Oscillometric Blood Pressure Devices Research Articles

Comparison of cardiac output estimates obtained from the Antares oscillometric pulse wave analysis algorithm and from Doppler transthoracic echocardiography.

In cardiology, cardiac output (CO) is an important parameter for assessing cardiac function. While invasive thermodilution procedures are the gold standard for CO assessment, transthoracic Doppler echocardiography (TTE) has become the established method for routine CO assessment in daily clinical practice. However, a demand persists for non-invasive approaches, including oscillometric pulse wave analysis (PWA), to enhance the accuracy of CO estimation, reduce complications associated with invasive procedures, and facilitate its application in non-intensive care settings. Here, we aimed to compare the TTE and oscillometric PWA algorithm Antares for a non-invasive estimation of CO. Non-invasive CO data obtained by two-dimensional TTE were compared with those from an oscillometric blood pressure device (custo med GmbH, Ottobrunn, Germany) using the integrated algorithm Antares (Redwave Medical GmbH, Jena, Germany). In total, 59 patients undergoing elective cardiac catheterization for clinical reasons (71±10 years old, 76% males) were included. Agreement between both CO measures were assessed by Bland-Altman analysis, Student's t-test, and Pearson correlations. The mean difference in CO was 0.04 ± 1.03 l/min (95% confidence interval for the mean difference: -0.23 to 0.30 l/min) for the overall group, with lower and upper limits of agreement at -1.98 and 2.05 l/min, respectively. There was no statistically significant difference in means between both CO measures (P = 0.785). Statistically significant correlations between TTE and Antares CO were observed in the entire cohort (r = 0.705, P<0.001) as well as in female (r = 0.802, P<0.001) and male patients (r = 0.669, P<0.001). The oscillometric PWA algorithm Antares and established TTE for a non-invasive estimation of CO are highly correlated in male and female patients, with no statistically significant difference between both approaches. Future validation studies of the Antares CO are necessary before a clinical application can be considered.

CARDIAC OUTPUT ESTIMATION: PULSE WAVE ANALYSIS (ANTARES) HIGHLY CORRELATES TO ECHOCARDIOGRAPHY ASSESSMENT

Objective: Evaluation of cardiac output (CO) is crucial for understanding cardiac function and diagnosis of heart failure. While invasive thermodilution procedures serve as the gold standard for CO assessment, routine clinical practice has widely adopted transthoracic Doppler echocardiography (TTE) as the established non-invasive method. Nevertheless, there is a persistent demand for alternative non-invasive approaches, aiming to improve the efficiency of CO estimation, mitigate complications associated with invasive methods, and extend its application to non-intensive care settings, all of which potentially can be offered by oscillometric pulse wave analysis (PWA). This study aims to compare the non-invasive estimation of CO using TTE and the oscillometric PWA algorithm Antares. Design and method: We compared non-invasive cardiac output data obtained through two-dimensional transthoracic echocardiography with data obtained from an oscillometric blood pressure device (custo med GmbH, Ottobrunn, Germany) utilizing the integrated Antares algorithm (Redwave Medical GmbH, Jena, Germany). A total of 59 patients, undergoing elective cardiac catheterization for clinical reasons, were included in the study (mean age 71±10 years, 24% females), but only echocardiography-data with CO were used for analysis. Agreement between the two CO measurement methods (TTE versus Antares) was evaluated through Bland-Altman analysis, Student's t-test, and Pearson correlations. Results: The mean difference in CO was 0.04 ± 1.03 l/min. No statistically significant difference in means was observed between the two CO measurement methods. Significant correlations between transthoracic echocardiography (TTE) and Antares CO were evident in the overall population (r=0.71), as well as in both, female (r=0.80) and male patients (r=0.67; all p&lt;0.001). Conclusions: The oscillometric PWA algorithm Antares and the established TTE exhibit strong correlations for non-invasive CO estimation in both male and female patients, with no statistically significant differences between the two approaches. This study opens the door to a valid and simple detection of heart failure that is seamlessly integrated into a quick and easy-to-perform upper arm blood pressure measurement.

Short-term impact of a healthy and typical Australian dietary pattern on cardiometabolic outcomes: insights from a randomised, cross-over feeding study

Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305 Australia.Cardiovascular disease (CVD) remains a major cause of global mortality. Poor diet quality, characterised by excessive consumption of energy-dense, nutrient-poor foods and insufficient intake of fruits, vegetables, and whole grains, is associated with an increased risk of CVD(1). This study compares the impact of two short-term dietary interventions, a Healthy Australian Diet adhering to national guidelines and a Typical Australian Diet representing current national consumption patterns, on several cardiometabolic outcomes. These outcomes include body weight, waist circumference (WC), body fat percentage (BFP), blood pressure (BP), fasting blood lipids and glucose concentrations. Data from an eight-week randomised, cross-over feeding study involving 34 adults (53% female, age 38.4 ± 18.1 years) were analysed, with participants randomly assigned to consume each diet for two weeks, separated by a two-week washout period. During each feeding phase, all food items were provided to ensure compliance. The Healthy Australian Diet adhered to the Australian Dietary Guidelines(2), including a balanced intake of the five food groups and meeting Acceptable Macronutrient Distribution Range targets(3), with saturated fat limited to ≤10% of energy. The Typical Australian Diet was formulated based on apparent consumption patterns in Australia(4), setting total fat intake at 40% of energy and total saturated fat at 15% of energy. Comprehensive data collection occurred at four key visits: week 0 (end of run-in; baseline 1), week 2 (post-feeding phase 1), week 4 (end of washout, baseline 2), and week 8 (post-feeding phase 2). Trained personnel measured WC using a tensible tape, while body weight and BFP measurements were obtained using bioimpedance analysis (Inbody 270; Biospace Co, Seoul, Korea). Blood pressure was recorded using the Uscom BP+ supra-systolic oscillometric central blood pressure device. Blood glucose and lipid (triglycerides, total-, low-density lipoprotein- [LDL] and high-density lipoprotein- [HDL] cholesterol) concentrations were measured after a 12-hour fast by an accredited pathology service. Differential changes in cardiometabolic variables between intervention groups were evaluated using linear mixed-effect models, adjusting for diet sequence, feeding phase, and subject ID as a random variable to account for potential autocorrelation. Post-hoc pairwise comparisons were conducted to assess the impact effects of each diet. There were no significant differences between the Healthy Australian Diet and the Typical Australian Diet with respect to weight, BFP, WC, blood triglycerides, systolic and diastolic BP. However, the Healthy Australian Diet led to a significantly greater decrease in total-, LDL-, HDL- and non-HDL cholesterol, and fasting blood glucose relative to the Typical Australian Diet (p&lt;0.001). The results underscore the importance of promoting dietary intakes that align with Australian Dietary Guidelines for optimising the risk of CVD and impaired glucose tolerance. Conversely, the Typical Australian Dietary pattern demonstrated detrimental cardiometabolic effects over a short period of just two weeks.

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.

INVASIVE VALIDATION OF THE ANTARES ALGORITHM FOR ESTIMATING CENTRAL BLOOD PRESSURE IN PATIENTS WITH CHRONIC KIDNEY DISEASE

Objective: Chronic kidney disease (CKD) is characterized by decreased renal autoregulatory capacity, increased proteinuria, and direct transmission of systemic blood pressure to the glomeruli. Thereby, an increase in central (aortic) blood pressure (cBP) accelerates the progression of CKD. Antares is a pulse wave analysis algorithm designed to allow a non-invasive estimation of cBP using automated oscillometric blood pressure devices. We aimed to compare the invasively measured cBP with the estimated cBP using the Antares algorithm in patients with CKD. Design and method: 26 patients with stages 3-5 CKD (eGFR &lt;60 ml/min/1.73m2, 88% stage 3 CKD, age 78±9 years, BMI 29±5 kg/m2, 65% male) were included and cBP was measured invasively during elective coronary angiography and simultaneously non-invasively using the custo screen 400 device (custo med GmbH, Ottobrunn, Germany) with the integrated Antares algorithm (Redwave Medical GmbH, Jena, Germany). Results: The mean difference for cBP was -0.7 ± 6.3 mmHg for central systolic BP (cSBP), -2.0 ± 5.1 mmHg for central mean arterial pressure (cMAP) and -4.2 ± 7.2 mmHg for central diastolic BP (cDBP). High correlations were found between estimated and invasively measured cBP (cSBP, r = 0.96; cMAP, r = 0.92; cDBP, r = 0.77; all p&lt;0.001). Conclusions: The present study demonstrates that the Antares algorithm can estimate cBP with high accuracy in patients with CKD. Measurement of cBP and subsequent therapeutic interventions could improve renal and cardiovascular prognosis in these patients.

OFFICE BLOOD PRESSURE VARIABILITY: WITHIN SESSION STABILITY ACROSS CONSECUTIVE MEASUREMENTS USING OSCILLOMETRIC DEVICES

Objective: Blood pressure (BP) is routinely monitored by healthcare providers and during drug development. For improvement in accuracy, several oscillometric devices perform multiple sequential inflations, rather than relying on a single inflation, to determine a mean systolic and diastolic blood pressure (SBP, DBP). Blood pressure is known to vary physiologically throughout a day, and over the course of days and weeks, due to intrinsic and extrinsic factors. Little data has been published describing the variability of SBP and DBP recorded minutes apart using oscillometric methods (i.e. within session variability). Design and method: We investigated the stability of within session SBP and DBP across 4 datasets by evaluating differences between 3 consecutive inflations recorded 1-2 minutes apart using a clinically validated oscillometric BP monitor that passed the ANSI/AAMI/ISO 2013, ESH-IP 2002 and BHS 1993 protocols (Table 1). These datasets included patients with controlled or uncontrolled hypertension. Results: Data were available from over 10.000 measurement pairs. The differences between inflation 1 and 2 were within ±10, 20 and 30 mmHg for 78.1, 94.4 and 97.9% of the SBP measurements, respectively. For the DBP, 90.7, 95.5 and 97.3 % of the differences between inflation 1 and 2 were within ±10, 15 and 20 mmHg, respectively. A similar trend was seen between inflation 2 and 3. Table 1: Categorical Analysis of BP changes between consecutive inflations. Conclusions: Our data demonstrate substantial variability between consecutive oscillometric BP measurements performed a few minutes apart. Over 20% of the time, consecutive inflations show an absolute change in SBP of at least 10 mmHg. It is unclear whether this represents true physiologic changes in BP or is partly artefactual due to failure of a device's algorithm to determine BP accurately from the oscillometric waveform. These data suggest that criteria for within session variability for automated oscillometric blood pressure devices should be established, including a threshold for repeating the session after 10 minutes of rest.

PS-BPC03-2: NIGHTTIME HOME BLOOD PRESSURE WAS ASSOCIATED WITH ADVERSE OUTCOMES IN SUBCLINICAL HEART FAILURE PATIENTS

Objective: Nighttime blood pressure (BP) has stronger association with target organ damage and cardiovascular outcome than office BP, 24-hr BP, and awake BP in hypertensives. However, clinical significance of nocturnal BP, especially home nocturnal BP, was not established in heart failure (HF) patients. We hypothesized that nighttime home BP was associated with adverse outcome and investigated the association between nighttime home BP and the outcome in subclinical HF patients. Design and method: We analyzed 394 patients with NT-proBNP &gt; 125pg/ml from a practitioner-based population with at least one cardiovascular risk factor who underwent home BP monitoring in the Japan Morning Surge-Home Blood Pressure study. Morning, evening and nighttime home BP were measured by validated, automatic, and oscillometric home BP devices, and cardiovascular events were followed up. Results: During a mean follow-up of 4.2 years, 43 cardiovascular events occurred. Morning home SBP, evening home SBP and nighttime home SBP were higher in event group than in non-event group (150 ± 23 vs 140 ± 17 mmHg, p = 0.01, 142 ± 22 vs 131 ± 16 mmHg, p &lt; 0.01, 133 ± 22 vs 125 ± 17 mmHg, p &lt; 0.01, respectively). In multivariate Cox regression analysis adjusting for significant variables, average of evening home SBP, and nighttime home SBP were significant predictors of the outcome (HR 1.02, 95%CI: 1.01–1.04, p = 0.01, HR 1.02, 95%CI: 1.01–1.04, p = 0.03, respectively). When nighttime home SBP of 120mmHg was used as cutoff, nighttime home SBP &gt; 120mmHg was significantly associated with the outcome (HR 2.46, 95%CI 1.06–5.68, p = 0.04). Conclusions: Elevated nighttime home BP was significant predictor of cardiovascular outcomes in subclinical HF patients.

Invasive validation of the Antares algorithm for determining central blood pressure based on upper arm oscillometric pulse waves in patients with type 2 diabetes

IntroductionAntares is a pulse wave analysis (PWA) algorithm designed to allow a non-invasive estimation of central (aortic) blood pressure (cBP) using automated oscillometric blood pressure (BP) devices. Diabetes may affect...

JS-HOPE ASIA-3: HOME BLOOD PRESSURE MONITORING: EVIDENCE BEHIND THE 722 PROTOCOL

Home blood pressure (HBP) has been recognized as a prognostic predictor for cardiovascular events, and integrated into the diagnosis and management of hypertension. With increasing accessibility of oscillometric blood pressure devices, HBP monitoring is easy to perform, more likely to obtain reliable estimation of blood pressures, and feasible to document long-term blood pressure variations, compared to office and ambulatory blood pressures. To obtain reliable HBP estimates, a standardized HBP monitoring protocol is essential. A consensus regarding the optimal duration and frequency of HBP monitoring is yet to be established. Based on the current evidence, the “722” protocol, which stands for 2 measurements on one occasion, 2 occasions a day (morning and evening), and over a consecutive of 7 days, is most commonly used in clinical studies and recommended in relevant guidelines and consensus documents. HBP monitoring based on the “722” protocol fulfills the minimal requirement of blood pressure measurements to achieve agreement of blood pressure classifications defined by office blood pressures and to predict cardiovascular risks. In the Taiwan HBP consensus, the frequency of repeating the “722” protocol of HBP monitoring according to different scenarios of hypertension management, from every 2 weeks to 3 months, is recommended. It is reasonable to conclude that the “722” protocol for HBP monitoring is clinically justified and can serve as a basis for standardized HBP monitoring.

Subjects Conceived through Assisted Reproductive Technologies Display Normal Arterial Stiffness.

Multiple studies reported signs of vascular dysfunction in subjects conceived through assisted reproductive technologies (ART). The assessment of arterial stiffness in this cohort seems beneficial for risk stratification. Regional arterial stiffness of the abdominal aorta (AAO) and the common carotid arteries (CCA) was evaluated sonographically using two-dimensional speckle tracking in subjects conceived through ART and spontaneously conceived peers. Global arterial stiffness was assessed utilizing an oscillometric blood pressure device. The cohorts of 67 ART subjects and 86 spontaneously conceived peers (11.31 (8.10-18.20) years vs. 11.85 (8.72-18.27) years, p = 0.43) did not differ significantly in parameters of regional and global arterial stiffness. In the sub-analysis of study participants ≥10 years of age, markers of arterial stiffness did not display significant differences between both groups. However, a higher tendency of brachial systolic blood pressure was demonstrated in the ART cohort compared to the control group (120.18 ± 9.57 mmHg vs. 116.55 ± 8.05 mmHg, p = 0.050). The present study displayed no significant differences in arterial stiffness between ART subjects and spontaneously conceived peers. Moreover, this study suggests that arterial stiffness does not elevate more profoundly in ART subjects with increasing age. Further studies are required for a more detailed cardiovascular risk stratification of the ART cohort.

Ambulatory Arterial Stiffness, Salivary Inflammation, And Physical Activity In Young Adults With And Without Covid-19

COVID-19 illness may cause a dysregulated systemic inflammatory response, leading to cardiovascular damage and an increased risk for cardiovascular disease (CVD). Physical activity (PA) is inversely associated with systemic inflammation and CVD risk and may be a cardioprotective lifestyle factor for individuals recovering from COVID-19. PURPOSE: 1) To compare CVD risk, assessed as arterial stiffness and systemic inflammatory levels, between young adults recovering from COVID-19 and uninfected controls, and 2) to explore PA as a mediator for the relationship of COVID-19 infection history with arterial stiffness and systemic inflammation. METHODS: Analyses were performed on 23 COVID-19 (15 females, 25.0 ± 8.9 years, 24.1 ± 3.5 kg/m2) and 32 control participants (18 females, 24.4 ± 6.5 years, 25.1 ± 3.5 kg/m2). Arterial stiffness was estimated as pulse wave velocity (PWV) during 24-hour ambulatory blood pressure monitoring with an oscillometric blood pressure device. Systemic inflammation was assessed as salivary C-reactive protein (CRP) levels using the passive drool method. PA was objectively measured via accelerometry and assessed as moderate-to-vigorous PA (MVPA). An independent samples t-test was used to compare measures of arterial stiffness and systemic inflammation between the COVID-19 and control groups. Mediation analysis was used to determine whether there was a significant indirect effect of COVID-19 infection history through MVPA on arterial stiffness and CRP levels. RESULTS: There were no significant differences (p > 0.05) between the SARS-CoV-2 and control groups in PWV (5.0 ± 0.5 m/s vs. 5.1 ± 0.5 m/s) or CRP levels (765.4 ± 672.9 pg/mL vs. 526.3 ± 674.8 pg/mL). Mediation analysis did not reveal a significant indirect effect of COVID-19 infection history through MVPA on arterial stiffness (estimate = 0.02, 95% CI = -0.05 - 0.24) or CRP levels (estimate = 0.03, 95% CI = -0.07 - 0.16). CONCLUSION: These results suggest there are no differences in arterial stiffness and systemic inflammation between young adults recovering from COVID-19 and uninfected controls, and that MVPA may not significantly mediate the relationship for COVID-19 infection history with arterial stiffness and systemic inflammation. Young adults recovering from COVID-19 may not have a heightened CVD risk compared to controls.

Standardized home blood pressure monitoring: Rationale behind the 722 protocol.

Home blood pressure (HBP) has been recognized as a prognostic predictor for cardiovascular events, and integrated into the diagnosis and management of hypertension. With increasing accessibility of oscillometric blood pressure devices, HBP monitoring is easy to perform, more likely to obtain reliable estimation of blood pressures, and feasible to document long‐term blood pressure variations, compared to office and ambulatory blood pressures. To obtain reliable HBP estimates, a standardized HBP monitoring protocol is essential. A consensus regarding the optimal duration and frequency of HBP monitoring is yet to be established. Based on the current evidence, the “722” protocol, which stands for two measurements on one occasion, two occasions a day (morning and evening), and over a consecutive of 7 days, is most commonly used in clinical studies and recommended in relevant guidelines and consensus documents. HBP monitoring based on the “722” protocol fulfills the minimal requirement of blood pressure measurements to achieve agreement of blood pressure classifications defined by office blood pressures and to predict cardiovascular risks. In the Taiwan HBP consensus, the frequency of repeating the “722” protocol of HBP monitoring according to different scenarios of hypertension management, from every 2 weeks to 3 months, is recommended. It is reasonable to conclude that the “722” protocol for HBP monitoring is clinically justified and can serve as a basis for standardized HBP monitoring.

Evaluating novel approaches for estimating awake and sleep blood pressure: design of the Better BP Study – a randomised, crossover trial

IntroductionFor many people, blood pressure (BP) levels differ when measured in a medical office versus outside of the office setting. Out-of-office BP has a stronger association with cardiovascular disease (CVD)...

Forest Bathing Is Better than Walking in Urban Park: Comparison of Cardiac and Vascular Function between Urban and Forest Parks.

Forest bathing is beneficial for human health. To investigate whether walking in forest or urban parks affects cardiovascular functions (CVFs), the present study was conducted in five forest trails in the Xitou Experimental Forest and in five urban parks in Taipei city. We recruited 25 adult volunteers for an observational pilot study in forest parks (n = 14) and urban parks (n = 11). CVFs were assessed by measuring the arterial pressure waveform using an oscillometric blood pressure (BP) device. The baseline and paired differences of systolic BP (SBP), central end SBP, heart rate, left ventricle (LV) dP/dt max and cardiac output in participants were lower before and after walking in a forest park than those in an urban park. In addition, the systemic vascular compliance and brachial artery compliance of those who walked in a forest park were significantly higher compared with those in an urban park. Linear mixed models demonstrated lower levels of SBP by 5.22 mmHg, heart rate by 2.46 beats/min, and cardiac output by 0.52 L/min, and LV dP/dt max by 146.91 mmHg/s among those who walked in forest compared to those in an urban park after controlling covariates. This study provides evidence of the potential beneficial effects of walking exercise in forest parks on CVFs.

Seasonal Effects of High-Altitude Forest Travel on Cardiovascular Function: An Overlooked Cardiovascular Risk of Forest Activity.

Cardiovascular physiological responses involving hypoxemia in low temperature environments at high altitude have yet to be adequately investigated. This study aims to demonstrate the health effects of hypoxemia and temperature changes in cardiovascular functions (CVFs) by comparing intra-individual differences as participants ascend from low (298 m, 21.9 °C) to high altitude (2729 m, 9.5 °C). CVFs were assessed by measuring the arterial pressure waveform according to cuff sphygmomanometer of an oscillometric blood pressure (BP) device. The mean ages of participants in winter and summer were 43.6 and 41.2 years, respectively. The intra-individual brachial systolic, diastolic BP, heart rate, and cardiac output of participants significantly increased, as participants climbed uphill from low to high altitude forest. Following the altitude increase from 298 m to 2729 m, with the atmosphere gradually reducing by 0.24 atm, the measured average SpO2 of participants showed a significant reduction from 98.1% to 81.2%. Using mixed effects model, it is evident that in winter, the differences in altitude affects CVFs by significantly increases the systolic BP, heart rate, left ventricular dP/dt max and cardiac output. This study provides evidence that cardiovascular workload increased significantly among acute high-altitude travelers as they ascend from low to high altitude, particularly in winter.

Abstract P128: Direct Observed Therapy In Suspected Resistant Hypertension Is Safe

Introduction: Direct observed therapy (DOT) has emerged as a method for assessment of adherence, particularly in patients with apparent treatment-resistant hypertension (ATRH), in clinical care as well as research. We have previously demonstrated that direct observed therapy resulted in controlled hypertension in 30% of patients with ATRH. In this study we report on the safety of DOT in terms of change in blood pressure (BP) and hypotensive symptoms. Methods: Patients with ATRH were enrolled in a prospective study of DOT, which was followed by ambulatory blood pressure monitoring on the same day and at one month. DOT was performed by administering all prescribed BP lowering drugs, supervised by a nurse in an outpatient clinic setting. BP and vitals were measured at baseline and every 30 minutes until BP plateau based on two consecutive BP readings. All BP measurements during DOT were performed using an automated oscillometric BP device. In this study, we report the change in BP during DOT, with incidence of orthostatic symptoms, and decrease in systolic BP &gt; 20 mm Hg as outcomes of interest. Results: 50 patients underwent DOT, 32 men, mean age 62 years on median 4 BP lowering drugs (range 3 to 7). The mean baseline BP was 146/77 mm Hg , and the lowest BP during DOT was 129/68 mm Hg. The median decrease in systolic BP was 14 mm Hg (range 0 to 60) and diastolic BP was 8 mm Hg (range 0 to 37). 5 patients (10%) developed orthostatic symptoms during DOT, none of which required any interventions, and resolved with continued observation. A decrease of &gt; 20 mm Hg in systolic BP was seen in 19 patients (38%), and a systolic BP of &lt; 110 mm Hg was seen in only 6 patients (12%). Conclusions: DOT caused decrease in BP by &gt;20 mmHg in about 40% of patients. While these large acute decreases in BP were largely asymptomatic, close observation of BP is required until peak BP lowering effect wanes. As decrease in BP is driven by the degree of non-adherence and number of prescribed BP lowering drugs, our safety record has limitation dictated by the number of subjects enrolled, and relatively small number of patients with more than 5 BP lowering drugs.

Feasibility of non-invasive measurement of central blood pressure and arterial stiffness in shock.

Patients in haemodynamic shock are in need for an intensive care treatment. Invasive haemodynamic monitoring is state of the art for these patients. However, evolved, non-invasive blood pressure monitoring devices offer advanced functions like the assessment of central blood pressure and arterial stiffness. We analysed the feasibility of two oscillometric blood pressure devices in patients with shock. We performed a monocentre prospective study, enrolling 57 patients admitted to the intensive care unit (ICU), due to septic and/or cardiogenic shock. We assessed invasive and non-invasive peripheral and central blood pressure <24hours and 48hours after admission on the ICU. Additional haemodynamic parameters such as pulse wave velocity (PWV), augmentation pressure and augmentation index were obtained through Mobil-o-Graph PWA (IEM) and SphygmoCor XCEL (AtCor Medical). A complete haemodynamic assessment was successful in all patients (48) with the Mobil-o-Graph 24hours PWA and in 29 patients with the SphygmoCor XCEL (P=.001), when cases of death or device malfunction were excluded. Reasons for failure were severe peripheral artery disease, haemodynamic instability, oedema and agitation. Invasive blood pressure showed a sufficient correlation with both devices; however, large differences between invasive and non-invasive techniques were recorded in Bland-Altmann analysis (P<.05 for all parameters). PWV differed between the two devices. Non-invasive peripheral blood pressure measurement remains a rescue technique. However, non-invasive assessment of arterial stiffness and central blood pressure is possible in patients with septic or cardiogenic shock. Further studies are required to assess their clinical significance for patients in shock.

CNN-Based LCD Transcription of Blood Pressure From a Mobile Phone Camera.

Routine blood pressure (BP) measurement in pregnancy is commonly performed using automated oscillometric devices. Since no wireless oscillometric BP device has been validated in preeclamptic populations, a simple approach for capturing readings from such devices is needed, especially in low-resource settings where transmission of BP data from the field to central locations is an important mechanism for triage. To this end, a total of 8192 BP readings were captured from the Liquid Crystal Display (LCD) screen of a standard Omron M7 self-inflating BP cuff using a cellphone camera. A cohort of 49 lay midwives captured these data from 1697 pregnant women carrying singletons between 6 weeks and 40 weeks gestational age in rural Guatemala during routine screening. Images exhibited a wide variability in their appearance due to variations in orientation and parallax; environmental factors such as lighting, shadows; and image acquisition factors such as motion blur and problems with focus. Images were independently labeled for readability and quality by three annotators (BP range: 34–203 mm Hg) and disagreements were resolved. Methods to preprocess and automatically segment the LCD images into diastolic BP, systolic BP and heart rate using a contour-based technique were developed. A deep convolutional neural network was then trained to convert the LCD images into numerical values using a multi-digit recognition approach. On readable low- and high-quality images, this proposed approach achieved a 91% classification accuracy and mean absolute error of 3.19 mm Hg for systolic BP and 91% accuracy and mean absolute error of 0.94 mm Hg for diastolic BP. These error values are within the FDA guidelines for BP monitoring when poor quality images are excluded. The performance of the proposed approach was shown to be greatly superior to state-of-the-art open-source tools (Tesseract and the Google Vision API). The algorithm was developed such that it could be deployed on a phone and work without connectivity to a network.

Screening for atrial fibrillation during automated blood pressure measurement among patients admitted to internal medicine ward

Atrial fibrillation (AF), the commonest sustained cardiac arrhythmia affecting the adult population, is often casually discovered among hospitalized people. AF onset is indeed triggered by several clinical conditions such as acute inflammatory states, infections, and electrolyte disturbance, frequently occurring during the hospitalization. We aimed to evaluate whether systematic AF screening, performed through an automated oscillometric blood pressure (BP) device (Microlife WatchBP Office AFIB, Microlife AG, Switzerland), is effective for detecting AF episodes in subjects admitted to an Internal Medicine ward. 163 patients consecutively hospitalized at the Unit of Internal Medicine of the “Santa Maria” Terni University Hospital between November 2019 and January 2020 (mean age ± standard deviation: 77 ± 14 years, men proportion: 40%) were examined. Simultaneously with BP measurement and AF screening, a standard 12-lead electrocardiogram (ECG) was performed in all subjects. AF was diagnosed by ECG in 29 patients (18%). AF screening showed overall 86% sensitivity and 96% specificity. False negatives (n = 4) had RR-interval coefficient of variation lower than true positives (n = 25, p < 0.01), suggesting a regular ventricular rhythm during AF. The repeated evaluation substantially confirmed the same level of agreement. AF screening was positive in all patients with new-onset AF (n = 6, 100%). Systematic AF screening in patients admitted to Internal Medicine wards, performed using the Microlife WatchBP Office AFIB, is feasible and effective. The opportunity to implement such technology in daily routine clinical practice to prevent undiagnosed AF episodes in hospitalized patients should be the subject of further research.

Differences in oscillometric blood pressure readings between unsupported and supported back conditions.

Appropriate body posture is important for accurate blood pressure (BP) measurement. However, the impact of an unsupported back on BP readings is currently controversial. This study included 224 subjects (18-86 years old, 54.5 ± 15.5 years old, 105 males). BP was measured with an oscillometric BP device randomly following one of two protocols for back support conditions: (1) supported-unsupported-supported-unsupported, or (2) unsupported-supported-unsupported-supported. The average of the two systolic BP (SBP) and diastolic BP (DBP) readings in the same position was recorded as the final BP value. The differences in BP between the unsupported and supported back conditions were calculated as delta BP. Moreover, the percentage variation in BP (PV) was calculated with the formula delta BP/BP with an unsupported back. Multivariable regression analysis evaluated the impact of age, sex, hypertension history and supported BP level on PV. The SBP/DBP levels measured with an unsupported back were slightly higher than those when the back was supported (132.7 ± 19.5/79.6 ± 12.9 mmHg vs. 130.3 ± 20.0/78.5 ± 14.3 mmHg), and the delta SBP (2.3 mmHg) was statistically significant. The multivariable regression analysis showed that age was a positive factor but supported SBP level as a negative factor for systolic PV, while age and supported DBP level were positive factors, but hypertension history was a negative factor for diastolic PV. For a group participant, the mean difference in oscillometric SBP/DBP in the unsupported back position was 2.3/1.0 mmHg higher than that in the supported back position.