Accurate Blood Pressure Measurement Research Articles

Investigating the Sources of Variability in Blood Pressure Monitoring Systems

Accurate and reliable blood pressure measurement is critical for diagnosing and managing hypertension properly. Based on a consensus document announced in the Journal of Hypertension, this is so much so that a 5.0 mm Hg BP measurement error can result in incorrect hypertension classification in 84 million individuals worldwide. Understanding how BP measurement goes wrong and how to tackle them can improve the diagnosis and management of hypertension. Unfortunately, BP measurement is problematically performed in clinical practice, accumulating errors that inappropriately alter management decisions in 20% to 45% of cases. In this study, the sources of variability from the aspects of the blood pressure monitoring system were attempted to be scrutinized. The variability increases with additive properties such as pressure gauge inaccuracy, cuff tightness, and cloth over-measurement. An artificial plastic arm was created to measure the pressure with multiple monitors. The study concluded that each monitor had its inherent characteristics in increasing monitor pressures concerning the actual pressure, and further, the increases in cuff loosening distance and the cloth-over layers might cause more significant variability, as hypothesized in this study. The study could more clearly verify the reason for blood pressure measurement variability.

A Wireless Noninvasive Blood Pressure Measurement System Using MAX30102 and Random Forest Regressor for Photoplethysmography Signals

Hypertension, often termed “the silent killer”, is associated with cardiovascular risk and requires regular blood pressure (BP) monitoring. However, existing methods are cumbersome and require medical expertise, which is worsened by the need for physical contact, particularly during situations such as the coronavirus pandemic that started in 2019 (COVID-19). This study aimed to develop a cuffless, continuous, and accurate BP measurement system using a photoplethysmography (PPG) sensor and a microcontroller via PPG signals. The system utilizes a MAX30102 sensor and ESP-WROOM-32 microcontroller to capture PPG signals that undergo noise reduction during preprocessing. Peak detection and feature extraction algorithms were introduced, and their output data were used to train a machine learning model for BP prediction. Tuning the model resulted in identifying the best-performing model when using a dataset from six subjects with a total of 114 records, thereby achieving a coefficient of determination of 0.37/0.46 and a mean absolute error value of 4.38/4.49 using the random forest algorithm. Integrating this model into a web-based graphical user interface enables its implementation. One probable limitation arises from the small sample size (six participants) of healthy young individuals under seated conditions, thereby potentially hindering the proposed model’s ability to learn and generalize patterns effectively. Increasing the number of participants with diverse ages and medical histories can enhance the accuracy of the proposed model. Nevertheless, this innovative device successfully addresses the need for convenient, remote BP monitoring, particularly during situations like the COVID-19 pandemic, thus making it a promising tool for cardiovascular health management.

Accurate Blood Pressure Measurement Using Smartphone's Built-in Accelerometer

Efficient blood pressure (BP) monitoring in everyday contexts stands as a substantial public health challenge that has garnered considerable attention from both industry and academia. Commercial mobile phones have emerged as a promising tool for BP measurement, benefitting from their widespread popularity, portability, and ease of use. Most mobile phone-based systems leverage a combination of the built-in camera and LED to capture photoplethysmography (PPG) signals, which can be used to infer BP by analyzing the blood flow characteristics. However, due to low Signal-to-Noise (SNR), various factors such as finger motion, improper finger placement, skin tattoos, or fluctuations in environmental lighting can distort the PPG signal. These distortions consequentially affect the performance of BP estimation. In this paper, we introduce a novel sensing system that utilizes the built-in accelerometer of a mobile phone to capture seismocardiography (SCG) signals, enabling accurate BP measurement. Our system surpasses previous mobile phone-based BP measurement systems, offering advantages such as high SNR, ease of use, and power efficiency. We propose a triple-stage noise reduction scheme, integrating improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN), recursive least squares (RLS) adaptive filter, and soft-thresholding, to effectively reconstruct high-quality heartbeat waveforms from initially contaminated raw SCG signals. Moreover, we introduce a data augmentation technique encompassing normalization coupled with temporal-sliding, effectively augmenting the diversity of the training sample set. To enable battery efficiency on smartphone, we propose a resource-efficient deep learning model that incorporates resource-efficient convolution, shortcut connections, and Huber loss. We conduct extensive experiments with 70 volunteers, comprising 35 healthy individuals and 35 individuals diagnosed with hypertension, under a user-independent setting. The excellent performance of our system demonstrates its capacity for robust and accurate daily BP measurement.

Possibilities to increase reliability and accuracy of blood pressure measurement taking into account blood hydrodynamics and biomechanics of processes during compression of shoulder tissues with a pneumatic cuff

Systolic and diastolic BP values are determined guided by measurement signals (Korotkoff tones, oscillations). The source of these signals are hydrodynamic processes occurring in the artery under the influence of cuff pressure on the upper arm. The article is devoted to the study of these processes. The value of body tissues pressure on the artery walls is equal to the value of air pressure in the cuff only at the middle of the cuff and smoothly decreases to zero to its edges. Such non-uniformity of distribution of body tissues pressure on the artery walls is caused by the physical property of elasticity of their shape, which was not taken into account earlier. Therefore, the equality of the value of blood pressure on the artery walls from its inner side and the value of body tissues pressure on the artery walls from its outer side is possible only at one point. At this point, the open part of the artery passes into its constricted part, and the point itself is called the boundary of arterial constriction. The pulsations of blood pressure in the artery caused by the heart cause rhythmic movements of this boundary along the artery. Therefore, the arterial walls open up when the constriction boundary is moved in the distal direction. When the convergence boundary is moved in the proximal direction, the walls of the artery connect. During systole, when the blood pressure exceeds the air pressure in the cuff, the boundary of compression moves distally across the middle of the cuff. At the same time, a blood flow front is formed beyond the middle of the cuff, moving towards the distal edge of the cuff. When this edge is reached, the artery opens across the entire width of the cuff. In the diastole periods following systole, the blood pressure decreases. As a result, the blood pressure drops below the air pressure in the cuff, and the arterial wall at the midpoint of the cuff interconnect again. In this case, there is a re-boundary of constriction moving in the proximal direction. Thus, the hydrodynamics of blood in the artery is completely determined by the movements of the boundary of its compression. This hydrodynamics is substantiated theoretically and confirmed experimentally. It is shown that oscillations of air pressure in the cuff, Korotkoff tones and surface pulse waves are different consequences of a single biomechanical process, which allows us to consider in detail the formation of oscillations, surface pulse waves, as well as to put forward a physically justified version of the Korotkoff tones.

OFFICE BP MEASUREMENT USING CONICAL CUFFS IN OBESE CHILDREN AND ADOLESCENTS

Objective: Findings from adult studies suggest that tronco-conical cuffs should be used for accurate blood pressure (BP) measurement in obese individuals with large arm circumference (AC). The aim of the present study was to examine differences in office blood pressure (BP) levels using conical cuffs compared to standard-shaped cylindrical cuffs in obese children and adolescents. Design and method: We performed an observational study enrolling 37 obese children and adolescents consequently recruited from the outpatient clinics of the Obesity Unit at General University Hospital Consortium of Valencia. The device used for the office BP measurements was OMRON HBP-1320 (HBP-1320-E). Middle AC was measured in all participants and the appropriate cuff size was selected among five sizes of conical and three sizes of regular cylindrical cuffs. Results: Mean participants’ age was 11.8±2.5 years, mean BMI was 28.8±3.4 kg/m2, BMI z-score was 2.1 ± 0.3, and mean AC was 30.0±3.6 cm. There was no statistical significance in BP levels measured by cylindrical compared to conical cuffs (mean difference cylindrical-conical cuff was -0.22±6.55 mmHg for SBP, -0.02±0.81 for SBP z-score, -0.70±4.95 mmHg for DBP, and -0.06±0.44 for DBP z-score). The analysis was repeated after excluding participants aged <9 years old, retrieving similar results. A significant positive association was found between the measurements obtained by cylindrical and conical cuffs in both mean and z-score SBP and DBP values (p <0.001). Bland-Altman analysis showed good agreement, with 94.6% of the values for all BP parameters, lying between the limits of agreement. No proportional bias was detected (p >0.05). Conclusions: The use of conical cuffs resulted in similar office BP levels in obese children and adolescents suggesting no advantage in enhancing tolerability and accuracy of office BP measurement in these patients. Although conical cuffs may be considered an alternative for office BP measurements in obese children, their reliability should be confirmed in larger populations and different settings. Acknowledgments: This abstract is based on the work of the COST Action HyperChildNET (CA19115), with the support of COST (European Cooperation in Science and Technology) and the Horizon 2020 Framework Program of the European Union.

UNATTENDED AUTOMATIC BLOOD PRESSURE MEASUREMENTS VS. CONVENTIONAL OFFICE READINGS IN PREDICTING HYPERTENSION-MEDIATED ORGAN DAMAGE

Objective: Hypertension, a major cardiovascular risk, requires accurate blood pressure measurement. Conventional office measurements (OBPM) are error-prone and systematically biased by the white coat effect. Unattended office blood pressure measurement (UOBPM) is emerging as an alternative to mitigate this bias. However, its ability to predict hypertension-mediated organ damage (HMOD), indicating disease progression, remains debated. This study compares UOBPM with OBPM in terms of their association with various HMODs, including left ventricular hypertrophy (LVH), left atrial enlargement (LAE), left ventricular systolic and diastolic dysfunction, intima-media complex (IMT) thickening, microalbuminuria and abnormal pulse wave velocity (PWV). Design and method: Hypertensive patients without overt cardiovascular disease were recruited, interviewed, and examined. Subsequently, blood pressure measurements were conducted in standard conditions in a randomized sequence in each patient: 1) UOBPM: After 5 minutes of solitary rest in the examination room, blood pressure was automatically measured three times at 1-minute intervals with OMRON HEM 907 device. 2) OBPM: After 5 minutes of rest, a physician performed three automated measurements at 1-minute intervals with the same device. Subsequent evaluations aimed to detect HMODs, including echocardiography, carotid artery ultrasound, PWV assessment, and laboratory tests. Receiver operating characteristic (ROC) analysis was performed for each HMOD in both measurement groups, and the areas under the ROC curves were compared. Results: The study enrolled 219 patients(55% females, mean age 55 ±14 years). The average systolic blood pressure in UOBPM was lower by 4,2 mmHg (p<0,001) compared to OBP while the difference in diastolic pressure was 1,9 mmHg (p<0,001). Both measurement methods were associated with the presence of the following HMODs: LAE, IMT thickening, and abnormal PWV. Neither method allowed for the prediction of LVH, systolic and diastolic dysfunction of the left ventricle, elevated ACR, or the presence of atherosclerotic plaques in the carotid arteries. Furthermore, ROC curve analyses revealed no difference between the two methods in predicting HMOD (Table 1). Conclusions: Both measurement techniques exhibited satisfactory predictive ability for the presence of certain HMOD. However, based on the study results, no significant differences could be inferred between the two methods with respect to their predictive performance.

Using Data Augmentation to Improve the Accuracy of Blood Pressure Measurement Based on Photoplethysmography

Convenient and accurate blood pressure (BP) measurement is of great importance in both clinical and daily life. Although deep learning (DL) can achieve cuff-less BP measurement based on Photoplethysmography (PPG), the performance of DL is affected by few-shot data. Data augmentation becomes an effective way to enhance the size of the training data. In this paper, we use cropping, flipping, DTW barycentric averaging (DBA), generative adversarial network (GAN) and variational auto-encoder (VAE) for the data augmentation of PPG. Furthermore, a PE–CNN–GRU model is designed for cuff-less BP measurement applying position encoding (PE), convolutional neural networks (CNNs) and gated recurrent unit (GRU) networks. Experiment results based on real-life datasets show that VAE is the most suitable method for PPG data augmentation, which can reduce the mean absolute error (MAE) of PE–CNN–GRU when measuring systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 18.80% and 19.84%. After the data augmentation of PPG, PE–CNN–GRU achieves accurate and cuff-less BP measurement, thus providing convenient support for preventing cardiovascular diseases.

Unattended automatic blood pressure measurements vs conventional office readings in predicting hypertension-mediated organ damage.

Hypertension is a leading cardiovascular risk factor. Accurate blood pressure (BP) measurement is pivotal in hypertension diagnosis and management. Conventional office blood pressure measurements (OBPMs) are error‑prone, exacerbated by the white‑coat effect. Unattended automated office blood pressure measurement (UAOBPM) is emerging as an alternative, mitigating the white‑coat effect. However, its ability to predict hypertension‑mediated organ damage (HMOD) remains disputable. This study compares UAOBPM with OBPM in terms of their association with various types of HMOD, including left ventricular hypertrophy, left atrial enlargement, left ventricular systolic and diastolic dysfunction, intima‑media complex thickening, microalbuminuria, and abnormal pulse wave velocity. A total of 219 hypertensive patients were recruited, interviewed, and examined. Subsequently, BP measurements were conducted in a randomized manner: 1) UAOBPM, after 5 minutes of solitary rest in an examination room, BP was automatically measured 3 times at 1‑minute intervals; 2) OBPM, after 5 minutes of rest, a physician performed 3 consecutive BP measurements at 1‑minute intervals. Subsequent evaluations aimed to detect HMOD and included echocardiography, carotid artery ultrasound, pulse wave velocity assessment, and laboratory tests. UAOBP values were lower than the OBP ones (mean [SD], 124.7 [14.4] vs 128.2 [14.2] mm Hg; P <0.001 for systolic BP, and 73.3 [10.2] vs 75.2 [10.6] mm Hg; P <0.001 for diastolic BP). Correlation and receiver operating characteristic curve analyses revealed no superiority of either method in predicting HMOD. The UAOBPM did not prove superior to OBPM in predicting HMOD. Further research is warranted to determine the role of UAOBPM in clinical practice.

Evaluation of the oscillometric method for noninvasive blood pressure measurement during cuff deflation and cuff inflation with reference to intra-arterial blood pressure.

There is little quantitative clinical data available to support blood pressure measurement accuracy during cuff inflation. In this study of 35 male and 5 female lightly anaesthetized subjects aged 64.1 ± 9.6 years, we evaluate and compare the performance of both the oscillometric ratio and gradient methods during cuff deflation and cuff inflation with reference to intra-arterial measurements. We show that the oscillometric waveform envelopes (OWE), which are key to both methods, exhibit significant variability in both shape and smoothness leading to at least 15% error in the determination of mean pressure (MP). We confirm the observation from our previous studies that K1 Korotkoff sounds underestimate systolic blood pressure (SBP) and note that this underestimation is increased during cuff inflation. The estimation of diastolic blood pressure (DBP) is generally accurate for both the ratio and the gradient method, with the latter showing a significant increase during inflation. Since the gradient method estimates SBP and DBP from points of maximum gradient on each OWE recorded, it may offer significant benefits over the ratio method. However, we have shown that the ratio method can be optimized for any data set to achieve either a minimum mean error (ME) of close to 0 mmHg or minimum root mean square error (RMSE) with standard deviation (SD) of <5.0 mmHg. We conclude that whilst cuff inflation may offer some advantages, these are neither significant nor substantial, leaving as the only benefit, the potential for more rapid measurement and less patient discomfort.

Noninvasive Blood Pressure Monitoring via a Flexible and Wearable Piezoresistive Sensor.

In the present global context, continuous blood pressure (BP) monitoring is paramount in addressing the global mortality rates attributed to hypertension. Achieving precise insights into the human cardiovascular system necessitates accurate measurement of BP, and the accuracy depends on the faithful recording of oscillations or pulsations. This task ultimately depends on the caliber of the pressure sensor embedded in the BP device. In this context, we have fabricated a flexible resistive pressure sensor based on reduced graphene oxide (rGO) and a polydimethylsiloxane (PDMS) sponge that is highly flexible and sensitive. The designed device operates effectively with a minimal bias voltage of 500 mV, at which point it showed its maximum relative change in current, reaching approximately 25%. Additionally, the sensing device showed a notable change in resistance values, exhibiting almost 100% change in resistance when subjected to a pressure of 400 mmHg and high sensitivity of 0.27 mmHg-1. After promising outcomes were obtained during static pressure measurement, the sensor was used for BP monitoring in humans. The sensor accurately traced the oscillometric waveform (OMW) for distinct systolic blood pressure (SBP) and diastolic blood pressure (DBP) combinations to cover a range of medical situations, including hypotension, standard or normal, and hypertension. The values of SBP, DBP, and MAP were derived from the sensor's output using the MAA technique, and the errors in these values concerning the simulator and the traditional BP monitor follow the universal AAMI/ESH/ISO protocols. Bland-Altman (B&A) correlation and scatter plots were used to compare the sensor's results and further validate the proposed sensor. The sensor showed the mean and standard deviation error in the SBP, DBP, and MBP of -0.2 ± 5.9, -0.5 ± 7, and -0.9 ± 4.7 mmHg when compared with the noninvasive blood pressure (NIBP) simulator. The pulse rate (PR) was also calculated from the same OMW for the specified value of 80 beats per minute (bpm) given by the simulator and reported a mean PR value of ∼81 bpm, close to the reference value. The findings show that the flexible resistive sensing device can accurately measure BP and replace the existing sensors of BP devices.

Clinical Skills Training: Do Medical Students Have Enough Knowledge of Accurate Blood Pressure Measurement When They Graduate?

Clinical Skills Training: Do Medical Students Have Enough Knowledge of Accurate Blood Pressure Measurement When They Graduate?

Are aneroid and digital sphygmomanometers as reliable and accurate as mercury sphygmomanometers?

Background: The accurate measurement of blood pressure (BP) is crucial for effectively treating hypertension, which stands as a primary risk factor for both cardiovascular disease and premature mortality. The shift from mercury to nonmercury sphygmomanometers in developing countries due to environmental concerns prompts an evaluation of the accuracy of these alternatives. Aims and Objectives: The objectives of this study were to evaluate the precision of non-mercury instruments in diagnosing hypertension and to analyze interarm differences in both systolic and diastolic BP using three different sphygmomanometers. Materials and Methods: Sixty subjects aged 18–25 were included. BP measurements were taken from both arms using different types of sphygmomanometers. Statistical analysis involved paired t-tests, Chi-square tests for correlations, and a significance threshold of P &lt; 0.05. Results: Significant differences in systolic BP readings were observed between the gold standard (mercury manometer) and digital/aneroid devices (P = 0.00). Compared to the mercury manometer, both digital and aneroid devices showed limited accuracy in detecting hypertension. Kappa agreement was moderate at 0.57. Despite high specificity (100%), sensitivity was lower at 44.4%, indicating a risk of missing true positive cases. Both devices exhibited a sensitivity of 25%, with fair to poor agreement (kappa values) in identifying cardiovascular risk compared to the mercury reference. Conclusion: This study underscores the diminished reliability of both aneroid and digital devices in detecting hypertension and assessing cardiovascular risk using specified interarm BP criteria. These findings emphasize the crucial need for further research and caution when relying on non-mercury devices in clinical settings.

Physiological impact of a single cup of coffee on systemic blood pressure and heart rate – A randomized controlled trial

Background: Coffee is a prevalent beverage that is consumed on a global scale. This study was done to depict the immediate effects of caffeine on systemic blood pressure (BP) and heart rate (HR) in young healthy, normotensive individuals who consume coffee on an infrequent basis, using validated non-invasive techniques. The acute properties of caffeine have been the subject of numerous studies, and we’ll be exploring the latest findings on this topic. Thus, we think that it is more useful to ascertain if a typical cup of coffee can produce a significant rise in BP and HR. Aims and Objectives: This research aimed to examine the effect of a single cup of coffee on the HR and BP of young healthy adults. Materials and Methods: The study was conducted on 68 participants from 1st-year MBBS students enrolled in the study of those 4 were excluded as two males showed systemic BP of &gt;140/80 and we have excluded two females to maintain an equal male and female ratio. In a randomized double-blind, placebo-controlled study, 64 healthy subjects were first divided into caffeine and placebo groups. One cup of coffee and a placebo drink were administered orally to 64 healthy, normotensive adults, and BP (systolic BP [SBP], diastolic BP [DBP]) and HR were observed. Results: Administration of caffeine shows increased systolic and DBP from 0 to 30 min after coffee intake was significantly higher in the caffeine group than in the placebo group. The mean SBP, DBP at 90 min in the caffeine group was compared to the mean SBP, DBP at 90 min in the placebo group. The mean difference in both was statistically significant with a P &lt; 0.001. Conclusion: The present study concludes that the ingestion of a single cup of caffeinated coffee may elicit a significant increase in both systolic and DBP, as well as in HR, among young, healthy, and sporadic coffee consumers. Notably, such a rise in physiological parameters may interfere with the accuracy of BP measurements taken in the few hours following coffee intake, especially in individuals who consume coffee on an occasional basis.

First-in-Human Study for Evaluating the Accuracy of Smart Ring Based Cuffless Blood Pressure Measurement.

Recently, a ring-type cuffless blood pressure (BP) measuring device has been developed. This study was a prospective, single arm, first-in-human pivotal trial to evaluate accuracy of BP measurement by the new device. The ring-type smart wearable monitoring device measures photoplethysmography signals from the proximal phalanx and transmits the data wirelessly to a connected smartphone. For the BP comparison, a cuff was worn on the arm to check the reference BP by auscultatory method, while the test device was worn on the finger of the opposite arm to measure BP simultaneously. Measurements were repeated for up to three sets each on the left and right arms. The primary outcome measure was mean difference and standard deviation of BP differences between the test device and the reference readings. We obtained 526 sets of systolic BP (SBP) and 513 sets of diastolic BP (DBP) from 89 subjects, with ranges of 80 to 175 mmHg and 43 to 122 mmHg for SBP and DBP, respectively. In sample-wise comparison, the mean difference between the test device and the reference was 0.16 ± 5.90 mmHg (95% limits of agreement [LOA], -11.41, 11.72) in SBP and -0.07 ± 4.68 (95% LOA, -9.26, 9.10) in DBP. The test device showed a strong correlation with the reference for SBP (r = 0.94, P < 0.001) and DBP (r = 0.95, P < 0.001). There were consistent results in subject-wise comparison. The new ring-type BP measuring device showed a good correlation for SBP and DBP with minimal bias compared with an auscultatory method.

Investigation of Accuracy of Blood Pressure Measurement by Conical Wrapping Techniques According to Arm Circumference in Obese Patients

Amaç: Obez bireylerin konik kol şekline sahip olması nedeniyle manşet kola yerleştirildiğinde kol üst kısmını tam olarak sararken kolun distal kısmında cilt yüzeyi ile manşet arasında boşluk kalmaktadır. Bu durum obez bireylerde kan basıncı ölçümünde yanlış sonuçlara neden olmaktadır. Çalışmamız kol çevresine göre çapraz manşet uygulaması ile silindirik ve intraarterial kan basıncı sonuçlarını karşılaştırılarak geniş kol çevresine sahip bireyler için en uygun ve ulaşılabilir yöntemin ortaya konması amaçlanmıştır.&#x0D; Gereç ve Yöntemler: Araştırmanın örneklemini, Nisan-Ağustos 2021 tarihleri arasında Genel Yoğun Bakım ünitelerinde radyal kateter arter basıncı takibi ile izlenen 92 hasta oluşturmuştur. Araştırmaya BKİ 25 kg/m2 ve üzeri olan, kol çevresi 35 cm ve üzeri olan hastalar dahil edilmiştir. &#x0D; Bulgular: İntraarterial kan basıncı ölçüm sonuçları ile çapraz manşet bağlama yöntemiyle yapılan kan basıncı ölçüm sonuçlarının karşılaştırılmasına göre; çapraz manşet bağlama yöntemine göre sistolik kan basıncı 2.71 mmHg (p=0.00) ve diyastolik kan basıncı 2.04 mmHg (p=0.00) daha düşük olduğu bulunmuştur. Çapraz bağlama yöntemi ile ölçülen sistolik ve diyastolik kan basıncı ile intraarterial sistolik ve diyastolik kan basıncı ölçümleri arasında anlamlı ve pozitif yönlü korelasyon olduğu bulunmuştur.&#x0D; Sonuç: Çalışmamızın sonucunda, obez hastalarda tüm manşet bağlama yöntemleri KB değerleri intraarterial ölçüm değerleri ile anlamlı bir ilişki göstermektedir. Ancak çapraz manşet baglama yöntemi sistolik sonuçları intraarterial sistolik kan basıncı ölçüm sonuçlarına daha yakın olduğu belirlenmiştir.

Improvement of in-office Blood Pressure targets in an Academic primary care setting

Background &#x0D; Accurate blood pressure (BP) measurement in an office-based setting is essential for diagnosis and management of hypertension. Staff education on proper blood pressure measurement technique and recording is a focus of recent hypertension guidelines. (1) Compared with other methods, unattended Automated Office Blood Pressure (AOBP) devices reduce measurement errors and improve BP Management. (2,3,4) The addition of AOBP to staff education needs to be assessed objectively. &#x0D; &#x0D; Objectives &#x0D; To determine the effect of staff education on proper BP measurement and addition of AOBP devices on BP targets in an academic general internal medicine clinic. &#x0D; &#x0D; Methods &#x0D; Education was provided to the medical staff on how to appropriately check BP in general and on the proper use of the AOBP devices. Education was repeated in several intervals to ensure consistency in practice. Six AOBP Hillrom (Welch Allyn spot 4400) devices were deployed for the clinic. Devices allowed for three automated readings 1 minute apart eliminating the first reading and keeping the other 2 readings. Staff were instructed to document two blood pressure readings into the electronic medical record. The number of patients who completed two BP measurements documented in the EMR over time. &#x0D; &#x0D; Results &#x0D; Our results showed timely education with refreshers, increased BP measurement protocol and improvement in BP recordings. Adherence to 2 BP checks increased from 40% in Dec-21 to 99% Jun-23. The percentage of patients with improved BP increased from 40% to 76% after staff education and addition of AOBP. &#x0D; &#x0D; Conclusion &#x0D; Timely education of medical staff and the addition of AOBP could increase the accuracy of in-office BP measurement. &#x0D; &#x0D; Key word: Internal medicine &#x0D; Type of submission: Abstract

Performance of the Aktiia optical blood pressure measurement device in the elderly: a comparison with double blinded auscultation in different body positions

Background: Accurate blood pressure (BP) measurement is essential for the correct diagnosis and management of hypertension (HTN) especially in the elderly population. As with of all BP devices, the accuracy of cuffless devices must be verified. This study (NCT04027777) aimed to evaluate the performance of a wrist cuffless optical BP device in an elderly population cohort in different body positions with auscultation as the reference measurement. Design and methods Patients aged 65-85 years with different BP categories but without diabetes were recruited. After an initial calibration based on auscultatory measurements, BP estimation from the Aktiia Bracelet (Aktiia SA, Switzerland) were compared to reference double-blinded auscultatory measurements in sitting, standing and lying positions on four separate visits distributed over one month. In the absence of a universal standard for cuffless BP device at the time of the study, modified ISO81060-2 criteria were used for performance analysis. Results Thirty-five participants were included in the analysis fulfilling the inclusion requirements of ISO 81060-2. A total of 469 paired measurements were obtained with overall 83% acceptance rate. Differences (mean ± SD) between Aktiia Bracelet and auscultation for systolic BP were -0.26 ± 9.96 mmHg for all body positions aggregated (sitting 1.23 ± 7.88 mmHg, standing -1.81 ± 11.11 mmHg, lying -1.8 ± 9.96 mmHg). Similarly, differences for diastolic BP were -0.75 ± 7.0 mmHg (0.2 ± 5.55 mmHg, -5.35 ± 7.75 mmHg and -0.94 ± 7.47 mmHg, respectively). Standard deviation of the averaged differences per subject for systolic/diastolic BP was 3.8/2.5 mmHg in sitting and 4.4/3.7 mmHg for all body positions aggregated. Conclusions Overall, this study demonstrates a similar performance of the Aktiia Bracelet compared to auscultation in an elderly population in body positions representative of daily activities. The use of more comfortable, non-invasive, and non-occlusive BP monitors during long periods may facilitate e-health and may contribute to better management of HTN, including diagnosis and treatment of HTN, in the elderly.

First-in-human study for evaluating the accuracy of blood pressure measurement using the ring-type device with a photoplethysmography

Abstract Background Early diagnosis of hypertension and optimal blood pressure (BP) control are important for prevention of cardiovascular morbidity and mortality. The 24-hour BP is better predictive of cardiovascular outcome than the office BP. However, conventional non-invasive BP measurement by sphygmomanometer has limitations in obtaining continuous BP and its variability in daily life. Recently, a ring-type BP measuring device, CART-I Plus (Sky Lab Inc, South Korea) without a cuff has been developed. Purpose This study was a prospective, single arm, first-in-human pivotal trial to evaluate accuracy of blood pressure measurement by the new device. Methods The ring-type smart wearable blood monitoring device measures photoplethysmography signals from the proximal phalanx and transmits the data wirelessly to the connected smartphone, to monitor the BP (Figure 1). A cuff was worn on arm to check the reference BP by auscultation, while the test device was worn on the finger of the opposite arm to check the test BP simultaneously. Measurements were repeated for up to three sets each on the left and right arms. The primary outcome measure was mean error and standard deviation of BP differences between the test device and the reference readings. Results The final analysis included 89 subjects, 47% of whom were male, with a mean age of 40.1 years. We collected 526 sets of systolic BP (SBP) and 513 sets of diastolic BP (DBP), with ranges of 80 to 175 mmHg and 43 to 122 mmHg, respectively. In sample-wise comparison (Figure 2), the mean error between the test device and the reference was 0.16 ± 5.90 mmHg (95% limit of agreements [LOA] -11.41 to 11.72) in SBP and -0.07 ± 4.68 (95% LOA -0.26 to 9.10) in DBP. The test device showed a good correlation with the reference for SBP (r=0.94, p&amp;lt;0.001) and DBP (r=0.95, p&amp;lt;0.001). In subject-wise comparison, the test device showed a good correlation with the reference for SBP (r=0.98, p&amp;lt;0.001) and DBP (r=0.98, p&amp;lt;0.001), with a mean error of 0.17 ± 3.67 mmHg (95% LOA -7.04 to 7.7) in SBP and 0.02 ± 3.21 mmHg (95% LOA -6.27 to 6.31) in DBP. Conclusion The new ring-type BP measuring device had a good correlation for SBP and DBP with minimal bias compared with a auscultation method. It has the potential to provide accurate BP in daily life.

Validation of a novel cuffless photoplethysmography-based wristband for measuring blood pressure according to the regulatory standard

Abstract Background Blood pressure is a key paramater in acute and chronic cardiovascular diseases (CVD) [1]. However, obtaining reliable and reproducible cuff blood pressure (BP) measurements is challenging. We demonstrate that a wristband-based PPG measurement in combination with a custom developed BP algorithm represents a possible alternative to cuff BP measurements. Purpose This study aimed to validate a novel cuffless photopletysmography (PPG)-based non-invasive wristband for continuous BP monitoring in accordance with ISO 81060-2:2019. Methods The study compared PPG-guided BP algorithm predictions with subclavian arterial reference measurements taken during cardiac catheterization. Eligible patients were consecutively included, and eligibility was screened following ISO 81060-2:2019 requirements. Reference measurements were performed using a validated invasive BP monitoring device with a sampling rate of 100Hz. PPG signals were collected using six light emission diodes and two photodiodes at a sampling rate of 128Hz. Three sequential initialization measurements were taken using a validated blood pressure cuff before the cardiac catheterization exam. These measurements, along with approximately 100 additional features (PPG-derived and based on patient demographics), were used as input for the machine learning-based BP algorithm. Correlation, mean error, and standard deviation (SD) were determined for systolic and diastolic BP measurements between the BP algorithm predictions and invasive reference measurements Results The study included 97 patients from whom 420 individual 30-second samples were obtained. The mean age, weight, and height of the analysed subjects were 67.1 (SD 11.1), 83.4 (SD 16.1), and 174.1 (SD 10.0), respectively. In 48 samples (11%), systolic BP was ≤100mmHg, while in 106 samples (25%), systolic BP was ≥160mmHg. Diastolic BP was ≤70 mmHg in 222 samples (53%) and ≥85 mmHg in 99 samples (24%). The BP algorithm predictions showed a high correlation with invasive reference measurements for systolic (r = 0.985) and diastolic (r = 0.961) BP measurements. The mean error of the BP algorithm predictions compared to the invasive reference measurements was ±3.7 mmHg (SD 4.4 mmHg) and ±2.5 mmHg (SD 3.7 mmHg) for systolic and diastolic BP, respectively. Results were similar within each gender and skin colour category (Fitzpatrick I-VI). Conclusion This study demonstrates that a wristband-based PPG measurement in combination with the developed BP algorithm can provide accurate continuous BP measurements across a wide range of BP distributions. Therefore, wristband BP monitoring may serve as a valid and less burdensome alternative to cuff BP measurements for both in-hospital and at-home BP monitoring. However, further research is necessary to evaluate the precision of the BP algorithm during movement and the stability of the predictions over time.figure of BP

Abstract 17197: Team-Based Care for Uncontrolled Hypertension in Accountable Care Organizations: A Simulation Study

Background and Objectives: Team-based care (TBC) is associated with greater blood pressure (BP) reductions than usual care, particularly when non-physicians titrate antihypertensive medications, but has yet to be widely adopted. This analysis projected the effectiveness of TBC among patients with uncontrolled hypertension from three accountable care organizations (ACOs): Columbia University Medical Center (New York), Cedars-Sinai Medical Center (California), and Ochsner Accountable Care Network (Louisiana). Methods: The Cardiovascular Disease (CVD) Policy Model is a computer model that simulates modifiable hypertension care processes (i.e., office visit frequency, BP measurement accuracy, medication intensification, and patient medication adherence) and has been validated to reproduce TBC outcomes. We used the CVD Policy Model to simulate the ACO population aged &gt;=65 years with BP &gt;=140/90 mmHg at two outpatient visits in 2015, and project BP and CVD outcomes out to 10 years with usual care alone vs. one year of TBC followed by a return to usual care. Hypertension usual care processes were derived from national sources and published literature. The model was calibrated to reproduce systolic BP reductions with TBC at one year vs. usual care from a published meta-analysis, which were stratified by the team member responsible for antihypertensive medication titration: -5.0 (95%CI -7.9, -2.2) mmHg with physician titration and -10.5 (95%CI -16.2, -4.8) mmHg with non-physician titration. Results: The ACO population with uncontrolled BP (N=9,788) had a mean (SD) age of 76.3 (7.8) years; 66.6% were white and 59.8% female. The mean BP (SD) at baseline was 151.1 (13.0)/78.1 (10.6) mmHg and 39.1% had a history of CVD. Compared with usual care at 10 years, TBC with non-physician titration was projected to increase the proportion with BP &lt;140/90 mmHg by 16.0% and TBC with physician titration by 4.2%. Relative to usual care, TBC with non-physician titration was projected to prevent 20.8 CVD events per 1000 individuals and TBC with physician titration to prevent 6.6 CVD events. Conclusion: Universal adoption of TBC, especially with non-physician titration, could improve achievement of quality benchmark BP control goals and prevent CVD events in ACO populations.