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Journal of the American Association For... Sep 2022Noninvasive blood pressure measurement devices have gained popularity in recent years as an alternative to radiotelemetry and other invasive blood pressure measurement...
Noninvasive blood pressure measurement devices have gained popularity in recent years as an alternative to radiotelemetry and other invasive blood pressure measurement techniques. While many factors must be considered when choosing a measurement method, specific variables should be evaluated when using a tail-cuff blood pressure technique. Rodents have complex and dynamic thermal biology processes that involve fluctuating vasomotor tone of the tail. This and other factors that affect vascular tone, such as the autonomic response to stress, significantly affect peripheral blood flow. Awareness and consideration of thermoregulatory states and vasomotor tone can increase success and decrease variability when measuring blood pressure measurements using a tail-cuff measurement technique.
Topics: Animals; Blood Pressure; Blood Pressure Determination; Body Temperature Regulation; Rodentia; Tail
PubMed: 35948400
DOI: 10.30802/AALAS-JAALAS-22-000006 -
Burns : Journal of the International... Nov 2018Accurate blood pressure monitoring is essential for burn management, with the intra-arterial line method being the gold standard. Here we evaluated agreement between...
INTRODUCTION
Accurate blood pressure monitoring is essential for burn management, with the intra-arterial line method being the gold standard. Here we evaluated agreement between cuff and intra-arterial line methods.
METHODS
Data from burned children admitted from 1997 to 2016 were retrospectively reviewed. Simultaneously collected intra-arterial and cuff measurements were cross-matched and linear regression performed to assess agreement for systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP).
RESULTS
We identified 9969 matches for SBP, DBP, and MAP in 872 patients (579 male) aged 8±5years with burns covering 52±20% of the total body surface area and a hospitalization lasting 33±31 days. Intra-arterial lines had a complication rate of 1%. The mean bias (95% CI) between methods was 1.3 (0.5, 2.1) mm Hg for SBP, -6.4 (-7.0, -5.7) mmHg for DBP, and -5.8 (-6.4, -5.3) mmHg for MAP. The standard deviation of the bias (95% limit of agreement) was 12.1 (-22.5, 25.1) mmHg for SBP, 9.9 (-25.8, 13.0) mmHg for DBP, and 8.7 (-22.8, 11.1) mmHg for MAP.
CONCLUSIONS
Cuff measurements vary widely from those of intra-arterial lines, which have a low complication rate. Intra-arterial lines are advisable when tight control of the hemodynamic response is essential.
Topics: Adolescent; Arterial Pressure; Blood Pressure Determination; Burns; Catheterization, Peripheral; Child; Child, Preschool; Female; Humans; Hypertension; Hypotension; Male; Trauma Severity Indices
PubMed: 30153960
DOI: 10.1016/j.burns.2018.03.001 -
American Journal of Physiology. Heart... Oct 2021Signal-averaged sympathetic transduction of blood pressure (BP) is inversely related to resting muscle sympathetic nerve activity (MSNA) burst frequency in healthy...
Signal-averaged sympathetic transduction of blood pressure (BP) is inversely related to resting muscle sympathetic nerve activity (MSNA) burst frequency in healthy cohorts. Whether this represents a physiological compensatory adaptation or a methodological limitation, remains unclear. The current analysis aimed to determine the contribution of methodological limitations by evaluating the dependency of MSNA transduction at different levels of absolute BP. Thirty-six healthy participants (27 ± 7 yr, 9 females) underwent resting measures of beat-to-beat heart rate, BP, and muscle sympathetic nerve activity (MSNA). Tertiles of mean arterial pressure (MAP) were computed for each participant to identify cardiac cycles occurring below, around, and above the MAP operating pressure (OP). Changes in hemodynamic variables were computed across 15 cardiac cycles within each MAP tertile to quantify sympathetic transduction. MAP increased irrespective of sympathetic activity when initiated below the OP, but with MSNA bursts provoking larger rises (3.0 ± 0.9 vs. 2.1 ± 0.7 mmHg; < 0.01). MAP decreased irrespective of sympathetic activity when initiated above the OP, but with MSNA bursts attenuating the drop (-1.3 ± 1.1 vs. -3.1 ± 1.2 mmHg; < 0.01). In participants with low versus high resting MSNA (12 ± 4 vs. 32 ± 10 bursts/min), sympathetic transduction of MAP was not different when initiated by bursts below (3.2 ± 1.0 vs. 2.8 ± 0.9 mmHg; = 0.26) and above the OP (-1.0 ± 1.3 vs. -1.6 ± 0.8 mmHg; = 0.08); however, low resting MSNA was associated with a smaller proportion of MSNA bursts firing above the OP (15 ± 5 vs. 22 ± 5%; < 0.01). The present analyses demonstrate that the signal-averaging technique for calculating sympathetic transduction of BP is influenced by the timing of an MSNA burst relative to cyclic oscillations in BP. The current signal-averaging technique for calculating sympathetic transduction of blood pressure does not consider the arterial pressure at which each muscle sympathetic burst occurs. A burst firing when mean arterial pressure is above the operating pressure was associated with a decrease in blood pressure. Thus, individuals with higher muscle sympathetic nerve activity demonstrate a reduced sympathetic transduction owing to the weighted contribution of more sympathetic bursts at higher levels of arterial pressure.
Topics: Adult; Arterial Pressure; Blood Pressure Determination; Cardiovascular System; Electric Impedance; Electrodiagnosis; Female; Humans; Male; Muscle, Skeletal; Photoplethysmography; Rest; Sympathetic Nervous System; Time Factors; Young Adult
PubMed: 34506224
DOI: 10.1152/ajpheart.00422.2021 -
Scientific Reports Jan 2023There is a growing emphasis being placed on the potential for cuffless blood pressure (BP) estimation through modelling of morphological features from the...
There is a growing emphasis being placed on the potential for cuffless blood pressure (BP) estimation through modelling of morphological features from the photoplethysmogram (PPG) and electrocardiogram (ECG). However, the appropriate features and models to use remain unclear. We investigated the best features available from the PPG and ECG for BP estimation using both linear and non-linear machine learning models. We conducted a clinical study in which changes in BP ([Formula: see text]BP) were induced by an infusion of phenylephrine in 30 healthy volunteers (53.8% female, 28.0 (9.0) years old). We extracted a large and diverse set of features from both the PPG and the ECG and assessed their individual importance for estimating [Formula: see text]BP through Shapley additive explanation values and a ranking coefficient. We trained, tuned, and evaluated linear (ordinary least squares, OLS) and non-linear (random forest, RF) machine learning models to estimate [Formula: see text]BP in a nested leave-one-subject-out cross-validation framework. We reported the results as correlation coefficient ([Formula: see text]), root mean squared error (RMSE), and mean absolute error (MAE). The non-linear RF model significantly ([Formula: see text]) outperformed the linear OLS model using both the PPG and the ECG signals across all performance metrics. Estimating [Formula: see text]SBP using the PPG alone ([Formula: see text] = 0.86 (0.23), RMSE = 5.66 (4.76) mmHg, MAE = 4.86 (4.29) mmHg) performed significantly better than using the ECG alone ([Formula: see text] = 0.69 (0.45), RMSE = 6.79 (4.76) mmHg, MAE = 5.28 (4.57) mmHg), all [Formula: see text]. The highest ranking features from the PPG largely modelled increasing reflected wave interference driven by changes in arterial stiffness. This finding was supported by changes observed in the PPG waveform in response to the phenylephrine infusion. However, a large number of features were required for accurate BP estimation, highlighting the high complexity of the problem. We conclude that the PPG alone may be further explored as a potential single source, cuffless, blood pressure estimator. The use of the ECG alone is not justified. Non-linear models may perform better as they are able to incorporate interactions between feature values and demographics. However, demographics may not adequately account for the unique and individualised relationship between the extracted features and BP.
Topics: Humans; Female; Child; Male; Blood Pressure; Blood Pressure Determination; Photoplethysmography; Machine Learning; Electrocardiography
PubMed: 36653426
DOI: 10.1038/s41598-022-27170-2 -
American Family Physician Sep 2021
Topics: Blood Pressure; Blood Pressure Determination; Humans
PubMed: 34523901
DOI: No ID Found -
Journal of Clinical Hypertension... Jul 2018A summary of statements for blood pressure (BP) measurement in the evaluation of hypertension in the 21st century by 25 international experts is provided. The status of...
A summary of statements for blood pressure (BP) measurement in the evaluation of hypertension in the 21st century by 25 international experts is provided. The status of office, home and ambulatory BP measurement techniques are discussed. Office BP measurement, whether automated (preferred), or otherwise, should only be used as a screening measurement, and diagnostic decisions for the initiation and titration of drug treatment should be based on out-of-office measurements (ambulatory or home). The hardware and software requirements and the adaptations of BP measuring devices to record other cardiovascular functions, such as arrhythmias, and adaptations for smartphone use and for electronic transmission are discussed. Regulatory bodies are urged to make accuracy and performance assessment mandatory before marketing BP measuring devices. The legal implications of manufacturing inaccurate devices are noted.
Topics: Blood Pressure; Blood Pressure Determination; Blood Pressure Monitoring, Ambulatory; History, 21st Century; Humans; Hypertension; Office Visits; Reproducibility of Results; Sphygmomanometers
PubMed: 30003700
DOI: 10.1111/jch.13323 -
Sensors (Basel, Switzerland) Jan 2020This paper presents a newly-designed and realized Invasive Blood Pressure (IBP) device for the simulation on patient's monitors. This device shows improvements and...
This paper presents a newly-designed and realized Invasive Blood Pressure (IBP) device for the simulation on patient's monitors. This device shows improvements and presents extended features with respect to a first prototype presented by the authors and similar systems available in the state-of-the-art. A peculiarity of the presented device is that all implemented features can be customized from the developer and from the point of view of the end user. The realized device has been tested, and its performances in terms of accuracy and of the back-loop measurement of the output for the blood pressure regulation utilization have been described. In particular, an accuracy of ±1 mmHg at 25 °C, on a range from -30 to 300 mmHg, was evaluated under different test conditions. The designed device is an ideal tool for testing IBP modules, for zero setting, and for calibrations. The implemented extended features, like the generation of custom waveforms and the Universal Serial Bus (USB) connectivity, allow use of this device in a wide range of applications, from research to equipment maintenance in clinical environments to educational purposes. Moreover, the presented device represents an innovation, both in terms of technology and methodologies: It allows quick and efficient tests to verify the proper functioning of IBP module of patients' monitors. With this innovative device, tests can be performed directly in the field and faster procedures can be implemented by the clinical maintenance personnel. This device is an open source project and all materials, hardware, and software are fully available for interested developers or researchers.
Topics: Blood Pressure; Blood Pressure Determination; Blood Pressure Monitors; Calibration; Equipment Design; Humans; Monitoring, Physiologic; Software
PubMed: 31906383
DOI: 10.3390/s20010259 -
American Journal of Hypertension Aug 2021Conventional measures for assessing arterial stiffness are inherently pressure dependent. Whereas statistical pressure adjustment is feasible in (larger) populations, it...
BACKGROUND
Conventional measures for assessing arterial stiffness are inherently pressure dependent. Whereas statistical pressure adjustment is feasible in (larger) populations, it is unsuited for the evaluation of an individual patient. Moreover, statistical "correction" for blood pressure may actually correct for: (i) the acute dependence of arterial stiffness on blood pressure at the time of measurement; and/or (ii) the remodeling effect that blood pressure (hypertension) may have on arterial stiffness, but it cannot distinguish between these processes.
METHODS
We derived-assuming a single-exponential pressure-diameter relationship-3 theoretically pressure-independent carotid stiffness measures suited for individual patient evaluation: (i) stiffness index β0, (ii) pressure-corrected carotid pulse wave velocity (cPWVcorr), and (iii) pressure-corrected Young's modulus (Ecorr). Using linear regression analysis, we evaluated in a sample of the CATOD study cohort changes in mean arterial pressure (ΔMAP) and comparatively the changes in the novel (Δβ0, ΔcPWVcorr, and ΔEcorr) as well as conventional (ΔcPWV and ΔE) stiffness measures after a 2.9 ± 1.0-year follow-up.
RESULTS
We found no association between ΔMAP and Δβ0, ΔcPWVcorr, or ΔEcorr. In contrast, we did find a significant association between ΔMAP and conventional measures ΔcPWV and ΔE. Additional adjustments for biomechanical confounders and traditional risk factors did neither materially change these associations nor the lack thereof.
CONCLUSIONS
Our newly proposed pressure-independent carotid stiffness measures avoid the need for statistical correction. Hence, these measures (β0, cPWVcorr, and Ecorr) can be used in a clinical setting for (i) patient-specific risk assessment and (ii) investigation of potential remodeling effects of (changes in) blood pressure on intrinsic arterial stiffness.
Topics: Ambulatory Care Facilities; Blood Pressure; Blood Pressure Determination; Carotid Arteries; Elastic Modulus; Humans; Pulse Wave Analysis; Reproducibility of Results; Vascular Stiffness
PubMed: 33564865
DOI: 10.1093/ajh/hpab028 -
JAMA Network Open Aug 2022
Topics: Blood Pressure; Blood Pressure Determination; Blood Pressure Monitoring, Ambulatory; Humans; Technology
PubMed: 36044220
DOI: 10.1001/jamanetworkopen.2022.32775 -
Sensors (Basel, Switzerland) May 2022Painless, cuffless and continuous blood pressure monitoring sensors provide a more dynamic measure of blood pressure for critical diagnosis or continuous monitoring of...
Painless, cuffless and continuous blood pressure monitoring sensors provide a more dynamic measure of blood pressure for critical diagnosis or continuous monitoring of hypertensive patients compared to current cuff-based options. To this end, a novel flexible, wearable and miniaturized microstrip patch antenna topology is proposed to measure dynamic blood pressure (BP). The methodology was implemented on a simulated five-layer human tissue arm model created and designed in High-Frequency Simulation Software “HFSS”. The electrical properties of the five-layer human tissue were set at the frequency range (2−3) GHz to comply with clinical/engineering standards. The fabricated patch incorporated on a 0.4 mm epoxy substrate achieved consistency between the simulated and measured reflection coefficient results at flat and bent conditions over the frequency range of 2.3−2.6 GHz. Simulations for a 10 g average specific absorption rate (SAR) based on IEEE-Standard for a human arm at different input powers were also carried out. The safest input power was 50 mW with an acceptable SAR value of 3.89 W/Kg < 4W/Kg. This study also explored a novel method to obtain the pulse transit time (PTT) as an option to measure BP. Pulse transmit time is based on obtaining the time difference between the transmission coefficient scattering waveforms measured between the two pairs of metallic sensors underlying the assumption that brachial arterial geometries are dynamic. Consequently, the proposed model is validated by comparing it to the standard nonlinear Moens and Korteweg model over different artery thickness-radius ratios, showing excellent correlation between 0.76 ± 0.03 and 0.81 ± 0.03 with the systolic and diastolic BP results. The absolute risk of arterial blood pressure increased with the increase in brachial artery thickness-radius ratio. The results of both methods successfully demonstrate how the radius estimates, PTT and pulse wave velocity (PWV), along with electromagnetic (EM) antenna transmission propagation characteristics, can be used to estimate continuous BP non-invasively.
Topics: Blood Pressure; Blood Pressure Determination; Humans; Hypertension; Pulse Wave Analysis; Wearable Electronic Devices
PubMed: 35684617
DOI: 10.3390/s22113996