Pulse Curve Research Articles

Use Them but Do Not Abuse Them

In the studied sample the prevalence of 1st degree obesity was 70.4%. In 1st degree obesity, a significant increase in the stiffness index and the duration of the pulse wave are recorded, which were significantly more often associated with the type of the “A” pulse curve. In 3rd degree obesity, a significant increase in the level of central aortic and systolic blood pressure was accompanied by a statistically significant increase in the level of augmentation index and the value of augmentation index brought to a pulse of 75 beats per minute. In persons with obesity, a relationship was noted between the value of body mass index with a stiffness index, an alternative stiffness index, and A2d4 vascular parameters.

The Stiffness of the Blood Vessels as a Component of Cardionephro - Cerebrovascular Risk for Obesity

In the studied sample the prevalence of 1st degree obesity was 70.4%. In 1st degree obesity, a significant increase in the stiffness index and the duration of the pulse wave are recorded, which were significantly more often associated with the type of the “A” pulse curve. In 3rd degree obesity, a significant increase in the level of central aortic and systolic blood pressure was accompanied by a statistically significant increase in the level of augmentation index and the value of augmentation index brought to a pulse of 75 beats per minute. In persons with obesity, a relationship was noted between the value of body mass index with a stiffness index, an alternative stiffness index, and A2d4 vascular parameters.

Perioperative hemodynamic monitoring: Still a place for cardiac filling pressures?

The clinical usefulness of the so-called "static" cardiac filling pressures - central (CVP) and pulmonary-artery-occlusion-pressure (PAOP) - has come into question for guiding hemodynamic therapy due to their poor ability to predict fluid responsiveness in comparison with other monitoring modalities such as transpulmonary thermodilution-derived volumetric measurements, dynamic variables for assessing fluid responsiveness, and the potential risks associated with pulmonary artery catheterization. This contrasts with observations in multiple patient populations showing a clear association between increased CVP and PAOP levels and poor outcomes, probably due to a reduction in effective perfusion pressure (mean arterial pressure minus CVP) and their role as effectiveness parameters of the cardiovascular system. Furthermore, clinical studies have revealed beneficial effects when interpreting CVP and PAOP dynamically and combining them with flow-related hemodynamic variables. Taking into account the additional information derived from bedside CVP and PAOP pulse curve interpretation, cardiac filling pressures remain an important hemodynamic monitoring tool.

The BivalveGlycymeris pilosaas an Archive of14C in the Mediterranean Sea

ABSTRACTThis study combines radiocarbon (14C) analysis and sclerochronology research, an approach that to the best of our knowledge, has not yet been applied using bivalves from the Mediterranean Sea. We analyzed shells from the North Adriatic Sea: live- and dead-collected specimens of the infaunal bivalveGlycymeris pilosaand two dead-collected specimens ofGlycymerissp. According to crossdating results, growth increment time series obtained from acetate peels of the dead-collectedG. pilosa(S3FP11) indicate the potential for creating longer chronologies from live and dead-collected specimens. The greatest longevity was seen in the dead-collectedGlycymerissp. specimen S3F3, estimated to be ~130 years (started growing AD 1678–1742 and died AD 1826–1860), indicating the potential to extendGlycymerisgrowth increment chronologies to past centuries. The highest ∆14C values obtained corresponded to the calendar year 1974. The14C record obtained fromG. pilosacorrelates well with the modeled surface ocean (mixed-layer) bomb pulse curve (Reimer et al. 2009). Based on the results obtained from the shell growth increment assigned to AD 1950, the reservoir age and reservoir correction (ΔR) are 264±23 years and –6±32 years, respectively.

Value of the oxygen pulse curve for the diagnosis of coronary artery disease.

This study investigated the value of oxygen (O(2)) pulse curves obtained during cardiopulmonary exercise testing (CPET) for the diagnosis of coronary artery disease (CAD). Forty patients with known coronary anatomy (35.0 % normal, 27.0 % single-vessel and 38.0 % multivessel CAD) underwent CPET with radiotracer injection at peak exercise, followed by myocardial scintigraphy. O(2) pulse curves were classified as: A-normal, B-probably normal (normal slope with low peak value); C-probably abnormal (flat, with low peak value); or D-definitely abnormal (descending slope). Sensitivity, specificity, positive and negative predictive values of the O(2) pulse curve pattern (A or B vs. C or D) for the diagnosis of CAD were, respectively, 38.5 %, 81.3 %, 76.9 %, and 44.8 %. The concordance rate between the abnormal O(2) pulse curve pattern and ischemia in myocardial scintigraphy was 38.1 %. Age and the extent of scintigraphic perfusion defect, but not the abnormal O(2) pulse curve patterns (B or C or both combined) were independently associated with CAD. In conclusion, the O(2) pulse curve pattern has low diagnostic performance for the diagnosis of obstructive CAD, and the abnormal curve pattern was not associated with myocardial ischemia defined by scintigraphy.

Use of photoplethysmography to predict mortality in intensive care units.

PurposeThe aim of this study was to evaluate and compare the capacity to predict hemodynamic variables obtained with photoplethysmography (PPG) and Acute Physiology and Chronic Health Evaluation (APACHE II) in patients hospitalized in the intensive care unit (ICU).Materials and methodsA prospective cohort study was conducted in the adult ICU of Hospital Nossa Senhora da Conceição, located in Tubarão, Santa Catarina, Brazil. The data collected included the diagnosis for hospitalization, age, gender, clinical or surgical profile, PPG pulse curve signal, and APACHE II score in the first 24 hours. A bivariate and a multivariate logistic regressions were performed, with death as an outcome. A mortality model using artificial neural networks (ANNs) was proposed.ResultsA total of 190 individuals were evaluated. Most of them were males (6:5), with a median age of 67 (54–75) years, and the main reasons for hospitalization were cardiovascular and neurological causes; half of them were surgical cases. APACHE II median score was 14 (8–19), with a median length of stay of 6 (3–15) days, and 28.4% of the patients died. The following factors were associated with mortality: age (OR=1.023; 95% CI 1.001–1.044; P=0.039), clinical profile (OR=5.481; 95% CI 2.646–11.354; P<0.001), APACHE II (OR=1.168; 95% CI 1.106–1.234; P<0.001), heart rate in the first 24 hours (OR=1.020; 95% CI 1.001–1.039; P=0.036), and time between the systolic and diastolic peak (∆T) intervals obtained with PPG (OR=0.989; 95% CI 0.979–0.998; P=0.015). Compared with the accuracy (area under the receiver-operating characteristic curve) 0.780 of APACHE II (95% CI 0.711–0.849; P<0.001), the multivariate logistic model showed a larger area of 0.858 (95% CI 0.803–0.914; P<0.001). In the model using ANNs, the accuracy was 0.895 (95% CI 0.851–0.940; P<0.001).ConclusionThe mortality models using variables obtained with PPG, with the inclusion of epidemiological parameters, are very accurate and, if associated to APACHE II, improve prognostic accuracy. The use of ANN was even more accurate, indicating that this tool is important to help in the clinical judgment of the intensivist.

P628Development and validation of a standardized method to quantify the oxygen pulse curve during cardiopulmonary exercise testing

P628Development and validation of a standardized method to quantify the oxygen pulse curve during cardiopulmonary exercise testing

Methods for increasing the accuracy of recording the parameters of the cardiovascular system in double-beam photoplethysmography

Photoplethysmography has recently become more widespread among non-invasive methods for obtaining information on the state of physiological systems of the human body. Serial photoplethysmographs are intended for use in clinics and require special care, therefore, interest in portable media developed on the basis of modern sensors and microcontrollers is growing, which would not only make this method available for individual use, but also expand its capabilities through the use of light of various spectral ranges. Such devices require modified signal processing techniques that allow them to be used in mobile applications. The aim of the work is to develop methods for processing signals from a modern two-beam sensor operating in the red and infrared ranges for the analysis of photoplethysmography on a mobile device (smartphone or tablet). A device using the microcontroller and radio module in the Bluetooth standard allows you to continuously record pulse waves, determine the level of oxygen in the blood, calculate peak-peak intervals and heart rate. The use of the two-beam sensor for registration and the implementation of the developed signal processing methods in the Android operation system application increase the accuracy of setting the maximums on pulse curve and provide a relative error in determining the heart rate and pulse-to-pulse intervals relative to the certified electrocardiograph at 9.2% and 9.6% respectively, with an average level of interference and an average activity. An Android operation system mobile device (tablet, smartphone) allows you to visualize the measurement results, store data in the internal memory, and transfer them to the server for further processing.

Signal Separation for Transabdominal Non-invasive Fetal Pulse Oximetry using Comb Filters.

Non-invasive fetal pulse oximetry is the application of reflection pulse oximetry to the abdomen of a pregnant woman. Light sources and detectors areplaced on the belly. Emitted photons travel through maternal and fetal tissue and back to the detectors. The captured photoplethysmogram (PPG) is a complex mixture of the maternal and fetal pulse curve. A purely fetal PPG in time domain is needed to estimate the oxygen level of the unborn child. In this work we describe the application of comb filters to separate the fetalfrom the maternal signal. Finite element simulations and phantom measurements are utilized to generate and measure synthetic signals at different heart rates and noise levels. Comb filters with peak frequencies matched to the fetal heart rate are applied to the mixed PPGs. The filtered signals prove that the extraction of the fetal signal is sufficient even at a distance between the maternal and the fetal signal magnitudes of around 80 dB. The resulting signal quality is sufficient for beat to beat analysis and feature extraction in the time domain. We conclude that comb filtering is a suitable signal separation method for non-invasive fetal pulse oximetry.

Application of double metal/dielectric gratings in optical displacement detection.

A high-resolution displacement detection based on in-plane and out-of-plane moving gratings is discussed in this paper. To improve the detective resolution and stability, a model of a double metal/dielectric optical grating is established to investigate the tolerance of grating parameters. The zero-order optical diffraction efficiency of the grating is calculated by rigorous coupled-wavelength analysis, which depends on the grating parameters. The dependency relation curves are a cosine and pulse curve, respectively, for in-plane movement with the highest slope superior to 0.29%/nm and the highest resolution can reach to 0.01nm, and for out-of-plane movement with the highest slope superior to 1.63%/nm and the optimum resolution can reach to 0.002nm. These results indicate that the in-plane effect is feasible for a long-range and high-resolution displacement detection, and the out-of-plane effect is suitable for small-range and high-resolution displacement detection. Both kinds of effects provide a designed solution for the development of a high-resolution displacement sensor.

Patterns of Oxygen Pulse Curve in Response to Incremental Exercise in Patients with Chronic Obstructive Pulmonary Disease \u2013 An Observational Study

In COPD, pulmonary hyperinflation causes decreased stroke volume thereby decreased oxygen pulse (O2P). While O2P flattening is related to myocardial ischemia in cardiac patients, O2P patterns have seldom been explored in COPD. The aims of the study were to investigate O2P-curve patterns and associated factors in COPD. Seventy-five patients with stable COPD were enrolled. The demographics, cardiac size, physiological measurements and stress EKG were compared among O2P-curve pattern groups. An algorithm to identify O2P-curve patterns was developed in 28 patients. In the remaining 45 patients after excluding two with poor effort, this algorithm revealed 20 (44%) flattening, 16 (36%) increasing, and nine (20%) decreasing patterns. The flattening-type group had lower body mass, cardiac size, and diffusing capacity, and larger lung volumes (p = 0.05–<0.0001) compared to the increasing-type group. During exercise, the flattening-type group had a lower operable O2P and more hyperventilation and dyspnea (p = 0.02–<0.01). None had ST-T changes. Most differences were related to body mass and mildly to inspiratory fraction. The decreasing-type group performed higher effort than the increasing-type group (p < 0.05). In conclusion, O2P flattening was common and was associated with reduced body mass and pulmonary hyperinflation rather than with myocardial ischemia. The decreasing-type may be caused by motivation to exercise.

PP.24.10] LEFT VENTRICULAR DIASTOLIC FUNCTION IN RELATION TO HEMODYNAMIC LOAD COMPONENTS IN A GENERAL POPULATION

Objective: It was suggested that the contribution of central pulsatility to left ventricular (LV) diastolic dysfunction might be mediated by the hemodynamic loads of forward and backward (reflected) pulse waves and their ratio. Therefore, in the general population study, we investigated the relation between echocardiographic indexes of LV diastolic function and central hemodynamic components derived by flow-independent wave separation analysis. Design and method: In 755 participants, using echocardiography, we assessed LV dimensions, transmitral blood flow and mitral annular tissue Doppler velocities. From the central pressure waveform obtained by radial applanation tonometry, we derived central pulse pressure (cPP). Forward (Pf) and backward (Pb) wave amplitudes and their ratio (i.e. reflection magnitude, RM) were derived using triangular-flow wave separation analysis as implemented in SphygmoCor® software. Despite good quality of pulse wave recordings, the wave separation algorithm failed to retrieve Pf and Pb in 139 subjects (18.4%). Thus, this analysis included 616 subjects (46.1% women; mean age, 49.2 years). Results: Age explained most of the variance in cPP (24.6%), Pb (33.2%) and RM (36.1%; P < 0.0001 for all), but was not correlated with Pf. We also observed that age altered direct correlation between Pf and Pb (Pint < 0.0001). Other independent clinical correlates of cPP, Pf, Pb and RM were body mass index, heart rate, mean arterial pressure and use of antihypertensive drugs. In multivariable-adjusted analyses, transmitral early (E) and late (A) diastolic peak velocity and E/e’ ratio (reflecting LV filling pressure) increased with amplitudes of cPP, Pf and Pb in both men and women (P < 0.025). Of all LV diastolic indexes, only E/A ratio was independently associated with RM in men (P = 0.019). After full adjustment, LV mass index increased with cPP and Pb in men only (P < 0.040). Conclusions: Low feasibility of yielding Pf and Pb amplitudes from pulse curves by the current triangular-flow algorithm might limit the clinical utility of this approach. We demonstrated that LV diastolic function indexes were related to both forward and backward wave amplitudes, favoring the use of the composite central pulse wave for prediction of LV diastolic dysfunction.

Peat bogs in northern Alberta, Canada reveal decades of declining atmospheric Pb contamination

AbstractPeat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmospheric deposition of Pb, a valuable tracer of human activities. In each profile, the maximum Pb enrichment is found well below the surface. Radiometric age dating using three independent approaches (14C measurements of plant macrofossils combined with the atmospheric bomb pulse curve, plus 210Pb confirmed using the fallout radionuclides 137Cs and 241Am) showed that Pb contamination has been in decline for decades. Today, the surface layers of these bogs are comparable in composition to the “cleanest” peat samples ever found in the Northern Hemisphere, from a Swiss bog ~ 6000 to 9000 years old. The lack of contemporary Pb contamination in the Alberta bogs is testimony to successful international efforts of the past decades to reduce anthropogenic emissions of this potentially toxic metal to the atmosphere.

Principle study on the signal connection at transabdominal fetal pulse oximetry

Abstract Transabdominal fetal pulse oximetry is an approach to measure oxygen saturation of the unborn child non-invasively. The principle of pulse oximetry is applied to the abdomen of a pregnant woman, such that the measured signal includes both, the maternal and the fetal pulse curve. One of the major challenges is to extract the shape of the fetal pulse curve from the mixed signal for computation of the oxygen saturation. In this paper we analyze the principle kind of connection of the fetal and maternal pulse curves in the measured signal. A time varying finite element model is used to rebuild the basic measurement environment, including a bulk tissue and two independently pulsing arteries to model the fetal and maternal blood circuit. The distribution of the light fluence rate in the model is computed by applying diffusion equation. From the detectors we extracted the time dependent fluence rate and analyzed the signal regarding its components. The frequency spectra of the signals show peaks at the fetal and maternal basic frequencies. Additional signal components are visible in the spectra, indicating multiplicative coupling of the fetal and maternal pulse curves. We conclude that the underlying signal model of algorithms for robust extraction of the shape of the fetal pulse curve, have to consider additive and multiplicative signal coupling.

Modeling and Analysis of Cushioning Performance for Multi-layered Corrugated Structures

The objective of this study was to develop cushion curves models and analyze the cushioning performance of multi-layered corrugated structures (MLCS) using a method based on dynamic stress-energy relationship. Methods: Cushion tests were performed for developing cushion curve models under 12 combinations of test conditions: three different combinations of drop height, material thickness, and static stress for each of four levels of energy densities between 15 and 60 kJ/m 3 . Results: Dynamic stress and energy density for MLCS followed an exponential relationship. Cushion curve models were developed as a function of drop height, material thickness, and static stress for different paperboards and flute types. Generally, the differences between the shock pulse (transmitted peak acceleration) and cushion curve (position and width of belly portion) for the first drop and the averaged second to fifth drop were greater than those for polymer-based cushioning materials. Accordingly, the loss of cushioning performance of MLCS was estimated to be greater than that of polymer-based cushioning materials with the increasing number of drops. The position of the belly of the cushion curve of MLCS tends to shift upward to the left with increasing drop height, and the belly portion became narrower. However, depending on material thickness, under identical conditions, the cushion curve of MLCS showed an opposite tendency. Conclusions: The results of this study can be useful for environment-friendly and optimal packaging design as shock and vibrations are the key factors in cushioning packaging design.

Improved FPGA controlled artificial vascular system for plethysmographic measurements

Abstract The fetal oxygen saturation is an important parameter to determine the health status of a fetus, which is until now mostly acquired invasively. The transabdominal, fetal pulse oximetry is a promising approach to measure this non-invasively and continuously. The fetal pulse curve has to be extracted from the mixed signal of mother and fetus to determine its oxygen saturation. For this purpose efficient algorithms are necessary, which have to be evaluated under constant and reproducable test conditions. This paper presents the improved version of a phantom which can generate artificial pulse waves in a synthetic tissue phantom. The tissue phantom consists of several layers that mimic the different optical properties of the fetal and maternal tissue layers. Additionally an artificial vascular system and a dome, which mimics the bending of the belly of a pregnant woman, are incorporated. To obtain data on the pulse waves, several measurement methods are included, to help understand the behavior of the signals gained from the pulse waves. Besides pressure sensors and a transmissive method we integrated a capacitive approach, that makes use of the so called “Pin Oscillator” method. Apart from the enhancements in the tissue phantom and the measurements, we also improved the used blood substitute, which reproduces the different absorption characteristics of fetal and maternal blood. The results show that the phantom can generate pulse waves similar to the natural ones. Furthermore, the phantom represents a reference that can be used to evaluate the algorithms for transabdominal, fetal pulse oximetry.

The impact pulse and restoration curves: Going beyond mitigation and stabilization

Abstract Mitigation measures proposed as a response to the carbon and climate problem represent only the first half of a complete solution. Proactively repairing the damage through restoration represents the remaining half, which must entail the capture and storage of trillions of tons of carbon dioxide (CO2). Given that the time required for natural processes to restore the concentration of atmospheric CO2 to its baseline level is on the order of centuries, timely removal must involve carbon dioxide removal (CDR) geoengineering. Idealized impact and restoration scenarios, which build upon earlier conceptions of stabilization wedges, are proposed as conceptual tools with which to frame policy responses. These scenarios suggest that climate policy must weigh tradeoffs between nearer-term mitigation measures and longer-term CDR interventions. The tradeoffs depend on whether we wish to minimize the magnitude (peak CO2 concentration) or duration (time to reach pre-industrial CO2 levels) of the impact. Generalizing beyond the specific example of climate change, more rigorous consideration of technology-dependent impact and restoration scenarios can help provide a much-needed reality check for both environmental alarmism and technological optimism. This check is important as humanity transitions from the unintentional Anthropocene to the intentional Anthropocene over the course of this century. The prospect of the intentional Anthropocene also raises important ethical questions about the human-nature relationship.

The Predictive Value of Pulse Oximeters for Pulse Improvement after Angiography in Infants and Children.

BackgroundInformation from pulse oximeter waves confirms the presence of a pulse and helps obtain waves from tissue when the supplying artery is not readily accessible.ObjectivesThis study determined the predictive value of pulse oximeters for detecting improved arterial pulses after angiography.Patients and MethodsThis cross-sectional, multi-center study included 467 4-day-old to 12-year-old patients and was conducted from January 2012 to January 2016. Angiographies were performed on 12-year-old or younger children for various medical reasons using venous, arterial, or both types of paths. The posterior malleolar or dorsalis pedis were palpated in punctured lower extremities. In the absence of a pulse, pulse oximetry was performed to identify pulse curves at 1 hour, 6 hours, and 12 hours after each angiography.ResultsPulse oximetry displayed the pulses of 319 patients immediately following each angiography. Of these, 262 patients had palpable pulses at 6 hours after angiography (P < 0.0001), while 57 patients had no palpable pulse. Of these 57 patients, 15 had no palpable pulse at 12 hours after angiography (P < 0.0001). The odds of pulse improvement in children 6 hours after catheter angiography were 76% for the arterial path, 90% for the venous path, and 83.2% for both paths. At 12 hours after catheter angiography, these values increased to 91.6% for the arterial path, 100% for the venous path, and 95.9% for both paths.ConclusionsThe pulse oximeter can display the pulse curve immediately (1 hour) after angiography and indicate pulse improvement at 12 hours maximally following an angiography. In this case, heparin alone may be used instead of thrombolytic agents.

Ophtalmoplethysmography in ocular blood flow assessment

Introduction and purpose. Ocular blood flow (OBF) impairment is observed in more than 50 % of all ocular disorders. There is often an association with systemic hemodynamics. To evaluate ophthalmoplethysmographic parameters in normal subjects taking into account individual frequency-response OBF characteristics. Methods. 251 subjects without ophthalmic pathological findings (except incipient cataract in elderly) were examined using ophtalmoplethysmograph OP-A (SKTB Optimed, Moscow, Russia, calibrated by optimized method). Ocular biometry, intraocular pressure, blood pressure (BP), heart rate (HR) were also evaluated. Probands were divided into subgroups by gender and age. Results. The duration of the anacrotic part of the pulse curve ranged between 0.23±0.04 sec and 0.32±0.06 sec; the duration of the catacrotic part of the pulse curve was between 0.58±0.09 sec and 0.75±0.11 sec; the anacrotic/catacrotic ratio ranged between 0.34±0.07 and 0.55±0.1; the systolic increase of ocular anterior segment volume (SIOASV) ranged between 7.35±3.21 μl and 11.15±4.42 μl; SlOASV per minute was between 464.1±153.6 μl and 578.1±175.7 μl. Time characteristics of the plethysmographic curve highly correlate with HR. Conclusions. Ophtalmoplethysmography is a valuable tool for OBF evaluation. Normal OBF ophthalmoplethysmographic parameters vary significantly (ranging between 165.6 and 1388.4 μl/min). OBF evaluation should not be performed without systemic BP and HR examination.

Investigation of Input Signal Curve Effect on Formed Pulse of Hydraulic-Powered Pulse Machine

Well drilling machines should have as high efficiency factor as it is possible. This work proposes factors that are affected by change of input signal pulse curve. A series of runs are conducted on mathematical model of hydraulic-powered pulse machine. From this experiment, interrelations between input pulse curve and construction parameters are found. Results of conducted experiment are obtained with the help of the mathematical model, which is created in Simulink Matlab. Keywords – mathematical modelling; impact machine; output signal amplitude; input signal curve.