Volume Pulse Research Articles

Fatigue Detection Based on Blood Volume Pulse Signal and Multi‐Physical Features

ABSTRACTFatigue detection holds paramount importance in the timely identification of safety hazards. Nonetheless, prevailing fatigue detection methodologies often overlook the diverse spectrum of fatigue features or temporal cues. To address this lacuna, we introduce fatigue detection based on blood volume pulse signal and multi‐physical features (FDBVPS‐MF). Initially, a non‐invasive technique is employed to extract the blood volume pulse signal (BVPS) from the forehead region, which is subsequently fed into a one‐dimensional convolutional neural network (1D CNN) to formulate a fatigue detection model based on BVPS. Concurrently, features such as percentage of eyelid closure (PERCLOS), blink frequency (BF), and maximum closing time (MCT) are computed from eye images, and amalgamated with yawning frequency (YF) derived from mouth images to generate multi‐physical features (MF). MF is then input into the 1D CNN network to construct a fatigue detection model based on MF. Subsequently, employing weights, derived through Adaboosting, a fusion approach is executed to integrate the outputs of the two fatigue detection models, thus facilitating multi‐modal fatigue detection. On the UTA‐RLDD dataset, the proposed FDBVPS‐MF exhibits an accuracy and precision of 88.9% and 88.2%, respectively. Experimental findings substantiate the superior efficacy of FDBVPS‐MF over conventional methodologies.

Pulsed peritoneal dialysis in an experimental rat model: A first experience.

Peritoneal dialysis (PD) is commonly performed using either intermittent or tidal exchanges, whereas other exchange techniques such as continuous flow PD are little used. Previous research indicated that stirring the intra-peritoneal dialysate markedly increases small solute clearances. Here, we tested the hypothesis that stirring of the dialysate increases small solute clearances by using a novel exchange technique where the dialysate is pulsed back and forth during the treatment without addition of fresh fluid. PD was performed in anesthetized Sprague-Dawley rats with either no pulsations (20 mL fill volume), 2 mL (10%) pulses (21 mL fill volume), or 5 mL (25%) pulses (22.5 mL fill volume) utilizing a pulse flow rate of 5 mL/min. The higher fill volume for the pulsed treatments compensates for the fact that the average intra-peritoneal volume would otherwise be lower in pulsed treatments. Water and solute transport were closely monitored during the treatment. Net ultrafiltration decreased significantly during pulsed PD with the 25% pulse volume. The 60 min sodium dip was unaltered, whereas the fluid absorption rate was increased for the 25% group. Solute clearances did not significantly differ between groups, except for a slightly lower calcium clearance in the 25% group. Our data indicate that stirring the dialysate using pulsed exchanges does not provide any advantage compared to conventional exchange techniques. In contrast, pulsed treatments had slightly lower ultrafiltration and small solute transport. The present findings may have implications regarding the choice of tidal volume in automated PD, favoring smaller tidal volumes.

Physiological response to pain in patients with temporomandibular joint disorders during physiotherapy

Pain assessment in patients with temporomandibular joint (TMJ) disorders during physiotherapy is a challenging yet desired task. Our study addresses two issues. First, we compare the pain perception in patients with TMJ disorders and a control group. The hand dynamometer is verified as an alternate pain self-report device in the second stage. For the dynamometer validation, we employed a cuff-pressure test to induce pain of various intensities. In the second stage, physiological signals (electrodermal activity and blood volume pulse) have been acquired during the physiotherapy in a control group and patients suffering from TMJ disorder. The linear mixed-effects modeling is carried out to find differences in pain and no pain states, considering subjects’ health condition. The main result of the present pilot study is that physiological reactions to painful physiotherapy do not differ between patients with chronic pain and the control group. This finding concludes that studies on TMJ disorder procedures may also be performed on healthy subjects.

Relevance of high glycaemic index breakfast for heart rate variability among collegiate students with early and late chronotypes

ABSTRACT Plasma glucose spikes affect cardiac autonomic modulation resulting in a decrease of heart rate variability (HRV). We hypothesize that a later chronotype or a higher morning plasma melatonin level is associated with larger decreases of HRV following an early high glycaemic index (GI) breakfast. In persons with an early (n = 21) or a late (n = 15) chronotype who consumed a high GI breakfast at 7 a.m. glucose data were continuously monitored. Time domain HRV parameters were calculated from blood volume pulses derived by wireless wrist worn multisensor. HRV changes (values after minus values before breakfast) were associated with chronotype by multivariable linear regression adjusted for age, sex and baseline levels. Morning plasma melatonin levels were determined from samples drawn on the run-in day. Time domain parameters indicate a higher HRV before high GI breakfast in both chronotypes. A later chronotype tended to be associated with smaller decreases of mean interbeat intervals (p = 0.08) only; no associations were seen with morning melatonin levels. This exploratory analysis in a small sample provides a first indication that in young healthy adults later chronotype might be associated with reduced ANS activation following a high GI breakfast. Future studies should elucidate whether this indicates parasympathetic or sympathetic inhibition.

A Novel Labeling Method of Physiological-based Pressure Pain Assessment Among Patients With and Without Chronic Low Back Pain

Pain, especially chronic pain, is a complicated and subjective experience, threatening global healthcare as one of the most severe health problems. Traditionally, pain is assessed by Visual Analog Scale to indicate the pain intensity by the patient’s self-report, causing them to become biased by various psychosocial factors. In this study, we performed two distinct labeling methods to assess the pressure pain in Quantitative Sensory Testing and to differentiate healthy controls and chronic low back pain patients: time period labels and percentage timestamp labels. Physiological signals such as blood volume pulse and galvanic skin response were collected. The time period labeling method was to segment via fixed time windows. The percentage timestamp labeling method was to select the timestamp labels based on the percentage of the threshold or the tolerance time. Both methods demonstrate different advantages when visualizing the information of different pain states and different participant groups.

Peculiarities of the regional hemodynamics in patients with mono- and bilateral herpes simplex virus stromal keratitis

Background. Herpes simplex virus keratitis (HSVK) is the main cause of blindness in the world resulted from corneal pathology. The blood circulation system of the eye plays an important role in the effective implementation of the immune response. The purpose of the study: to determine the influence of the factor of laterality of the stromal HSVK on the ocular hemodynamics and the frequency of complications. Material and methods. Primary stromal HSVK (was registered for the first time and lasted no more than 3 months) was diagnosed in 32 people (35 eyes), 205 patients (226 eyes) had recurrent stromal HSVK. Among these patients, stromal HSVK was detected both in one eye — unilateral, and in two eyes — bilateral. Complications of stromal HSVK includes: the presence of a transparent graft — in 23 eyes and its opacity — in 10 eyes, secondary glaucoma — in 6 eyes, condition after corneal ulcer — in 16 eyes. The average age of the patients (M ± SD) is 42.2 ± 15.0 years. The control group consisted of 16 healthy volunteers (32 eyes) of similar age. The standard technique of rheoophthalmogram on the ReoCom computer rheograph (Kharkiv, Ukraine) was used. The following indicators were analyzed: rheographic quotient (RQ, ‰) (pulse volumetric blood filling); α1/T (%) — the tone of the large vessels of the eye; velocity of blood filling V (Ohm/s). Results. Patients with stromal HSVK had mainly monolateral eye lesion — 89.8 %, and bilateral lesion was present in 10.2 % of cases. There were no significant differences in the frequency of laterality between primary and recurrent stromal HSVK. In case of recurrence of complicated unilateral and bilateral stromal HSVK, the volumetric pulse blood filling was 17.6 and 30.3 % lower, respectively, than in uncomplicated course, which determines the insufficiency of blood supply to the eye. The rate of blood filling in complicated stromal HSVK was lower than in uncomplicated one by 23 %. At the recurrence of bilateral stromal HSVK, the RQ was higher by 26.4 %, and the rate of blood filling was higher by 36.3 % compared to unilateral one. There were no differences in remission. The tone of the large vessels of the eye with bilateral stromal HSVK is 14 % lower than with unilateral course. Conclusions. In case of recurrent stromal HSVK, the volume pulse blood filling of the eye and its velocity are higher, and the vascular tone is lower than in case of unilateral one, both uncomplicated and complicated. It is assumed that such a significant activation of the ocular hemodynamics is compensatory and contributes to a greater local immune response and improvement of trophism.

Empatica E4 Assessment of Child Physiological Measures of Listening Effort During Remote and In-Person Communication.

Telepractice is a growing service model that delivers aural rehabilitation to deaf and hard-of hearing children via telecommunications technology. Despite known benefits of telepractice, this delivery approach may increase patients' listening effort (LE) characterized as an allocation of cognitive resources toward an auditory task. The study tested techniques for collecting physiological measures of LE in normal-hearing (NH) children during remote (referred to as tele-) and in-person communication using the wearable Empatica E4 wristband. Participants were 10 children (age range: 9-12 years old) who came to two tele- and two in-person weekly sessions, order counterbalanced. During each session, the children heard a short passage read by the clinical provider, completed an auditory passage comprehension task, and self-rated their effort as a part of the larger study. Measures of electrodermal activity and blood volume pulse amplitude were collected from the child E4 wristband. No differences in child subjective, physiological measures of LE or passage comprehension scores were found between in-person sessions and telesessions. However, an effect of treatment duration on subjective and physiological measures of LE was identified. Children self-reported a significant increase in LE over time. However, their physiological measures demonstrated a trend indicating a decrease in LE. A significant association between subjective measures and the passage comprehension task was found suggesting that those children who reported more effort demonstrated a higher proportion of correct responses. The study demonstrated the feasibility of collection of physiological measures of LE in NH children during remote and in-person communication using the E4 wristband. The results suggest that measures of LE are multidimensional and may reflect different sources of, or cognitive responses to, increased listening demand. https://doi.org/10.23641/asha.27122064.

Effects of epileptic seizures on the quality of biosignals recorded from wearables.

Wearable nonelectroencephalographic biosignal recordings captured from the wrist offer enormous potential for seizure monitoring. However, signal quality remains a challenging factor affecting data reliability. Models trained for seizure detection depend on the quality of recordings in peri-ictal periods in performing a feature-based separation of ictal periods from interictal periods. Thus, this study aims to investigate the effect of epileptic seizures on signal quality, ensuring accurate and reliable monitoring. This study assesses the signal quality of wearable data during peri-ictal phases of generalized tonic-clonic and focal to bilateral tonic-clonic seizures (TCS), focal motor seizures (FMS), and focal nonmotor seizures (FNMS). We evaluated accelerometer (ACC) activity and the signal quality of electrodermal activity (EDA) and blood volume pulse (BVP) data. Additionally, we analyzed the influence of peri-ictal movements as assessed by ACC (ACC activity) on signal quality and examined intraictal subphases of focal to bilateral TCS. We analyzed 386 seizures from 111 individuals in three international epilepsy monitoring units. BVP signal quality and ACC activity levels differed between all seizure types. We found the largest decrease in BVP signal quality and increase in ACC activity when comparing the ictal phase to the pre- and postictal phases for TCS. Additionally, ACC activity was strongly negatively correlated with BVP signal quality for TCS and FMS, and weakly for FNMS. Intraictal analysis revealed that tonic and clonic subphases have the lowest BVP signal quality and the highest ACC activity. Motor elements of seizures significantly impair BVP signal quality, but do not have significant effect on EDA signal quality, as assessed by wrist-worn wearables. The results underscore the importance of signal quality assessment methods and careful selection of robust modalities to ensure reliable seizure detection. Future research is needed to explain whether seizure detection models' decisions are based on signal responses induced by physiological processes as opposed to artifacts.

Self-toughening and self-reinforcing of polypropylene via melt-volume-pulsation-induced crystalline network

To achieve low-cost self-toughening and self-reinforcing is highly desired for the application and recycling of polypropylene (PP) but remains unresolved. This work reports the construction of a robust crystalline network via a volume pulsation injection molding (VPIM) process to meet the challenge. In particular, it is found that melt volume pulsation under a normal packing pressure can induce the formation of high-content γ-lamellae in PP. These γ-lamellae can effectively connect α-lamellae to construct the robust crystalline network, which imparts PP with greatly enhanced mechanical properties. Moreover, the robustness of the crystalline network and the mechanical properties of PP can be easily regulated by tuning the pulsatile frequency. Compared with those of conventional injection-molded samples, impact strength, yield strength, and tensile modulus of VPIM samples can be enhanced by 584.70 %, 13.96 %, and 29.84 %, respectively. To reveal the processing-structure-properties relationships, the microstructure and mechanical properties of PP under different processing conditions were discussed in detail. Furthermore, a theoretical analysis of the mechanical energy of polymer melt during volume pulsation process was conducted. The results disclose that the frequency-dependent microstructure and properties of PP are closely related to the frequency-dependent mechanical energy gained by melt. Hence, this paper paves a new avenue toward the low-cost self-toughening and self-reinforcing of PP for value-added application.

Energy‐Water Asynchrony Principally Determines Water Available for Runoff From Snowmelt in Continental Montane Forests

ABSTRACTChanges in the volume, rate, and timing of the snowmelt water pulse have profound implications for seasonal soil moisture, evapotranspiration (ET), groundwater recharge, and downstream water availability, especially in the context of climate change. Here, we present an empirical analysis of water available for runoff using five eddy covariance towers located in continental montane forests across a regional gradient of snow depth, precipitation seasonality, and aridity. We specifically investigated how energy‐water asynchrony (i.e., snowmelt timing relative to atmospheric demand), surface water input intensity (rain and snowmelt), and observed winter ET (winter AET) impact multiple water balance metrics that determine water available for runoff (WAfR). Overall, we found that WAfR had the strongest relationship with energy‐water asynchrony (adjusted r2 = 0.52) and that winter AET was correlated to total water year evapotranspiration but not to other water balance metrics. Stepwise regression analysis demonstrated that none of the tested mechanisms were strongly related to the Budyko‐type runoff anomaly (highest adjusted r2 = 0.21). We, therefore, conclude that WAfR from continental montane forests is most sensitive to the degree of energy‐water asynchrony that occurs. The results of this empirical study identify the physical mechanisms driving variability of WAfR in continental montane forests and are thus broadly relevant to the hydrologic management and modelling communities.

Comparison of feature learning methods for non-invasive interstitial glucose prediction using wearable sensors in healthy cohorts: a pilot study

BackgroundAlterations in glucose metabolism, especially the postprandial glucose response (PPGR), are crucial contributors to metabolic dysfunction, which underlies the pathogenesis of metabolic syndrome (MetSyn). Personalized low-glycemic diets (PLGD) have shown promise in reducing postprandial glucose spikes. However, current methods such as invasive continuous glucose monitoring (CGM) or multi-omics data integration to assess PPGR come with limitations, including cost and invasiveness, hindering widespread adoption in primary disease prevention. Our aim is to assess machine-learning algorithms for predicting individual PPGR using non-invasive wearable data, thereby circumventing the limitations associated with existing approaches. By identifying the most accurate model, we seek to provide a more accessible and efficient method for managing glucose metabolism. MethodsThis data-driven analysis utilized the experimental dataset from the SENSE (”Systemische Ernährungsmedizin”) study. Healthy participants used an Empatica E4 wristband and Abbott Freestyle Libre 3 CGM for ten days. Blood volume pulse (BVP), electrodermal activity (EDA), heart rate (HR), skin temperature (TEMP), and the corresponding CGM values were measured. Subsequently, four data-driven deep learning (DL) model-convolutional neural network (CNN), lightweight transformer (LTF), long short-term memory with attention (LSTM-A), and Bi-directional LSTM (BiLSTM)-were implemented and compared to determine the potential of DL in predicting interstitial glucose levels without involving food and activity logs. ResultsThe proposed BiLSTM achieved the best interstitial glucose prediction performance, with an average root mean squared error (RMSE) of 13.42 mg/dL, an average mean absolute percentage error (MAPE) of 0.12, and only 3.01% values falling within area D in Clarke error grid analysis (CEGA), incorporating the leave-one-out cross-validation (LOOCV) strategy for a five-minute prediction horizon. ConclusionThe findings of this study may demonstrate the feasibility of transferring knowledge gained from invasive glucose monitoring devices to non-invasive approaches. Furthermore, it emphasizes the promising prospects of combining deep learning with wearable technologies to predict glucose levels in healthy individuals.

Utilizing the '5 in 1 Magic Touch' CCRTV method for early detection of severe dengue warning signs in pediatric patients: A case study from a Type C Hospital in Indonesia

Background: Dengue fever, prevalent in tropical and subtropical regions, is recognized by WHO as a significant global health threat. Early detection of severe dengue symptoms, especially in resource-limited settings, is critical for patient outcomes. The "5 in 1 Magic Touch - CCRTV" method, which evaluates Color, Capillary Refill Time, Temperature, Pulse Rate, and Pulse Volume, provides a simple yet effective approach to monitor hemodynamics and identify early warning signs of severe dengue. Case Description: In a case study, a 3-year-old boy was admitted with fever, shortness of breath, weakness, nausea, vomiting, and epigastric pain. On the third day, he entered a critical phase with symptoms of pale extremities, delayed capillary refill time, high fever, and a weak, rapid pulse. Thorax examination revealed severe plasma leakage, pulmonary edema, and right pleural effusion, indicating a pre-shock state. The patient required close clinical monitoring, regular fluid balance management, and frequent blood tests to guide treatment. Conclusion:The CCRTV assessment method allowed for the early identification of the pre-shock condition, facilitating timely and appropriate intervention. This case highlights the potential of the CCRTV method for improving prognosis in severe dengue cases. The effectiveness of this method warrants further research, particularly in its ability to predict outcomes and improve recovery rates in children with severe dengue.

Properties of core specimens according to core diameter and coarse aggregate volume

Among methods for safety diagnosis of concrete, estimation of the compressive strength using core specimens, despite excellent accuracy, is less preferred than non-destructive testing methods due to a number of problems. Therefore, the object of the present study is to produce basic data for estimation of small-diameter core specimens by analyzing the ratio of compressive strength versus core specimen diameter, and analyzing the correlations between coarse aggregate volume and ultrasonic pulse velocity. Results showed that the compressive strength tends to decrease as the diameter of the core specimen decreases, and that the ultrasonic pulse velocity tends to increase with the coarse aggregate volume.

A hybrid transposed attention based deep learning model for wearable and explainable stress recognition

Stress is a prevalent issue in modern society which affects a large percentage of the population. Stress has negative effects on human daily lives such as reduced memory and concentration levels, forgetfulness, restlessness, and weakness. Although it is challenging to extinguish stress from human lives, monitoring and controlling its consequences can be implemented. Current methods for stress monitoring often lack interpretability of results and making it difficult to provide an interpretable system for immediate mental health counseling and intervention. Wearable devices are of growing interest due to the impact of the COVID-19 pandemic on mental health, as wearables provide monitoring of physiological parameters which helps in measuring stress levels. Here, an investigation on the feasibility of using wrist and chest-based multimodal physiological signals collected from wearables is executed for stress classification and identification of underlying modalities that impact the stress. Multimodalities from wrist and chest sensors are used to examine the three-class classification, baseline, stress and amusement. For improved and visualized effects, the multimodal signals from wearables were transformed into images. Then, a hybrid model was introduced, which comprised of attentive convolution neural network (CNN), transposed attentive CNN connections with long-short term memory (LSTM) and followed by attention layer for efficient feature extraction and improved classification accuracy. Results found that the proposed model with images provided 97 % accuracy and 96 % F1-score for chest wearable and 94 % accuracy and 93 % F1-score for wrist wearable data. Additionally, the post-hoc explainability approach (Local interpretable model agnostic applications, LIME) provided visual representations of contributing features from each signal for each class. LIME shows electrodermal activity (EDA), temperature (TEMP) and respiration (RESP) to be the significant factor in stress recognition from chest wearable and blood volume pulse (BVP) and EDA from wrist wearable. Additionally, increasing the number of features of the explainable model influences the modalities influence on the model explainability. The results establish a benchmark for explainable stress recognition using different sensor data.

Multiband accelerated 2D EPI for multi-echo brain QSM at 3 T.

Data for QSM are typically acquired using multi-echo 3D gradient echo (GRE), but EPI can be used to accelerate QSM and provide shorter acquisition times. So far, EPI-QSM has been limited to single-echo acquisitions, which, for 3D GRE, are known to be less accurate than multi-echo sequences. Therefore, we compared single-echo and multi-echo EPI-QSM reconstructions across a range of parallel imaging and multiband acceleration factors. Using 2D single-shot EPI in the brain, we compared QSM from single-echo and multi-echo acquisitions across combined parallel-imaging and multiband acceleration factors ranging from 2 to 16, with volume pulse TRs from 21.7 to 3.2 s, respectively. For single-echo versus multi-echo reconstructions, we investigated the effect of acceleration factors on regional susceptibility values, temporal noise, and image quality. We introduce a novel masking method based on thresholding the magnitude of the local field gradients to improve brain masking in challenging regions. At 1.6-mm isotropic resolution, high-quality QSM was achieved using multi-echo 2D EPI with a combined acceleration factor of 16 and a TR of 3.2 s, which enables functional applications. With these high acceleration factors, single-echo reconstructions are inaccurate and artefacted, rendering them unusable. Multi-echo acquisitions greatly improve QSM quality, particularly at higher acceleration factors, provide more consistent regional susceptibility values across acceleration factors, and decrease temporal noise compared with single-echo QSM reconstructions. Multi-echo acquisition is more robust for EPI-QSM across parallel imaging and multiband acceleration factors than single-echo acquisition. Multi-echo EPI can be used for highly accelerated acquisition while preserving QSM accuracy and quality relative to gold-standard 3D-GRE QSM.

Acute Limb Ischemia Management and Complications: From Catheter-Directed Thrombolysis to Long-Term Follow-up.

Acute limb ischemia (ALI) is a vascular emergency that needs to be diagnosed and treated quickly to prevent permanent tissue damage and amputation. Catheter-directed thrombolysis is a possible treatment option for mild to moderate ALI, with improved results from endovascular procedures and thrombolytic drugs. However, patients receiving thrombolysis may experience higher rates of distal embolization, serious bleeding events, and stroke than those undergoing surgery. The review article emphasizes the need for postoperative and extended management of ALI patients, including monitoring for compartment syndrome, managing reperfusion damage, and reducing changeable cardiovascular risk factors such as lipid-lowering therapy, diabetes management, and smoking cessation. Complications that can arise from thrombolytic therapy are also discussed, including hemorrhagic complications, minor bleeding, and reperfusion damage, with recommendations to monitor patients closely during treatment and discontinue therapy immediately if any abnormalities are detected. Follow-up evaluations for patients, including Doppler ultrasound, ankle brachial index, pulse volume recordings, and laboratory tests, are recommended to ensure the best possible outcome for patients with ALI.

The effect of home ultrasound on maternal anxiety in patients with previous recurrent pregnancy loss: A randomized control trial

BackgroundPatients with previous recurrent pregnancy loss are subject to increased maternal anxiety and reduced antenatal attachment during the subsequent pregnancy. Maternal anxiety is associated with worse pregnancy and neonatal outcomes. Home ultrasound is a feasible tool with the potential to alleviate maternal anxiety by ensuring fetal well-being. ObjectiveThis study aimed to investigate the impact of complementing standard prenatal care with twice-weekly telemedicine visits incorporating home ultrasound on maternal anxiety and antenatal attachment in individuals with a history of recurrent pregnancy loss. Study designIn this randomized controlled trial, patients with a history of 2 or more prior abortions were randomized early in their subsequent pregnancy in a 1:1 ratio into either the control group, which received standard high-risk prenatal care, or the study group, which received additional twice-weekly home-ultrasound sessions. The home-ultrasound scans assessed fetal pulse, movements, and amniotic fluid volume, aiming to provide maternal reassurance. Patients performed the scans themselves using the Pulsenmore device, with real-time guidance from a physician. Maternal anxiety was assessed using the validated State-Trait Anxiety Inventory Scale (STAI-S) and the Revised Prenatal Distress Questionnaire (NuPDQ), while maternal attachment was measured with the validated Maternal Antenatal Attachment Scale (MAAS-2) at 3 time points during pregnancy. The primary outcome was the STAI-S score at the final prenatal visit. A sample size of 50 patients was calculated to detect a 20% difference in the primary outcome. ResultsOf the 57 patients recruited, 50 completed the follow-up, 25 in each group. There were no significant differences in demographics between the groups. The primary outcome (STAI score at the last visit) was significantly lower in the device group compared to the control group (P=.037). In addition, the study group exhibited a greater reduction in STAI scores between the first and last visits (P=.045), and a significantly higher MAAS score at the end of the follow-up period (P=.046). ConclusionIntegrating routine home-ultrasound telemedicine visits into prenatal care can significantly reduce maternal anxiety during pregnancy and contribute to greater maternal attachment in individuals with a history of recurrent pregnancy loss. These results emphasize the potential benefits of home ultrasound as a tool to alleviate anxiety, provide a sense of control, and foster a deeper maternal connection among pregnant individuals who have experienced previous pregnancy loss.

Identifying digital biomarkers of illness activity and treatment response in bipolar disorder with a novel wearable device (TIMEBASE): protocol for a pragmatic observational clinical study.

Bipolar disorder is highly prevalent and consists of biphasic recurrent mood episodes of mania and depression, which translate into altered mood, sleep and activity alongside their physiological expressions. The IdenTifying dIgital bioMarkers of illnEss activity and treatment response in BipolAr diSordEr with a novel wearable device (TIMEBASE) project aims to identify digital biomarkers of illness activity and treatment response in bipolar disorder. We designed a longitudinal observational study including 84 individuals. Group A comprises people with acute episode of mania (n = 12), depression (n = 12 with bipolar disorder and n = 12 with major depressive disorder (MDD)) and bipolar disorder with mixed features (n = 12). Physiological data will be recorded during 48 h with a research-grade wearable (Empatica E4) across four consecutive time points (acute, response, remission and episode recovery). Group B comprises 12 people with euthymic bipolar disorder and 12 with MDD, and group C comprises 12 healthy controls who will be recorded cross-sectionally. Psychopathological symptoms, disease severity, functioning and physical activity will be assessed with standardised psychometric scales. Physiological data will include acceleration, temperature, blood volume pulse, heart rate and electrodermal activity. Machine learning models will be developed to link physiological data to illness activity and treatment response. Generalisation performance will be tested in data from unseen patients. Recruitment is ongoing. This project should contribute to understanding the pathophysiology of affective disorders. The potential digital biomarkers of illness activity and treatment response in bipolar disorder could be implemented in a real-world clinical setting for clinical monitoring and identification of prodromal symptoms. This would allow early intervention and prevention of affective relapses, as well as personalisation of treatment.

A retrospective study of the effects of a vasopressor bolus on systolic slope (dP/dt) and dynamic arterial elastance (Eadyn)

BackgroundTo enhance the utility of functional hemodynamic monitoring, the variables systolic slope (dP/dt) and dynamic arterial elastance (Eadyn) are calculated by the Hypotension Prediction Index (HPI) Acumen® Software. This study was designed to characterize the effects of phenylephrine and ephedrine on dP/dt and Eadyn.MethodsThis was a retrospective, non-randomized analysis of data collected during two clinical studies. All patients required intra-operative controlled mechanical ventilation and had an indwelling radial artery catheter connected to an Acumen IQ sensor. Raw arterial pressure waveform data was downloaded from the patient monitor and all hemodynamic measurements were calculated off-line. The anesthetic record was reviewed for bolus administrations of either phenylephrine or ephedrine. Cardiovascular variables prior to drug administration were compared to those following vasopressor administrations. The primary outcome was the difference for dP/dt and Eadyn at baseline compared with the average after the bolus administration. All data sets demonstrated non-normal distributions so statistical analysis of paired and unpaired data followed the Wilcoxon matched pairs signed-rank test or Mann-Whitney U test, respectively.Results201 doses of phenylephrine and 100 doses of ephedrine were analyzed. All data sets are reported as median [95% CI]. Mean arterial pressure (MAP) increased from 62 [54,68] to 78 [76,80] mmHg following phenylephrine and from 59 [55,62] to 80 [77,83] mmHg following ephedrine. Stroke volume and cardiac output both increased. Stroke volume variation and pulse pressure variation decreased. Both drugs produced significant increases in dP/dt, from 571 [531, 645] to 767 [733, 811] mmHg/sec for phenylephrine and from 537 [509, 596] to 848 [779, 930] mmHg/sec for ephedrine. No significant changes in Eadyn were observed.ConclusionBolus administration of phenylephrine or ephedrine increases dP/dt but does not change Eadyn. dP/dt demonstrates potential for predicting the inotropic response to phenylephrine or ephedrine, providing guidance for the most efficacious vasopressor when treating hypotension.Trial registrationData was collected from two protocols. The first was deemed to not require written, informed consent by the Institutional Review Board (IRB). The second was IRB-approved (Effect of Diastolic Dysfunction on Dynamic Cardiac Monitors) and registered on ClinicalTrials.gov (NCT04177225).

A digital volume pulse device-finger photo pulse plethysmography to trace the vascular integrity amongst the low back pain subjects with lumbar disc degenerative diseases diagnosed by MRI analysis.

Finger photo pulse plethysmography is a simple, inexpensive and non-invasive method for measurement of arterial stiffness. The objective is to assess the correlation of arterial stiffness in low back pain subjects with lumbar disc degeneration. Thirty-four back pain patients of both sexes in age group of 30-65 were included. Anthropometric measures like height, body weight, body mass index (BMI) were included. Stiffness index (SI) and reflection index (RI) were measured from the digital volume pulse waveform. There was a negative correlation between SI/RI and no correlation between SI and RI with BMI in both sexes. A significant correlation found between weight and BMI in both sexes. Arterial stiffness may not have any influence on disc degeneration. BMI showed some influence on disc degeneration and back pain.