Blood Pressure Measurement Methods Research Articles

Usefulness of noninvasive blood pressure measurement in captive Red Panda (Ailurus fulgens).

The red panda (Ailurus fulgens) can be found in zoos around the world, and various behavioral restraint procedures are used as part of their health care. Wild animals that are kept in zoos, including red pandas, are known to have a longer life span than those in the wild. Therefore, the health management of aging animals is considered especially important for zoos that maintain many precious wild animals. Blood pressure measurement is important for determining cardiovascular dynamics, however there are no reports of blood pressure measurements performed in red pandas without anesthesia. In this study, we measured blood pressure in four red pandas, over 4 years to establish a blood pressure measurement method using behavioral restraints. As a result, the blood pressure of red pandas was found to be similar to that of dogs and cats. In addition, in one case of red panda that evaluated high blood pressure during the measurement period, we added the antihypertensive drug and showed good effect for improvement of hypertension on long- term monitoring. Blood pressure values obtained using noninvasive methods were useful for red pandas. Moreover, these data were considered important for animal welfare.

Real-time Blood Pressure Prediction on Wearable Devices using Edge Based Deep Neural Networks: A Hardware-software Co-design Approach

This paper presents the hardware realization of a real-time blood pressure (BP) prediction model for wearable devices, utilizing long short-term memory (LSTM) deep neural networks (DNNs). The proposed system uses both electrocardiogram (ECG) and photoplethysmogram (PPG) signal values for BP prediction. It aims to address the limitations of traditional BP measurement methods, providing a low error, minimal computational overhead, more accurate and convenient alternative system for individuals with hypertension or at risk for cardiovascular diseases. The utilization of split matrix approach leads to a reduction in hardware complexity across the entire system. This technique involves breaking down the larger weight matrices used in the computations of DNNs into smaller matrices. This fragmentation results in a decrease in the complexity of the hardware responsible for performing matrix vector multiplications (MVMs) within LSTMs. The resultant architecture of the predictive model gains several advantages, including a lowered level of complexity in terms of the space occupied by individual cells, decreased processing delay, and reduced power consumption. Furthermore, this approach enables the achievement of a notably improved minimum achievable clock period of 2.972 ns. This prediction model can operate locally on wearable devices, reducing the reliance on cloud computing and improving privacy and security. The performance evaluations are carried out using both analytical and implementation results. The results indicate that the proposed model can be practically applied to real-world problems and can potentially enhance the accuracy of various machine-learning tasks.

BP-Diff: a conditional diffusion model for cuffless continuous BP waveform estimation using U-Net.

Continuous monitoring of blood pressure (BP) is crucial for daily healthcare. Although invasive methods provide accurate continuous BP measurements, they are not suitable for routine use. Photoplethysmography (PPG), a non-invasive technique that detects changes in blood volume within the microcirculation using light, shows promise for BP measurement. The primary goal of this study is to develop a novel cuffless method based on PPG for accurately estimating continuous BP.
Approach. We introduce BP-Diff, an end-to-end method for cuffless continuous BP waveform estimation utilizing a conditional diffusion probability model combined with a U-Net architecture. This approach takes advantage of the stochastic properties of diffusion models and the strong feature representation capabilities of U-Net. It integrates the continuous BP waveform as the initial status and uses the PPG signal and its derivatives as conditions to guide the training and sampling process.
Main results. BP-Diff was evaluated using both uncalibrated and calibrated schemes. The results indicate that, when uncalibrated, BP-Diff can accurately track BP dynamics, including peak and valley positions, as well as timing. After calibration, BP-Diff achieved highly accurate BP estimations. The mean absolute error (MAE) of the estimated BP waveforms, along with the systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) from the calibrated BP-Diff model, were 2.99 mmHg, 2.6 mmHg, 1.4 mmHg, and 1.44 mmHg, respectively. Consistency tests, including Bland-Altman analysis and Pearson correlation, confirmed its high reliability compared to reference BP. BP-Diff meets the American Association for Medical Instrumentation (AAMI) standards and has achieved a Grade A from the British Hypertension Society (BHS).
Significance. This study utilizes PPG signals to develop a novel cuffless continuous BP measurement method, demonstrating superiority over existing approaches. The method is suitable for integration into wearable devices, providing a practical solution for continuous BP monitoring in everyday healthcare.

Unattended versus conventional blood pressure measurements in hospitalized hypertensive patients.

This study aims to compare the differences between unattended and conventional blood pressure measurements in hospitalized hypertensive patients. In fall of 2019, hypertensive patients at Ruijin Hospital underwent two rounds of unattended and conventional (nurse-monitored) blood pressure measurement. Both rounds used the same electronic blood pressure monitor with measurements taken three times, 30 s apart. Comparison was made using intra-class correlation coefficients, Bland-Altman plots, paired t-tests, etc. Among the 92 subjects in the study, the median age was 50 years old, with women accounting for 33.7%. Among the subjects, the median duration of hypertension was 8.0 years. The prevalence of diabetes, coronary heart disease, and stroke were 26.1%, 5.4%, and 6.5%, respectively. Whether unattended or conventional measurements were taken first, the average blood pressure measured first was slightly higher than the one measured later, but the difference was within 1-2 mmHg. Except that the average DBP during the round of conventional blood pressure measurements was significantly reduced by 1.6 mmHg compared to the conventional DBP, there were no other significant differences. Subgroup analysis by age, gender, BMI, and diabetes showed no significant difference in blood pressure measurement results between unattended and conventional methods. No significant difference was observed between unattended and conventional methods of blood pressure measurement in hospitalized hypertensive patients. Unattended blood pressure measurement can be adopted as the current standard for blood pressure management in hospitalized patients.

Validation of TMB-2285-BT wrist blood pressure monitor in general population according to the ISO 81060-2:2018 + Amd.1:2020 Protocol.

The objective of this study is to evaluate the accuracy of the wrist blood pressure (BP) monitor (TMB-2285-BT) in general population according to international standard of ISO 81060-2:2018+Amd.1:2020. The TMB-2285-BT BP monitor is an oscillometric device measuring BP from wrist. A single cuff for wrist sizes of 13.5-21.5 cm was used for the test device. The study was performed according to the 'International Standard (ISO 81060-2:2018 + Amd.1:2020) protocol' using the same-arm sequential BP measurement method. Subjects (n ≥ 85) fulfilling the age, gender, BP, and cuff distribution criteria of the protocol were enrolled. For criterion 1, the mean difference of SBP and DBP between the test device and the reference device was -0.27 mmHg and -0.80 mmHg, respectively. For criterion 2, the SD of the averaged paired determinations of SBP and DBP for the test device and the reference device was 2.60 and 2.06 mmHg, respectively, both of which were less than 6.95 and 6.89 mmHg. The accuracy of the test device fulfilled the requirements of the criterion 1 and 2 of ISO 81060-2:2018 + Amd.1:2020. The TMB-2285-BT wrist BP monitor can be recommended for home BP measurement for general population.

Abstract 50: The Comparison of Office Blood Pressure with Morning Home Blood Pressure: Self-Automated Measurement

Background: Morning hypertension is associated with poor cardiovascular outcomes. However, office blood pressure (OBP) remains a gold standard in hypertension monitoring and management. Unfortunately, the accuracy in OBP measurement is problematic. Objectives: This study aimed to determine whether routine or unattended OBP could accurately represent home blood pressure (HBP) in patients with hypertension. Methods: We conducted a single-center, cross-sectional study. Hypertensive patients aged between 18 and 80 years, capable of performing self-automated blood pressure measurement, were included in the study. Three self-automated methods of blood pressure measurement were performed: Routine OBP, unattended OBP, and HBP. All participants were instructed to rest for at least 5 minutes prior to measuring blood pressure, and HBP was recorded twice daily, in the morning and at night, for a week after the enrolled visit without antihypertensive medication adjustment. Results: Overall 190 consecutive patients were enrolled, with a mean age of 65.2 ±7.5 years old. Half of the patients had coronary artery disease or type 2 diabetes as comorbidities. Routine OBP was significantly higher than unattended OBP and HBP. Interestingly, Systolic values of unattended OBP were similar to those of morning HBP (mean difference -0.6 ±16.0 mmHg, p=0.641) with moderate correlation (r=0.516, p<0.001). Although diastolic values of unattended OBP were lower than those of morning HBP (mean difference -3.3 ±9.0 mmHg, p<0.001), the values were moderately correlated (r=0.581, p<0.001). Bland-Alman plots between unattended OBP and morning HBP were shown in Figure 1. Both systolic and diastolic values of unattended OBP and average HBP were significantly different (mean difference -3.5 ±14.9 mmHg, p=0.002, and 1.6 ±8.6 mmHg, p=0.013, respectively). Conclusion: Unattended OBP method could effectively represent morning HBP, thus advocating to use in clinical practice.

P084 BLOOD PRESSURES MEASUREMENT WITH SITTING ON THE FLOOR POSITION FOR THE HOME BLOOD PRESSURE MONITORING FOR ASIAN LIFESTYLE

Objectives: The current standard method for home blood pressure (BP) measurement involves taking measurements while sitting in a chair. In cultures where floor sitting is common as like in Asian countries, the protocol only using sitting on the chair position can not be applied because of a lack of research for interchangeability. Methods & Materials: Among the participants who visited for evaluation of central blood pressure or pulse wave velocity, a total of 116 participants who agreed to participate in the study were randomly selected. All subjects rested for 5 minutes, and BP measurements were taken at 1-minute intervals according to a randomly assigned order of standard method (chair-sitting) and BP in a seated on the floor (floor-sitting). Results: Of the 116 participants, the median age was 67.5 (with an interquartile range of 59.0 to 75.0), and 82% were male. There were no significant differences in systolic BP (SBP, 127.0 [115.0, 142.2] mmHg in chair-sitting and 129.0 [115.5, 142.2] mmHg in floor-sitting, P = 0.228) and diastolic BP (DBP, 73.5 [66.0, 83.0] mmHg in chair-sitting and 72.0 [66.8, 81.3] mmHg in floor-sitting, P = 0.839) between the two positions. Conclusions: These findings provide important insights into securing the reliability of home BP measurements through the commonly practiced floor-sitting posture in cultures where floor sitting is common. Furthermore, this could serve as substantial evidence for providing specific home BP measurement guidelines to patients who adhere to a floor-sitting lifestyle.

P067 HOME BLOOD PRESSURE MEASUREMENTS ARE NOT PERFORMED ACCORDING TO GUIDELINES AND STANDARDIZED EDUCATION IS URGENTLY NEEDED: A MIXED-METHODS STUDY AMONG AUSTRALIAN ADULTS

Background and Objective. Home blood pressure (BP) measurement should be undertaken according to guideline recommendations to ensure accurate BP measurement. Patient education is required to provide knowledge and skills for home BP measurement. However, little is known about how BP is measured at home and what education is provided to patients, which was the aim of this study. Methods. A 30-item survey (n=350) and interviews (n=34) among Australian adults who measure BP at home (June–December 2023). Survey questions included steps taken and education received for home BP measurement. Interviews were conducted among a purposive sample to explore survey topics in detail. Results. No participants reported always undertaking home BP measurement according to all the guideline recommendations (Figure 1). However, most participants measured BP seated (n=316, 90%), with the cuff on a bare arm (n=269, 77%) and legs uncrossed (n=232, 66%). In addition, most participants recorded their BP measurements (n=280, 80%) and reported them to a medical professional (n=232, 79%). Interview participants reported measuring BP in an ad-hoc manner, using different steps each time they measure BP at home. “I [measure BP] at different times of the day after doing different things”. Only 37% (n=112) participants received education for home BP measurement. Interview participants who received education described healthcare practitioners giving verbal instructions for BP measurement. However, there were no differences in performing home BP measurement according to guideline recommendations between participants that received education and those that did not. In the absence of education, many interview participants described mimicking BP measurement methods of their healthcare provider. “I do it the way I’ve seen them do it”. Conclusions. This study found that home BP measurement is not performed according to guideline recommendations and standardised, high-quality education is rarely delivered on how to measure BP at home. These findings highlight an urgent need for effective education strategies to support high-quality home BP measurement to appropriately inform BP management.

Validation of combiomed hipermax-BF model A7101 automatic oscillometric upper-arm sphygmomanometer in general population: AAMI/ESH/ISO universal standard (ISO 81060-2:2018/Amd 1:2020).

This study evaluates the accuracy of the Hipermax-BF model A7101 (Combiomed, Havana, Cuba) automatic oscillometric upper-arm sphygmomanometer for office and home use in general population as part of the HEARTS in the Americas initiative. The research was developed according to the Universal Standard AAMI/ESH/ISO ISO 81060-2:2018/Amd 1:2020. The subjects were recruited according to the requirements of age, gender, blood pressure values and upper-arm circumference. The same upper-arm sequential blood pressure measurement method was used. For measurements with the device under test, the 2-piece cuff from 22-44 cm limb circumference range was used. 92 subjects were recruited and 85 were analyzed. Mean age was 44.8 ± 14.7 years, mean upper-arm circumference was 32.3 ± 6.2, and 56.5% were female. For Validation Criterion 1, the mean value ± standard deviation of the differences in readings between the device under test and the reference device was 1.2 ± 4.9/0.8 ± 4.9 mmHg (systolic/diastolic). For both pressures, in criterion 1 the standard requires a mean value of the differences ≤ ± 5 mmHg and a standard deviation ≤ ± 8 mmHg. For Validation Criterion 2, the standard deviation of the mean blood pressure differences per subject was 4.2/4.2 mmHg (systolic/diastolic). According to Table 1 of criterion 2, for the mean values of 1.2/0.8 mmHg (systolic/diastolic), the maximum allowable standard deviation had to be < 6.84 for systolic and < 6.89 for diastolic pressure. The Combiomed Hipermax-BF A7101 automatic sphygmomanometer meets the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018/Amd 1:2020) in the general population.

Absolute cardiovascular risk assessment using ‘real world’ clinic blood pressures compared to standardized unobserved and ambulatory methods: an observational study

Clinic blood pressure (BP) is recommended for absolute cardiovascular disease (CVD) risk assessment. However, in ‘real-world’ settings, clinic BP measurement is unstandardised and less reliable compared to more rigorous methods but the impact for absolute CVD risk assessment is unknown. This study aimed to determine the difference in absolute CVD risk assessment using real-world clinic BP compared to standardised BP methods. Participants were patients (n = 226, 59 ± 15 years; 58% female) with hypertension referred to a BP clinic for assessment. ‘Real-world’ clinic BP was provided by the referring doctor. All participants had unobserved automated office BP (AOBP) and 24-h ambulatory BP monitoring (ABPM) measured at the clinic. Absolute CVD risk was calculated (Framingham) using systolic BP from the referring doctor (clinic BP), AOBP and ABPM, with agreement assessed by Kappa statistic. Clinic systolic BP was 18 mmHg than AOBP and daytime ABPM and 22 mmHg higher than 24-h ABPM (p < 0.001). Subsequently, absolute CVD risk scores using clinic BP were higher compared to AOBP, daytime ABPM and 24-h ABPM (10.4 ± 8.1%, 7.8 ± 6.4%, 7.8 ± 6.3%, and 7.3 ± 6.1%, respectively, P < 0.001). As a result, more participants were classified as high CVD risk using clinic BP (n = 89, 40%) compared with AOBP (n = 44, 20%) daytime ABPM (n = 38, 17%) and 24-h ABPM (n = 38, 17%) (p < 0.001) with weak agreement in risk classification (κ = 0.57[0.45–0.69], κ = 0.52[0.41–0.64] and κ = 0.55[0.43–0.66], respectively). Real-world clinic BP was higher and classified twice as many participants at high CVD risk compared to AOBP or ABPM. Given the challenges to high-quality BP measurement in clinic, more rigorous BP measurement methods are needed for absolute CVD risk assessment.

Assessment of blood pressure variability: characteristics and comparison of blood pressure measurement methods.

Previous studies have reported that blood pressure variability (BPV) is associated with the risk of cardiovascular events independent of blood pressure (BP) levels. While there is little evidence from intervention trials examining whether suppressing BPV is useful in preventing cardiovascular disease, it is suggested that detection of abnormally elevated BPV may be useful in reducing cardiovascular events adding by complementing management of appropriate BP levels. Cuffless BP devices can assess beat-to-beat BPV. Although cuffless BP monitoring devices have measurement accuracy issues that need to be resolved, this is an area of research where the evidence is accumulating rapidly, with many publications on beat-to-beat BPV over several decades. Ambulatory BP monitoring (ABPM) can assess 24-hour BPV and nocturnal dipping patterns. Day-to-day BPV and visit-to-visit BPV are assessed by self-measured BP monitoring at home and office BP measurement, respectively. 24 h, day-to-day, and visit-to-visit BPV have been reported to be associated with cardiovascular prognosis. Although there have been several studies comparing whether ABPM and self-measured BP monitoring at home is the superior measurement method of BPV, no strong evidence has been accumulated that indicates whether ABPM or self-measured home BP is superior. ABPM and self-measured BP monitoring have their own advantages and complement each other in the assessment of BPV.

Validation of the AViTA upper-arm blood pressure monitor BP636 with multiple cuff sizes in the general population according to the ANSI/AAMI/ISO 81060-2:2018/Amd1:2020.

To determine the accuracy of the AViTA BP636 upper-arm home blood pressure (BP) monitor in general populations with small to extra-large arms according to the ANSI/AAMI/ISO Universal Standard (ISO 81060-2 : 2018/Amd1 : 2020). The AViTA BPM636 was utilized on 85 adult participants with upper-arm circumferences ranging from 15 to 52 cm, and four cuffs of different sizes (small: 15-22 cm, normal: 22-33 cm, large: 33-42 cm, and extra large: 42-52 cm) were used in this study. The recruitment fulfills the criteria of the ANSI/AAMI/ISO Universal Standard 81060-2 : 2018/Amd1 : 2020 in the general population using the same arm sequential BP measurement method. For validation criterion 1, the mean ± SD of the differences between the test device and reference blood pressure readings was -0.35 ± 4.68/0.56 ± 3.93 mmHg (systolic/diastolic) for adults. The mean difference of SBP between the test device and the reference device was -0.35 mmHg with a SD of 3.50 mmHg, wh{ich was within the acceptable range for criterion 2 (i.e. less than 6.93 mmHg) Similarly, the mean difference in DBP was 0.56 mmHg with a SD of 3.38 mmHg, which also met the criterion 2 (i.e. within 6.91 mmHg). AViTA BPM636 passed the criteria of the ANSI/AAMI/ISO 81060-2 : 2018/Amd 1 : 2020 protocol. It can be recommended for home-based BP measurements in the general population and people with extra-large arms ranging from 42 to 52 cm.

Real-World Treatment of Hypertension on Hemodialyses Data from a Large Polish Database.

The prevalence of hypertension among patients with end-stage kidney disease (ESKD) undergoing hemodialysis (HD) ranges from 72 to 88% depending on applied diagnostic criteria and the chosen method of blood pressure measurement. Despite the guidelines recommending the widespread use of renin-angiotensin system blockers (RASBs) in patients with kidney disease, their utilization in patients on HD may be suboptimal, especially in patients with preserved diuresis. This hesitance that often steams from concern is often due to fear of a decrease in eGFR and a subsequent decrease in diuresis. The aim of this study was to compare clinical characteristics, blood pressure, safety, and HD adequacy indices in hypertensive HD patients on multiple antihypertensive drug regimens, including diuretic treated with RASB (RASB group) or without RASB (no-RASB) with preserved residual diuresis. We sought to examine the real-life use of RASB in HD patients in relation to their clinical characteristics, blood pressure, safety, and HD adequacy. From a database of 5,879 patients receiving HD (mean age 65.2 ± 14.2 years, 60% of males) of the largest provider of HD in the country, we selected the subgroup treated with at least three antihypertensive medications including diuretics. We compared patients treated with RASB to counterparts without RASB (no-RASB). The RASB group has similar age and gender proportions as well as BMI and bioimpedance compared to counterparts. However, dry body mass was significantly lower in the RASB group (78.1 ± 18.3 kg vs. 80.0 ± 18.2 kg, p &lt; 0.017). Prevalence of diabetes mellitus was similar in both groups, but RASB-treated patients have cardiovascular diseases more frequently (70.1 vs. 60.8%; p &lt; 0.001). Systolic blood pressure and the number of antihypertensive drugs used were significantly higher in RASB patients than in counterparts (146 ± 16 mm Hg vs. 144 ± 15 mm Hg; p &lt; 0.001 and 4.1 ± 0.9 vs. 3.5 ± 0.5; p &lt; 0001, respectively). RASB-treated patients have significantly longer dialysis vintage (52.7 ± 44.4 months vs. 40.2 ± 40.9 months; p &lt; 0.001) and dialysis time (722 ± 87.1 min/week vs. 713 ± 93.4 min/week; p &lt; 0.017) than counterparts. Serum potassium was slightly but significantly higher in RASB (5.3 ± 0.8 mmol/L vs. 5.1 ± 0.7 mmol/L; p &lt; 0.01). In the real world setting, RASB can be safely used in HD patients treated with diuretics with preserved residual diuresis. Given that many HD patients present numerous multimorbidities, RASB should not only be considered as an additional hypotensive drug in poorly controlled hypertension but also in other compelling indications in HD patients. The tendency toward hyperkalemia in HD patients could be effectively managed with appropriate diet and HD prescription adjustments.

Validation of the DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor in the general population according to the ISO 81060-2:2018/AMD 1:2020 protocol.

The aim of this study was to evaluate the accuracy of the DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor in the general population according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). The test monitor was used to measure SBP and DBP and pulse rate in the wrists using the oscillometric method. According to this protocol using the same-arm sequential blood pressure measurement method, subjects were recruited to fulfill the age, sex, blood pressure, and cuff distribution criteria of the Universal Standard. A single cuff for wrist sizes of 13.5-21.5 cm was used. A total of 85 subjects were included in this study. According to Criterion 1, the mean difference in SBP between the test device and the reference device was 0.89 mmHg, with a SD of 7.76 mmHg. The mean difference of DBP was -1.44 mmHg, with a SD of 6.23 mmHg. The mean difference between SBP and DBP was less than 5.0 mmHg, and the SD was less than 8.0 mmHg, which met the requirements. According to Criterion 2, the SD of the mean differences of SBP between the test device and the reference device per subject was 5.65 mmHg, which was less than 6.88 mmHg and met the requirements. The SD of the mean differences of DBP between the test device and the reference device per subject was 5.61 mmHg, which was less than 6.78 mmHg and met the requirements. The DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor met the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). It can be recommended for home and clinical use.

Patient experiences with blood pressure measurement methods for hypertension diagnosis: Qualitative findings from the BP-CHECK study.

Out-of-office blood pressure (BP) measurement is recommended when making a new hypertension diagnosis. In practice, however, hypertension is primarily diagnosed using clinic BP. The study objective was to understand patient attitudes about accuracy and patient-centeredness regarding hypertension diagnostic methods. Qualitative study within a randomized controlled diagnostic study conducted between May 2017 and March 2019 comparing the accuracy and acceptability of BP measurement methods among patients in an integrated healthcare delivery system. All participants completed 24-hour ambulatory blood pressure monitoring (ABPM), plus either clinic BP, home BP monitoring (HBPM), or kiosk BP diagnostic testing. Qualitative interviewees (aged 31-76 years, n=35) were recruited from the main study. Participants who completed HBPM found it to be comfortable and low burden, and believed it produced accurate results. Participants in the clinic arm described clinic measurements as inconvenient. Participants in the kiosk arm overall did not favor kiosks due to concerns about accuracy and privacy. Participants described ABPM as the most accurate method due to repeated measurements over the 24-hour period in real-world contexts, but many found it uncomfortable and disruptive. Participants also noted methods that involved repeated measures such as HBPM and ABPM particularly influenced their understanding of whether or not they had hypertension. Hypertension diagnostic methods that include more BP measurements help patients gain a deeper understanding of BP variability and the lower reliability of infrequent measurements in clinic. These findings warrant implementing strategies to enhance out-office BP diagnostic testing in primary care.

Comparação da monitorização invasiva e não invasiva da pressão arterial em Cuniculus paca (Paca)

Cuniculus paca, a South American wild rodent with zootechnical potential, requires anesthesia for management procedures. However, limited information is available regarding safe monitoring of this animal under anesthesia. This study aimed to compare with gold standard invasive method and validate non-invasive blood pressure measurements using an oscillometric monitor in Cuniculus paca. Eight healthy adult females undergoing general anesthesia for follicular aspiration were included. Systolic, diastolic, and mean arterial pressures were measured simultaneous using, oscillometric non-invasive monitor with its cuff placed on the radial artery and an invasive catheter placed in the dorsal metatarsal artery. Measurements were compared using the t-test, correlated by Pearson test, and analyzed using the Bland-Altman concordance test. The results indicated that only systolic pressure measured by non-invasive oscillometric methos was similar to the pressure measurement by invasive method (P=0.6372, r=0.5969, bias 0.59±20.9 mmHg); while mean and diastolic pressures were underestimated by the non-invasive method. In conclusion, non-invasive oscillometric monitor provides a valid and reliable method for systolic blood pressure measurement in Cuniculus paca under general anesthesia.

Validation of oscillometric ratio and maximum gradient methods for non-invasive blood pressure measurement with intra-arterial blood pressure measurements as reference.

Most non-invasive blood pressure (BP) measurements are carried out using instruments which implement either the Ratio or the Maximum Gradient oscillometric method, mostly during cuff deflation, but more rarely during cuff inflation. Yet, there is little published literature on the relative advantages and accuracy of these two methods. In this study of 40 lightly sedated individuals aged 64.1 ± 9.6 years, we evaluate and compare the performance of the oscillometric ratio (K) and gradient (Grad) methods for the non-invasive estimation of mean pressure, SBP and DBP with reference to invasive intra-arterial values. There was no significant difference between intra-arterial estimates of mean pressure made via Korotkoff sounds (MP-OWE) or the gradient method (MP-Grad). However, 17.7% of MP-OWE and 15% of MP-Grad were in error by more than 10 mmHg. SBP-K and SBP-Grad underestimated SBP by 14 and 18 mmHg, whilst accurately estimating DBP with mean errors of 0.4 ± 5.0 and 1.7 ± 6.1 mmHg, respectively. Relative to the reference standard SBP-K, SBP-Grad and DBP-Grad were estimated with a mean error of -4.5 ± 6.6 and 1.4 ± 5.6 mmHg, respectively, noting that using the full range of recommended ratios introduces errors of 12 and 7 mmHg in SBP and DBP, respectively. We also show that it is possible to find ratios which minimize the root mean square error (RMSE) and the mean error for any particular individual cohort. We developed linear models for estimating SBP and SBP-K from a range of demographic and non-invasive OWE variables with resulting mean errors of 0.15 ± 5.6 and 0.3 ± 5.7 mmHg, acceptable according to the Universal standard.

More shadows than lights in the blood pressure measurement method?

More shadows than lights in the blood pressure measurement method?

Determining the optimal diagnostic and risk stratification approaches for people with hypertension in two rural populations in Kenya and The Gambia: a study protocol for IHCoR-Africa Work Package 2.

Sub-Saharan Africa (SSA) has one of the highest prevalences of hypertension worldwide. The impact of hypertension is of particular concern in rural SSA, where access to clinics and hospitals is limited. Improvements in the management of people with hypertension in rural SSA could be achieved by sharing diagnosis and care tasks between the clinic and the community. To develop such a community-centred programme we need optimal approaches to identify and risk stratify patients with elevated blood pressure. The aim of the study is to improve the evidence base for diagnosis and risk estimation for a community-centred hypertension programme in two rural settings in SSA. We will conduct a cross-sectional study of 1250 adult participants in Kilifi, Kenya and Kiang West, The Gambia. The study has five objectives which will determine the: (1) accuracy of three blood pressure (BP) measurement methods performed by community health workers in identifying people with hypertension in rural SSA, compared to the reference standard method; (2) relationship between systolic BP and cardiovascular risk factors; (3) prevalence of hypertension-mediated organ damage (HMOD); (4) accuracy of innovative point-of-care (POC) technologies to identify patients with HMOD; and (5) cost-effectiveness of different combinations of BP and HMOD measurements for directing hypertension treatment initiation. This study will determine the accuracy of three methods for community BP measurement and POC technologies for HMOD assessment. Using the optimal methods in this setting it will estimate the prevalence of hypertension and provide the best estimate to date of HMOD prevalence in SSA populations. The cost-effectiveness of decision-making approaches for initiating treatment of hypertension will be modelled. These results will inform the development of a community-centred programme to improve care for hypertensive patients living in rural SSA. Existing community engagement networks will be used to disseminated within the research setting.

UWB-enabled Sensing for Fast and Effortless Blood Pressure Monitoring

Blood Pressure (BP) is a critical vital sign to assess cardiovascular health. However, existing cuff-based and wearable-based BP measurement methods require direct contact between the user's skin and the device, resulting in poor user experience and limited engagement for regular daily monitoring of BP. In this paper, we propose a contactless approach using Ultra-WideBand (UWB) signals for regular daily BP monitoring. To remove components of the received signals that are not related to the pulse waves, we propose two methods that utilize peak detection and principal component analysis to identify aliased and deformed parts. Furthermore, to extract BP-related features and improve the accuracy of BP prediction, particularly for hypertensive users, we construct a deep learning model that extracts features of pulse waves at different scales and identifies the different effects of features on BP. We build the corresponding BP monitoring system named RF-BP and conduct extensive experiments on both a public dataset and a self-built dataset. The experimental results show that RF-BP can accurately predict the BP of users and provide alerts for users with hypertension. Over the self-built dataset, the mean absolute error (MAE) and standard deviation (SD) for SBP are 6.5 mmHg and 6.1 mmHg, and the MAE and SD for DBP are 4.7 mmHg and 4.9 mmHg.