Radial Artery Pulse Research Articles

Individualized analysis of pulse wave shape before and after a single accurate power exercise in patients with long-term chronic diseases

Objective: To observe and study the resting radial artery pulse wave and changes after a single individualized exercise in patients with long-term chronic diseases. Methods: We selected 16 patients with chronic disease (disease duration ≥5 years) who have been clearly diagnosed as hypertension and/or diabetes and/or hyperlipemia, and first completed the symptom-restricted limit cardiopulmonary exercise testing (CPET). Then a single individualized exercise with Δ50% power as the exercise intensity was completed within one week after CPET. We measured and recorded 50s pulse wave data before exercise and 10 min, 20 min, 30 min after exercise, then obtained each pulse wave characteristic point: starting point (B), main wave peak point (P1), trough of a repulse point (PL), crest of a repulse point (P2), and end point (E). The raw data of the abscissa (time T) and ordinate (amplitude Y) corresponding to each point were derived from the instrument. We treated the end point E of the previous pulse wave as the start point B of the next wave, returned TB to zero, and got the main observation indicators: YB, YP1, YPL, YP2 and TP1, TPL, TP2, TE, and calculated out ΔYP1, ΔYPL, ΔYP2, TE-TPL, (TE-TPL)/TPL, pulse rate, S1, S2 ,ΔYP2-ΔYPL and TP2-TPL as secondary observation indicators. Then calculated the occurrence rate of dicrotic wave with obvious crest. Finally we analyzed individually the 50 s pulse wave data of each patient before and after exercise, and then averaged all the data for overall analysis. Results: ①16 patients with long-term chronic diseases (males 14, females 2), ages (53.7±12.6, 28~80) years old, height (171.7±6.6, 155~183) cm, body weight (80.0±13.5, 54~98) kg. 2YB (91.5±10.8, 71.1~108.6), YP1 (203.6±24.7, 162.7~236.3), YPL (127.1±6.2, 118.2~140.3), YP2 (125.9±6.2, 115.7~137.7), TP1 ( 137.2±22.3, 103.0~197.1), TPL (368.7±29.5, 316.3~434.0), TP2 (422.7±32.8, 376.9~494.7), TE (883.4±95.0, 672.2~1003.3), ΔYP1 (112.1±33.8, 60.3~ 157.5), ΔYPL (35.5±14.2, 17.5~66.2), ΔYP2 (34.4±13.3, 20.0~62.9), TE-TPL (514.6±85.4, 341.4~621.9), (TE-TPL)/TPL (1.4±0.2, 1.0~1.7), pulse rate (68.8±8.4, 59.8~89.3), S1 (0.9±0.3, 0.4~1.4), S2 (0.0±0.0, -0.1~0.0), ΔYP2-ΔYPL (-1.2±2.6,- 6.5 ~ 2.5), TP2-TPL (54.0 ± 10.8, 33.6 ~ 81.1). ③10min after exercise, YB, YPL, YP2, TPL, TE decreased, YP1 increased. ΔYPL, TE-TPL, (TE-TPL)/TPL decreased, and ΔYP1, pulse rate, S1, ΔYP2-ΔYPL, TP2 -TPL increased (all P<0.05). The change trend of pulse wave at 20min and 30min after exercise was consistent with that at 10min after exercise, but most indicators gradually recovered to the resting level before exercise from 10 min. ④The appearance rate of dicrotic wave with obvious crest in 16 patients with long-term chronic disease at rest was 28.6%, and the appearance rate of 10 min (65.7%), 20 min (77.1%), 30 min (73.7%) after exercise was significantly increased (all P< 0.01). In 6 patients, the incidence of dicrotic waves with obvious peaks after exercise was significantly increased, and it could continue until 30 minutes. In 3 patients, the incidence increased significantly 10 minutes after exercise, and began to decrease at 20 minutes. In 1 patient, the rate of appearance only started to increase 20 minutes after exercise. In 2 patients, the incidence increased 10 minutes after exercise and then decreased. In 1 patient, the rate of occurrence increased briefly 20 minutes after exercise and then decreased. The incidence of 1 patient dropped after exercise and began to rise at 20 minutes. In 2 cases, the incidence rate did not increase after exercise, and it increased slightly after 30 minutes. Conclusion: In patients with long-term chronic diseases, the radial artery pulse wave is short and the dicrotic wave is not obvious or even disappears. After a single precise power exercise, the main wave increases, the position of the dicrotic wave decreases, and the amplitude increases. The specific response should be analyzed individually.

Fiber Bragg Grating-Based Pulse Monitoring Device for Real-Time Non-Invasive Blood Pressure Measurement—A Feasibility Study

The real-time, continuous, beat-to-beat blood pressure (BP) monitoring is vital in clinical scenarios such as operations theatres, ambulances etc. In the present study, a non-invasive BP monitoring methodology based on Fiber Bragg Grating sensors is reported. The design and development of Fiber Bragg Grating based Pulse Monitoring Device (FBGPM) is demonstrated which is capable of acquiring the radial arterial pulse pressure waveform effectively in real time. The Radial Arterial Pulse Pressure Waveform is acquired on beat to beat basis employing developed FBGPM in a clinical environment. Further, the recorded radial arterial pulse pressure waveform is processed to obtain systolic and diastolic BP by utilizing a standard non-invasive BP measurement device as a reference. The BP values obtained through FBGPM are then compared with the BP values obtained through an Intra-Arterial (IA) probe. The FBGPM is a chemically and electrically inert device which makes it an effective candidate for monitoring the real-time BP. The focus of the study is to demonstrate the feasibility of deploying developed FBGPM device in clinical environment to acquire beat-to-beat BP and subsequently compare the present device to the IA probe method of BP acquisition.

Individualization analysis of pulse wave shape characteristics before and after single precise power exercise in young healthy subjects

Objective: To observe and study the resting radial artery pulse wave and the pulse wave changes after a single individualized exercise in young healthy normal subjects. Methods: We selected 16 young healthy graduate students, advanced training doctors, and visiting scholars from Fuwai Hospital without any disease diagnosis and low daily exercise. They first completed the symptom-restricted limit cardiopulmonary exercise testing (CPET). A single individualized exercise with Δ50% power as the exercise intensity was completed within one week after CPET. We measured and recorded 50 s pulse wave data before exercise and 10 min, 20 min, 30min after exercise, let the instrument automatically fix the point and then manually recheck to obtain each pulse wave characteristic point: starting point (B), main wave peak point (P1), trough of a repulse point (PL), crest of a repulse point (P2), and end point (E), and the raw data of the abscissa (time T) and ordinate (amplitude Y) corresponding to each point were derived from the instrument. We treated the end point E of the previous pulse wave as the start point B of the next wave, returned TB to zero, and got the main observation indicators: YB, YP1, YPL, YP2 and TP1, TPL, TP2, TE, and calculated out ΔYP1 (YP1-YB), ΔYPL (YPL-YB), ΔYP2 (YP2-YB), TE-TPL, (TE-TPL)/TPL, pulse rate, S1 (the slope of main wave ascending branch), S2 (the slope of dicrotic ascending branch), ΔYP2-ΔYPL and TP2-TPL as secondary observation indicators; defined the dicrotic wave with obvious crest as YP2>YPL, and calculated the occurrence rate of dicrotic wave with obvious crest (number of waveforms with YP2>YPL in 50 s /total number of waveforms×100%). We analyzed individually the 50 s pulse wave data of each subject before and after exercise, and then averaged all the data for overall analysis. Results: ①16 healthy young subjects (males 10, females 6), age (30.6±6.4, 24~48) years old; height (170.4±8.2, 160~188) cm; body mass (63.9±12.8, 43~87) kg. ②YB (87.2±5.8, 78.1~95.9), YP1 (223.5±15.8, 192.7~242.3), YPL (122.8±7.8, 110.0~133.8), YP2 (131.4±4.9, 116.7~137.5), TP1 (126.2±42.2, 94.2~280.0), TPL (360.2±44.8, 311.5~507.3), TP2 (432.4±50.8, 376.2~589.0), TE (899.7±86.9, 728.3~1042.0). ΔYP1 (136.3±19.9, 96.8~ 158.6), ΔYPL (35.7±10.7, 16.0~55.7), ΔYP2 (44.3±8.1, 22.5~56.5), TE-TPL (539.5±79.3, 405.9~691.3), (TE-TPL)/TPL (1.5±0.3, 0.8~2.0), pulse rate (67.3±6.6, 57.6~82.4), S1 (1.1±0.2, 0.6~1.4), S2 (0.1±0.1, 0.0~0.2), ΔYP2-ΔYPL (8.6±6.1, 0.9 ~19.8), TP2-TPL (72.3±19.9, 38.3~108.4). ③10 min after exercise, YPL (97.0±13.2 vs 122.8±7.8), YP2 (109.6±12.8 vs 131.4±4.9), ΔYPL (6.6±9.8 vs 35.7±10.7), ΔYP2 (19.3±11.2 vs 44.3±8.1), TE (667.8±123.1 vs 899.7±86.9), TE-TPL (330.2±128.4 vs 539.5±79.3), (TE-TPL)/TPL (1.0±0.4 vs 1.5±0.3) decreased, while the pulse rate (92.2± 14.0 vs 67.3±6.6), ΔYP2-ΔYPL (12.7±9.7 vs 8.6±6.1), TP2-TPL (98.0±38.1 vs 72.3±19.9) increased (all P<0.05). The trend of pulse wave changes at 20 min and 30 min after exercise was consistent with that at 10 min after exercise, but from 20 min, most of the indicators gradually recovered to the resting level before exercise. ④The incidence of dicrotic waves with obvious peaks in 16 young healthy persons at rest was 94.5%, and increased at 10 min (96.3%), 20 min (98.5%), and 30 min (99.8%) after exercise (all P<0.01). Among them, the incidence of dicrotic waves with obvious peaks before and after exercise was maintained at about 100% in 10 subjects. The appearance rate of 2 cases had reached 100% before exercise, but it decreased at 10 minutes after exercise, and then continued to increase, at 30 minutes recovered to 100%. Three subjects had a low resting rate and started to increase after exercise. In 1 case, the rate was low only 20 minutes after exercise, considering the influence of human factors. Conclusion: The influence of exercise on the pulse wave of normal people is mainly reflected in the dicrotic wave. On the whole, after a single precise power exercise, the position of the dicrotic wave is reduced, the amplitude is deepened, and the appearance rate of the dicrotic wave with obvious crest is generally increased, and this change can be maintained for at least 30 minutes. From an individual point of view, the response trend of each subject is different.

A rare presentation of Takayasu\u2019s arteritis- unilateral finger clubbing \u2013 case report

BackgroundTakayasu’s arteritis (TA) is a granulomatous, large vessel vasculitis with a preponderance for young women. The inflammation results in disruption of the arterial endothelium causing stenosis, endoluminal thrombosis and aneurismal dilatation. Early disease presentation is with nonspecific general symptoms, and in such instances, the diagnosis can be missed. Unilateral clubbing is a manifestation of myriad of diseases, but is not a common sign of TA. In medical literature, only three such cases have been reported.Case presentationWe present a 24-year-old female who presented with multiple constitutional symptoms such as arthralgia, malaise, poor appetite and two episodes of syncope over 3 months’ duration. On examination, unilateral finger clubbing was observed in the right hand, with very low volume radial, ulnar and brachial artery pulses on the ipsilateral side. Her blood pressure measured on the unaffected arm, was normal. Inflammatory markers were elevated and magnetic resonance angiogram (MRA) confirmed TA.ConclusionAlthough rare, unilateral clubbing may be a manifestation of TA. Therefore, detection of unilateral clubbing should raise a strong clinical suspicion of TA and prompt early diagnosis and initiation of treatment.

The association between indices of blood pressure waveforms (PTC1 and PTC2) and incident heart failure.

The radial artery pulse waveform is a continuous measure of pressure throughout the cardiac cycle, and thus can provide more information than just systolic and diastolic blood pressures. New indices based on a Windkessel model of the waveform, PTC1 and PTC2, are related to arterial compliance and add information for prediction of incident cardiovascular disease (coronary heart disease, stroke, myocardial infarction) but their association with heart failure is unknown. Among 6229 adults (mean age 62 years) from four race/ethnic groups who were initially free of clinical cardiovascular disease and heart failure in 2000-2002, we evaluated the associations of baseline PTC1 and PTC2 with incident heart failure. Mean ± standard deviation PTC1 and PTC2 were 394 ± 334 and 94 ± 46 ms, respectively. During a median of 15.7 years follow-up, there were 357 heart failure events (148 with reduced, 150 with preserved, and 59 with unknown ejection fraction). After adjustment for traditional risk factors, the hazard ratio for heart failure per 1 standard deviation higher PTC2 was 0.73 (95% confidence interval: 0.63--0.85). Higher PTC2 was also significantly associated with lower risk of heart failure with reduced ejection fraction (hazard ratio = 0.67; 95% confidence interval: 0.56--0.80). There was no evidence of a significant association between PTC2 and heart failure with preserved ejection fraction or between PTC1 and heart failure. The PTC2 measure of the radial artery pulse waveform may represent a novel phenotype related to heart failure, especially heart failure with reduced ejection fraction.

Increased augmentation index in patients with Ehlers-Danlos syndrome

BackgroundEhlers-Danlos Syndrome (EDS) comprises a heterogeneous group of diseases characterized by joint hypermobility, connective tissue friability, and vascular fragility. Reliable prognostic factors predicting vascular disease progression (e.g. arterial aneurysms, dissections, and ruptures) in EDS patients are still missing. Recently, applanation tonometry derived augmentation index (AIx), an indirect marker of arterial stiffness, has shown to be positively associated with progression of aortic disease in Marfan syndrome. In this study, we assessed aortic AIx in patients with EDS and matched healthy controls.MethodsWe performed noninvasive applanation tonometry in 61 adults with EDS (43 women and 18 men aged 39.3 ± 14.6 years) and 61 age-, gender-, height-, and weight-matched healthy controls. Radial artery pulse waveforms were recorded and analyzed using the SphygmoCor System (AtCor Medical, Sydney, NSW, Australia). Calculated AIx was adjusted to a heart rate of 75/min. Groups were compared and association between AIx and EDS was determined by univariate and multivariate regression analysis.ResultsEDS patients were categorized in classical type EDS (34%), hypermobile type EDS (43%), vascular type EDS (5%), or remained unassignable (18%) due to overlapping features. EDS patients showed a significantly increased aortic AIx compared to healthy controls (22.8% ± 10.1 vs 14.8% ± 14.0, p < 0.001). EDS showed a positive association with AIx; independent of age, sex, height, blood pressure, medication, and pack years of smoking.ConclusionsPatients with EDS showed elevated AIx, indicating increased arterial stiffness when compared to healthy controls. Further investigations are needed in order to assess the prognostic value of increased AIx for cardiovascular outcomes in patients with EDS.

Independent predictors affecting the reduction of pediatric supracondylar humerus fractures: a retrospective cohort study.

Although it is important to understand the risk factors affecting the reduction of pediatric supracondylar humerus fractures (PSHFs), no inclusive study has been conducted so far. We performed a retrospective cohort study to identify the risk factors affecting the quality and difficulty of reduction for PSHFs. We reviewed 160 cases with a PSHF that had been surgically treated in our hospital between January 2007 and December 2019. We investigated age, sex, injured side, body mass index (BMI), modified Gartland classification, neurological deficit or an absent radial artery pulse at an initial examination, start time of the operation, waiting time from injury to surgery, operative time, reduction technique, and perioperative radiographic parameters. We calculated independent predictors of unsuccessful closed reduction, prolonged operative time, and malreduction using multivariate analyses. In a logistic regression analysis, modified Gartland type III was a significant predictor of unsuccessful closed reduction (OR 14.50 [95% CI 4.03-51.90]; P < 0.01) and BMI was a significant predictor of malrotation (OR 1.59 [95% CI 1.06-2.39]; P = 0.025). In a multiple linear regression analysis, BMI and open reduction were significant predictors of prolonged operative time (BMI, P = 0.011; open reduction, P < 0.01). If closed reduction fails, we should not hesitate to immediately switch to other methods. Obesity was an independent predictor of both prolonged operative time and malrotation, a finding that has not been previously reported. Rotational alignment should be carefully checked, especially for obese children, and accurately be reduced. Open reduction also extended operative time.

Homogeneity Permitted Robust Connection for Additive Manufacturing Stretchable Electronics.

Interface is the Achilles' heel in flexible electronics, where slipping, delamination, or cracking resulting from the intrinsic mechanical property mismatch of different materials might fail the device or cause degradation. Robust connections with strong interfacial strength and low interfacial impedance are highly desired in all kinds of flexible devices, especially when they require stretchability. Here, a new strategy of employing homogeneity is proposed to facilely achieve robust connection without introducing a third-party interlayer. The key to this strategy is implementing different functions in the same component materials, and in this work, this strategy is demonstrated by exploring the uniformity of carbon nanotube (CNT) in thermoplastic polyurethane (TPU) elastomer. Tuning the uniformity of CNT in TPU elastomer, two kinds of CNT-TPU composites (CTCs) are fabricated. They present contrasting properties of conductivity (281 folds), Young's modulus (7.1 folds), and strain sensitivity (15.7 folds) with the same weight fraction of CNT (15 wt %), and thus they can respectively act as strain sensor and interconnector in all-CNT-based stretchable strain monitoring electronics. The interlocking effect caused by spontaneous entanglement of surface polymer chains and the reconstruction of percolation network at the interface during drying confer the connection with robustness. The practical value of this strategy has been exemplified by the fabrication of a robust epidermis device via additive manufacturing. This epidermis device is patterned in a fractal motif for conformal contact and can sensitively monitor body motions and radial artery pulse.

ELECTRET CONDENSER MICROPHONE AS SENSOR IN ARTERIAL PULSE RECORDING DEVICE

One of the human pulses could be detected on an arterial radial that represents the human health condition. Several sensors could capture the pulse signal. However, it still needed a sensor with a small dimension and lightweight. One of the sensors that comply with those specifications is an electret condenser microphone (ECM). The ECM was designed to pick up the signal from the human radial arterial pulse. The ECM pick up system was equipped with an instrumentation amplifier and a signal processing system. The characteristic of the ECM was analyzed using a sixth-order polynomial equation. The equation was used to reconstruct the signal, which flattened the frequency response at the range of 0.5-4.5 Hz. The signal processing consists of an FFT, peak detection and a sixth-order anti-polynomial computational unit which is implemented in a computer. The minimum error was found at 1.5 Hz, which is closed to the designated frequency of the arterial pulse normal frequency.

Characteristics of Harmonic Indexes of the Arterial Blood Pressure Waveform in Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) is an important public health issue worldwide. T2DM correlates with cardiovascular disease. Arterial stiffness is also a key factor that can be thought of as a surrogate marker. Nevertheless, it was unclear which harmonic indexes of blood pressure waveforms (BPWs) from subjects' radial artery pulses would be affected by T2DM. Therefore, the objective of this study was to investigate whether and how harmonic indexes can be used to discriminate hemodynamic differences between patients with T2DM and non-T2DM. This helps us to build objective results no matter who conducts the examination instead of pulse diagnosis in traditional way. We enrolled T2DM and non-T2DM patients as experimental and control groups, respectively, from the Department of Family Medicine in the National Taiwan University Hospital and the Department of Internal Medicine in Taipei's Veterans General Hospital from December 2017 to January 2019. ANSWatch® Model TS-0411 was used to capture the BPWs. Amplitude proportions (Cn values) were calculated from harmonics 1–10 of the BPW using fast Fourier transform. Thirty-two T2DM and 15 non-T2DM patients were enrolled. T2DM patients had significant differences in C1 (p = 0.031) and C5 (p = 0.041). The study suggests that analyzing the harmonic characteristics of non-invasively measured BPW of radial artery may be a potential and easy-to-perform approach to discriminate T2DM-induced hemodynamic changes.

Machine Learning-Based Signal Quality Evaluation of Single-Period Radial Artery Pulse Waves: Model Development and Validation.

BackgroundThe radial artery pulse wave is a widely used physiological signal for disease diagnosis and personal health monitoring because it provides insight into the overall health of the heart and blood vessels. Periodic radial artery pulse signals are subsequently decomposed into single pulse wave periods (segments) for physiological parameter evaluations. However, abnormal periods frequently arise due to external interference, the inherent imperfections of current segmentation methods, and the quality of the pulse wave signals.ObjectiveThe objective of this paper was to develop a machine learning model to detect abnormal pulse periods in real clinical data.MethodsVarious machine learning models, such as k-nearest neighbor, logistic regression, and support vector machines, were applied to classify the normal and abnormal periods in 8561 segments extracted from the radial pulse waves of 390 outpatients. The recursive feature elimination method was used to simplify the classifier.ResultsIt was found that a logistic regression model with only four input features can achieve a satisfactory result. The area under the receiver operating characteristic curve from the test set was 0.9920. In addition, these classifiers can be easily interpreted.ConclusionsWe expect that this model can be applied in smart sport watches and watchbands to accurately evaluate human health status.

Predictive value of vascular health indicators on newly cardiovascular events: Preliminary validation of Beijing vascular health stratification system

To explore the predictive value of carotid femoral artery pulse wave velocity (CF-PWV), carotid radial artery pulse wave velocity (CR-PWV), cardio-ankle vascular index (CAVI), and ankle brachial index (ABI) on coronary heart disease (CHD) and cerebral infarction (CI), and the preliminary validation of Beijing vascular health stratification (BVHS). Subjects with at least 2 in-patient records were included into the study between 2010 and 2017 from Vascular Medicine Center of Peking University Shougang Hospital. Subjects with CHD or CI, and without data of vascular function at baseline were excluded. Eventually, 467 subjects free of CHD [cohort 1, mean age: (63.4±12.3) years, female 42.2%] and 658 subjects free of CI [cohort 2, mean age: (64.3±12.2) years, female 48.7%] at baseline were included. The first in-patient records were as the baseline data, the second in-patient records were as a following-up data. Cox proportional hazard regression was used to establish the predictive models of CHD or CI derived from BVHS by multivariable-adjusted analysis. The median follow-up time of cohort 1 and cohort 2 was 1.9 years and 2.1 years, respectively. During the follow-up, 164 first CHD events occurred in cohort 1 and 117 first CI events occurred in cohort 2. Four indicators were assessed as continuous variables simultaneously by multivariable-adjusted analysis. In cohort 1, CF-PWV, CR-PWV, ABI, and CAVI reached statistical significance in the multivariable-adjusted models (P<0.05). In cohort 2, only CAVI (P<0.05) was of statistical significance. In addition, the higher CF-PWV became a protector of CHD or CI (P<0.05). The prediction value of BVHS reached the statistical significance for CHD and CI in the unadjusted models (all P<0.05), however, BVHS could only predict the incidence of CHD (P<0.05), but not the incidence of CI (P>0.05) in the multivariable-adjusted models. CF-PWV, CR-PWV, ABI, and CAVI were associated factors of CHD independent of each other (P<0.05), only CAVI (P<0.05) was the risk factor of CI independent of the other three. The different vascular indicators might have different effect on CHD or CI. CAVI might be a stable predictor of both CHD and CI. Higher baseline CF-PWV was not necessarily a risk factor of CHD or CI because of proper vascular health management. BVHS was a potential factor for the prediction of CHD, and further research is needed to explore the prediction value for CI.

Evaluation of radial artery pulse pressure effects on detection of stroke volume changes after volume loading maneuvers in cardiac surgical patients.

BackgroundFluid responsiveness is defined as an increase in cardiac output (CO) or stroke volume (SV) of >10–15% after fluid challenge (FC). However, CO or SV monitoring is often not available in clinical practice. The aim of this study was to evaluate whether changes in radial artery pulse pressure (rPP) induced by FC or passive leg raising (PLR) correlates with changes in SV in patients after cardiac surgery.MethodsThis prospective observational study included 102 patients undergoing cardiac surgery, in which rPP and SV were recorded before and immediately after a PLR test and FC with 250 mL of Gelofusine for 10 min. SV was measured using pulse contour analysis. Patients were divided into responders (≥15% increase in SV after FC) and non-responders. The hemodynamic variables between responders and non-responders were analyzed to assess the ability of rPP to track SV changes.ResultsA total of 52% patients were fluid responders in this study. An rPP increase induced by FC was significantly correlated with SV changes after a FC (ΔSV-FC, r=0.62, P<0.01). A fluid-induced increase in rPP (ΔrPP-FC) of >16% detected a fluid-induced increase in SV of >15%, with a sensitivity of 91% and a specificity of 73%. The area under the receiver operating characteristic curve (AUROC) for the fluid-induced changes in rPP identified fluid responsiveness was 0.881 (95% CI: 0.802–0.937). A grey zone of 16–34% included 30% of patients for ΔrPP-FC. The ΔrPP-PLR was weakly correlated with ΔSV-FC (r=0.30, P<0.01). An increase in rPP induced by PLR (ΔrPP-PLR) predicted fluid responsiveness with an AUROC of 0.734 (95% CI: 0.637–0.816). A grey zone of 10–23% included 52% of patients for ΔrPP-PLR.ConclusionsChanges in rPP might be used to detect changes in SV via FC in mechanically ventilated patients after cardiac surgery. In contrast, changes in rPP induced by PLR are unreliable predictors of fluid responsiveness.

Accuracy Evaluation of Robotic Tonometry Pulse Sensor System Based on Radial Artery Pulse Wave Simulator

In this article, a robotic applanation tonometry pulse sensor system has been developed to easily detect the pulse pressure index (PPI) using a pulse sensor array and reduce the position errors caused by manual operation when measuring the pulsation location of the subject’s wrist using a robotic manipulator with automatic localization and pressurization. The amplitude change and shift of the pulse pressure (PP) caused by the unstable measurement angle of the tonometry device with a single sensor were measured and analyzed through an experiment with varying measurement angles. To evaluate the accuracy of the robotic tonometry system, the set PPI of the pulsatile simulator, which repeatedly generates artificial radial artery pulses, was compared with the PPI values estimated by the proposed methods. Accuracy evaluation of the pulse sensor indicates a coefficient of variability for the measured signals of up to 3.2% and a minimum accuracy of 93.7%; however, the PP calculated by a curve-fitting method applied to the measured signals from the array sensor was improved to an average of less than a 1.0% coefficient of variability and 97.9% accuracy. The developed robotic tonometry system represents a contribution to the radial pulse wave research field, which requires more accurate pulse wave analyses and PP measurements.

Acute Effect of High-Intensity Interval Versus Moderate-Intensity Continuous Exercise on Blood Pressure and Arterial Compliance in Middle-Aged and Older Hypertensive Women With Increased Arterial Stiffness.

Costa, EC, Kent, DE, Boreskie, KF, Hay, JL, Kehler, DS, Edye-Mazowita, A, Nugent, K, Papadopoulos, J, Stammers, AN, Oldfield, C, Arora, RC, Browne, RAV, and Duhamel, TA. Acute effect of high-intensity interval versus moderate-intensity continuous exercise on blood pressure and arterial compliance in middle-aged and older hypertensive women with increased arterial stiffness. J Strength Cond Res 34(5): 1307-1316, 2020-Hypertension and arterial stiffness are common in middle-aged and older women. This study compared the acute effect of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) on blood pressure (BP) and arterial compliance in middle-aged and older hypertensive women with increased arterial stiffness. Nineteen women (67.6 ± 4.7 years) participated in this randomized controlled crossover trial. Subjects completed a control, MICE (30 minutes at 50-55% of heart rate reserve [HRR]), and HIIE (10 × 1 minute at 80-85% of HRR, 2 minutes at 40-45% of HRR) session in random order. Blood pressure and large and small arterial compliance (radial artery pulse wave analysis) were measured at baseline and 30, 60, 90, and 120 minutes after sessions. A p < 0.05 was considered statistically significant. Systolic BP was reduced in ∼10 mm Hg after MICE at 30 minutes and after HIIE at all time points (30, 60, 90, and 120 minutes) after exercise compared with the control session (p < 0.05). Only HIIE showed lower systolic BP levels at 60, 90, and 120 minutes after exercise compared with the control session (∼10 mm Hg; p < 0.05). No changes were observed in diastolic BP, or in large and small arterial compliance (p > 0.05). High-intensity interval exercise elicited a longer systolic postexercise hypotension than MICE compared with the control condition, despite the absence of acute modifications in large and small arterial compliance.

Nonlinearly Frequency-Adaptive, Self-Powered, Proton-Driven Somatosensor Inspired by a Human Mechanoreceptor.

In the human skin, it has been well known that several mechanoreceptors uniquely sense external stimuli with specific frequencies and magnitudes. With regard to sensitivity, the output response shows nonlinearity depending on the frequency magnitude of the stimulus. We demonstrate a self-powered proton-driven solid-state somatosensor, which mimics a unique nonlinear response and intensity behavior of human mechanoreceptors. For this, a solid-state sensor is fabricated by combining a piezoelectric film and a proton generation device. The proton injection electrode and the Nafion layer conjugated with sulfonated graphene oxide are used for proton generation and transport. Two types of nonlinear signals from the sensor are similar to the Merkel/Ruffini (low deviation of threshold intensity), and in contrast, the behavior of Pacinian/Meissner (high deviation of threshold intensity) is simultaneously shown. The region of the most responsive frequency is also discriminated according to proton conduction. Moreover, it is asserted that unique signal patterns are obtained from the stimuli of various frequencies, such as respiration, radial artery pulse, and neck vibration, which naturally occur in the human body.

Adjacent Channel Interference Modeling of Single Vibration Point on Multichannel Dynamic Pressure Sensors

Pulse waves of a radial artery under different pressures applied through a cuff play an important role in disease diagnosis, especially in traditional chinese medicine (TCM). Pulse waves could be collected by a pressure sensor array affixed to an inflatable cuff. During a process of collecting pulse waves, one sensor of a sensor array moves up and down when the sensor is shocked by a pulse wave. Movement of the sensor leads to the passive displacement of other nearby sensors because of a connecting structure between them. Then, vibration signals will be generated by the nearby sensors although these sensors do not receive radial artery pulse waves. These vibration signals considered an interference are usually superimposed on real signals obtained from these nearby sensors and degrade signal quality. The problem mentioned above does not only generally exist in a pressure sensor array attached to a wristband but also is easy to ignore. This paper proposes a novel interference suppression algorithm based on Welch’s method for estimating and weakening adjacent sensor channel interference to overcome the problem. At first, a sensor array attached to an inflatable cuff and a vibration generator is proposed to establish an experimental platform for simplifying the pulse wave collection process. Then, the interference suppression algorithm is proposed according to mechanical analysis and Welch’s method based on the proposed sensor array and vibration generator. Next anti-interference abilities of the algorithm based on a simplified process are evaluated by different vibration frequencies and applied pressures. The anti-interference abilities of the algorithm based on pulse waves of the radial artery are evaluated indirectly. The results show that the novel interference suppression algorithm could weaken adjacent sensor channel interference and upgrade the signal quality.

Associations of Intraoperative Radial Arterial Systolic, Diastolic, Mean, and Pulse Pressures with Myocardial and Acute Kidney Injury after Noncardiac Surgery: A Retrospective Cohort Analysis.

Arterial pressure is a complex signal that can be characterized by systolic, mean, and diastolic components, along with pulse pressure (difference between systolic and diastolic pressures). The authors separately evaluated the strength of associations among intraoperative pressure components with myocardial and kidney injury after noncardiac surgery. The authors included 23,140 noncardiac surgery patients at Cleveland Clinic who had blood pressure recorded at 1-min intervals from radial arterial catheters. The authors used univariable smoothing and multivariable logistic regression to estimate probabilities of each outcome as function of patients' lowest pressure for a cumulative 5 min for each component, comparing discriminative ability using C-statistics. The authors further assessed the association between outcomes and both area and minutes under derived thresholds corresponding to the beginning of increased risk for the average patient. Out of 23,140 patients analyzed, myocardial injury occurred in 6.1% and acute kidney injury in 8.2%. Based on the lowest patient blood pressure experienced for greater than or equal to 5 min, estimated thresholds below which the odds of myocardial or kidney injury progressively increased (slope P < 0.001) were 90 mmHg for systolic, 65 mmHg for mean, 50 mmHg for diastolic, and 35 mmHg for pulse pressure. Weak discriminative ability was noted between the pressure components, with univariable C-statistics ranging from 0.55 to 0.59. Area under the curve in the highest (deepest) quartile of exposure below the respective thresholds had significantly higher odds of myocardial injury after noncardiac surgery and acute kidney injury compared to no exposure for systolic, mean, and pulse pressure (all P < 0.001), but not diastolic, after adjusting for confounding. Systolic, mean, and pulse pressure hypotension were comparable in their strength of association with myocardial and renal injury. In contrast, the relationship with diastolic pressure was poor. Baseline factors were much more strongly associated with myocardial and renal injury than intraoperative blood pressure, but pressure differs in being modifiable.

Development of Radial Artery Pulse Audiogram Sensing System for Fast Detection of Atrial Fibrillation and Pulse Amplitude Variation

Background: A new wearable pulse audiogram (PAG) of radial artery was developed with the main purpose to quickly screen atrial fibrillation (AF) and monitor pulse amplitude variation. Methods: Subjects with sinus rhythm (SR), AF, ectopic arrhythmia (EA), and a pacemaker rhythm (PM) were recruited to measure the PAG of radial artery. In total, 91 subjects were recruited: SR ( $n =45$ ), AF ( $n =21$ ), EA ( $n =11$ ), and PM ( $n =14$ ). For signal processing, the inter-pulse interval (IPI) and pulse height (PH) were extracted. Then, an automatic classification algorithm combining fuzzy c-means (FCM) or sample entropy (CEn) with an adaptive-network-based fuzzy inference system was constructed. The PAG data were divided into different segment lengths (10 to 30 beats) to investigate the robustness of the algorithm in short intervals. Furthermore, linear regression was performed to evaluate the relation between the normalized IPI and PH in the AF group. Results: The identification rate of AF increased with the number of beats and decreased with the number of classified types of arrhythmia. Results of combining CEn and FCM, or of FCM alone were better than those of CEn alone. When the combined method was used for the two types of arrhythmia and the number of beats was greater than 10, the rate of successful identification was greater than 90%, validating the technique. Furthermore, for the AF group, PH increased with IPI, while the amplitude of electrocardiogram (ECG) did not. Conclusions: Results indicated that our PAG can effectively identify AF, even in a time window as short as 10 beats. In addition, PAG can monitor the trend of pulse amplitude, possibility that cannot be offered by an ECG.

Development of a Mathematical Model for Age-Dependent Radial Artery Pulse Wave Analysis Based on Pulse Waveform Decomposition

Radial artery pulse waveforms (RAPWs) have been actively studied for decades because they provide critical health information, particularly related to risk factors of cardiovascular disease. The primary goal of this study is to develop a novel mathematical model that can regenerate age-dependent RAPWs by decomposing a single pulse pressure waveform (PPW). This study proposes to decompose a PPW into three waveform components with one forward wave component and two reflected wave components based on the physiology of pulse waveforms. Treated as basis functions, the three components with associated control parameters are incorporated in the proposed mathematical model. The underlying idea of the model is to generate desired pulse waveforms by combining basis functions whose characteristics depend on selection of control parameter values. For the current study, after determining the nine control parameters of the basis functions by post-processing algorithms, the proposed model for the PPW is derived from a linear combination of the basis functions. Using the model along with in vivo RAPW data, this study evaluates the performance of the model in regenerating PPWs for a wide range of ages from 85 years old to 15 years old. The results show an error of less than 6% between the PPWs numerically derived from the model and the in vivo data for the two key matrixes used in this study (the least-square error norm and the radial augmentation index), validating the effectiveness of the model. The model is applicable for RAPW simulator analysis and development.