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Annual International Conference of the... Jul 2020This work presents a new technique for the noninvasive measurement of systolic blood pressure (sBP), mean blood pressure (mBP) and diastolic blood pressure (dBP) using...
This work presents a new technique for the noninvasive measurement of systolic blood pressure (sBP), mean blood pressure (mBP) and diastolic blood pressure (dBP) using photo-plethysmographic (PPG) sensors when an artery is exposed to an external pressure. Two sets of experiments were performed: a first study combining PPG with an oscillometric device and the second combining PPG with a force/pressure sensor. These two experiments enable the estimation of BP values. PPG results were found to be comparable to oscillometric results, with bias and precision errors of -0.81 and 5.26 for sBP, 1.12 and 5.61 for mBP and 1.67 and 9.09 for dBP (n = 28). Furthermore, amplification over the brachial-to-finger path was found to be 1.02 ± 0.08 for mBP (n = 20) confirming that mBP does not undergo any amplification along the arterial tree whereas, for sBP, an amplification of 1.20 ± 0.12 (n = 7) was found for green wavelength, 1.35 ± 0.09 (n = 6) for red wavelength and 1.36 ± 0.09 (n = 6) for infrared wavelength. Thus, amplification for sBP is bigger for red and infrared wavelengths compared to green one.
Topics: Arterial Pressure; Arteries; Blood Pressure; Blood Pressure Determination; Humans; Oscillometry
PubMed: 33019108
DOI: 10.1109/EMBC44109.2020.9176730 -
Physical and Engineering Sciences in... Jun 2021In recent studies, the physiological parameters derived from human vital signals are found as the status response of the heart and arteries. In this paper, we therefore...
In recent studies, the physiological parameters derived from human vital signals are found as the status response of the heart and arteries. In this paper, we therefore firstly attempt to extract abundant vital features from photoplethysmography(PPG) signal, its multivariate derivative signals and Electrocardiogram(ECG) signal, which are verified its statistical significance in BP estimation through statistical analysis t-test. Afterwards, the optimal feature set are obtained by usnig mutual information coefficient analysis, which could investigate the potential associations with blood pressure. The optimized feature set are aid as an input to various machine learning strategies for BP estimation. The results indicates that AdaBoost based BP estimation model outperforms other regression methods. Concurrently, AdaBoost-based model is further analyzed by using the Histograms of Estimation Error and Bland-Altman Plot. The results also indicate the great BP estimation performance of the proposed BP estimation method, and it stays within the Advancement of Medical Instrumention(AAMI) standard. Regarding the British Hypertension Society (BHS), it achieves the grade A for DBP and grade B for MAP. Besides, the experimental result illustrated that our proposed BP estimation method could reduce the MAE and the STD, and improve the r for SBP, MAP and DBP estimation, respectively, which further demonstrates the feasibility of our proposed BP estimation method in this paper.
Topics: Arterial Pressure; Blood Pressure; Blood Pressure Determination; Electrocardiography; Humans; Photoplethysmography
PubMed: 33738778
DOI: 10.1007/s13246-021-00989-1 -
Journal of Hypertension Oct 2017The development and propagation of the aortic blood pressure wave remains poorly understood, despite its clear relevance to major organ blood flow and potential...
INTRODUCTION
The development and propagation of the aortic blood pressure wave remains poorly understood, despite its clear relevance to major organ blood flow and potential association with cardiovascular outcomes. The reservoir pressure model provides a unified description of the dual conduit and reservoir functions of the aorta. Reservoir waveform analysis resolves the aortic pressure waveform into an excess (wave related) and reservoir (compliance related) pressure. The applicability of this model to the pressure waveform as it propagates along the aorta has not been investigated in humans.
METHODS
We analysed invasively acquired high-fidelity aortic pressure waveforms from 40 patients undergoing clinically indicated coronary catheterization. Aortic waveforms were measured using a solid-state pressure catheter at five anatomical sites: the ascending aorta, the transverse aortic arch, the diaphragm, the level of the renal arteries, and at the aortic bifurcation. Ensemble average pressure waveforms were obtained for these sites for each patient and analysed to obtain the reservoir pressure [Pr(t)] and the excess pressure [Px(t)] at each aortic position.
RESULTS
Systolic blood pressure increased at a rate of 2.1 mmHg per site along the aorta, whereas diastolic blood pressure was effectively constant. Maximum Pr decreased only slightly along the aorta (changing by -0.7 mmHg per site), whereas the maximum of Px increased from the proximal to distal aorta (+4.1 mmHg per site; P < 0.001). The time, relative to the start of systolic upstroke, of the occurrence of the maximum excess pressure did not vary along the aorta. Of the parameters used to derive the reservoir pressure waveform the systolic and diastolic rate constants showed divergent changes with the systolic rate constant (ks) decreasing and the diastolic rate constant (kd) increasing along the aorta.
CONCLUSIONS
This analysis confirms the proposition that the magnitude of the calculated reservoir pressure waveform, despite known changes in aortic structure, is effectively constant throughout the aorta. A progressive increase of excess pressure accounts for the increase in pulse pressure from the proximal to distal aorta. The reservoir pressure rate constants seem to behave as arterial functional parameters. The accompanying decrease in ks and increase in kd are consistent with a progressive decrease in aortic compliance and increase in impedance. The reservoir pressure waveform therefore provides a model that might have utility in understanding the generation of central blood pressure and in specific cases might have clinical utility.
Topics: Aorta; Arterial Pressure; Blood Pressure Determination; Cardiac Catheterization; Cohort Studies; Compliance; Humans; Models, Cardiovascular; Signal Processing, Computer-Assisted
PubMed: 28582283
DOI: 10.1097/HJH.0000000000001424 -
Journal of Zoo and Wildlife Medicine :... Mar 2023Cardiovascular disease is common among chimpanzees (), and serial blood pressure monitoring in conscious animals may improve disease surveillance and guide hypertension...
Cardiovascular disease is common among chimpanzees (), and serial blood pressure monitoring in conscious animals may improve disease surveillance and guide hypertension treatment strategies. The objective of this study was to compare the accuracy of a noninvasive, oscillometric blood pressure monitor using a finger blood pressure cuff with invasively measured blood pressure in anesthetized chimpanzees. Twelve chimpanzees were anesthetized with tiletamine-zolazepam intramuscularly, intubated, and maintained on inhaled isoflurane to effect. Blood pressure measurements, which included systolic arterial pressure (SAP), mean arterial pressure (MAP), and diastolic arterial pressure (DAP), were collected simultaneously from an oscillometric blood pressure cuff placed on a forelimb digit (FBP) and a direct arterial catheter (IBP) every 5-10 min while anesthetized. One hundred paired samples were collected, and results were compared using Bland-Altman plots and analysis. FBP showed good agreement with IBP for SAP, MAP, and DAP but consistently overestimated values compared with IBP. FBP may be useful for serial blood pressure monitoring in conscious chimpanzees.
Topics: Animals; Blood Pressure; Pan troglodytes; Blood Pressure Determination; Arterial Pressure; Isoflurane; Blood Pressure Monitors
PubMed: 36971624
DOI: 10.1638/2021-0001 -
BMC Geriatrics Feb 2022Non-Invasive Continuous Arterial Pressure system (NICAP) allows continuous monitoring, timely detection of hypotension, and avoiding risks from invasive procedures. A... (Observational Study)
Observational Study
BACKGROUND
Non-Invasive Continuous Arterial Pressure system (NICAP) allows continuous monitoring, timely detection of hypotension, and avoiding risks from invasive procedures. A previous study showed good comparability of NICAP with arterial line in people with no evidence of cardiovascular disease. Therefore, the goal of this study was to investigate whether NICAP could be accurately applied to elderly patients.
METHODS
In this single-centered observational study, forty-one patients above 65 undergoing elective surgeries requiring artery catheterizations were enrolled from July 17, 2020, to June 25, 2021. Radial artery cannulation and NICAP monitoring were started before anesthesia. Blood pressure during the anesthesia induction and the whole surgery, trend of blood pressure changes, time needed for establishing continuous monitoring, and complications were recorded.
RESULTS
A total of 6751 valid pairs of blood pressure measurements were analyzed. In the Bland-Altman analysis, the arithmetic means for systolic, diastolic, and mean arterial pressure were 2.2, 3.3, and 2.8 mmHg, respectively. NICAP and arterial line correlation coefficients for systolic, diastolic, and mean arterial pressure were 0.49, 0.33, and 0.45, respectively. In the trending analysis, the polar concordance rates at 30 degrees were 70.9% for systolic, 67.7% for diastolic, and 69.3% for mean arterial blood pressure. During the anesthesia induction, the arithmetic means for systolic, diastolic, and mean arterial pressure in the Bland-Altman analysis were 1.7, -0.2, and 0.5 mmHg, respectively. NICAP and arterial line correlation coefficients for systolic, diastolic, and mean arterial pressure were 0.78, 0.61 and 0.75, respectively. No severe complications occurred.
CONCLUSIONS
NICAP has a poor correlation with the arterial line in elderly patients for the whole surgery or during anesthesia induction. Moreover, it showed poor comparability in the detection of blood pressure change trends with arterial lines. Our findings suggest that NICAP might not be sufficiently accurate to be applied clinically in elderly patients with comorbidities. More accurate calibration and iteration are needed.
Topics: Aged; Arterial Pressure; Arteries; Blood Pressure; Blood Pressure Determination; Humans; Vascular Access Devices
PubMed: 35130866
DOI: 10.1186/s12877-022-02803-3 -
Pediatric Research Feb 2024The normative blood pressure values in preterm infants still not well defined during postnatal transition. We aimed to create normative blood pressure (BP) reference...
BACKGROUND
The normative blood pressure values in preterm infants still not well defined during postnatal transition. We aimed to create normative blood pressure (BP) reference values in preterm infants <29 weeks gestational age recorded hourly during the postnatal transition.
METHODS
We included only data from hemodynamically stable newborns. Only BP values measured by umbilical arterial catheter (UAC) were included. The regression model showed that only gestational age and postnatal age in hours determine the BP.
RESULTS
We included 206 out of 547 admitted preterm infants. The BP increases with increasing gestational ages and overtime during the postnatal transition. We constructed 5 BP centile values for each gestational group. BP histograms show that the BP most of the time fluctuated between the 5th and 75th centile values, particularity during day one of life.
CONCLUSIONS
The BP trend values gradually increase in stable preterm infants during the postnatal transition, and preterm infants who do not follow this trend might require hemodynamics assessment.
IMPACT
The normative blood pressure is increasing gradually during the first 3 days after birth and is different with gestational ages. This is first normative blood pressure centile values in stable preterm infant and based on invasive blood pressure monitoring. The data enable more accurate monitoring of hemodynamics in preterm infants during postnatal transition.
Topics: Infant; Infant, Newborn; Humans; Infant, Premature; Blood Pressure; Gestational Age; Blood Pressure Determination; Arterial Pressure; Reference Values
PubMed: 37667035
DOI: 10.1038/s41390-023-02788-8 -
Annual International Conference of the... Jul 2019The aim was to propose a cuff-less, cost-efficient, and ultra-convenient blood pressure monitoring technique with a 3-axis accelerometer.
OBJECTIVE
The aim was to propose a cuff-less, cost-efficient, and ultra-convenient blood pressure monitoring technique with a 3-axis accelerometer.
METHODS
The efficacy of the proposed approach was examined in 8 young healthy volunteers undergoing different activities with a 3-axis accelerometer leveled on their upper chest. The 3-dimensional accelerations were exploited to select features for the calculation of systolic pressure (SP) and diastolic pressure (DP); the whole process involved signal processing, feature extraction, linear multivariate regression, and leave-one-out cross validations (LOOCV).
RESULTS
DP and SP could be approximated with the linear combination of the extracted features: the L norm of lateral acceleration for both DP and SP, state variation (defined in the proposed algorithm) of vertical acceleration for SP, and I-J interval (defined in ballistocardiogram) of vertical acceleration for DP. The correlation coefficient (r) of the estimated and the measured DP was 0.97, and for SP, r = 0.96. In LOOCV, our best validated results in difference errors were -0.02±3.82 mmHg for DP and -0.59 ± 7.46 mmHg for SP.
CONCLUSION
Compared to AAMI criteria, the proposed acceleration-based technique fulfilled the requirement. The accelerometer-based technique showed the potential to monitor blood pressure cuff-lessly, cost-efficiently, ultra-conveniently, and to be embedded in a long-term wearable device for clinical usage.
Topics: Accelerometry; Arterial Pressure; Ballistocardiography; Blood Pressure; Blood Pressure Determination; Humans
PubMed: 31947410
DOI: 10.1109/EMBC.2019.8857864 -
Revue Medicale Suisse Sep 2022Blood pressure measurement is one of the most frequently performed medical procedures. However, oscillometric BP measuring devices have some technical limitation and...
Blood pressure measurement is one of the most frequently performed medical procedures. However, oscillometric BP measuring devices have some technical limitation and alternative techniques should be considered. Manual auscultatory measurement is the preferred technique in atrial fibrillation. The BP in patients with left ventricular assist device can be estimated using a manual sphygmomanometer combined with Doppler opening signal. In patients with stenosing arterial disease of the upper limbs, the systolic BP can be estimated at lower extremities using a manual sphygmomanometer on the leg combined with pulse oximetry on the toe.
Topics: Arterial Pressure; Atrial Fibrillation; Blood Pressure; Blood Pressure Determination; Humans; Oscillometry
PubMed: 36103120
DOI: 10.53738/REVMED.2022.18.795.1698 -
The International Journal of Artificial... May 2019In rotary blood pump recipients with low blood pressure pulsatility, current oscillometric methods to measure blood pressure are not applicable. The aim of this study...
In rotary blood pump recipients with low blood pressure pulsatility, current oscillometric methods to measure blood pressure are not applicable. The aim of this study was to use ultrasonic Doppler flow measurements to determine blood pressure in this patient population noninvasively. In 28 rotary blood pump recipients, blood pressure was measured three times with the developed Doppler method and compared to the invasive arterial line (n = 15) or to the oscillometric Terumo Elemano BP monitor (n = 13). Blood velocities in the radial artery were recorded by the new Doppler sensor during cuff deflation. A sigmoid curve was fitted to a preprocessed velocity signal and the systolic and mean arterial pressures were determined. A total of 84 measurements were performed, and 17 recordings were visually excluded from further analysis due to obvious artifacts. Both the systolic and mean pressures derived by the Doppler method were in good accordance with the invasively measured pressure (3.7 ± 6.6 mmHg for the systolic and -2.1 ± 7.3 mmHg for the mean pressure). A good agreement between the oscillometric monitor and the Doppler method for the systolic (0.0 ± 6.0 mmHg) and mean (1.0 ± 5.9 mmHg) pressures was observed. In this study, a new Doppler blood pressure measurement system was developed and clinically validated. The novel sensor allows easier placement above the radial artery compared to commercial probes. An algorithm was developed which processes the Doppler signal robustly and is able to determine the systolic as well as the mean arterial blood pressure.
Topics: Aged; Algorithms; Arterial Pressure; Blood Flow Velocity; Blood Pressure Determination; Female; Heart Failure; Heart-Assist Devices; Humans; Male; Middle Aged; Radial Artery; Ultrasonography, Doppler
PubMed: 30854909
DOI: 10.1177/0391398819833371 -
Neurocritical Care Jun 2018
Topics: Arterial Pressure; Blood Pressure Determination; Brain Ischemia; Humans; Subarachnoid Hemorrhage
PubMed: 29873024
DOI: 10.1007/s12028-018-0555-3