to track changes in BP compared to a non-invasive, continuous BP monitor (reference BP; Human NIBP Nano system, ADInstruments, Dunedin, New Zealand) in an experimental laboratory set up. Design and method: After ethical approval, three external techniques (Figure 1) to induce BP changes via different physiological mechanisms, were applied in 23 healthy subjects. Continuous data from the prototype cuffless device on the upper arm was obtained simultaneously with reference BP measurements. The cuffless device measures skin temperature, 3D acceleration, 3D angular velocity and photoplethysmography. Data from 16 of the participants were used to train a machine learning model, which was then used to estimate BP (15-second resolution) on data from 7 other participants. The cuffless BP device was calibrated once using brachial cuff BP measurement (WatchBP O3, Microlife, Cambridge, United Kingdom). The present study provides preliminary results from a larger on-going study designed to evaluate performance of the cuffless device according to ISO 81060-3:2022 standard. Results: A timeseries plot displaying BP measurements from the cuffless and the reference device is displayed in Figure 2. The mean error (± corrected standard deviation of error) was 2.4 (± 7.9) mmHg for systolic blood pressure (SBP) and 1.7 (± 7.4) mmHg for diastolic blood pressure (DBP) for the accuracy requirement. The corresponding errors for stability requirements were 1.9 (± 8.1) and 1.9 (± 6.0) mmHg for SBP and DBP. Conclusions: The present study demonstrated that the prototype cuffless BP device could track BP changes with high accuracy in healthy subjects in a laboratory setting. The cuffless device fulfilled the acceptance criteria (± 6 (± 10) mmHg) for the accuracy and stability requirements from the ISO 81060-3:2022 standard. Further research is necessary to determine accuracy of the prototype cuffless BP device during real-life conditions as described in the 2023 ESH recommendations for the validation of cuffless devices.

Ability of a 24-h ambulatory cuffless blood pressure monitoring device to track blood pressure changes in clinical practice.

There is an increasing number of cuffless blood pressure (BP) measurement (BPM) devices. Despite promising results when comparing single measurements, the ability of these devices to track changes in BP levels over 24 h related to an initial calibration BP (CalibBP) is unknown. Our aim was to analyse this ability in a cuffless device using pulse transit time. We prospectively enrolled 166 participants for simultaneously performed cuffless (Somnotouch-NIBP) and cuff-based (Spacelabs 90217A/IEM Mobil-O-graph) 24 h BPM. As CalibBP for the cuffless device, first cuff-based BP was used. As surrogate for changes in BP levels after the CalibBP, we used the difference between the CalibBP and mean 24 h, awake and asleep BP measured by the two devices. In addition, we analysed the relationship between the difference of the CalibBP and the cuff-based BPM versus the difference between the cuff-based and the cuffless BPM devices. Mean(SD) difference between the CalibBP and mean 24hBP by the cuff-based or cuffless BP device were 7.4 (13.2) versus 1.8 (8.3) mmHg for systolic ( P < 0.0001) and 6.6 (6.8) versus 1.6 (5.8) mmHg for diastolic ( P < 0.0001). A near linear relationship was seen among the difference between the CalibBP and the cuff-based BPM values and the difference between the cuff-based and cuffless BPM device. Our data indicate a lower ability of the cuffless BPM device to track changes of BP levels after CalibBP. In addition, cuffless device accuracy was associated with the changes in BP levels after the initial CalibBP - the larger the BP level change, the larger the difference between the devices. https://www.clinicaltrials.gov ; Unique identifier: NCT03054688; NCT03975582.

Performance of wearable watch-type home blood pressure measurement devices in a real-world clinical sample.

Independent testing of home blood pressure (BP) measurement (HBPM) devices is often lacking, particularly among older and multi-morbid patients. We studied the Bpro G2 (using tonometry), Omron HeartGuide (using occlusive oscillometric technology), and Heartisans (using photoplethysmography) wrist watch HBPM devicesagainst a gold standard brachial sphygmomanometer. To test device performance, we used the ISO81060-2 protocol (though this protocol cannot formally validate cuffless devices). We also used linear mixed models to compare adjusted longitudinal BP measurements between devices. Finally, as a surrogate for usability, we recorded instances of device failure where no BP measurement was returned. We enrolled 128 participants (median [Q1-Q3] age 53 [40-65] years, 51% male, 46% on antihypertensive drugs), of whom 100 were suitable for the primaryanalysis. All three devices had mean BP values within 5mmHg of sphygmomanometry. However, due to insufficient reliability (e.g., wider than accepted standard deviations of mean BP), none of the three devices passed all criteria required by the ISO81060-2 protocol. In adjusted longitudinal analyses, the Omron device also systematically underestimated systolic and diastolic BP (-8.46mmHg; 95% CI 6.07, 10.86; p < 0.001; and -2.53mmHg; 95% CI -4.03, -1.03; p = 0.001; respectively). Nevertheless, compared to the Omron device, BPro and Heartisans devices had increased odds of failure (BPro: odds ratio [OR] 5.24; p < 0.0001; Heartisans: OR 5.61; p < 0.001). While we could not formally validate the cuffless devices, our results show that wearable technologies will require improvements to offer reliable BP assessment. This study also highlights the need for validation protocols specifically designed for cuffless BP measurement technologies.

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.

Current and Developing Technologies for BP Monitoring.

To discuss new and emerging technologies for blood pressure measurement and monitoring, including the limitations of current blood pressure measurement techniques, hopes for new device technologies, and the current barriers impeding change in this space. A number of new cuffless devices are being developed and poised to emerge on the marketplace in coming years. There are several different types of technologies and sensors currently under study. New guidelines for validation of cuffless blood pressure devices have recently been developed in anticipation of this change. The current standards for blood pressure device validation are specific to cuff-based technology and are insufficient for validating devices with cuffless-based technologies. In anticipation of a number of new cuffless technologies coming to market in the coming years, three sets of standards have been developed and published in recent years to address this gap.

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.

Effect of Cuff Inflation on Blood Pressure, Arousals, Sleep Efficiency, and Desaturations: Sub-Analysis of the VAST Pilot Study.

The influence of cuff inflations on night-time measurements during 24 h ambulatory blood pressure (BP) measurements is unknown. We investigated the potential effect of cuff inflations on sleep parameters using measurements taken simultaneously with a cuffless device using pulse-transit-time (PTT). On the first day of measurement, standard cuff-based 24 h BP and cuffless measurements were simultaneously performed on the right and left arms (CUFF/PTT-D). In this experiment, 1-2 days after the first measurement, the cuffless device was worn alone (PTT-D). Only data from the cuffless device were analyzed. The following mean sleep parameters were analyzed: mean systolic and diastolic BP, arousals, sleep efficiency, total arousals, arousal per hour, and desaturations. In total, 21 individuals were prospectively enrolled. The mean (SD) age was 47 (±15) years, and 57% were female. The mean systolic asleep BP during CUFF/PTT-D and during PTT-D were 131 (±21) and 131 (±26) mmHg, respectively. The mean diastolic asleep BP values during CUFF/PTT-D and during PTT-D were 80 (±14) and 84 (±14) mmHg, respectively (p = 0.860, p = 0.100, respectively). Systolic and diastolic asleep mean difference was 0.1 (±18.0) and -3.6 (±9.8) mmHg, respectively. There were significantly more total arousals during PTT-D (p = 0.042). There were no significant differences seen in sleep efficiency (p = 0.339) or desaturations (p = 0.896) between the two measurement periods. We could not show any significant impact from cuff inflations during sleep, as documented by PTT-D measurements.

Abstract P334: Comparing A Cuffless Device With Traditional Home Blood Pressure Monitoring In A Remote Hypertension Management Program: Primary Results Of The COOL-BP Study

Background: Innovative BP measurement technology with cuffless devices has the potential to enhance HTN control, especially with remote HTN management. Methods: Patients with uncontrolled BP at Mass General Brigham were managed by navigators and pharmacists in a digital remote HTN management program, based on home BP monitoring (HBPM) with digitally-connected arm cuffs. A subset was enrolled into the 6-month COntinual vs OccasionaL (COOL-BP) study, testing a wrist cuffless device (Aktiia SA, Switzerland). Asynchronous daytime weekly BP averages from both modalities were compared, including all readings from the cuffless device, and guideline-directed twice daily readings from HBPM. Of 38 patients who measured their BP with both devices, 25 collected at least one overlapping week of BPs with each device, with a minimum of 12 valid daytime readings over at least 3 days per week. Results: The scatter plots (Figure, top) showed moderate to strong correlation between 72 weekly average daytime BPs by HBPM and the cuffless device (r=0.57 for SBP; r=0.64 for DBP). The difference plots (Figure, bottom) showed that cuffless SBP was higher than HBPM (4.9±11.3 mmHg, p=0.01), while DBP was lower (-4.2±7.2 mmHg; p=0.003). Importantly, cuffless BPs were non-simultaneous with HBPM, included measurements in different body positions, and were much more numerous, which could help explain the differences between BP averages. Conclusion: Daytime weekly average home BPs with continual monitoring using a cuffless wrist device were comparable to those measured by traditional HBPM. These findings encourage exploring the use of continual cuffless monitoring for the remote management of HTN.

Abstract P114: Patient Preferences And Experiences With Cuffless Wrist Versus Upper Arm Cuff Blood Pressure Measurements In The CO ntinual Vs. O ccasiona L B lood P ressure Monitoring (COOL-BP) Study

Background: Cuffless BP devices can potentially enhance hypertension management and remote BP monitoring. Patient experience with these devices is a key driver of their acceptability and uptake. Methods: We implemented a remote hypertension program within the Mass General Brigham health system using traditional home BP monitoring to adjust medications. Selected patients in this program were enrolled in an ancillary study where BP was also measured via a cuffless wrist monitor (Aktiia SA, Switzerland). We analyzed patient experience surveys of all patients who successfully used each device for at least one full week in the program and completed surveys at 30, 60, and 180 days after enrollment. Final (180-day) surveys were analyzed. Results: Of 35 patients who used both devices, 34 completed all 3 surveys. Thirty-one patients (91%) indicated they preferred using the cuffless wrist monitor over the upper arm BP cuff, 1 (3%) preferred the BP cuff, and 2 (6%) had no preference. Top reasons for preference of the bracelet included ease of use, convenience, and number of readings (Figure). Most patients (27/34, 79%) used the cuffless device either daily or most days of the week, and 23 (68%) found it easy or very easy to use. Twenty-eight (82%) patients believed the bracelet could help manage their hypertension; 32 (94%) indicated that direct transmission of bracelet BP to their providers would be valuable. Conclusion: Among patients who used both traditional home BP monitoring and a cuffless continual BP monitoring bracelet in a remote hypertension management program, the vast majority found the cuffless device easier to use and more convenient, and preferred it over traditional BP cuffs.

Estimating Blood Pressure during Exercise with a Cuffless Sphygmomanometer.

Accurately measuring blood pressure (BP) is essential for maintaining physiological health, which is commonly achieved using cuff-based sphygmomanometers. Several attempts have been made to develop cuffless sphygmomanometers. To increase their accuracy and long-term variability, machine learning methods can be applied for analyzing photoplethysmogram (PPG) signals. Here, we propose a method to estimate the BP during exercise using a cuffless device. The BP estimation process involved preprocessing signals, feature extraction, and machine learning techniques. To ensure the reliability of the signals extracted from the PPG, we employed the skewness signal quality index and the RReliefF algorithm for signal selection. Thereafter, the BP was estimated using the long short-term memory (LSTM)-based neural network. Seventeen young adult males participated in the experiments, undergoing a structured protocol composed of rest, exercise, and recovery for 20 min. Compared to the BP measured using a non-invasive voltage clamp-type continuous sphygmomanometer, that estimated by the proposed method exhibited a mean error of 0.32 ± 7.76 mmHg, which is equivalent to the accuracy of a cuff-based sphygmomanometer per regulatory standards. By enhancing patient comfort and improving healthcare outcomes, the proposed approach can revolutionize BP monitoring in various settings, including clinical, home, and sports environments.

Home blood pressure-centered approach - from digital health to medical practice: HOPE Asia Network consensusstatement 2023.

Recent innovations in digital technology have enabled the simultaneous accumulation, and the linking and analysis of time-series big data relating to several factors that influence blood pressure (BP), including biological indicators, physical activity, and environmental information. Various approaches can be used to monitor BP: in the office/clinic; at home; 24-h ambulatory recording; or with wearable and cuffless devices. Of these, home BP monitoring is a reliable and convenient method, and is recommended for hypertension management by current national and international guidelines. This recommendation is based on evidence showing that home BP is an important predictor of cardiovascular, cerebrovascular and kidney disease in patients with hypertension. In addition, lifetime personalized health record (PHR)-based home BP with telemonitoring combined with co-interventions has been shown to lower BP more effectively than the traditional approach based on office BP. Thus, home BP represents a key metric for personalized anticipation medicine, from digital healthcare to digital medicine. This paper summarizes the latest evidence on home BP monitoring and proposes a Hypertension Cardiovascular Outcome Prevention and Evidence in Asia (HOPE Asia) Network consensus on a home BP-centered approach to the management of hypertension.

Transforming blood pressure control in primary care through a novel remote decision support strategy based on wearable blood pressure monitoring: The NEXTGEN-BP randomized trial protocol

Despite high blood pressure being the leading preventable risk factor for death, only 1 in 3 patients achieve target blood pressure control. Key contributors to this problem are clinical inertia and uncertainties in relying on clinic blood pressure measurements to make treatment decisions. The NEXTGEN-BP open-label, multicenter, randomized controlled trial will investigate the efficacy, safety, acceptability and cost-effectiveness of a wearable blood pressure monitor-based care strategy for the treatment of hypertension, compared to usual care, in lowering clinic blood pressure over 12 months. NEXTGEN-BP will enroll 600 adults with high blood pressure, treated with 0 to 2 antihypertensive medications. Participants attending primary care practices in Australia will be randomized 1:1 to the intervention of a wearable-based remote care strategy or to usual care. Participants in the intervention arm will undergo continuous blood pressure monitoring using a wrist-wearable cuffless device (Aktiia, Switzerland) and participate in 2 telehealth consultations with their primary care practitioner (general practitioner [GP]) at months 1 and 2. Antihypertensive medication will be up-titrated by the primary care practitioner at the time of telehealth consults should the percentage of daytime blood pressure at target over the past week be <90%, if clinically tolerated. Participants in the usual care arm will have primary care consultations according to usual practice. The primary outcome is the difference between intervention and control in change in clinic systolic blood pressure from baseline to 12 months. Secondary outcomes will be assessed at month 3 and month 12, and include acceptability to patients and practitioners, cost-effectiveness, safety, medication adherence and patient engagement. NEXTGEN-BP will provide evidence for the effectiveness and safety of a new paradigm of wearable cuffless monitoring in the management of high blood pressure in primary care. ACTRN12622001583730.

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.

NIGHT-TIME BLOOD PRESSURE AND BLOOD PRESSURE VARIABILITY IN HYPERTENSIVE PATIENTS WITH OR WITHOUT INSOMNIA. A PILOT STUDY

Objective: Recent studies found that insomnia is an independent risk factor for cardiovascular diseases, particularly arterial hypertension. Among the hypertensive population, insomnia could contribute to a worse blood pressure (BP) profile. In a sample of hypertensive patients, we compared those with and without insomnia with the aim of evaluating possible differences in BP, its variability, and breathing pattern. Design and method: We conducted a case-control study on patients with and without insomnia, based on the Insomnia Severity Index (ISI) questionnaire. Patients were recruited from the general practitioner's registry and were sent an invitation e-mail. All of them had long-lasting hypertension. One-hundred-and-fifty patients replied to the ISI questionnaire. Among them, twenty people with insomnia were selected (ISI greater than or equal to 15) and matched, based on their gender and age (±3 years), to 20 controls (with ISI lower than 15). All participants underwent night-time cardiorespiratory and 24-hour blood pressure monitoring by using a new cuff-less device that can estimate beat-to-beat BP (SomnoTouch-NIBP). Results: Comparing the two groups (insomnia vs. non-insomnia), no differences were observed in BP profile and all the respiratory indices, including the apnea-hypopnea index(AHI), the number of desaturations, and peripheral oxygen saturation (SpO2) values. Even the average BP and the indices of BP variability, such as the standard deviation (SD), the pressure coefficient of variation (CV), the BP dipping, and the nocturnal BP fluctuations (NBPF), were similar between the groups. Interestingly, to obtain the same average BP control, the insomnia group required a greater number of antihypertensive drugs (2,85 ± 0,88 vs. 1,95 ± 1,00 in the non-insomnia group; p&lt;0.01). Conclusions: Patients with insomnia may need more antihypertensive medications to achieve the same average BP as patients without insomnia. Anyhow, they did not show, as expected, higher BP variability. How much beat-to-beat BP estimations are reliable compared to BP measurements by standard cuff-based devices is still under debate.

ASSESSING WORKFLOW, SATISFACTION, AND POTENTIAL COST REDUCTION WHEN USING A CUFFLESS AMBULATORY BLOOD PRESSURE MONITOR

Objective: Hypertension is a major risk factor for cardiovascular diseases. Ambulatory blood pressure monitoring (ABPM) is used for the diagnosis of hypertension, however, currently-used devices have several drawbacks complicating their use and accuracy. We tested the workflow of a wearable photoplethysmography (PPG)-based cuffless device when compared to the traditional cuff-based ABPM device. Design and method: Patients were recruited in a single community clinic and randomly assigned to either a cuff-based or a PPG-based 24-hour ABPM test. An assessment team recorded the time to complete each workflow component with each device. Questionnaires on user experience and workflow were filled by physicians, nurses, and recruited patients. Results: Workflow assessment of onboarding patients showed that it was faster with the PPG-based device than with the cuff-based device (301.17±58.39 seconds vs 1185±172.34 seconds on average, respectively). The PPG-based device received a higher score in all aspects of usability. The direct manpower cost reduction was calculated as 108,000 USD per year for 4,500 tests. Conclusions: The PPG-based device has several advantages when compared to the traditional cuff-based ABPM device, potentially increasing both patient and medical staff satisfaction, and as a result, increasing compliance. This could help improve the diagnosis and treatment of hypertension in the community.

Optimizing the input feature sets and machine learning algorithms for reliable and accurate estimation of continuous, cuffless blood pressure

The advent of mobile devices, wearables and digital healthcare has unleashed a demand for accurate, reliable, and non-interventional ways to measure continuous blood pressure (BP). Many consumer products claim to measure BP with a cuffless device, but their lack of accuracy and reliability limit clinical adoption. Here, we demonstrate how multimodal feature datasets, comprising: (i) pulse arrival time (PAT); (ii) pulse wave morphology (PWM), and (iii) demographic data, can be combined with optimized Machine Learning (ML) algorithms to estimate Systolic BP (SBP), Diastolic BP (DBP) and Mean Arterial Pressure (MAP) within a 5 mmHg bias of the gold standard Intra-Arterial BP, well within the acceptable limits of the IEC/ANSI 80601-2-30 (2018) standard. Furthermore, DBP’s calculated using 126 datasets collected from 31 hemodynamically compromised patients had a standard deviation within 8 mmHg, while SBP’s and MAP’s exceeded these limits. Using ANOVA and Levene’s test for error means and standard deviations, we found significant differences in the various ML algorithms but found no significant differences amongst the multimodal feature datasets. Optimized ML algorithms and key multimodal features obtained from larger real-world data (RWD) sets could enable more reliable and accurate estimation of continuous BP in cuffless devices, accelerating wider clinical adoption.

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.