Commercial Pulse Research Articles

Screening moderate to severe obstructive sleep apnea with wearable device.

Obstructive sleep apnea (OSA) is a highly prevalent sleep-related breathing disorder usually diagnosed through polysomnography (PSG). Moderate to severe OSA can significantly increase morbidity and mortality. Existing screening tools have limited accuracy. This study aimed to evaluate the Wellue O2 ring, a commercial pulse oximeter ring, for screening moderate to severe OSA. A cross-sectional study included adults aged 18 and older suspected of having OSA who underwent PSG while wearing the Wellue O2 ring on their thumb. The oxygen desaturation index (ODI) from both the O2 ring and PSG was recorded. Sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated to determine the optimal ODI cutoff value for predicting moderate to severe OSA. The study included 190 participants (53.2% male) with an average age of 43 years and an average apnea-hypopnea index (AHI) of 50.4 events per hour. Among the participants, 84.7% had moderate to severe OSA. The optimal cutoff value for 11% ODI was 1.25 events per hour lasting 20s, with a sensitivity of 87.30% and a specificity of 78.70%. The area under the ROC curve for identifying moderate to severe OSA was 0.91. The Wellue O2 ring demonstrated high accuracy in detecting moderate to severe OSA and could be a viable alternative for screening in clinical settings due to its accessibility and ease of use. However, larger studies are required to validate its clinical utility for diagnosing and managing moderate to severe OSA.

Silver-decorated laser-induced graphene for a linear, sensitive, and almost hysteresis-free piezoresistive strain sensor

A new approach has recently emerged in graphene synthesis by direct laser writing (LIG), which is highly economical and scalable, unlike previous methods. Here, the sputtering method has been used to coat silver onto the laser-induced graphene-based sensor. The results demonstrate that the chosen approach substantially impacts the expected outcomes. The initial resistance values were consistent across the different sensor samples. The average resistance was slightly lower in the silver-coated samples compared to the uncoated samples, demonstrating the effectiveness of the Ag coating in enhancing the electrical conductivity of the LIG material. However, the difference in resistance was not statistically significant. The electromechanical behavior of the Ag-coated LIG strain sensor was tested under cyclic tensile strain. The gauge factor increased from 12.9-14.7 for the uncoated LIG sensor to 17.2-26.7 for the Ag-coated sensor, with the difference growing at higher strains. At 5%, 30%, and 70% strain, the gauge factor increased by 30%, 80%, and 82%, respectively. Sensors measuring 1-70% strain were developed, enabling use in various applications. Blood pulse measurements showed the silver-coated sample produced more uniform and reliable results than the uncoated sample. The number of beats matched a commercial pulse oximeter. This sensitivity, linearity, and reliability demonstrate the potential for commercializing these sensors.

Wearable broadband MoS2 photodetector for dual heart rate and UV detection powered by PDMS-MXene TENG

Wearable electronic devices capable of monitoring health parameters and environmental factors are tremendously desirable. Environmental energy harvesting as a power source is crucial to replace traditional batteries. This study aims to contribute to the development of sustainable and efficient wearable devices for health monitoring and environmental sensing. In this study, a self-powered wearable MoS2-based photodetector, integrated with a PDMS-MXene-based triboelectric nanogenerator (TENG) is presented. The TENG generates isometric AC voltage using a diode, and it is used to charge a capacitor for DC voltage output. The photodetector, with a responsivity of 1.25 × 105A/W, specific detectivity of 2×1013 Jones, millisecond response time, enhanced responsivity of 1.1×1010 V/W and specific detectivity of 9.5×1016 Jones while coupled with TENG, successfully measured heart rate using a 660 nm LED and compared well with a commercial pulse meter. Additionally, UV illumination was detected using a 395 nm LED in the AC mode of the TENG. The study’s results support the advancement of flexible, integrated, and sustainable wearable devices, offering solutions to challenges posed by current battery-powered devices.

Predicting stroke volume variation using central venous pressure waveform: a deep learning approach

Objective. This study evaluated the predictive performance of a deep learning approach to predict stroke volume variation (SVV) from central venous pressure (CVP) waveforms.Approach. Long short-term memory (LSTM) and the feed-forward neural network were sequenced to predict SVV using CVP waveforms obtained from the VitalDB database, an open-source registry. The input for the LSTM consisted of 10 s CVP waveforms sampled at 2 s intervals throughout the anesthesia duration. Inputs of the feed-forward network were the outputs of LSTM and demographic data such as age, sex, weight, and height. The final output of the feed-forward network was the SVV. The performance of SVV predicted by the deep learning model was compared to SVV estimated derived from arterial pulse waveform analysis using a commercialized model, EV1000.Main results. The model hyperparameters consisted of 12 memory cells in the LSTM layer and 32 nodes in the hidden layer of the feed-forward network. A total of 224 cases comprising 1717 978 CVP waveforms and EV1000/SVV data were used to construct and test the deep learning models. The concordance correlation coefficient between estimated SVV from the deep learning model were 0.993 (95% confidence interval, 0.992-0.993) for SVV measured by EV1000.Significance. Using a deep learning approach, CVP waveforms can accurately approximate SVV values close to those estimated using commercial arterial pulse waveform analysis.

Development of wearable device and synchronized Mobile application to monitor vital signs in real time

AbstractSilent hypoxia is a complication that can lead to severe respiratory disorders at a time when people feel well, especially in Covid-19, and lung destruction if not intervened early. In this paper, a wearable device and a mobile application synchronized with the device were developed to measure people’s vitals and reduce the risk of silent hypoxia. The device consists of 2 parts: a wristband and a finger-clip, and includes a micro-controller, a bluetooth module, a Li-Po battery and various sensors to measure body temperature, pulse and SpO2 values. It can measure body temperature, pulse and SpO2 instantly or at certain programmable intervals like a holter device through the mobile app. These measured values can be recorded and various analyzes can be performed on them. Also the measurement results can be sent via an e-mail. When the vitals reach or exceed the predefined risk levels, a notification can be generated. The proposed device was evaluated in various performance tests and compared to a commercial pulse oximeter as well as alternatives in the literature. It was tested for connectivity and transmission, battery endurance and field testing. In the comparison test, error values of 1.8%, 3.5% and 0.6% were achieved in SpO2, pulse and temperature measurements, respectively. The device is both a measurement and holter instrument for body temperature, pulse and SpO2 values. With this feature, it can be actively used by both patients and their relatives in hospital or home environment.

Development of an FPGA‐Based Pulse‐Height Analyzer for Scintillation Detectors in Gamma Energy Spectroscopy

This study presents the development of a Pulse Height Analyzer (PHA) using an FPGA‐based hardware platform, specifically the National Instruments MyRIO embedded device, for radiation detectors. Electronic pulses generated by the detector when exposed to radiation are triggered, digitized, and transferred to a data buffer. A pulse height analysis tool categorizes these pulses and stores pulse‐height information in registers or channels, enabling the construction of a pulse‐height distribution. The data of pulse‐height distribution is then recorded on a computer via a user‐friendly interface. The Pulse Height Analyzer was implemented using a 3‐inch by 3‐inch NaI(Tl) scintillation detector for gamma energy measurements, employing standard radioisotopes Na‐22 and Co‐60. Gamma energy spectra were acquired and analyzed. Our results demonstrate that the achieved energy resolution is comparable to that of the commercial Pulse Height Analyzers, such as EASY‐MCA 2K, a product of AMETEK Inc. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Effect of Skin Pigmentation and Finger Choice on Accuracy of Oxygen Saturation Measurement in an IoT-Based Pulse Oximeter.

Pulse oximeters are widely used in hospitals and homes for measurement of blood oxygen saturation level (SpO2) and heart rate (HR). Concern has been raised regarding a possible bias in obtaining pulse oximeter measurements from different fingertips and the potential effect of skin pigmentation (white, brown, and dark). In this study, we obtained 600 SpO2 measurements from 20 volunteers using three UK NHS-approved commercial pulse oximeters alongside our custom-developed sensor, and used the Munsell colour system (5YR and 7.5YR cards) to classify the participants' skin pigmentation into three distinct categories (white, brown, and dark). The statistical analysis using ANOVA post hoc tests (Bonferroni correction), a Bland-Altman plot, and a correlation test were then carried out to determine if there was clinical significance in measuring the SpO2 from different fingertips and to highlight if skin pigmentation affects the accuracy of SpO2 measurement. The results indicate that although the three commercial pulse oximeters had different means and standard deviations, these differences had no clinical significance.

Evaluating bag storage technologies for physical characteristics, loss reduction and economic viability in pulses

Meticulous selection of storage bags is vital to optimize grain preservation, mitigate losses, and improve rural income. A comprehensive comparative evaluation of four different commercial pulse storage bag technologies (Jute bag, Woven polypropylene bag (WPP), Purdue Improved crop storage bag (PICS), and Grainpro bag) was conducted alongside novel polypropylene reinforced Jute storage bag (PPRJ). The storage bags were examined for their physical properties (unit weight, coefficient of friction, breaking strength), water vapour transmission rate (WVTR), and effectiveness in preserving pulse (Bengal gram (Cicer arietinum, Var. Swetha ICCV -2)) quality and quantity during storage. Unit weight was highest for jute bags (0.14 ± 0.080 g/cm2), which reduced by 35.9 % after reinforcement with polypropylene, and lowest for Grainpro bags (0.03 ± 0.002 g/cm2). Jute bag exhibited the highest breaking strength (181.0 ± 1.06 kgf), which decreased by 23.7 % after reinforcement. Synthetic fiber bags had lower breaking strength and coefficient of friction, limiting their stacking ability. WVTR of the jute bag reduced by 39.2 % after reinforcement. The PICS bag offered the highest protection to stored Bengal gram. Weight loss was more than 25% and 10% of the initial grain weight in Jute and WPP, respectively, due to inefficient barrier properties, whereas the PPRJ bag was similarly effective as hermetic bags. The benefit-cost ratio ranged between 0.219 and 0.297 for the three profit-yielding bags (PICS, Grainpro, and PPRJ). Polypropylene-reinforced jute bags represent a promising advancement in sustainable grain storage practices. The significance of establishing hermetic conditions to suppress insect populations and safeguard grain quality was reaffirmed in the study.

Dynamic acoustic optimization of pulse tube refrigerators for rapid cooldown

Pulse tube refrigerators are a critical enabling technology for many disciplines that require low temperatures. These refrigerators dominate the total power consumption of most modern cryostats, including those that reach millikelvin temperatures using additional cooling stages. In state-of-the-art commercial pulse tube refrigerators, the acoustic coupling between the driving compressor and the refrigerator is fixed and optimized for operation at base temperature. We show that this optimization is incorrect during the cooldown process, which results in wasted power consumption by the compressor and slow cooldown speed. After developing analytic expressions that demonstrate the need for acoustic tuning as a function of temperature, we dynamically optimize the acoustics of a commercial pulse tube refrigerator and show that the cooldown speed can be increased to 1.7 to 3.5 times the original value. Acoustic power measurements show that loss mechanism(s)—and not the capacity of the compressor—limit the maximum cooling available at high temperatures, suggesting that even faster cooldown speeds can be achieved in the future. This work has implications for the accessibility of cryogenic temperatures and the cadence of research in many disciplines such as quantum computing.

Harnessing 2D Ruddlesden-Popper Perovskite with Polar Organic Cation for Ultrasensitive Multibit Nonvolatile Transistor-Type Photomemristors.

Photomemristors have been regarded as one of the most promising candidates for next-generation hardware-based neuromorphic computing due to their potentials of fast data transmission and low power consumption. However, intriguingly, so far, photomemristors seldom display truly nonvolatile memory characteristics with high light sensitivity. Herein, we demonstrate ultrasensitive photomemristors utilizing two-dimensional (2D) Ruddlesden-Popper (RP) perovskites with a highly polar donor-acceptor-type push-pull organic cation, 4-(5-(2-aminoethyl)thiophen-2-yl)benzonitrile+ (EATPCN+), as charge-trapping layers. High linearity and almost zero-decay retention are observed in (EATPCN)2PbI4 devices, which are very distinct from that of the traditional 2D RP perovskite devices consisting of nonpolar organic cations, such as phenethylamine+ (PEA+) and octylamine+ (OA+), and traditional 3D perovskite devices consisting of methylamine+ (MA+). The 2-fold advantages, including desirable spatial crystal arrangement and engineered energetic band alignment, clarify the mechanism of superior performance in (EATPCN)2PbI4 devices. The optimized (EATPCN)2PbI4 photomemristor also shows a memory window of 87.9 V and an on/off ratio of 106 with a retention time of at least 2.4 × 105 s and remains unchanged after >105 writing-reading-erasing-reading endurance cycles. Very low energy consumptions of 1.12 and 6 fJ for both light stimulation and the reading process of each status update are also demonstrated. The extremely low power consumption and high photoresponsivity were simultaneously achieved. The high photosensitivity surpasses that of a state-of-the-art commercial pulse energy meter by several orders of magnitude. With their outstanding linearity and retention, rabbit images have been rebuilt by (EATPCN)2PbI4 photomemristors, which truthfully render the image without fading over time. Finally, by utilizing the powerful ∼8 bits of nonvolatile potentiation and depression levels of (EATPCN)2PbI4 photomemristors, the accuracies of the recognition tasks of CIFAR-10 image classification and MNIST handwritten digit classification have reached 89% and 94.8%, respectively. This study represents the first report of utilizing a functional donor-acceptor type of organic cation in 2D RP perovskites for high-performance photomemristors with characteristics that are not found in current halide perovskites.

Self-calibrated pulse oximetry algorithm based on photon pathlength change and the application in human freedivers.

Pulse oximetry estimates the arterial oxygen saturation of hemoglobin () based on relative changes in light intensity at the cardiac frequency. Commercial pulse oximeters require empirical calibration on healthy volunteers, resulting in limited accuracy at low oxygen levels. An accurate, self-calibrated method for estimating is needed to improve patient monitoring and diagnosis. Given the challenges of calibration at low levels, we pursued the creation of a self-calibrated algorithm that can effectively estimate across its full range. Our primary objective was to design and validate our calibration-free method using data collected from human subjects. We developed an algorithm based on diffuse optical spectroscopy measurements of cardiac pulses and the modified Beer-Lambert law (mBLL). Recognizing that the photon mean pathlength () varies with related absorption changes, our algorithm aligns/fits the normalized (across wavelengths) obtained from optical measurements with its analytical representation. We tested the algorithm with human freedivers performing breath-hold dives. A continuous-wave near-infrared spectroscopy probe was attached to their foreheads, and an arterial cannula was inserted in the radial artery to collect arterial blood samples at different stages of the dive. These samples provided ground-truth via a blood gas analyzer, enabling us to evaluate the accuracy of estimation derived from the NIRS measurement using our self-calibrated algorithm. The self-calibrated algorithm significantly outperformed the conventional method (mBLL with a constant ratio) for estimation through the diving period. Analyzing 23 ground-truth data points ranging from 41% to 100%, the average absolute difference between the estimated and the ground truth is for our algorithm, significantly lower than the observed with the conventional approach. By factoring in the variations in the spectral shape of relative to , our self-calibrated algorithm enables accurate estimation, even in subjects with low levels.

Calibration of terahertz sampling detectors for intense unipolar picosecond current pulses in waveguides

Terahertz pulses are nowadays commonly used in many areas of condensed matter physics to access material properties and explore transport phenomena at fast timescales. However, little work has been devoted to the full characterization of such pulses when confined in waveguides. In this work, we fabricate terahertz photoconductive switch detectors, located at various points along a coplanar waveguide, and sample the electrical pulses that pass by the detectors. Two different but consistent methods were developed to calibrate the pulse amplitude. Notably, we synchronize a commercial pulse generator with the laser in order to sample nanosecond-wide pulses with the photoswitch detectors, effectively turning the setup into an on-chip high-frequency sampling oscilloscope. Both methods give identical results on pulse current, voltage, and field amplitudes and enable an absolute characterization of the electrical pulse propagation along the waveguide. These techniques constitute a reliable tool to explore (non-linear) phenomena such as current or field induced magnetization switching or phase transitions, which take place at high THz intensities.

A Low-Cost Electroporator for Genetically Modifying Social Amoeba Dictyostelium Discoideum

The social amoeba Dictyostelium discoideum is a commonly used eukaryotic model organism for the study of cell division, chemotaxis, differentiation, phagocytosis, and other cellular processes. Electroporation is an effective and efficient method for delivering plasmid DNA into D. discoideum, an invaluable tool for studying intracellular processes. The technology is readily available but often prohibitively expensive. Although several custom-built electroporation devices have been developed, none deliver the specific 8.5kV/cm exponentially decaying waveform required for D. discoideum transformation. The present study examined whether a simple, inexpensive device can be built to produce this waveform through a simple resistor-capacitor (RC) circuit. A pulse generator RC circuit was built incorporating inexpensive electronic components and a 3D printed cuvette chamber. All four possible combinations of custom-built and commercial pulse generators and custom-built and commercial cuvette chambers were used to transform D. discoideum cells with a plasmid encoding green fluorescent protein (GFP). There were no significant differences in the number of surviving cells immediately following or 24 hours post-transformation between the systems. All combinations of custom-built and commercial systems achieved comparably high transformation efficiency shown by percent of cells expressing GFP six days after the transformation. Since the waveform-specific electroporation system we present here can be built by non-experts with easily obtainable materials and 3D printing, we envision this device to benefit investigators in areas with low research budgets and educators in multiple STEM fields.

PO-05-052 COMPARISON OF SIMULTANEOUS, MATCHED PROGRAMMING AMBULATORY RHYTHM DETECTION BETWEEN A NOVEL EXTRAVASCULAR AND STANDARD TRANSVENOUS ICD SYSTEMS

A novel extravascular (EV) ICD lead (AtaCor Medical, San Clemente, CA) is under development for sensing and defibrillation of ventricular tachyarrhythmias (VF) using commercial DF-4 compatible ICD pulse generators (PG). The purpose of this analysis is to perform a within-patient comparison of sensing and detection of ambulatory spontaneous cardiac rhythms between a novel EV-ICD system and a simultaneously implanted standard transvenous (TV) ICD system. In the non-randomized, single-center SECURE EV Study (NCT05099289), human subjects (n=18) were implanted with two ICD systems: (1) the Research EV-ICD system and (2) a standard TV-ICD system. The Research EV-ICD Lead was implanted into the anterior mediastinum and fixated at the fascial plane along the left parasternum. The EV-ICD lead was then tunneled subcutaneously to a left lateral pocket. The TV-ICD was implanted in standard fashion along the left or right subclavian with endocardial lead placement. The ICD pulse generators were programmed with matched sensitivity, detection zones and discrimination features to compare appropriate and inappropriate ambulatory sensing function. The EV-ICD systems were implanted for up to 90-days and were left in a “recording only” mode to store events without therapy delivery. Each implant system was interrogated over the 90- day study period to compare adjudicated stored events between the two systems. Matched and unmatched stored electrograms of appropriate and inappropriate episodes were valuated. The prototype EV-ICD lead placement was successful in 16/18 (89%) subjects. The median follow-up duration for the EV ICD lead was 90 days (mean = 71 days). During the follow up, spontaneous tachycardia events were stored in 7 (44%) subjects (2 patients with 3 matched appropriate events (Figure 1) and 5 patients with matched and unmatched inappropriate events). Two EV ICD subjects had unmatched inappropriate sensing events due to noise caused by a broken anode cable and another due to oversensing diaphragm myopotentials not seen by the TV ICD. Early experience with a prototype left, anterior parasternal EV ICD lead is highly correlative in automatically sensing and detecting cardiac rhythms such as VF using commercially available ICD PGs. Further iterations of the EV ICD lead should improve specificity.

EFFECT OF EXTRUSION PARAMETERS ON PHYSICAL PROPERTIES OF TUR DAL (PIGEON PEA) ANALOGUES DEVELOPED FROM TUR DAL BROKENS

Dehusking and splitting are typically the steps involved in converting pulses into dal. The milling losses in commercial pulse mills can be attributed to the small brokens and fine powders found during scoring and concurrent dehusking and splitting operations. The fracture of dal kernels during the milling process is a problem in the dal milling industry, and customers don’t generally like these broken kernels. The only way to turn these unused milling fractions into profitable products is through extrusion cooking. Extrusion cooking of flour of redgram dal brokens with addition of some additives was done to prepare Tur dal analogues at various extrusion process parameters. The effect of barrel temperature (120 – 175 oC), feed moisture content (18-25%), feed rate (40-60 kg/h) and screw speed (100-220 rpm) on bulk density, expansion ratio and hardness of Tur dal analogues were investigated. To develop the prediction model, a central composite rotable design (CCRD) using response surface method (RSM) was applied. Each variable’s impact on the responses was measured via regression equations. The second-order quadratic regression model fit the variation adequately. The significance was established at p0.05. An increase in bulk density and decrease in expansion ratio with increase in feed moisture content and feed rate was observed. The bulk density and hardness increased as the barrel temperature increased when the feed moisture content was lower; conversely, when the feed moisture content was higher, the bulk density and hardness reduced as the barrel temperature increases.

Self-Driven Photo-Polarized Water Molecule-Triggered Graphene-Based Photodetector.

Flowing water can be used as an energy source for generators, providing a major part of the energy for daily life. However, water is rarely used for information or electronic devices. Herein, we present the feasibility of a polarized liquid-triggered photodetector in which polarized water is sandwiched between graphene and a semiconductor. Due to the polarization and depolarization processes of water molecules driven by photogenerated carriers, a photo-sensitive current can be repeatedly produced, resulting in a high-performance photodetector. The response wavelength of the photodetector can be fine-tuned as a result of the free choice of semiconductors as there is no requirement of lattice match between graphene and the semiconductors. Under zero voltage bias, the responsivity and specific detectivity of Gr/NaCl (0.5 M)W/N-GaN reach values of 130.7 mA/W and 2.3 × 109 Jones under 350 nm illumination, respectively. Meanwhile, using a polar liquid photodetector can successfully read the photoplethysmography signals to produce accurate oxygen blood saturation and heart rate. Compared with the commercial pulse oximetry sensor, the average errors of oxygen saturation and heart rate in the designed photoplethysmography sensor are ~1.9% and ~2.1%, respectively. This study reveals that water can be used as a high-performance photodetector in informative industries.

Simple and Easily Interpretable Flap Monitoring Method Using a Commercial Pulse Oximeter and a Widely Used Bedside Patient Monitor.

Background Various methods for monitoring after free flap surgery have been reported in the literature. Among them, pulse oximetry shows a sensitive reaction to vascular issues, and it is easy to interpret visually. However, previous reports used special equipment that was less commonly used and difficult to generalize. In this study, we used a commercial pulse oximeter and a widely used bedside patient monitor to monitor transplanted free tissue and lower extremities of healthy subjects with impaired circulation. Methods A reflectance pulse oximeter sensor was attached on the flap after free tissue transplantation. The sensor was connected to a bedside patient monitor, and the flap oxygen saturation (SpO2) levels and arterial waveforms were continuously monitored. Additionally, blood circulation disorder was induced in the lower limbs of healthy volunteers using pressure cuff inflation on the thigh, and the waveform and SpO2 levels on the pulse oximeter attached to the lower leg were monitored. Results Twenty-two patients were included in this study. No postoperative vascular issues were observed in any case. Pulse oximeters showed normal rhythmic wavelengths, and the flap SpO2 level ranged approximately >90%. The pulse oximeter waveform rapidly disappeared during arterial occlusion in the thigh pressure cuff inflation test, and the waveform flattened and the SpO2 level decreased slightly during venous congestion. Conclusion Flap monitoring using a commercially available pulse oximeter and a bedside patient monitor is a versatile, easy-to-interpret, and useful method. Changes in waveform and SpO2 levels appear during arterial and venous circulation disorders, and these changes can be differentiated.

Acute effects of cardiac contractility modulation stimulation in conventional 2D and 3D human induced pluripotent stem cell-derived cardiomyocyte models.

Cardiac contractility modulation (CCM) is a medical device therapy whereby non-excitatory electrical stimulations are delivered to the myocardium during the absolute refractory period to enhance cardiac function. We previously evaluated the effects of the standard CCM pulse parameters in isolated rabbit ventricular cardiomyocytes and 2D human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) monolayers, on flexible substrate. In the present study, we sought to extend these results to human 3D microphysiological systems to develop a robust model to evaluate various clinical CCM pulse parameters in vitro. HiPSC-CMs were studied in conventional 2D monolayer format, on stiff substrate (i.e., glass), and as 3D human engineered cardiac tissues (ECTs). Cardiac contractile properties were evaluated by video (i.e., pixel) and force-based analysis. CCM pulses were assessed at varying electrical 'doses' using a commercial pulse generator. A robust CCM contractile response was observed for 3D ECTs. Under comparable conditions, conventional 2D monolayer hiPSC-CMs, on stiff substrate, displayed no contractile response. 3D ECTs displayed enhanced contractile properties including increased contraction amplitude (i.e., force), and accelerated contraction and relaxation slopes under standard acute CCM stimulation. Moreover, 3D ECTs displayed enhanced contractility in a CCM pulse parameter-dependent manner by adjustment of CCM pulse delay, duration, amplitude, and number relative to baseline. The observed acute effects subsided when the CCM stimulation was stopped and gradually returned to baseline. These data represent the first study of CCM in 3D hiPSC-CM models and provide a nonclinical tool to assess various CCM device signals in 3D human cardiac tissues prior to in vivo animal studies. Moreover, this work provides a foundation to evaluate the effects of additional cardiac medical devices in 3D ECTs.

Abstract 11951: Acute Cardiac Contractility Modulation Assessment in Conventional 2D Monolayers and 3D Engineered Cardiac Tissues Using Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Introduction: Cardiac contractility modulation (CCM) is a medical device therapy whereby non-excitatory electrical simulations are delivered to the myocardium during the absolute refractory period. We previously evaluated the effects of the standard CCM pulse parameters in isolated rabbit ventricular cardiomyocytes and 2D human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) monolayers, on flexible substrate. Hypothesis: In the present study, we sought to extend these results to 3D microphysiological systems to develop a human-based model to evaluate various clinical CCM pulse parameters in vitro. Methods: HiPSC-CMs were studied in conventional 2D monolayer format, on stiff substrate (i.e., glass), and as 3D human engineered cardiac tissues (ECTs). Cardiac contractile properties were evaluated by video-based analysis and custom force analysis. CCM pulses were assessed at varying clinical ‘doses’ using a commercial pulse generator. Robust response was observed at physiological Ca concentrations [1.8 mM] for 3D ECTs. Results: Under standard acute CCM stimulation 3D ECTs displayed enhanced contractile properties including increased peak contraction amplitude (i.e., force), and faster contraction and relaxation kinetics. Moreover, 3D ECTs displayed enhanced contractility in a CCM pulse parameter dependent manner. The observed effects subsided when the acute CCM stimulation was stopped and gradually returned to baseline. Under comparable conditions, conventional 2D monolayer hiPSC-CMs, on stiff substrate, displayed neutral response. Conclusions: These data represent the first study of acute CCM stimulation in a 3D hiPSC-CM model and provides a preclinical model to assess various CCM signals in human cardiac tissues prior to in vivo animal studies.

Development of a Low-Cost Pulse Oximeter for Taking Medical-Scientific Parameters to Monitor Remote Patients

The development of low-cost systems for measuring medical parameters is currently an important issue since this type of system ensures that any sector of the population can access these technologies. Likewise, pandemic situations, such as the one experienced some months ago due to SARS-CoV-2, require the rapid availability of diagnostic devices. One of the devices, which has turned out to be the most relevant in the early detection of respiratory problems, is the finger pulse oximeter. However, the default information that these devices offer is limited. This paper presents the process carried out to analyze the data measured by a commercial pulse oximeter and takes advantage of them to extract relevant information about the vital parameters of the patient that is being monitored, such as peripheral oxygen saturation (SpO2), pulse rate (bpm) (PR), respiratory rate (RR/min), perfusion index (%) (Pi), plethysmography wave, plethysmographic variation index (%) (PVi), the shape of the dicrotic fissure, and the area under the curve. To do this, the Bluetooth frames generated by the device are analyzed through reverse engineering and processed to obtain the aforementioned parameters. Finally, an application for Android devices is developed in order to facilitate the collection and reading of the parameters. The system is tested with different patients whose results are validated by a physician.