Numerical analysis of stress distribution in the upper arm tissues under an inflatable cuff：Implications for noninvasive blood pressure measurement

An inflatable cuff wrapped around the upper arm is widely used in noninvasive blood pressure measurement.However, the mechanical interaction between cuff and arm tissues, a factor that potentially affects the accuracy of noninvasive blood pressure measurement, remains rarely addressed. In the present study, finite element（FE） models were constructed to quantify intra-arm stresses generated by cuff compression, aiming to provide some theoretical evidence for identifying factors of importance for blood pressure measurement or explaining clinical observations. Obtained results showed that the simulated tissue stresses were highly sensitive to the distribution of cuff pressure on the arm surface and the contact condition between muscle and bone. In contrast, the magnitude of cuff pressure and small variations in elastic properties of arm soft tissues had little influence on the efficiency of pressure transmission in arm tissues. In particular, it was found that a thickened subcutaneous fat layer in obese subjects significantly reduced the effective pressure transmitted to the brachial artery, which may explain why blood pressure overestimation occurs more frequently in obese subjects in noninvasive blood pressure measurement.

A Deep Learning-Based Continuous Blood Pressure Measurement by Dual Photoplethysmography Signals

This study proposed a measurement platform for continuous blood pressure estimation based on dual photoplethysmography(PPG)sensors and a deep learning(DL)that can be used for continuous and rapid measurement of blood pressure and analysis of cardiovascular-related indicators.The proposed platform measured the signal changes in PPG and converted them into physiological indicators,such as pulse transit time(PTT),pulse wave velocity(PWV),perfusion index(PI)and heart rate(HR);these indicators were then fed into the DL to calculate blood pressure.The hardware of the experiment comprised 2 PPG components(i.e.,Raspberry Pi 3 Model B and analog-todigital converter[MCP3008]),which were connected using a serial peripheral interface.The DL algorithm converted the stable dual PPG signals acquired from the strictly standardized experimental process into various physiological indicators as input parameters and finally obtained the systolic blood pressure(SBP),diastolic blood pressure(DBP)and mean arterial pressure(MAP).To increase the robustness of the DL model,this study input data of 100 Asian participants into the training database,including those with and without cardiovascular disease,each with a proportion of approximately 50%.The experimental results revealed that the mean absolute error and standard deviation of SBP was 0.17±0.46 mmHg.The mean absolute error and standard deviation of DBP was 0.27±0.52 mmHg.The mean absolute error and standard deviation of MAP was 0.16±0.40 mmHg.

A blood pressure measurement method based on synergetics theory

The principle for blood pressure measurement using pulse transit time is introduced in this paper.And the math model of synergetics theory is studied in detail.The synergetics theory is applied in the analysis of blood pressure measurement data.The simulation results show that the application of synergetics theory is helpful to judge the normal blood pressure,and the accuracy is up to 80%.

Non-Contact Blood Pressure Measurement Based on IPPG

Blood pressure is an important physiological parameter to reflect human vital signs.In order to achieve the non-contact dynamic blood pressure acquisition based on ordinary optical camera,a theoretical understanding of the functional relationship between blood pressure and pulse wave signal conduction time.And through imaging photoelectric plethysmography(IPPG),pulse wave signal conduction time of forehead and hand was obtained with ordinary optical camera.First,the pulse wave conduction time was obtained by recording the video with an ordinary optical camera.Second,real-time blood pressure values were collected.Finally,based on the relationship between blood pressure and pulse wave conduction time,a non-contact blood pressure measurement prediction model was obtained through neural network fitting.So that non-contact blood pressure measurement with optical camera could be completed.The method in this paper has several advantages,such as low requirements on measuring equipment,low cost,and simple operation.It can let people get rid of the discomfort caused by measuring equipment such as cuff and can measure blood pressure at any time.The predicted blood pressure results were compared with an Omron wrist electronic sphygmomanometer.The calculated error of systolic blood pressure is-9.28%~3.16%,and the error of diastolic blood pressure is-9.84~4.35%.

Clinical and Therapeutic Evaluation of Hypertensives According to the Practice of Ambulatory Blood Pressure Measurement (ABPM) at the Bel Air International Clinic in Conakry from January 1, 2019 to November 30, 2022

Introduction: Ambulatory Blood Pressure Measurement (ABPM) is a non- invasive examination recommended for subjects at high cardiovascular risk, and those requiring a nocturnal drop in BP such as elderly and obese subjects, those with secondary hypertension or resistant, diabetics, subjects with metabolic syndrome or sleep apnea syndrome. The objective of this study was to evaluate the contribution of ABPM in the diagnosis and evaluation of the level of control of hypertension under treatment at the Bel Air international clinic. Materials and Methods: This is a retrospective, cross-sectional and descriptive study, carried out at the Bel Air International Clinic in Conakry (Guinea) between January 2019 and November 30, 2022. It included a consecutive series of 180 consenting patients recruited through an ambulatory measurement of 24-hour blood pressure from a FUGADA brand device. Results: We collected 180 patients, with a male predominance (sex-ratio M/F = 2.46). The mean age of the patients was 48.48 ± 14.23 years. The most represented age group was that of 32 to 42 years with 50 cases (27.8%) followed by that of 43 to 52 years with 42 cases or 23.3%. The indication was for diagnostic purposes in 106 cases 58.9%, the therapeutic evaluation in 58 patients (32.2%). The examination was prescribed by a cardiologist in 98 cases (54.4%), a general practitioner in 71 cases (39.4%), a neurologist in 11 cases (6.1%). In the therapeutic evaluation, high blood pressure was controlled in 24 patients (13.3%) and uncontrolled in 34 cases (18.9%). In the diagnostic indication, high blood pressure was confirmed in 79 cases (43.9%) with a statistically significant link (Chi2 = 4.57 and p-value = 0.032). The nycthemeral mean was 187.27 ± 26.22 mmHg for systolic blood pressure (SBP) and 110.37 ± 19.06 mmHg for diastolic blood pressure (DBP), during the day, 151.64 ± 21.45 mmHg for SBP and 71.59 ± 8.67 mmHg for diastolic blood pressure. During the study 65 patients (36.1%) were identified as dippers and 115 patients (63.9%) were no-dipping. The antihypertensive protocol used was monotherapy in 68 cases (37.8%), dual therapy in 46 cases (25.6%), triple therapy in 17 cases (9.4%). However 39 patients or 21.7% were not taking any antihypertensive. Conclusion: This preliminary study, despite the modest sample size, showed the importance of ABPM as a tool for diagnosis, monitoring of hypertensive patients and therapeutic adaptation. A large-scale national study would be necessary for the rational use of ambulatory blood pressure measurement in our context in order to improve the management of hypertensive patients.

Exercise-induced albuminuria and circadian blood pressure abnormalities in type 2 diabetes

AIMTo investigate the relationship between circadian vari-ations in blood pressure （BP） and albuminuria at rest, and during exercise in non-hypertensive type 2 diabetes （T2D） patients.METHODSWe conducted a cross-sectional study in well controlled T2D patients, non-hypertensive, without clinical pro-teinuria and normal creatinine clearance. In each parti-cipant, we recorded the BP using ambulatory bloodTankeu AT et al . Exercise-induced albuminuria and BP in T2DMpressure monitoring （ABPM） for 24-h, and albuminuria at rest and after a standardized treadmill exercise.RESULTSWe enrolled 27 type 2 patients with a median age of 52; and a mean duration of diabetes and HbA1c of 3.6 ± 0.8 years and 6.3% ± 0.5% respectively. Using a 24-h ABPM, we recorded a mean diurnal systolic blood pressure （SBP） of 128 ± 17 mmHg vs nocturnal of 123 ± 19 mmHg （ P = 0.004）, and mean diurnal diastolic blood pressure （DBP） of 83 ± 11 mmHg vs nocturnal 78 ± 14 mmHg （ P = 0.002）. There was a signifcant difference between albuminuria at rest [median = 23 mg, interquartile range （IQR） = 10-51] and after exercise （median = 35 mg, IQR = 23-80, P 〈 0.001）. Patients with exercise induced albuminuria had an increase in nocturnal BP values on all three components （128 mmHg vs 110 mmHg, P = 0.03 for SBP; 83 mmHg vs 66 mmHg, P = 0.04; 106 vs 83, P = 0.02 for mean arterial pressure）, as well as albuminuric patients at rest. Moreover, exercise induced albuminuria detect a less increase in nocturnal DBP （83 vs 86, P = 0.03） than resting albuminuria.CONCLUSIONExercise induced albuminuria is associated with anincrease in nocturnal BP values in T2D patients.

Exercise-induced albuminuria vs circadian variations in blood pressure in type 1 diabetes

AIM To investigated the relationship between exerciseinduced ambulatory blood pressure measurement(ABPM) abnormalities in type 1 diabetes mellitus(T1DM) adolescents. METHODS We conducted a case-control at the National Obesity Center of the Yaoundé Central Hospital, Cameroon. We compared 24 h ABPM and urinary albumin-to-creatinine ratio(ACR) at rest and after a standardized treadmill exercise between 20 Cameroonian T1 DM patients and 20 matched controls. T1 DM adolescents were aged 12-18 years, with diabetes for at least one year, without proteinuria, with normal office blood pressure(BP) and renal function according to the general referencepopulation. Non-diabetic controls were adolescents of general population matched for sex, age and BMI.RESULTS Mean duration of diabetes was 4.2 ± 2.8 years. The mean 24 h systolic blood pressure(SBP) and diastolic blood pressure(DBP) were respectively 116 ± 9 mm Hg in the diabetic group vs 111 ± 8 mm Hg in the nondiabetic(P = 0.06), and 69 ± 7 mm Hg vs 66 ± 5 mm Hg(P = 0.19). There was no difference in the diurnal pattern of BP in diabetes patients and non-diabetic controls(SBP: 118 ± 10 mm Hg vs 114 ± 10 mm Hg, P = 0.11; DBP: 71 ± 7 mm Hg vs 68 ± 6 mm Hg, P = 0.22). Nighttime BP was higher in the diabetic group with respect to SBP(112 ± 11 mm Hg vs 106 ± 7 mm Hg, P = 0.06) and to the mean arterial pressure(MAP)(89 ± 9 mm Hg vs 81 ± 6 mm Hg, P = 0.06). ACR at rest was similar in both groups(5.5 mg/g vs 5.5 mg/g, P = 0.74), but significantly higher in diabetes patients after exercise(10.5 mg/g vs 5.5 mg/g, P = 0.03). SBP was higher in patients having exercise-induced albuminuria(116 ± 10 mm Hg vs 108 ± 10 mm Hg, P = 0.09). CONCLUSION Exercise-induced albuminuria could be useful for early diagnosis of kidney damage in adolescents with T1 DM.

Investigation on the relationship between overpressure and sub-harmonic response from encapsulated microbubbles

Sub-harmonic component generated from microbubbles is proven to be potentially used in noninvasive blood pressure measurement. Both theoretical and experimental studies are performed in the present work to investigate the dependence of the sub-harmonic generation on the overpressure with different excitation pressure amplitudes and pulse lengths. With 4-MHz ultrasound excitation at an applied acoustic pressure amplitude of 0.24 MPa, the measured sub-harmonic amplitude exhibits a decreasing change as overpressure increases; while non-monotonic change is observed for the applied acoustic pressures of 0.36 MPa and 0.48 MPa, and the peak position in the curve of the sub-harmonic response versus the overpres- sure shifts toward higher overpressure as the excitation pressure amplitude increases. Furthermore, the exciting pulse with long duration could lead to a better sensitivity of the sub-harmonic response to overpressure. The measured results are ex- plained by the numerical simulations based on the Marmottant model. The numerical simulations qualitatively accord with the measured results. This work might provide a preliminary proof for the optimization of the noninvasive blood pressure measurement through using sub-harmonic generation from microbubbles.

Application of transcutaneous diffuse reflectance spectroscopy in the measurement of blood glucose concentration

In this paper, the propagation characteristics of near-infrared (NIR) light in the palm tissue are analyzed, and the principle and feasibility of using transcutaneous diffuse reflectance spectroscopy for non-invasive blood glucose detection are presented. An optical probe suitable for measuring the diffuse reflectance spectrum of human palm and a non-invasive blood glucose detection system using NIR spectroscopy are designed. Based on this system, oral glucose tolerance tests are performed to measure the blood glucose concentrations of two young healthy volunteers. The partial least square calibration model is then constructed by all individual experimental data. The final result shows that correlation coefficients of the two experiments between the predicted blood glucose concentrations and the reference blood glucose concentrations are 0.9870 and 0.9854, respectively. The root mean square errors of prediction of full cross validation are 0.54 and 0.52 mmol/1, respectively.

Real-time human blood pressure measurement based on laser self-mixing interferometry with extreme learning machine

In this paper, we present a method based on self-mixing interferometry combing extreme learning machine for real-time human blood pressure measurement. A signal processing method based on wavelet transform is applied to extract reversion point in the self-mixing interference signal, thus the pulse wave profile is successfully reconstructed. Considering the blood pressure values are intrinsically related to characteristic parameters of the pulse wave, 80 samples from the MIMIC-II database are used to train the extreme learning machine blood pressure model. In the experiment, 15 measured samples of pulse wave signal are used as the prediction sets. The results show that the errors of systolic and diastolic blood pressure are both within 5 mm Hg compared with that by the Coriolis method.

Diabetes and COVID-19:Role of insulin resistance as a risk factor for COVID-19 severity

Patients with diabetes are more susceptible to coronavirus disease 2019(COVID-19),and as a consequence,develop more severe form of disease.This is partly due to a systemic inflammatory state and pro thrombotic milieu seen in metabolic syndrome.In this review,we attempt to explore the pathogenetic links between insulin resistance and COVID-19 disease severity.Insulin resistance is an underlying condition for metabolic syndromes,including type 2 diabetes,which impairs insulin signaling pathways affecting metabolic and cardiovascular homeostasis.A high concentration of circulating insulin shifts the balance to mitogen activated protein kinase(MAPK)-dependent signaling and causes endothelial cell damage.The phosphatidylinositol 3 kinase and MAPK dependent signaling pathways maintain a balance between nitric oxide-dependent vasodilator and endothelin-1 dependent vasoconstriction actions of insulin.Vascular smooth muscle cell dysfunction is responsible for inflammation and blood coagulation leading to microvascular and macrovascular complications in diabetes.Hyperactivity in renin-angiotensin system is implicated in development of islet oxidative stress and subsequentβ-cell dysfunction,as it alters the islet blood flow.These deleterious effects of insulin resistance involving altered blood pressure,vascular dysfunction,and inflammation could be associated with increased severity in COVID-19 patients.We conclude that clinical and/or biochemical markers of insulin resistance should be included as prognostic markers in assessment of acute COVID-19 disease.

An assessment on the wideband and narrowband methods for ultrasonic blood flow measurements

A comparison study on the ultrasonic blood flow estimation methods is carried out in this paper. The methods are divided into two classes-narrowband and wideband techniques.The pulsed Doppler systems and the autocorrelation methods are essentially the narrowband estAnators. They give the results with low velocity resolution and probably the aliased spectrum.The wider the frequency band of the signals, the worse the results. Time domain crosscorrelation technique, wideband makimum likelihood estimation and 2D Fourier transform method are three wideband techniques. The high velocity resolution and the ability of anti-aliasing are shown by these wideband estimation strategies.

Simultaneous blood flow and oxygenation measurements using an off-the-shelf spectrometer

Blood oxygenation and flow are both important parameters in a living body. In this Letter, we introduce a simple configuration to simultaneously measure blood flow and oxygenation using an off-the-shelf spectrometer. With the integration time of 10 ms, flow phantom measurements, a liquid blood phantom test, and an arm cuff occlusion paradigm were performed to validate the feasibility of the system. We expect this proof-of-concept study would be widely adopted by other researchers for acquiring both blood flow and oxygenation changes due to its straightforward configuration and the possibility of multimodal measurement.

Doctor Reports New Way to Measure Blood Sugar

对“糖尿病”及其危害,本文有一简略说明: Diabetes occurs when blood sugar,or glucose,a source of body fuel,is toohigh and the body is not able to burn it.The disease can lead to blindness,organdiseases,stroke and death. 句中的一个动词burn令我们过目难忘。此外,此疾引起的后果也令人生畏:blindness,organ diseases,stroke and death. 要测得患者的血糖含量,就得验血,就得像本文所讲的那样“pricking(刺;戳)the skin and drawing a tiny amount of blood”。 美国宾夕法尼亚州立大学的研究人员研制了a hand—held ultrasound(超声波)machine,验血者可免受皮肉之苦,而又可测量到准确的血糖含量。 文章末尾有一条信息:美国人中糖尿病患者约占总人口的6％。