Articles de revues : « Hemodynamic sensor »

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Turcott, Robert. « Extravascular hemodynamic acoustic sensor ». Journal of the Acoustical Society of America 113, n^o 5 (2003) : 2397. http://dx.doi.org/10.1121/1.1584191.

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Weidenmüller, Jens, Oezgue Dogan, Alexander Stanitzki, Mario Baum, Tim Schröder, Dirk Wünsch, Michael Görtz et Anton Grabmaier. « Implantable multi-sensor system for hemodynamic controlling ». tm - Technisches Messen 85, n^o 5 (25 mai 2018) : 359–65. http://dx.doi.org/10.1515/teme-2017-0116.

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Abstract A miniaturized implantable multi-sensor system for cardiovascular monitoring of physiological parameters is presented. High accuracy pressure measurements within the vessel can be performed by a capacitive pressure sensor. Additional information about the patient, e. g., sudden movement, inclination or increased temperature can be obtained by additional sensor components such as an acceleration sensor and a temperature sensor unit. This information facilitates compensation of interferences for more accurate pressure measurements. A multi-functional ASIC enables, amongst others, sensor signal processing, power management and telemetric communication with extracorporeal electronics. Sensor chips, the multi-functional ASIC and passive components are assembled on a LTCC circuit board in which an antenna coil is integrated for telemetric energy and data transmission at a frequency of 13.56 MHz. In order to support further miniaturization, the implant shall be encapsulated with a stack of very thin and hermetic ceramics applied by ALD instead of using bulky metal housings. Further encapsulation with polymers, which can be functionalised with appropriate biomolecules, is necessary for a proper shape, a biocompatible interface to the surrounding tissue and, thereby, reduction of thrombogenicity.

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NABUTOVSKY, YELENA, TODD PAVEK et ROBERT TURCOTT. « Chronic Performance of a Subcutaneous Hemodynamic Sensor ». Pacing and Clinical Electrophysiology 35, n^o 8 (3 mai 2012) : 919–26. http://dx.doi.org/10.1111/j.1540-8159.2012.03419.x.

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Lippert, M., E. Zima, G. Czygan et B. Merkely. « INTRACARDIAC IMPEDANCE AS HEMODYNAMIC SENSOR : FEASIBILITY STUDY ». Biomedizinische Technik/Biomedical Engineering 48, s1 (2003) : 248–49. http://dx.doi.org/10.1515/bmte.2003.48.s1.248.

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Oláh, Attila, Mihály Ruppert, Tamás István Orbán, Ágota Apáti, Balázs Sarkadi, Béla Merkely et Tamás Radovits. « Hemodynamic characterization of a transgenic rat strain stably expressing the calcium sensor protein GCaMP2 ». American Journal of Physiology-Heart and Circulatory Physiology 316, n^o 5 (1 mai 2019) : H1224—H1228. http://dx.doi.org/10.1152/ajpheart.00074.2019.

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A novel transgenic rat strain has recently been generated that stably expresses the genetically engineered calcium sensor protein GCaMP2 in different cell types, including cardiomyocytes, to investigate calcium homeostasis. To investigate whether the expression of the GCaMP2 protein itself affects cardiac function, in the present work we aimed at characterizing in vivo hemodynamics in the GCaMP2 transgenic rat strain. GCaMP2 transgenic rats and age-matched Sprague-Dawley control animals were investigated. In vivo hemodynamic characterization was performed by left ventricular (LV) pressure-volume analysis. Postmortem heart weight data showed cardiac hypertrophy in the GCaMP2 group (heart-weight-to-tibial-length ratio: 0.26 ± 0.01 GCaMP2 vs. 0.23 ± 0.01 g/cm Co, P < 0.05). We detected elevated mean arterial pressure and increased total peripheral resistance in transgenic rats. GCaMP2 transgenesis was associated with prolonged contraction and relaxation. LV systolic function was not altered in transgenic rats, as indicated by conventional parameters and load-independent, sensitive indices. We found a marked deterioration of LV active relaxation in GCaMP2 animals (τ: 16.8 ± 0.7 GCaMP2 vs. 12.2 ± 0.3 ms Co, P < 0.001). Our data indicated myocardial hypertrophy, arterial hypertension, and impaired LV active relaxation along with unchanged systolic performance in the heart of transgenic rats expressing the GCaMP2 fluorescent calcium sensor protein. Special caution should be taken when using transgenic models in cardiovascular studies. NEW & NOTEWORTHY Genetically encoded Ca2+-sensors, like GCaMP2, are important tools to reveal molecular mechanisms for Ca2+-sensing. We provided left ventricular hemodynamic characterization of GCaMP2 transgenic rats and found increased afterload, cardiac hypertrophy, and prolonged left ventricular relaxation, along with unaltered systolic function and contractility. Special caution should be taken when using this rodent model in cardiovascular pharmacological and toxicological studies.

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Benza, Raymond L., Mark Doyle, David Lasorda, Kishan S. Parikh, Priscilla Correa-Jaque, Nima Badie, Greg Ginn et al. « Monitoring Pulmonary Arterial Hypertension Using an Implantable Hemodynamic Sensor ». Chest 156, n^o 6 (décembre 2019) : 1176–86. http://dx.doi.org/10.1016/j.chest.2019.06.010.

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Morton, Patricia Gonce. « Rate-Responsive Cardiac Pacemakers ». AACN Advanced Critical Care 2, n^o 1 (1 février 1991) : 140–49. http://dx.doi.org/10.4037/15597768-1991-1022.

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Pacemaker technology continues to advance in the direction of restoring a normal hemodynamic response under varying physiologic conditions. Rate-responsive pacemakers meet this challenge by adjusting the pacing rate in response to a sensed physiologic variable other than sinus node activity. In an effort to design the ideal rate-responsive system, various physiologic cues have been tested. To translate shifts in the sensed physiologic indicator into an appropriate pacing rate, specialized sensor systems also have been developed and include mechanical, chemical, thermal, and electrical sensors. Although each sensor system offers advantages and disadvantages, continued research and clinical experience will determine the future of this exciting new form of cardiac pacing

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Illa, Míriam, Laura Pla, Sergio Berdún, Mònica Mir, Lourdes Rivas, Samuel Dulay, Nicole Picard-Hagen, Josep Samitier, Eduard Gratacós et Elisenda Eixarch. « Miniaturized Electrochemical Sensors to Monitor Fetal Hypoxia and Acidosis in a Pregnant Sheep Model ». Biomedicines 9, n^o 10 (28 septembre 2021) : 1344. http://dx.doi.org/10.3390/biomedicines9101344.

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Perinatal asphyxia is a major cause of severe brain damage and death. For its prenatal identification, Doppler ultrasound has been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. We have evaluated the performance of a miniaturized multiparametric sensor aiming to evaluate tissular oxygen and pH changes continuously in an umbilical cord occlusion (UCO) sheep model. The electrochemical sensors were inserted in fetal hindlimb skeletal muscle and electrochemical signals were recorded. Fetal hemodynamic changes and metabolic status were also monitored during the experiment. Additionally, histological assessment of the tissue surrounding the sensors was performed. Both electrochemical sensors detected the pO2 and pH changes induced by the UCO and these changes were correlated with hemodynamic parameters as well as with pH and oxygen content in the blood. Finally, histological assessment revealed no signs of alteration on the same day of insertion. This study provides the first evidence showing the application of miniaturized multiparametric electrochemical sensors detecting changes in oxygen and pH in skeletal muscular tissue in a fetal sheep model.

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Mahnken, Andreas H., Ute Urban, Holger Fassbender, Uwe Schnakenberg, Felix Schoth et Thomas Schmitz-Rode. « Telemetric Catheter-Based Pressure Sensor for Hemodynamic Monitoring : Experimental Experience ». CardioVascular and Interventional Radiology 32, n^o 4 (2 avril 2009) : 714–19. http://dx.doi.org/10.1007/s00270-009-9556-0.

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Smolyakov, Yuri N., Boris I. Kuznik, Svetlana A. Kalashnikova, Nikolay A. Nolfin, Ekaterina V. Fedorenko et Mankhar Mikhailovich Mikhahanov. « Adaptation reactions of hemodynamic systems on artificially modulated stress in healthy individuals ». I.P. Pavlov Russian Medical Biological Herald 27, n^o 4 (11 janvier 2020) : 443–50. http://dx.doi.org/10.23888/pavlovj2019274443-450.

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Aim. To study the influence of artificially created stress on hemodynamic parameters of peripheral microcirculation and variability of the heart rhythm in somatically healthy young individuals. Materials and Methods. In the study 30 individuals were involved (of them 16 men) with the mean age 18.21.1 years. An artificial stress was created using Stroop method. Assessment of characteristics of hemodynamics of microcirculation (HM) was performed by the method of dynamic scattering of light from erythrocytes. The signal was integrated in the form of three hemodynamic indexes: HI (Hemodynamic Indexes). Low frequency index (HI1) was determined by a slow interlayer interaction, high frequency area (HI3) characterized fast shearing of layers. HI2 took intermediate position (precapillary and capillary blood flow). Variability of cardiointervals isolated from pulse component, was assessed by method of variation pulsometry (Heart Rate Variability, HRV). Results. In the course of study, increase in the heart rate (HR) in the stage of testing was observed that confirms a high extent of stress load. In hemodynamics, redistribution of blood flow was noted toward slow shear velocities (near-wall blood flow). After cessation of stress load, hemodynamic parameters declined and returned to previous values. Parameters characterizing variability of rhythm LF (sympathetic component), HF (vagal activity), CVI (non-linear parasympathetic index) showed a tendency to growth; here, LF/HF ratio did not change. Conclusion. In result of the carried out study it was possible to formulate a multifactor picture of variation of parameters of microcirculation and of autonomic regulation of cardiac rhythm specific of reactions of adaptation to induced stress. The quantitative criteria of the obtained shears may be integrated into stress indexes to be used in clinical practice. A portable mDLS sensor may be supplemented with specific assessment criteria and used for monitoring of adaptive reactions induced by stressful situations, and for taking early diagnostic and prognostic decisions in the clinical practice, and for self-control of a patient.

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Guo, Cheng-Yan, Kuan-Jen Wang et Tung-Li Hsieh. « Piezoelectric Sensor for the Monitoring of Arterial Pulse Wave : Detection of Arrhythmia Occurring in PAC/PVC Patients ». Sensors 21, n^o 20 (19 octobre 2021) : 6915. http://dx.doi.org/10.3390/s21206915.

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Previous studies have found that the non-invasive blood pressure measurement method based on the oscillometric method is inaccurate when an arrhythmia occurs. Therefore, we propose a high-sensitivity pulse sensor that can measure the hemodynamic characteristics of the pulse wave and then estimate the blood pressure. When an arrhythmia occurs, the hemodynamics of the pulse wave are abnormal and change the morphology of the pulse wave. Our proposed sensor can measure the occurrence of ectopic beats from the radial artery, and the detection algorithm can reduce the error of blood pressure estimation caused by the distortion of ectopic beats that occurs when the pulse wave is measured. In this study, we tested patients with premature atrial contraction (PAC) or premature ventricular contraction (PVC) and analyzed the morphology of the pulse waves when the sensor detected the ectopic beats. We discuss the advantages of using the Moens–Korteweg equation to estimate the blood pressure of patients with arrhythmia, which is different from the oscillometric method. Our research provides a possible arrhythmia detection method for wearable devices and can accurately estimate blood pressure in a non-invasive way during an arrhythmia.

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Radhoe, Sumant P., et Jasper J. Brugts. « CardioMEMS™ : a tool for remote hemodynamic monitoring of chronic heart failure patients ». Future Cardiology 18, n^o 3 (mars 2022) : 173–83. http://dx.doi.org/10.2217/fca-2021-0076.

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Remote monitoring is becoming increasingly important for management of chronic heart failure patients. Recently, hemodynamic monitoring by measuring intracardiac filling pressures has been gaining attention. It is believed that hemodynamic congestion precedes clinical congestion by several weeks and that remote hemodynamic monitoring therefore enables clinicians to intervene in an early stage and prevent heart failure hospitalizations. The CardioMEMS HF system (Abbott, CA, USA) is a sensor capable of measuring pulmonary artery pressures as a surrogate of left ventricular filling pressures. Clinical evidence for CardioMEMS has been convincing in terms of efficacy and safety. This article provides detailed information on the CardioMEMS HF system and summarizes all available evidence of this promising technique.

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Sacchi, Stefania, Danilo Contardi, Paolo Pieragnoli, Giuseppe Ricciardi, Andrea Giomi et Luigi Padeletti. « Hemodynamic Sensor in Cardiac Implantable Electric Devices : The Endocardial Accelaration Technology ». Journal of Healthcare Engineering 4, n^o 4 (décembre 2013) : 453–64. http://dx.doi.org/10.1260/2040-2295.4.4.453.

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Calvi, Valeria, Giovanni Pizzimenti, Marco Lisi, Giuseppe Doria, Ludovico Vasquez, Francesco Lisi, Salvatore Felis et al. « Hemodynamic Surveillance of Ventricular Pacing Effectiveness with the Transvalvular Impedance Sensor ». Advances in Medicine 2014 (2014) : 1–7. http://dx.doi.org/10.1155/2014/307168.

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The Transvalvular Impedance (TVI) is derived between atrial and ventricular pacing electrodes. A sharp TVI increase in systole is an ejection marker, allowing the hemodynamic surveillance of ventricular stimulation effectiveness in pacemaker patients. At routine follow-up checks, the ventricular threshold test was managed by the stimulator with the supervision of a physician, who monitored the surface ECG. When the energy scan resulted in capture loss, the TVI system must detect the failure and increase the output voltage. A TVI signal suitable to this purpose was present in 85% of the tested patients. A total of 230 capture failures, induced in 115 patients in both supine and sitting upright positions, were all promptly recognized by real-time TVI analysis (100% sensitivity). The procedure was never interrupted by the physician, as the automatic energy regulation ensured full patient’s safety. The pulse energy was then set at 4 times the threshold to test the alarm specificity during daily activity (sitting, standing up, and walking). The median prevalence of false alarms was 0.336%. The study shows that TVI-based ejection assessment is a valuable approach to the verification of pacing reliability and the autoregulation of ventricular stimulation energy.

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Paternot, Alexis, Philippe Aegerter, Aurélie Martin, Jonathan Ouattara, Sabrina Ma, Sherifa Adjavon, Bernard Trillat, Pascal Alfonsi, Marc Fischler et Morgan Le Guen. « Screening for postoperative vital signs abnormalities, and particularly hemodynamic ones, by continuous monitoring : protocol for the Biobeat-Postop cohort study ». F1000Research 10 (7 octobre 2021) : 622. http://dx.doi.org/10.12688/f1000research.54781.2.

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Background: Postoperative hypotension associated with postoperative morbidity and early mortality has been studied previously. Hypertension and other hemodynamic, respiratory, and temperature abnormalities have comparatively understudied during the first postoperative days. Methods: This bi-centre observational cohort study will include 114 adult patients undergoing non-cardiac surgery hospitalized on an unmonitored general care floor and wearing a multi-signal wearable sensor, allowing remote monitoring (Biobeat Technologies Ltd, Petah Tikva, Israel). The study will cover the first 72 hours after discharge of the patient from the post-anaesthesia care unit. Several thresholds will be used for each variable (arterial pressure, heart rate, respiratory rate, oxygen saturation, and skin temperature). Data obtained using the sensor will be compared to data obtained during the routine nurse follow-up. The primary outcome is hemodynamic abnormality. The secondary outcomes are postoperative respiratory and temperature abnormalities, artefacts and blank/null outputs from the wearable device, postoperative complications, and finally, the ease of use of the device. We hypothesize that remote monitoring will detect abnormalities in vital signs more often or more quickly than the detection by nurses’ routine surveillance. Discussion: A demonstration of the ability of wireless sensors to outperform standard monitoring techniques paves the way for the creation of a loop which includes this monitoring mode, the automated creation of alerts, and the sending of these alerts to caregivers. Trial registration: ClinicalTrials.gov, NCT04585178. Registered on October 14, 2020

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Paternot, Alexis, Philippe Aegerter, Aurélie Martin, Jonathan Ouattara, Sabrina Ma, Sherifa Adjavon, Bernard Trillat, Pascal Alfonsi, Marc Fischler et Morgan Le Guen. « Screening for postoperative complications by continuous monitoring : protocol for the Biobeat-Postop cohort study ». F1000Research 10 (21 juillet 2021) : 622. http://dx.doi.org/10.12688/f1000research.54781.1.

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Background: Postoperative hypotension associated with postoperative morbidity and early mortality has been studied previously. Hypertension and other hemodynamic, respiratory, and temperature abnormalities have comparatively understudied during the first postoperative days. Methods: This bi-centre observational cohort study will include 114 adult patients undergoing non-cardiac surgery hospitalized on an unmonitored general care floor and wearing a multi-signal wearable sensor, allowing remote monitoring (Biobeat Technologies Ltd, Petah Tikva, Israel). The study will cover the first 72 hours after discharge of the patient from the post-anaesthesia care unit. Several thresholds will be used for each variable (arterial pressure, heart rate, respiratory rate, oxygen saturation, and skin temperature). Data obtained using the sensor will be compared to data obtained during the routine nurse follow-up. The primary outcome is hemodynamic abnormality. The secondary outcomes are postoperative respiratory and temperature abnormalities, artefacts and blank/null outputs from the wearable device, postoperative complications, and finally, the ease of use of the device. We hypothesize that remote monitoring will detect abnormalities in vital signs more often or more quickly than the detection by nurses’ routine surveillance. Discussion: A demonstration of the ability of wireless sensors to outperform standard monitoring techniques paves the way for the creation of a loop which includes this monitoring mode, the automated creation of alerts, and the sending of these alerts to caregivers. Trial registration: ClinicalTrials.gov, NCT04585178. Registered on October 14, 2020

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Rali, Aniket S., Zubair Shah, Andrew Sauer et Kamal Gupta. « Late Migration of a CardioMEMS TM Wireless Pulmonary Artery Hemodynamic Monitoring Sensor ». Circulation : Heart Failure 10, n^o 4 (avril 2017) : e003948. http://dx.doi.org/10.1161/circheartfailure.117.003948.

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Pahlevan, Niema M., et Ray V. Matthews. « Cardiac Triangle Mapping : A New Systems Approach for Noninvasive Evaluation of Left Ventricular End Diastolic Pressure ». Fluids 4, n^o 1 (22 janvier 2019) : 16. http://dx.doi.org/10.3390/fluids4010016.

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Noninvasive and practical assessment of hemodynamics is a critical unmet need in the treatment of both chronic and acute cardiovascular diseases. Particularly, the ability to monitor left ventricular end-diastolic pressure (LVEDP) noninvasively offers enormous benefit for managing patients with chronic congestive heart failure. Recently, we provided proof of concept that a new cardiac metric, intrinsic frequency (IF), derived from mathematical analysis of non-invasively captured arterial waveforms, can be used to accurately compute cardiovascular hemodynamic measures, such as left ventricle ejection fraction (LVEF), by using a smartphone. In this manuscript, we propose a new systems-based method called cardiac triangle mapping (CTM) for hemodynamics evaluation of the left ventricle. This method is based on intrinsic frequency (IF) and systolic time interval (STI) methods that allows computation of LVEDP from noninvasive measurements. Since the CTM method only requires arterial waveform and electrocardiogram (ECG), it can eventually be adopted as a simple smartphone-based device, an inexpensive hand-held device, or perhaps (with future design modifications) a wearable sensor. Such devices, combined with this method, would allow for remote monitoring of heart failure patients.

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Behnia, Mehrdad, Sherry Powell, Linda Fallen, Houman Tamaddon et Masud Behnia. « Correlation of stroke Volume Measurement between sonosite portable Echocardiogram and Edwards Flotrac sensor-Vigileo Monitor in an Intensive care Unit ». Clinical Medicine Insights : Circulatory, Respiratory and Pulmonary Medicine 7 (janvier 2013) : CCRPM.S12498. http://dx.doi.org/10.4137/ccrpm.s12498.

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Purpose Stroke volume (SV) is a parameter that is being recognized as an endpoint in fluid resuscitation algorithms. Its role is now being realized as an important variable in hemodynamic assessment in various clinical scenarios such as septic and cardiogenic shocks. Direct measurement of stroke volume (SV) and its novel corollary, stroke volume variation (SVV) derived by proprietary software, are preferred over mean cardiac output (CO) measurements because they render a more accurate reflection of hemodynamic status independent of heart rate. Flotrac-Vigileo monitor (FTV) (Edwards Lifesciences, Irvine, CA, USA) is a system that uses a complex algorithm analyzing arterial waveform to calculate SV, SVV, and CO. We assessed the feasibility of obtaining SV measurements with a portable echocardiogram and validated its accuracy with the FTV system in mechanically ventilated patients in our intensive care unit (ICU). Furthermore, we emphasized the importance of hemodynamic measurements and familiarity with critical care echocardiography for the intensivists. Methods Ten patients who were on mechanical ventilation were studied. A femoral arterial line was connected to the FTV system monitoring SV and CO. A portable echocardiogram (M-Turbo; Sonosite, Bothell, WA) was used to measure SV. CO was calculated by multiplying SV by heart rate. No patient had arrhythmia. We used biplane Simpson's method of discs to calculate SV in which subtraction of end-systolic volume from end-diastolic volume yields the SV Results The comparison of simultaneous SV and CO measurements by echocardiography with FTV showed a strong correlation between the 2. (For SV, y = 0.9545x + 3.3, R2 = 0.98 and for CO, y = 0.9104x + 7.7074, R2 = 0.97). Conclusions In our small cohort, the SV and CO measured by a portable echocardiogram (Sonosite M-Turbo) appears to be closely correlated with their respective values measured by FTV. Portable echocardiography is a reliable noninvasive tool for the hemodynamic assessment of the critically ill. Its results need further validation with gold standard measures in a larger cohort of patients. However, our results suggest portable echocardiography could be an attractive tool in assessment of different hemodynamic scenarios in the critically ill.

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Feltracco, P., S. Barbieri, H. Galligioni, E. Bertoldi et C. Ori. « PRAM vs FloTrac-sensor/VigileoTM for hemodynamic monitoring during liver resection - preliminary date ». European Journal of Anaesthesiology 28 (juin 2011) : 37. http://dx.doi.org/10.1097/00003643-201106001-00112.

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Mehmood, Muddassir, Richa Agarwal, Amresh Raina, Priscilla Correa-Jaque et Raymond L. Benza. « Hemodynamic Response to Treatment of Iron Deficiency Anemia in Pulmonary Arterial Hypertension : Longitudinal Insights from an Implantable Hemodynamic Monitor ». Pulmonary Circulation 6, n^o 4 (décembre 2016) : 616–18. http://dx.doi.org/10.1086/688670.

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Despite new therapeutic options, pulmonary arterial hypertension (PAH) remains a progressive disease associated with substantial morbidity and mortality. As such, additional strategies for monitoring and adjunctive management of this disease are important. A 59-year-old woman with scleroderma-associated PAH received an implantable hemodynamic monitor (IHM) as part of a research protocol at our institution. Pulmonary artery pressures, heart rate, and cardiac output (sensor-based algorithm) were measured on a daily basis, and parameters of right ventricular (RV) performance and afterload were calculated. At the time of IHM implant, the patient had functional class III symptoms, was receiving triple-drug therapy, and had normal hemoglobin levels. Four months after implant, and with further optimization of prostacyclin therapy, she had improvement in her symptoms. However, shortly thereafter, while the patient was receiving stable drug therapy, her case regressed with worsening symptoms, and the patient received a new diagnosis of iron deficiency anemia. Oral iron supplementation resulted in normalization of hemoglobin levels and improvement in the patient's iron profile. A gradual and sustained reduction in pulmonary pressures was noted after initiation of oral iron accompanied by increased RV performance and favorable reduction in RV afterload. The patient had significant symptomatic improvement. Iron deficiency is an underappreciated yet easily treatable risk factor in PAH. Use of IHM in this case longitudinally illustrates the optimization of pulmonary hemodynamics and RV afterload in tandem with clinical improvement achieved by a simple therapy.

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Orlov, Kirill, Vyacheslav Panarin, Alexey Krivoshapkin, Dmitry Kislitsin, Vadim Berestov, Timur Shayakhmetov et Anton Gorbatykh. « Assessment of periprocedural hemodynamic changes in arteriovenous malformation vessels by endovascular dual-sensor guidewire ». Interventional Neuroradiology 21, n^o 1 (février 2015) : 101–7. http://dx.doi.org/10.15274/inr-2014-10096.

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Endovascular embolization is an important modality in the treatment of brain AVMs. Nowadays staged embolization is the method of choice for the prevention of perioperative hemorrhagic complications. Current theory suggests that simultaneous occlusion of more than 60% of AVM volume induces significant redistribution local blood flow. That, in turn, may lead to hemorrhage due to AVM rupture. Aside from angiographic findings, there is still no method that predicts the degree of safe partial embolization. Intraluminal measurement of flow velocity and pressure in the vicinity of the AVM nidus might allow detecting the changes in local hemodynamics. That can provide a valuable data and shed the light on the origin of vascular catastrophes. Ten patients underwent 12 embolization sessions with intraluminal flow velocity and pressure monitoring. The measurements were performed by dual-sensor guidewire. The “Combomap” (Volcano) system with Combowire microguidewires was chosen for measurements, as there is a documented experience of safe use of said guidewires in the cerebral vasculature. The findings observed during the study matched empirical data as well as the current physiological hypothesis of AVM hemorrhage. In conjunction with DSA runs, intraluminal flow velocity and pressure monitoring has the potential to become a valuable tool in AVM treatment.

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BORDACHAR, PIERRE, STEPHANE GARRIGUE, PHILIPPE RITTER, SYLVAIN PLOUX, LOUIS LABROUSSE, CYRIL CASSET, MICHEL HAISSAGUERRE et PIERRE DOS SANTOS. « Contributions of a Hemodynamic Sensor Embedded in an Atrial Lead in a Porcine Model ». Journal of Cardiovascular Electrophysiology 22, n^o 5 (13 octobre 2010) : 579–83. http://dx.doi.org/10.1111/j.1540-8167.2010.01930.x.

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Orlov, Kirill, Vyacheslav Panarin, Alexey Krivoshapkin, Dmitry Kislitsin, Vadim Berestov, Timur Shayakhmetov et Anton Gorbatykh. « Assessment of periprocedural hemodynamic changes in arteriovenous malformation vessels by endovascular dual-sensor guidewire ». Interventional Neuroradiology 21, n^o 1 (février 2015) : 101–7. http://dx.doi.org/10.1177/inr-2014-10096.

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CHIRIFE, RAUL. « Acquisition of Hemodynamic Data and Sensor Signals for Rate Control from Standard Pacing Electrodes ». Pacing and Clinical Electrophysiology 14, n^o 11 (novembre 1991) : 1563–65. http://dx.doi.org/10.1111/j.1540-8159.1991.tb02727.x.

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西本, 千尋, 求. 佐藤, 淳. 吉岡 et 隆. 芝本. « A study on the possibility of a new hemodynamic monitoring using a piezoelectric sensor ». Iryou kikigaku (The Japanese journal of medical instrumentation) 92, n^o 5 (2022) : 519–24. http://dx.doi.org/10.4286/jjmi.92.519.

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Kuznik, B. I., Y. N. Smolyakov, S. O. Davydov, N. N. Tsybikov, O. G. Maksimova, A. V. Malinina, L. Shenkman, A. Kaminsky et I. Fine. « Impact of Fitness Status on the Optically Measured Hemodynamic Indexes ». Journal of Healthcare Engineering 2018 (2018) : 1–7. http://dx.doi.org/10.1155/2018/1674931.

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The physiological characteristics of skin blood flow can be described in terms of the hemodynamic indices (HI). The HI is derived from the laser speckle characteristics, which are governed by the cutaneous blood flow. A miniaturized dynamic light-scattering sensor was used to measure the speckle pattern from the finger root. Three groups of subjects from 15 to 25 years of age were tested. The first group included subjects who are actively engaged in sport activities; the second group included subjects with low level of physical activity; and the third group included healthy controls with moderate physical activity. The HI parameters were measured prior to and after the performance of a determined physical load. As a marker of cardiovascular fitness (CVF), we used the postload decay rate of HI. We found that the hemodynamic response to the physical load provides a statistically significant correlation with the postload heart rate decay. It was also found that postocclusion increase of the arterial HI is more prominent in the group with higher physical activity. These results indicate that hemodynamic indices can be used as an additional marker for cardiovascular fitness level.

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CERCENELLI, L., et E. MARCELLI. « CARDIAC APEX ROTATION ASSESSED BY AN IMPLANTABLE GYRO SENSOR : CORRELATION WITH A LV PRESSURE-DERIVED MYOCARDIAL PERFORMANCE INDEX IN EXPERIMENTALLY INDUCED ISCHEMIA ». Journal of Mechanics in Medicine and Biology 15, n^o 02 (avril 2015) : 1540013. http://dx.doi.org/10.1142/s0219519415400138.

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Despite many investigators have focused attention on cardiac apex rotation (CAR) as a sensitive marker of left ventricle (LV) function, no studies have been specifically aimed to evaluate the correlation of CAR with myocardial performance index (MPI), a well-known index of both systolic and diastolic performance. In four sheep, we measured CAR using a miniature gyro sensor epicardically positioned at LV apex and we evaluated the beat-to-beat correlation between CAR and a myocardial performance index calculated from LV-pressure (LVP) measurements (MPILVP). We also compared CAR with hemodynamic parameters (LVdP/dtMAX, LVdP/dtMIN). A strong negative correlation was observed between CAR and MPILVP during the experimental cardiac conditions (baseline, acute ischemia induced by coronary ligation and release of ligation). At 30 s after ligation a marked decrease of CAR was observed, while LVdP/dtMAX showed minor changes. CAR has good potential to reflect changes of global myocardial performance and to predict hemodynamic changes in acute impairment of cardiac function.

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Woldbaek, Per Reidar, Tævje Andreas Strømme, Jørn Bodvar Sande, Geir Christensen, Theis Tønnessen et Arnfinn Ilebekk. « Evaluation of a new fiber-optic pressure recording system for cardiovascular measurements in mice ». American Journal of Physiology-Heart and Circulatory Physiology 285, n^o 5 (novembre 2003) : H2233—H2239. http://dx.doi.org/10.1152/ajpheart.01123.2002.

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We have tested a new fiber-optic pressure recording system, Samba, with a thin fiber [outer diameter (OD) = 0.25 mm] and a pressure sensor (length and OD = 0.42 mm) attached to the end. The accuracy of the system tested in vitro was good, with a coefficient of variation of 2.54% at 100 mmHg. The drift was <0.45 mmHg/h, and the temperature sensitivity was ∼0.07 mmHg/1°C between 22 and 37°C. The frequency response characteristics were similar to a 1.4-Fr Millar catheter (0–200 Hz). Introduction of the Samba sensor from the right carotid artery into the left ventricle in six mice caused no drop in mean aortic pressure, whereas introduction of a 1.4-Fr Millar catheter (OD = 0.47 mm; n = 6) caused a pressure drop from 91.6 ± 9.2 to 65.1 ± 6.2 mmHg; P < 0.05. Thus the Samba sensor system may represent a new alternative to assess hemodynamic variables in the murine cardiovascular system.

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Zhang, Xiao, Muhammad S. Noor, Clinton B. McCracken, Zelma H. T. Kiss, Orly Yadid-Pecht et Kartikeya Murari. « CMOS Image Sensor and System for Imaging Hemodynamic Changes in Response to Deep Brain Stimulation ». IEEE Transactions on Biomedical Circuits and Systems 10, n^o 3 (juin 2016) : 632–42. http://dx.doi.org/10.1109/tbcas.2015.2453256.

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Convertino, Victor A., Steven G. Schauer, Erik K. Weitzel, Sylvain Cardin, Mark E. Stackle, Michael J. Talley, Michael N. Sawka et Omer T. Inan. « Wearable Sensors Incorporating Compensatory Reserve Measurement for Advancing Physiological Monitoring in Critically Injured Trauma Patients ». Sensors 20, n^o 22 (10 novembre 2020) : 6413. http://dx.doi.org/10.3390/s20226413.

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Vital signs historically served as the primary method to triage patients and resources for trauma and emergency care, but have failed to provide clinically-meaningful predictive information about patient clinical status. In this review, a framework is presented that focuses on potential wearable sensor technologies that can harness necessary electronic physiological signal integration with a current state-of-the-art predictive machine-learning algorithm that provides early clinical assessment of hypovolemia status to impact patient outcome. The ability to study the physiology of hemorrhage using a human model of progressive central hypovolemia led to the development of a novel machine-learning algorithm known as the compensatory reserve measurement (CRM). Greater sensitivity, specificity, and diagnostic accuracy to detect hemorrhage and onset of decompensated shock has been demonstrated by the CRM when compared to all standard vital signs and hemodynamic variables. The development of CRM revealed that continuous measurements of changes in arterial waveform features represented the most integrated signal of physiological compensation for conditions of reduced systemic oxygen delivery. In this review, detailed analysis of sensor technologies that include photoplethysmography, tonometry, ultrasound-based blood pressure, and cardiogenic vibration are identified as potential candidates for harnessing arterial waveform analog features required for real-time calculation of CRM. The integration of wearable sensors with the CRM algorithm provides a potentially powerful medical monitoring advancement to save civilian and military lives in emergency medical settings.

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Johnston, Paul W., John Anderson et A. A. Jennifer Adgey. « 959-104 The Potential Use of Impedance Cardiography as a Hemodynamic Sensor for Automated External Defibrillators ». Journal of the American College of Cardiology 25, n^o 2 (février 1995) : 211A. http://dx.doi.org/10.1016/0735-1097(95)92334-2.

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Yap, Sing-Chien, Mark G. Hoogendijk, Suzanne D. A. Valk, Sweder W. Van de Poll, Peter van der Kemp et Tamas Szili-Torok. « Conductor cable externalization in an atrial hemodynamic sensor lead in a patient presenting with inappropriate shocks ». HeartRhythm Case Reports 5, n^o 12 (décembre 2019) : 582–85. http://dx.doi.org/10.1016/j.hrcr.2019.09.002.

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Jermyn, Rita A., Gregory Ginn, Charisma Kumar, Rupinder Bharmi et Phil Adamson. « Real World Transmission Compliance in Patients Managed with Hemodynamic Guided Medical Care Using an Implantable Sensor ». Journal of Cardiac Failure 22, n^o 8 (août 2016) : S20. http://dx.doi.org/10.1016/j.cardfail.2016.06.068.

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Doorey, Andrew J., Mandip Gakhal et Michael J. Pasquale. « Utilization of a pressure sensor guidewire to measure bileaflet mechanical valve gradients : Hemodynamic and echocardiographic sequelae ». Catheterization and Cardiovascular Interventions 67, n^o 4 (2006) : 535–40. http://dx.doi.org/10.1002/ccd.20675.

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Гусева, Е. С., С. О. Давыдов, Б. И. Кузник, Ю. Н. Смоляков, П. П. Терешков, Е. В. Фефелова et Н. Н. Цыбиков. « Effect of moderate physical exercises on the relationship of variability of the heart rhythm with the level of blood pressure and hemodynamic functions in women with essential hypertension ». Zhurnal «Patologicheskaia fiziologiia i eksperimental`naia terapiia», n^o 2 (28 juin 2021) : 10–21. http://dx.doi.org/10.25557/0031-2991.2021.02.10-21.

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Цель исследования - изучение взаимосвязи между вариабельностью сердечного ритма (ВСР) системой гемостаза и гемодинамическими функциями у женщин больных эссенциальной гипертензией (ГБ) в зависимости от методов применяемой терапии. Методика. Под наблюдением находились 72 женщины, страдающие гипертонической болезнью. Обследовано 2 группы пациенток: 1-я группа (ГБ-1) находилась на медикаментозной терапии, 2-я (ГБ-2) - наряду с медикаментозной терапией регулярно на протяжении 2-3 лет проходила не менее 3 полуторамесячных курсов кинезитерапии. Для изучения гемодинамики был использован датчик динамического рассеяния света (miniature Dynamic Light Scattering - mDLS) от Elfi-Tech (Rehovot, Israel), измеряющий сигналы, инициированные кожным кровотоком и использующий методику разложения сигнала на частотные компоненты, связанные с разными гемодинамическими источниками. Из пульсовой компоненты mDLS сигнала извлекалась информация о вариабельности RR интервалов, и рассчитывались индикаторы вариабельности сердечного ритма. Изучали показатели свёртывающей системы крови: активированное парциальное тромбопластиновое время - (АПТВ), протромбиновое время (ПТВ) с вычислением МНО, тромбиновое время (ТВ), концентрация фибриногена, факторов II (протромбин), IIa (тромбин), IX и Х [10]. Кроме перечисленных методов исследования определялся пространственный рост фибринового сгустка, осуществляемый с помощью прибора «Регистратор Тромбодинамики Т-2». Достоинством способа является его объективность и то, что программой предусмотрена фоторегистрация роста сгустка через 5, 15 и 30 мин. Результаты. Как в группе ГБ-1, так и ГБ-2 выявлены многочисленные корреляционные связи между различными показателями ВСР, системы гемостаза и гемодинамических Данные представленные в виде матрицы свидетельствуют о том, что сдвиги в системе гемостаза и гемодинамики у больных ГБ-1, обусловленные деятельностью сердца и осуществляемые при участии как симпатического, так и парасимпатического отделов АНС способствуют возникновению тромботических осложнений. В то же время у больных ГБ-2 ВСР практически не коррелирует с показателями системы гемостаза и в меньшей степени связана с гемодинамические функции, благодаря чему состояние гемостаза и гемодинамики приближается к показателям здоровых женщин. Между тем, выявленные взаимосвязи между системой гемостаза и гемодинамическими функциями как у больных ГБ-1, так и ГБ-2 направлены на предотвращение внутрисосудистого свёртывания крови. Заключение. Применение систематической умеренной физической нагрузки на протяжении 2 - 3 лет способствует нормализации взаимоотношений между ВСР, системой гемостаза и гемодинамическими функциями у больных ГБ и способствует более устойчивой нормализации кровяного давления. Aim. To study the relationship between heart rate variability (HRV), hemostasis, and hemodynamic functions in women with essential hypertension (EH), depending on the method of therapy. Methods. 72 women with hypertension were monitored. Two patient groups were evaluated: the first group (EH-1) had recceived only drug therapy and the second group (EH-2), in addition to drug therapy, had regularly participated in at least three 1.5 mos long courses of kinesitherapy over a 2-3 years period. To study hemodynamics, we used a miniature Dynamic Light Scattering (mDLS) sensor from Elfi-Tech (Rehovot, Israel), which measures signals initiated by skin blood flow and uses a technique for decomposing the signal into frequency components associated with different hemodynamic sources. Information on the variability of RR intervals was extracted from the pulse component of the mDLS signal, and parameters of heart rate variability were calculated. Indexes of the coagulation system were studied, including activated partial thromboplastin time (APTT), prothrombin time (PTT) with calculation of INR, thrombin time (TT), concentrations of fibrinogen and factors II (prothrombin), IIa (thrombin), IX, and X [10]. In addition, spatial fibrin clot growth was determined with a Thrombodynamics Registrator T-2 apparatus. The method benefits are its objectivity and a possibility of photorecording of the clot growth at 5, 15 and 30 min. Results. Both in the EH-1 and EH-2 groups, numerous correlations were detected between various parameters of HRV, the hemostatic system, and hemodynamic functions, as well as between the parameters of the hemostatic system and hemodynamic functions. The data are presented in the form of a matrix. The data indicate that shifts in the hemostatic and hemodynamic systems of EH-1 patients induced by cardiac activity and resulting from activities of both the sympathetic and parasympathetic sections of the autonomic nervous system (ANS) are aimed at enhancing the hemostatic properties of blood, and this contributes to thrombotic complications. At the same time, in EH-2 patients, HRV had practically no effect on the hemostatic system and to a lesser extent was related with the hemodynamic function. Due to this, the state of hemostasis and hemodynamics in EH-2 patients approaches the state found in healthy women. In addition, the relationship between the hemostatic system and hemodynamic function in both EH-1 and EH-2 patients are aimed at preventing intravascular coagulation. Conclusion. The use of systematic, moderate physical activity for 2 to 3 years helps hypertensive patients to normalize the relationship between HRV, the hemostatic system, and hemodynamic functions. This contributes to a more normal and stable blood pressure.

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Tran, Jeffrey S., Aaron M. Wolfson, Daniel O’Brien, Omid Yousefian et David M. Shavelle. « A Systems-Based Analysis of the CardioMEMS HF Sensor for Chronic Heart Failure Management ». Cardiology Research and Practice 2019 (17 juillet 2019) : 1–7. http://dx.doi.org/10.1155/2019/7979830.

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Background. Hemodynamic-guided therapy using the CardioMEMS™ system has been shown to reduce heart failure hospitalization (HFH) in both clinical trials and real-world settings. However, the CardioMEMS system requires input from multiple independent elements to achieve its effect, and no studies have been done to investigate those elements. Consistent patient participation and health care provider participation are two of those key elements, and this study sought to assess how they affect HFHs. Methods. This was a single-center, retrospective cohort study of patients with the CardioMEMS sensor. The primary outcome was the number of HFH days patients experienced in the 1 year following CardioMEMS sensor implant. The primary independent variables were the average number of days between patient transmissions of data and the average number of days between health care provider reviews of those data. Covariates included patient demographics, medical comorbidities, history of HFHs, and initial pressure response to hemodynamic-guided therapy at 28 days after implant. Data were fit to a zero-inflated negative binomial regression. Results. Seventy-eight patients were included in the study. The mean age was 64 ± 15 years, 52 (67%) were male, and 58 (76%) had heart failure with reduced ejection fraction. During the study period, there were 538 cumulative HFH patient-days. Based on the regression model, there was an exponential relationship between HFH days and the mean number of days between patient transmissions (IRR = 1.74, 95% CI: 1.09–2.75, p=0.019). There was also an exponential relationship between HFH days and the mean number of days between health care provider reviews (IRR = 1.03, 95% CI: 1.01–1.05, p=0.013). Conclusions. This single-center study suggests that more frequent patient transmissions and health care provider reviews of the CardioMEMS system are associated with a decreased number of HFH days, but larger multicentered studies are required. Further systems-based analyses of the CardioMEMS system may be a useful approach to guiding effective use of the CardioMEMS device.

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Atzmon, Yuval, Efrat Ben Ishay, Mordechai Hallak, Romi Littman, Arik Eisenkraft et Rinat Gabbay-Benziv. « Continuous Maternal Hemodynamics Monitoring at Delivery Using a Novel, Noninvasive, Wireless, PPG-Based Sensor ». Journal of Clinical Medicine 10, n^o 1 (22 décembre 2020) : 8. http://dx.doi.org/10.3390/jcm10010008.

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Objective: To evaluate continuous monitoring of maternal hemodynamics during labor and delivery utilizing an innovative, noninvasive, reflective photoplethysmography-based device. Study design: The Biobeat Monitoring Platform includes a wearable wristwatch monitor that automatically samples cardiac output (CO), blood pressure (BP), stroke volume (SV), systemic vascular resistance (SVR), heart rate (HR) every 5 s and uploads all data to a smartphone-based app and to a data cloud, enabling remote patient monitoring and analysis of data. Low-risk parturients at term, carrying singletons pregnancies, were recruited at early delivery prior to the active phase. Big data analysis of the collected data was performed using the Power BI analysis tool (Microsoft). Next, data were normalized to visual presentation using Excel Data Analysis and the regression tool. Average measurements were compared before and after rupture of membranes, epidural anesthesia, fetal delivery, and placental expulsion. Results: Eighty-one parturients entered analysis. Epidural anesthesia was associated with a slight elevation in CO (5.5 vs. 5.6, L/min, 10 min before and after EA, p < 0.05) attributed to a non-significant increase in both HR and SV. BP remained stable as of counter decrease in SVR (1361 vs. 1319 mmHg⋅min⋅mL−1, 10 min before and after EA, p < 0.05). Fetal delivery was associated with a peak in CO after which it rapidly declined (6.0 vs. 7.2 vs. 6.1 L/min, 30 min before vs. point of delivery vs. after delivery, p < 0.05). The mean BP remained stable throughout delivery with a slight increase at fetal delivery (92 vs. 95 vs. 92.1 mmHg, p < 0.05), reflecting the increase in CO and decrease in SVR (1284 vs. 1112 vs. 1280 mmHg⋅min⋅mL−1, p < 0.05)with delivery. Placental expulsion was associated with a second peak in CO and decrease in SVR. Conclusions: We presented a novel application of noninvasive hemodynamic maternal monitoring throughout labor and delivery for both research and clinical use.

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Chiang, Chao, Tu, Kao, Yang, Tarng et Wey. « Machine Learning Classification for Assessing the Degree of Stenosis and Blood Flow Volume at Arteriovenous Fistulas of Hemodialysis Patients Using a New Photoplethysmography Sensor Device ». Sensors 19, n^o 15 (4 août 2019) : 3422. http://dx.doi.org/10.3390/s19153422.

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The classifier of support vector machine (SVM) learning for assessing the quality of arteriovenous fistulae (AVFs) in hemodialysis (HD) patients using a new photoplethysmography (PPG) sensor device is presented in this work. In clinical practice, there are two important indices for assessing the quality of AVF: the blood flow volume (BFV) and the degree of stenosis (DOS). In hospitals, the BFV and DOS of AVFs are nowadays assessed using an ultrasound Doppler machine, which is bulky, expensive, hard to use, and time consuming. In this study, a newly-developed PPG sensor device was utilized to provide patients and doctors with an inexpensive and small-sized solution for ubiquitous AVF assessment. The readout in this sensor was custom-designed to increase the signal-to-noise ratio (SNR) and reduce the environment interference via maximizing successfully the full dynamic range of measured PPG entering an analog–digital converter (ADC) and effective filtering techniques. With quality PPG measurements obtained, machine learning classifiers including SVM were adopted to assess AVF quality, where the input features are determined based on optical Beer–Lambert’s law and hemodynamic model, to ensure all the necessary features are considered. Finally, the clinical experiment results showed that the proposed PPG sensor device successfully achieved an accuracy of 87.84% based on SVM analysis in assessing DOS at AVF, while an accuracy of 88.61% was achieved for assessing BFV at AVF.

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Ting, Chih-Tai, Jaw-Wen Chen, Mau-Song Chang et Frank Chi-Pong Yin. « Arterial Hemodynamics in Prehypertensives ». International Journal of Hypertension 2019 (1 avril 2019) : 1–9. http://dx.doi.org/10.1155/2019/3961723.

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Compared to age-matched normotensive adults, those with essential hypertension have been shown to have distinct arterial hemodynamic abnormalities consisting of increased peripheral resistance, pulse wave velocity, and wave reflection magnitude as well as decreased wave reflection time and aortic compliance. These abnormalities are further exacerbated by beta-adrenergic blockade. To see if there are similar hemodynamic abnormalities that antedate the onset of fixed hypertension, we compared age-matched normotensives with prehypertensives selected from patients undergoing diagnostic cardiac catheterization. Ascending aortic pressure and flow were measured with a micromanometer and flow velocity sensor in the baseline state and after beta-adrenergic blockade. In the baseline state the prehypertensive compared to the normotensive group had elevated blood pressure, resistance, left ventricular end-diastolic pressure (LVEDP), and wave reflections. Beta-adrenergic blockade increased resistance, LVEDP, and wave reflections in both groups. Some of these findings are the same as those we previously reported in young persons with established, essential hypertension. The differences in LVEDP and wave reflections, both in the baseline state and after beta-blockade, were still present in subgroups with no differences in blood pressure. Hence, the elevated wave reflections in prehypertensives do not appear to be directly related to the level of blood pressure. These results support the notion that the elevated blood pressure in hypertension may represent a later manifestation of an already abnormal vascular system rather than the vascular abnormalities resulting from hypertension. Consequently, even before blood pressure becomes elevated, early diagnosis and treatment of the vascular abnormalities in prehypertensives may be warranted.

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Haghiashtiani, Ghazaleh, Kaiyan Qiu, Jorge D. Zhingre Sanchez, Zachary J. Fuenning, Priya Nair, Sarah E. Ahlberg, Paul A. Iaizzo et Michael C. McAlpine. « 3D printed patient-specific aortic root models with internal sensors for minimally invasive applications ». Science Advances 6, n^o 35 (août 2020) : eabb4641. http://dx.doi.org/10.1126/sciadv.abb4641.

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Minimally invasive surgeries have numerous advantages, yet complications may arise from limited knowledge about the anatomical site targeted for the delivery of therapy. Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure for treating aortic stenosis. Here, we demonstrate multimaterial three-dimensional printing of patient-specific soft aortic root models with internally integrated electronic sensor arrays that can augment testing for TAVR preprocedural planning. We evaluated the efficacies of the models by comparing their geometric fidelities with postoperative data from patients, as well as their in vitro hemodynamic performances in cases with and without leaflet calcifications. Furthermore, we demonstrated that internal sensor arrays can facilitate the optimization of bioprosthetic valve selections and in vitro placements via mapping of the pressures applied on the critical regions of the aortic anatomies. These models may pave exciting avenues for mitigating the risks of postoperative complications and facilitating the development of next-generation medical devices.

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Guo, Cheng-Yan, Hao-Ching Chang, Kuan-Jen Wang et Tung-Li Hsieh. « An Arterial Compliance Sensor for Cuffless Blood Pressure Estimation Based on Piezoelectric and Optical Signals ». Micromachines 13, n^o 8 (16 août 2022) : 1327. http://dx.doi.org/10.3390/mi13081327.

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Objective: Blood pressure (BP) data can influence therapeutic decisions for some patients, while non-invasive devices that continuously monitor BP can provide patients with a more comprehensive BP assessment. Therefore, this study proposes a multi-sensor-based small cuffless BP monitoring device that integrates a piezoelectric sensor array and an optical sensor, which can monitor the patient’s physiological signals from the radial artery. Method: Based on the Moens–Korteweg (MK) equation of the hemodynamic model, pulse wave velocity (PWV) can be correlated with arterial compliance and BP can be estimated. Therefore, the novel method proposed in this study involves using a piezoelectric sensor array to measure the PWV and an optical sensor to measure the photoplethysmography (PPG) intensity ratio (PIR) signal to estimate the participant’s arterial parameters. The parameters measured by multiple sensors were combined to estimate BP based on the P–β model derived from the MK equation. Result: We recruited 20 participants for the BP monitoring experiment to compare the performance of the BP estimation method with the regression model and the P–β model method with arterial compliance. We then compared the estimated BP with a reference device for validation. The results are presented as the error mean ± standard deviation (SD). Based on the regression model method, systolic blood pressure (SBP) was 0.32 ± 5.94, diastolic blood pressure (DBP) was 2.17 ± 6.22, and mean arterial pressure (MAP) was 1.55 ± 5.83. The results of the P–β model method were as follows: SBP was 0.75 ± 3.9, DBP was 1.1 ± 3.12, and MAP was 0.49 ± 2.82. Conclusion: According to the results of our proposed small cuffless BP monitoring device, both methods of estimating BP conform to ANSI/AAMI/ISO 81060-2:20181_5.2.4.1.2 criterion 1 and 2, and using arterial parameters to calibrate the MK equation model can improve BP estimate accuracy. In the future, our proposed device can provide patients with a convenient and comfortable BP monitoring solution. Since the device is small, it can be used in a public place without attracting other people’s attention, thereby effectively improving the patient’s right to privacy, and increasing their willingness to use it.

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Tolia, Sunit, Zubair Khan, Gunjan Gholkar et Marcel Zughaib. « Validating Left Ventricular Filling Pressure Measurements in Patients with Congestive Heart Failure : CardioMEMS™ Pulmonary Arterial Diastolic Pressure versus Left Atrial Pressure Measurement by Transthoracic Echocardiography ». Cardiology Research and Practice 2018 (15 juillet 2018) : 1–6. http://dx.doi.org/10.1155/2018/8568356.

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Background. Routine ambulatory echocardiographic estimates of left ventricular (LV) filling pressures are not cost-effective and are occasionally fraught with anatomic, physiologic as well as logistical limitations. The use of implantable hemodynamic devices such as CardioMEMS Heart Failure (HF) System has been shown to reduce HF-related readmission rates by remote monitoring of LV filling pressures. Little is known about the correlation between CardioMEMS and echocardiography-derived estimates of central hemodynamics. Methods. We performed a prospective, single-center study enrolling seventeen participants with New York Heart Association functional class II-III HF and preimplanted CardioMEMS sensor. Simultaneous CardioMEMS readings and a limited echocardiogram were performed at individual clinic visits. Estimated left atrial pressure (LAP) by echocardiogram was calculated by the Nagueh formula. Linear regression was used as a measure of agreement. Variability between methods was evaluated by Bland–Altman analysis. Results. Mean age was 74 ± 9 years; 59% (10/17) were males. LV systolic dysfunction was present in 76% (13/17) of subjects. Mean PAdP was 18 ± 4 mmHg and 19 ± 5 mmHg for CardioMEMS and echocardiographic-derived estimates, respectively, with a significant correlation between both methods (r2=0.798, p≤0.001). Conclusions. Our study illustrates a direct linear correlation between PAdP measured by CardioMEMS and simultaneous measurement of LV filling pressures derived by echocardiography.

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Siddiquee, Masudur R., Roozbeh Atri, J. Sebastian Marquez, S. M. Shafiul Hasan, Rodrigo Ramon et Ou Bai. « Sensor Location Optimization of Wireless Wearable fNIRS System for Cognitive Workload Monitoring Using a Data-Driven Approach for Improved Wearability ». Sensors 20, n^o 18 (7 septembre 2020) : 5082. http://dx.doi.org/10.3390/s20185082.

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Functional Near-Infrared Spectroscopy (fNIRS) is a hemodynamic modality in human cognitive workload assessment receiving popularity due to its easier implementation, non-invasiveness, low cost and other benefits from the signal-processing point of view. Wearable wireless fNIRS systems used in research have promisingly shown that fNIRS could be used in cognitive workload assessment in out-of-the-lab scenarios, such as in operators’ cognitive workload monitoring. In such a scenario, the wearability of the system is a significant factor affecting user comfort. In this respect, the wearability of the system can be improved if it is possible to minimize an fNIRS system without much compromise of the cognitive workload detection accuracy. In this study, cognitive workload-related hemodynamic changes were acquired using an fNIRS system covering the whole forehead, which is the region of interest in most cognitive workload-monitoring studies. A machine learning approach was applied to explore how the mean accuracy of the cognitive workload classification accuracy varied across various sensing locations on the forehead such as the Left, Mid, Right, Left-Mid, Right-Mid and Whole forehead. The statistical significance analysis result showed that the Mid location could result in significant cognitive workload classification accuracy compared to Whole forehead sensing, with a statistically insignificant difference in the mean accuracy. Thus, the wearable fNIRS system can be improved in terms of wearability by optimizing the sensor location, considering the sensing of the Mid location on the forehead for cognitive workload monitoring.

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Djelić, Marina, Sanja Mazić et Dejan Žikić. « A novel laboratory approach for the demonstration of hemodynamic principles : the arterial blood flow reflection ». Advances in Physiology Education 37, n^o 4 (décembre 2013) : 321–26. http://dx.doi.org/10.1152/advan.00176.2012.

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In the frame of a laboratory training course for medicine students, a new approach for laboratory exercises has been applied to teach the phenomena of circulation. The exercise program included measurements of radial artery blood flow waveform for different age groups using a noninvasive optical sensor. Arterial wave reflection was identified by measurements of blood flow waveforms before and after arterial branching. Students were able to distinguish between different waveforms of blood flow within different age groups. Furthermore, students were given the opportunity to explore the effect of aging on the elasticity of blood vessels. This exercise is an introduction to the fundamental physical laws of hemodynamics that can facilitate the learning and understanding of cardiovascular physiology to students of medicine.

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Yamaguchi, Takahiro, Hiroaki Takehara, Yoshinori Sunaga, Makito Haruta, Mayumi Motoyama, Yasumi Ohta, Toshihiko Noda, Kiyotaka Sasagawa, Takashi Tokuda et Jun Ohta. « Implantable self-reset CMOS image sensor and its application to hemodynamic response detection in living mouse brain ». Japanese Journal of Applied Physics 55, n^o 4S (11 mars 2016) : 04EM02. http://dx.doi.org/10.7567/jjap.55.04em02.

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Mohammed, Noor, Kim Cluff, Mark Sutton, Bernardo Villafana-Ibarra, Benjamin E. Loflin, Jacob L. Griffith, Ryan Becker, Subash Bhandari, Fayez Alruwaili et Jaydip Desai. « A Flexible Near-Field Biosensor for Multisite Arterial Blood Flow Detection ». Sensors 22, n^o 21 (1 novembre 2022) : 8389. http://dx.doi.org/10.3390/s22218389.

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Modern wearable devices show promising results in terms of detecting vital bodily signs from the wrist. However, there remains a considerable need for a device that can conform to the human body’s variable geometry to accurately detect those vital signs and to understand health better. Flexible radio frequency (RF) resonators are well poised to address this need by providing conformable bio-interfaces suitable for different anatomical locations. In this work, we develop a compact wearable RF biosensor that detects multisite hemodynamic events due to pulsatile blood flow through noninvasive tissue–electromagnetic (EM) field interaction. The sensor consists of a skin patch spiral resonator and a wearable transceiver. During resonance, the resonator establishes a strong capacitive coupling with layered dielectric tissues due to impedance matching. Therefore, any variation in the dielectric properties within the near-field of the coupled system will result in field perturbation. This perturbation also results in RF carrier modulation, transduced via a demodulator in the transceiver unit. The main elements of the transceiver consist of a direct digital synthesizer for RF carrier generation and a demodulator unit comprised of a resistive bridge coupled with an envelope detector, a filter, and an amplifier. In this work, we build and study the sensor at the radial artery, thorax, carotid artery, and supraorbital locations of a healthy human subject, which hold clinical significance in evaluating cardiovascular health. The carrier frequency is tuned at the resonance of the spiral resonator, which is 34.5 ± 1.5 MHz. The resulting transient waveforms from the demodulator indicate the presence of hemodynamic events, i.e., systolic upstroke, systolic peak, dicrotic notch, and diastolic downstroke. The preliminary results also confirm the sensor’s ability to detect multisite blood flow events noninvasively on a single wearable platform.

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Yoo, Ahn, Cserey, Lee et Seo. « Reliability and Validity of Non-invasive Blood Pressure Measurement System Using Three-Axis Tactile Force Sensor ». Sensors 19, n^o 7 (11 avril 2019) : 1744. http://dx.doi.org/10.3390/s19071744.

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Blood pressure (BP) is a physiological parameter reflecting hemodynamic factors and is crucial in evaluating cardiovascular disease and its prognosis. In the present study, the reliability of a non-invasive and continuous BP measurement using a three-axis tactile force sensor was verified. All the data were collected every 2 min for the short-term experiment, and every 10 min for the long-term experiment. In addition, the effects on the BP measurement of external physical factors such as the tension to the radial artery on applying the device and wrist circumference were evaluated. A high correlation between the measured BP with the proposed system and with the cuff-based non-invasive blood pressure, and reproducibility, were demonstrated. All data satisfied the Association for the Advancement of Medical Instrumentation criteria. The external physical factors did not affect the measurement results. In addition to previous research indicating the high reliability of the arterial pulse waveforms, the present results have demonstrated the reliability of numerical BP values, and this implies that the three-axis force sensor can be used as a patient monitoring device.

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Atzmon, Yuval, Efrat Ben Ishay, Erik Eisenkraft, Mordechai Hallak et Rinat Gabbay-Benziv. « 376 Maternal age impact on hemodynamic monitoring at delivery evaluated by a novel non-invasive PPG-based sensor ». American Journal of Obstetrics and Gynecology 224, n^o 2 (février 2021) : S244—S245. http://dx.doi.org/10.1016/j.ajog.2020.12.399.

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Atzmon, Yuval, Efrat Ben Ishay, Erik Eisenkraft, Mordechai Hallak et Rinat Gabbay-Benziv. « 377 Maternal obesity and hemodynamic adaptation to epidural anesthesia : evaluation using a novel non-invasive PPG-based sensor ». American Journal of Obstetrics and Gynecology 224, n^o 2 (février 2021) : S245. http://dx.doi.org/10.1016/j.ajog.2020.12.400.

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