Chronic kidney disease and orthostatic hypotension in hospitalised older adults.

PURPOSE: Orthostatic hypotension (OH) may predispose older adults to health complications leading to functional impairment. Despite the central role of the kidney in blood pressure control, the contribution of renal function in orthostatic hypotension is poorly investigated. To verify the association between Chronic Kidney Disease (CKD) and OH a population of hospitalised elderly patients with comorbidities was studied. MATERIALS AND METHODS: 174 patients were consecutively admitted to Acute Geriatric Wards. On admission, patients underwent postural systolic (SBP) and diastolic (DBP) blood pressure evaluation by automatic oscillometric device after 10 min rest in lying position, and in standing position at time 0, 1, 3 and 5 min. CKD was assumed for estimated glomerular filtration rate (e-GFR) less than 60 mL/min/1.73 m2. RESULTS: The mean age of the population enrolled was 74.4 ± 7.0. OH was found in 46.0% and CKD in 56.3% of patients, respectively. A lower e-GFR was observed in patients with (56.1 ± 16.7 mL/min/1.73 m2) than in those without OH (61.1 ± 15.9 mL/min/1.73 m2) (p < 0.05). A greater fall in SBP at 0-min (12.8 ± 6.3 vs. 7.7 ± 3.2 mmHg) and at 1-min (8.4 ± 4.5 vs. 5.7 ± 2.8 mmHg) was found in CKD patients in respect to patients without CKD during active standing test (p < 0.05). Similarly, a DBP reduction at 0-min and at 1-min was observed in CKD patients in respect to patients without CKD (p < 0.05). A multivariate logistic regression analysis showed that CKD was associated to OH (OR 2.426; 95%CI 1.192-4.937; p = 0.014). CONCLUSIONS: CKD is associated to OH in hospitalised older adults.

Recent Innovations in Footwear and the Role of Smart Footwear in Healthcare-A Survey.

Smart shoes have ushered in a new era of personalised health monitoring and assistive technologies. Smart shoes leverage technologies such as Bluetooth for data collection and wireless transmission, and incorporate features such as GPS tracking, obstacle detection, and fitness tracking. As the 2010s unfolded, the smart shoe landscape diversified and advanced rapidly, driven by sensor technology enhancements and smartphones' ubiquity. Shoes have begun incorporating accelerometers, gyroscopes, and pressure sensors, significantly improving the accuracy of data collection and enabling functionalities such as gait analysis. The healthcare sector has recognised the potential of smart shoes, leading to innovations such as shoes designed to monitor diabetic foot ulcers, track rehabilitation progress, and detect falls among older people, thus expanding their application beyond fitness into medical monitoring. This article provides an overview of the current state of smart shoe technology, highlighting the integration of advanced sensors for health monitoring, energy harvesting, assistive features for the visually impaired, and deep learning for data analysis. This study discusses the potential of smart footwear in medical applications, particularly for patients with diabetes, and the ongoing research in this field. Current footwear challenges are also discussed, including complex construction, poor fit, comfort, and high cost.

Combined Cardiac and Respiratory Monitoring from a Single Signal: A Case Study Employing the Fantasia Database.

This study proposes a novel method for obtaining the electrocardiogram (ECG) derived respiration (EDR) from a single lead ECG and respiration-derived cardiogram (RDC) from a respiratory stretch sensor. The research aims to reconstruct the respiration waveform, determine the respiration rate from ECG QRS heartbeat complexes data, locate heartbeats, and calculate a heart rate (HR) using the respiration signal. The accuracy of both methods will be evaluated by comparing located QRS complexes and inspiration maxima to reference positions. The findings of this study will ultimately contribute to the development of new, more accurate, and efficient methods for identifying heartbeats in respiratory signals, leading to better diagnosis and management of cardiovascular diseases, particularly during sleep where respiration monitoring is paramount to detect apnoea and other respiratory dysfunctions linked to a decreased life quality and known cause of cardiovascular diseases. Additionally, this work could potentially assist in determining the feasibility of using simple, no-contact wearable devices for obtaining simultaneous cardiology and respiratory data from a single device.

Staged approach for correction of anomalous venous return to the azygos vein.

Partial anomalous pulmonary venous return into the azygous vein is a rare pathological finding. We describe the case of a 28-year-old girl who had a successful staged approach to treat this rare congenital heart disease. To avoid potential connection of a systemic venous return to the left atrium, the proximal part of the azygous vein was occluded with a percutaneous approach, then the azygous vein flow was redirected into the left atrium with a surgical procedure.

Management of acute cardiovascular complications in pregnancy.

The growing population of women with heart disease of reproductive age has been associated with an increasing number of high-risk pregnancies. Pregnant women with heart disease are a very heterogeneous population, with different risks for maternal cardiovascular, obstetric, and foetal complications. Adverse cardiovascular events during pregnancy pose significant clinical challenges, with uncertainties regarding diagnostic and therapeutic approaches potentially compromising maternal and foetal health. This review summarizes best practice for the treatment of common cardiovascular complications during pregnancy, based on expert opinion, current guidelines, and available evidence. Topics covered include heart failure (HF), arrhythmias, coronary artery disease, aortic and thromboembolic events, and the management of mechanical heart valves during pregnancy. Cardiovascular pathology is the leading cause of non-obstetric morbidity and mortality during pregnancy in developed countries. For women with pre-existing cardiac conditions, preconception counselling and structured follow-up during pregnancy are important measures for reducing the risk of acute cardiovascular complications during gestation and at the time of delivery. However, many women do not receive pre-pregnancy counselling often due to gaps in what should be lifelong care, and physicians are increasingly encountering pregnant women who present acutely with cardiac complications, including HF, arrhythmias, aortic events, coronary syndromes, and bleeding or thrombotic events. This review provides a summary of recommendations on the management of acute cardiovascular complication during pregnancy, based on available literature and expert opinion. This article covers the diagnosis, risk stratification, and therapy and is organized according to the clinical presentation and the type of complication, providing a reference for the practicing cardiologist, obstetrician, and acute medicine specialist, while highlighting areas of need and potential future research.

Electrodeless Heart and Respiratory Rate Estimation during Sleep Using a Single Fabric Band and Event-Based Edge Processing.

Heart rate (HR) and respiratory rate (RR) are two vital parameters of the body medically used for diagnosing short/long-term illness. Out-of-the-body, non-skin-contact HR/RR measurement remains a challenge due to imprecise readings. "Invisible" wearables integrated into day-to-day garments have the potential to produce precise readings with a comfortable user experience. Sleep studies and patient monitoring benefit from "Invisibles" due to longer wearability without significant discomfort. This paper suggests a novel method to reduce the footprint of sleep monitoring devices. We use a single silver-coated nylon fabric band integrated into a substrate of a standard cotton/nylon garment as a resistive elastomer sensor to measure air and blood volume change across the chest. We introduce a novel event-based architecture to process data at the edge device and describe two algorithms to calculate real-time HR/RR on ARM Cortex-M3 and Cortex-M4F microcontrollers. RR estimations show a sensitivity of 99.03% and a precision of 99.03% for identifying individual respiratory peaks. The two algorithms used for HR calculation show a mean absolute error of 0.81 ± 0.97 and 0.86±0.61 beats/min compared with a gold standard ECG-based HR. The event-based algorithm converts the respiratory/pulse waveform into instantaneous events, therefore reducing the data size by 40-140 times and requiring 33% less power to process and transfer data. Furthermore, we show that events hold enough information to reconstruct the original waveform, retaining pulse and respiratory activity. We suggest fabric sensors and event-based algorithms would drastically reduce the device footprint and increase the performance for HR/RR estimations during sleep studies, providing a better user experience.

Seizure Detection: A Low Computational Effective Approach without Classification Methods.

Epilepsy is a severe neurological disorder that is usually diagnosed by using an electroencephalogram (EEG). However, EEG signals are complex, nonlinear, and dynamic, thus generating large amounts of data polluted by many artefacts, lowering the signal-to-noise ratio, and hampering expert interpretation. The traditional seizure-detection method of professional review of long-term EEG signals is an expensive, time-consuming, and challenging task. To reduce the complexity and cost of the task, researchers have developed several seizure-detection approaches, primarily focusing on classification systems and spectral feature extraction. While these methods can achieve high/optimal performances, the system may require retraining and following up with the feature extraction for each new patient, thus making it impractical for real-world applications. Herein, we present a straightforward manual/automated detection system based on the simple seizure feature amplification analysis to minimize these practical difficulties. Our algorithm (a simplified version is available as additional material), borrowing from the telecommunication discipline, treats the seizure as the carrier of information and tunes filters to this specific bandwidth, yielding a viable, computationally inexpensive solution. Manual tests gave 93% sensitivity and 96% specificity at a false detection rate of 0.04/h. Automated analyses showed 88% and 97% sensitivity and specificity, respectively. Moreover, our proposed method can accurately detect seizure locations within the brain. In summary, the proposed method has excellent potential, does not require training on new patient data, and can aid in the localization of seizure focus/origin.

Changes in Forcecardiography Heartbeat Morphology Induced by Cardio-Respiratory Interactions.

The cardiac function is influenced by respiration. In particular, various parameters such as cardiac time intervals and the stroke volume are modulated by respiratory activity. It has long been recognized that cardio-respiratory interactions modify the morphology of cardio-mechanical signals, e.g., phonocardiogram, seismocardiogram (SCG), and ballistocardiogram. Forcecardiography (FCG) records the weak forces induced on the chest wall by the mechanical activity of the heart and lungs and relies on specific force sensors that are capable of monitoring respiration, infrasonic cardiac vibrations, and heart sounds, all simultaneously from a single site on the chest. This study addressed the changes in FCG heartbeat morphology caused by respiration. Two respiratory-modulated parameters were considered, namely the left ventricular ejection time (LVET) and a morphological similarity index (MSi) between heartbeats. The time trends of these parameters were extracted from FCG signals and further analyzed to evaluate their consistency within the respiratory cycle in order to assess their relationship with the breathing activity. The respiratory acts were localized in the time trends of the LVET and MSi and compared with a reference respiratory signal by computing the sensitivity and positive predictive value (PPV). In addition, the agreement between the inter-breath intervals estimated from the LVET and MSi and those estimated from the reference respiratory signal was assessed via linear regression and Bland-Altman analyses. The results of this study clearly showed a tight relationship between the respiratory activity and the considered respiratory-modulated parameters. Both the LVET and MSi exhibited cyclic time trends that remarkably matched the reference respiratory signal. In addition, they achieved a very high sensitivity and PPV (LVET: 94.7% and 95.7%, respectively; MSi: 99.3% and 95.3%, respectively). The linear regression analysis reported almost unit slopes for both the LVET (R2 = 0.86) and MSi (R2 = 0.97); the Bland-Altman analysis reported a non-significant bias for both the LVET and MSi as well as limits of agreement of ±1.68 s and ±0.771 s, respectively. In summary, the results obtained were substantially in line with previous findings on SCG signals, adding to the evidence that FCG and SCG signals share a similar information content.

Ductal ligation timing and neonatal outcomes: a 12-year bicentric comparison.

Patent ductus arteriosus (PDA) is common among extremely preterm infants. In selected cases, surgical PDA ligation may be required. The timing for PDA ligation may depend upon a variety of factors, with potential clinical implications. We aimed to investigate the impact of different surgical PDA managements on ligation timing and neonatal outcomes. Inborn infants < 32 weeks of gestation and < 1500 g admitted at two tertiary Neonatal Intensive Care Units that underwent PDA ligation between 2007 and 2018 were enrolled in this retrospective cohort study and split into the following groups based on their surgical management: on-site bedside PDA ligation (ONS) vs. referral to an off-site pediatric cardiac surgery (OFS). Neonatal characteristics, surgical timing, and clinical outcomes of the enrolled infants were compared between the groups. Multivariate analysis was performed to evaluate the impact of PDA ligation timing on significantly different outcomes. Seventy-eight neonates (ONS, n = 39; OFS, n = 39) were included. Infants in the ONS group underwent PDA ligation significantly earlier than those in the OFS group (median age 12 vs. 36 days, p < 0.001) with no increase in postoperative mortality and complications. The multivariate analysis revealed a significant association between PDA ligation timing, late-onset sepsis prevalence (OR 1.045, 0.032), and oxygen need at discharge (OR 1.037, p = 0.025).Conclusions: Compared with off-site surgery, on-site bedside ligation allows an earlier surgical closure of PDA, with no apparent increase in mortality or complications. Earlier PDA ligation may contribute to reduced rates of late-onset sepsis and post-discharge home oxygen therapy, with possible cost-benefit implications. What is known: • Ineffective or contraindicated pharmacological closure of a hemodynamically significant PDA may require a surgical ligation. • Available literature comparing the effect of early vs. late PDA ligation on the main neonatal morbidities has yield contrasting results. What is new: • The availability of a cardiac surgery service performing bedside PDA ligation allows an earlier intervention compared to patient referral to an off-site center, with no difference in postoperative mortality and complications compared to off-site surgery. • Earlier PDA ligation was associated with a lower prevalence of late-onset sepsis and of oxygen need at discharge, with possible cost-benefit implications.

Lung ultrasound compared with bedside chest radiography in a paediatric cardiac intensive care unit.

AIM: Postoperative recovery of children with heart disease is encumbered by pulmonary complications like pneumothorax (PNX), pleural effusion (PLE), interstitial oedema and pulmonary consolidation (PC). Recently, lung ultrasound (LUS) has become an important diagnostic tool for evaluation of pulmonary diseases in the paediatric context. LUS is accurate in diagnosing pleural and parenchymal diseases. The aim of this study was to evaluate the accuracy of LUS in the identification of PNX, PLE and PC in a paediatric population of patients with congenital heart disease after heart surgery. METHODS: Fifty-three patients aged 0-17 years who underwent cardiac surgery were evaluated in the postoperative period by chest X-ray (CXR) and LUS at the same time. The methods where compared for recognition of PNX, PLE and PC. RESULTS: LUS showed a good agreement for PNX and a moderate agreement for both PLE and PC. LUS also showed a significantly superior relative sensitivity than CXR for PC and PLE and a significantly inferior relative sensitivity for PNX. CONCLUSION: This study confirms that LUS has a sufficient agreement rate with the current clinical standard (CXR). Non-inferiority in diagnosis together with the easiness of bedside performance makes LUS a very attractive tool for the paediatric cardiac intensive care unit.

Biosignal-Based Human-Machine Interfaces for Assistance and Rehabilitation: A Survey.

As a definition, Human-Machine Interface (HMI) enables a person to interact with a device. Starting from elementary equipment, the recent development of novel techniques and unobtrusive devices for biosignals monitoring paved the way for a new class of HMIs, which take such biosignals as inputs to control various applications. The current survey aims to review the large literature of the last two decades regarding biosignal-based HMIs for assistance and rehabilitation to outline state-of-the-art and identify emerging technologies and potential future research trends. PubMed and other databases were surveyed by using specific keywords. The found studies were further screened in three levels (title, abstract, full-text), and eventually, 144 journal papers and 37 conference papers were included. Four macrocategories were considered to classify the different biosignals used for HMI control: biopotential, muscle mechanical motion, body motion, and their combinations (hybrid systems). The HMIs were also classified according to their target application by considering six categories: prosthetic control, robotic control, virtual reality control, gesture recognition, communication, and smart environment control. An ever-growing number of publications has been observed over the last years. Most of the studies (about 67%) pertain to the assistive field, while 20% relate to rehabilitation and 13% to assistance and rehabilitation. A moderate increase can be observed in studies focusing on robotic control, prosthetic control, and gesture recognition in the last decade. In contrast, studies on the other targets experienced only a small increase. Biopotentials are no longer the leading control signals, and the use of muscle mechanical motion signals has experienced a considerable rise, especially in prosthetic control. Hybrid technologies are promising, as they could lead to higher performances. However, they also increase HMIs' complexity, so their usefulness should be carefully evaluated for the specific application.

Respiration Monitoring via Forcecardiography Sensors.

In the last few decades, a number of wearable systems for respiration monitoring that help to significantly reduce patients' discomfort and improve the reliability of measurements have been presented. A recent research trend in biosignal acquisition is focusing on the development of monolithic sensors for monitoring multiple vital signs, which could improve the simultaneous recording of different physiological data. This study presents a performance analysis of respiration monitoring performed via forcecardiography (FCG) sensors, as compared to ECG-derived respiration (EDR) and electroresistive respiration band (ERB), which was assumed as the reference. FCG is a novel technique that records the cardiac-induced vibrations of the chest wall via specific force sensors, which provide seismocardiogram-like information, along with a novel component that seems to be related to the ventricular volume variations. Simultaneous acquisitions were obtained from seven healthy subjects at rest, during both quiet breathing and forced respiration at higher and lower rates. The raw FCG sensor signals featured a large, low-frequency, respiratory component (R-FCG), in addition to the common FCG signal. Statistical analyses of R-FCG, EDR and ERB signals showed that FCG sensors ensure a more sensitive and precise detection of respiratory acts than EDR (sensitivity: 100% vs. 95.8%, positive predictive value: 98.9% vs. 92.5%), as well as a superior accuracy and precision in interbreath interval measurement (linear regression slopes and intercepts: 0.99, 0.026 s (R2 = 0.98) vs. 0.98, 0.11 s (R2 = 0.88), Bland-Altman limits of agreement: ±0.61 s vs. ±1.5 s). This study represents a first proof of concept for the simultaneous recording of respiration signals and forcecardiograms with a single, local, small, unobtrusive, cheap sensor. This would extend the scope of FCG to monitoring multiple vital signs, as well as to the analysis of cardiorespiratory interactions, also paving the way for the continuous, long-term monitoring of patients with heart and pulmonary diseases.

Wearable Bluetooth Triage Healthcare Monitoring System.

Triage is the first interaction between a patient and a nurse/paramedic. This assessment, usually performed at Emergency departments, is a highly dynamic process and there are international grading systems that according to the patient condition initiate the patient journey. Triage requires an initial rapid assessment followed by routine checks of the patients' vitals, including respiratory rate, temperature, and pulse rate. Ideally, these checks should be performed continuously and remotely to reduce the workload on triage nurses; optimizing tools and monitoring systems can be introduced and include a wearable patient monitoring system that is not at the expense of the patient's comfort and can be remotely monitored through wireless connectivity. In this study, we assessed the suitability of a small ceramic piezoelectric disk submerged in a skin-safe silicone dome that enhances contact with skin, to detect wirelessly both respiration and cardiac events at several positions on the human body. For the purposes of this evaluation, we fitted the sensor with a respiratory belt as well as a single lead ECG, all acquired simultaneously. To complete Triage parameter collection, we also included a medical-grade contact thermometer. Performances of cardiac and respiratory events detection were assessed. The instantaneous heart and respiratory rates provided by the proposed sensor, the ECG and the respiratory belt were compared via statistical analyses. In all considered sensor positions, very high performances were achieved for the detection of both cardiac and respiratory events, except for the wrist, which provided lower performances for respiratory rates. These promising yet preliminary results suggest the proposed wireless sensor could be used as a wearable, hands-free monitoring device for triage assessment within emergency departments. Further tests are foreseen to assess sensor performances in real operating environments.

Aortic arch geometry predicts outcome in patients with Loeys-Dietz syndrome independent of the causative gene.

This study aimed to investigate the potential association between imaging features and cardiovascular outcomes in patients with Loeys­Dietz syndrome (LDS). We performed a retrospective cohort study of 36 patients with LDS and described cardiovascular events and imaging data. We observed different clinical courses in patients with LDS, irrespective of the causative gene. Angular or elongated aortic arch geometry correlated with aortic dissection (R = .39, p = .02), occurrence of the first cardiovascular event before 45 years of age (R = .36, p = .03), and the number of operations (R = 0.47, p = .004), but not with age (R = −.05, p = .79) or the causative gene (R = −0.04, p = .79). Relative absences of cardiovascular events at ages 20, 40, and 60 were 100, 75, and 56%, respectively, in patients with "romanesque" aortic arches, and 74, 39, and 21%, respectively, in patients with "gothic" and "elongated" aortic arches (p = .03). Angular or elongated aortic arch geometry is associated with early­onset of disease and a worse cardiovascular outcome in LDS patients. Large multicenter studies are warranted to elucidate the impact of aortic arch morphology evaluation in clinical practice.

Enigmatic Phytomyxid Parasite of the Alien Seagrass Halophila stipulacea: New Insights into Its Ecology, Phylogeny, and Distribution in the Mediterranean Sea.

Marine phytomyxids represent often overlooked obligate biotrophic parasites colonizing diatoms, brown algae, and seagrasses. An illustrative example of their enigmatic nature is the phytomyxid infecting the seagrass Halophila stipulacea (a well-known Lessepsian migrant from the Indo-Pacific to the Mediterranean Sea). In the Mediterranean, the occurrence of this phytomyxid was first described in 1995 in the Strait of Messina (southern Italy) and the second time in 2017 in the Aegean coast of Turkey. Here we investigated, using scuba diving, stereomicroscopy, light and scanning electron microscopy, and molecular methods, whether the symbiosis is still present in southern Italy, its distribution in this region and its relation to the previous reports. From the total of 16 localities investigated, the symbiosis has only been found at one site. A seasonal pattern was observed with exceptionally high abundance (> 40% of the leaf petioles colonized) in September 2017, absence of the symbiosis in May/June 2018, and then again high infection rates (~ 30%) in September 2018. In terms of anatomy and morphology as well as resting spore dimensions and arrangement, the symbiosis seems to be identical to the preceding observations in the Mediterranean. According to the phylogenetic analyses of the 18S rRNA gene, the phytomyxid represents the first characterized member of the environmental clade "TAGIRI-5". Our results provide new clues about its on-site ecology (incl. possible dispersal mechanisms), hint that it is rare but established in the Mediterranean, and encourage further research into its distribution, ecophysiology, and taxonomy.

Validation of "(fr)AGILE": a quick tool to identify multidimensional frailty in the elderly.

BACKGROUND: Several tools have been proposed and validated to operationally define frailty. Recently, the Italian Frailty index (IFi), an Italian modified version of Frailty index, has been validated but its use in clinical practice is limited by long time of administration. Therefore, the aim of this study was to create and validate a quick version of the IFi (AGILE). METHODS: Validation study was performed by administering IFi and AGILE, after a Comprehensive Geriatric Assessment (CGA) in 401 subjects aged 65 or over (77 ± 7 years). AGILE was a 10-items tool created starting from the more predictive items of the four domains of frailty investigated by IFi (mental, physical, socioeconomic and nutritional). AGILE scores were stratified in light, moderate and severe frailty. At 24 months of follow-up, death, disability (taking into account an increase in ADL lost ≥1 from the baseline) and hospitalization were considered. Area under curve (AUC) was evaluated for both IFi and AGILE. RESULTS: Administration time was 9.5 ± 3.8 min for IFi administered after a CGA, and 2.4 ± 1.2 min for AGILE, regardless of CGA (p < 0.001). With increasing degree of frailty, prevalence of mortality increased progressively from 6.5 to 41.8% and from 9.0 to 33.3%, disability from 16.1 to 64.2% and from 22.1 to 59.8% and hospitalization from 17.2 to 58.7% and from 27.0 to 52.2% with AGILE and IFi, respectively (p = NS). Relative Risk for each unit of increase in AGILE was 56, 44 and 24% for mortality, disability and hospitalization, respectively and was lower for IFi (8, 7 and 4% for mortality, disability and hospitalization, respectively). The AUC was higher in AGILE vs. IFi for mortality (0.729 vs. 0.698), disability (0.715 vs. 0.682) and hospitalization (0.645 vs. 0.630). CONCLUSIONS: Our study shows that AGILE is a rapid and effective tool for screening multidimensional frailty, able to predict mortality, disability and hospitalization, especially useful in care settings that require reliable assessment instruments with short administration time.

Type 2 myocardial infarction: is it a geriatric syndrome?

Type 2 myocardial infarctions (T2-MI) is a type of necrosis that results from reduced oxygen supply and/or increased demand secondary to other causes unrelated to acute coronary atherothrombosis. The development and implementation of sensitive and high-sensitivity cardiac necrosis marker and the age-related increase of comorbidity lead to a boost of the frequency of T2-MI. T2-MI is often a complication of a high degree of clinical frailty in older adults, emerging as a "geriatric syndrome". Age-related non-cardiovascular causes may be the triggering factors and are strongly associated with the diagnosis, treatment, and prognosis of T2-MI. To date, there are no guidelines on management of this pathology in advancing age. Patient-centered approach and comprehensive geriatric assessment play a key role in the diagnosis, therapy and prognosis of geriatric patients with T2-MI.

Continuous Vital Monitoring During Sleep and Light Activity Using Carbon-Black Elastomer Sensors.

The comfortable, continuous monitoring of vital parameters is still a challenge. The long-term measurement of respiration and cardiovascular signals is required to diagnose cardiovascular and respiratory diseases. Similarly, sleep quality assessment and the recovery period following acute treatments require long-term vital parameter datalogging. To address these requirements, we have developed "VitalCore", a wearable continuous vital parameter monitoring device in the form of a T-shirt targeting the uninterrupted monitoring of respiration, pulse, and actigraphy. VitalCore uses polymer-based stretchable resistive bands as the primary sensor to capture breathing and pulse patterns from chest expansion. The carbon black-impregnated polymer is implemented in a U-shaped configuration and attached to the T-shirt with "interfacing" material along with the accompanying electronics. In this paper, VitalCore is bench tested and compared to gold standard respiration and pulse measurements to verify its functionality and further to assess the quality of data captured during sleep and during light exercise (walking). We show that these polymer-based sensors could identify respiratory peaks with a sensitivity of 99.44%, precision of 96.23%, and false-negative rate of 0.557% during sleep. We also show that this T-shirt configuration allows the wearer to sleep in all sleeping positions with a negligible difference of data quality. The device was also able to capture breathing during gait with 88.9%-100% accuracy in respiratory peak detection.

Forcecardiography: A Novel Technique to Measure Heart Mechanical Vibrations onto the Chest Wall.

This paper presents forcecardiography (FCG), a novel technique to measure local, cardiac-induced vibrations onto the chest wall. Since the 19th century, several techniques have been proposed to detect the mechanical vibrations caused by cardiovascular activity, the great part of which was abandoned due to the cumbersome instrumentation involved. The recent availability of unobtrusive sensors rejuvenated the research field with the most currently established technique being seismocardiography (SCG). SCG is performed by placing accelerometers onto the subject's chest and provides information on major events of the cardiac cycle. The proposed FCG measures the cardiac-induced vibrations via force sensors placed onto the subject's chest and provides signals with a richer informational content as compared to SCG. The two techniques were compared by analysing simultaneous recordings acquired by means of a force sensor, an accelerometer and an electrocardiograph (ECG). The force sensor and the accelerometer were rigidly fixed to each other and fastened onto the xiphoid process with a belt. The high-frequency (HF) components of FCG and SCG were highly comparable (r > 0.95) although lagged. The lag was estimated by cross-correlation and resulted in about tens of milliseconds. An additional, large, low-frequency (LF) component, associated with ventricular volume variations, was observed in FCG, while not being visible in SCG. The encouraging results of this feasibility study suggest that FCG is not only able to acquire similar information as SCG, but it also provides additional information on ventricular contraction. Further analyses are foreseen to confirm the advantages of FCG as a technique to improve the scope and significance of pervasive cardiac monitoring.