Assessing screw length impact on bone strain in proximal humerus fracture fixation via surrogate modelling.

A high failure rate is associated with fracture plates in proximal humerus fractures. The causes of failure remain unclear due to the complexity of the problem including the number and position of the screws, their length and orientation in the space. Finite element (FE) analysis has been used for the analysis of plating of proximal humeral fractures, but due to computational costs is unable to fully explore all potential screw combinations. Surrogate modelling is a viable solution, having the potential to significantly reduce the computational cost whilst requiring a moderate number of training sets. This study aimed to develop adaptive neural network (ANN)-based surrogate models to predict the strain in the humeral bone as a result of changing the length of the screws. The ANN models were trained using data from FE simulations of a single humerus, and after defining the best training sample size, multiple and single-output models were developed. The best performing ANN model was used to predict all the possible screw length configurations. The ANN predictions were compared with the FE results of unseen data, showing a good correlation (R2 = 0.99) and low levels of error (RMSE = 0.51%-1.83% strain). The ANN predictions of all possible screw length configurations showed that the screw that provided the medial support was the most influential on the predicted strain. Overall, the ANN-based surrogate model accurately captured bone strains and has the potential to be used for more complex problems with a larger number of variables.

Development and validation of a biomechanically fidelic surgical training knee model.

Knee arthroplasty technique is constantly evolving and the opportunity for surgeons to practice new techniques is currently highly dependent on the availability of cadaveric specimens requiring certified facilities. The high cost, limited supply, and heterogeneity of cadaveric specimens has increased the demand for synthetic training models, which are currently limited by a lack of biomechanical fidelity. Here, we aimed to design, manufacture, and experimentally validate a synthetic knee surgical training model which reproduces the flexion dependent varus-valgus (VV) and anterior-posterior (AP) mechanics of cadaveric knees, while maintaining anatomic accuracy. A probabilistic finite element modeling approach was employed to design physical models to exhibit passive cadaveric VV and AP mechanics. Seven synthetic models were manufactured and tested in a six-degree-of-freedom hexapod robot. Overall, the synthetic models exhibited cadaver-like VV and AP mechanics across a wide range of flexion angles with little variation between models. In the extended position, two models showed increased valgus rotation (<0.5°), and three models showed increased posterior tibial translation (<1.7 mm) when compared to the 95% confidence interval (CI) of cadaveric measurements. At full flexion, all models showed VV and AP mechanics within the 95% CI of cadaveric measurements. Given the repeatable mechanics exhibited, the knee models developed in this study can be used to reduce the current reliance on cadaveric specimens in surgical training.

A novel method to quantify breathing effort from respiratory mechanics and esophageal pressure.

Breathing effort is important to quantify to understand mechanisms underlying central and obstructive sleep apnea, respiratory-related arousals, and the timing and effectiveness of invasive or noninvasive mechanically assisted ventilation. Current quantitative methods to evaluate breathing effort rely on inspiratory esophageal or epiglottic pressure swings or changes in diaphragm electromyographic (EMG) activity, where units are problematic to interpret and compare between individuals and to measured ventilation. This paper derives a novel method to quantify breathing effort in units directly comparable with measured ventilation by applying respiratory mechanics first principles to convert continuous transpulmonary pressure measurements into "attempted" airflow expected to have arisen without upper airway obstruction. The method was evaluated using data from 11 subjects undergoing overnight polysomnography, including six patients with obesity with severe obstructive sleep apnea (OSA), including one who also had frequent central events, and five healthy-weight controls. Classic respiratory mechanics showed excellent fits of airflow and volume to transpulmonary pressures during wake periods of stable unobstructed breathing (means ± SD, r2 = 0.94 ± 0.03), with significantly higher respiratory system resistance in patients compared with healthy controls (11.2 ± 3.3 vs. 7.1 ± 1.9 cmH2O·L-1·s, P = 0.032). Subsequent estimates of attempted airflow from transpulmonary pressure changes clearly highlighted periods of acute and prolonged upper airway obstruction, including within the first few breaths following sleep onset in patients with OSA. This novel technique provides unique quantitative insights into the complex and dynamically changing interrelationships between breathing effort and achieved airflow during periods of obstructed breathing in sleep.NEW & NOTEWORTHY Ineffective breathing efforts with snoring and obstructive sleep apnea (OSA) are challenging to quantify. Measurements of esophageal or epiglottic pressure swings and diaphragm electromyography are useful, but units are problematic to interpret and compare between individuals and to measured ventilation. This paper derives a novel method that uses esophageal pressure and respiratory mechanics first principles to quantify breathing effort as "attempted" flow and volume in units directly comparable with measured airflow, volume, and ventilation.

Modelling the Effects of Growth and Remodelling on the Density and Structure of Cancellous Bone.

A two-stage model is proposed for investigating remodelling characteristics in bone over time and distance to the growth plate. The first stage comprises a partial differential equation (PDE) for bone density as a function of time and distance from the growth plate. This stage clarifies the contributions to changes in bone density due to remodelling and growth processes and tracks the rate at which new bone emanates from the growth plate. The second stage consists of simulating the remodelling process to determine remodelling characteristics. Implementing the second stage requires the rate at which bone moves away from the growth plate computed during the first stage. The second stage is also needed to confirm that remodelling characteristics predicted by the first stage may be explained by a realistic model for remodelling and to compute activation frequency. The model is demonstrated on microCT scans of tibia of juvenile female rats in three experimental groups: sham-operated control, oestrogen deprived, and oestrogen deprived followed by treatment. Model predictions for changes in bone density and remodelling characteristics agree with the literature. In addition, the model provides new insight into the role of treatment on the density of new bone emanating from the growth plate and provides quantitative descriptions of changes in remodelling characteristics beyond what has been possible to ascertain by experimentation alone.

Swept-Source OCT Mid-Peripheral Retinal Irregularity in Retinal Detachment and Posterior Vitreous Detachment Eyes.

Irregularities in retinal shape have been shown to correlate with axial length, a major risk factor for retinal detachment. To further investigate this association, a comparison was performed of the swept-source optical coherence tomography (SS OCT) peripheral retinal shape of eyes that had either a posterior vitreous detachment (PVD) or vitrectomy for retinal detachment. The objective was to identify a biomarker that can be tested as a predictor for retinal detachment. Eyes with a PVD (N = 88), treated retinal detachment (N = 67), or retinal tear (N = 53) were recruited between July 2020 and January 2022 from hospital retinal clinics in South Australia. The mid-peripheral retina was imaged in four quadrants with SS OCT. The features explored were patient age, eye axial length, and retinal shape irregularity quantified in the frequency domain. A discriminant analysis classifier to identify retinal detachment eyes was trained with two-thirds and tested with one-third of the sample. Retinal detachment eyes had greater irregularity than PVD eyes. A classifier trained using shape features from the superior and temporal retina had a specificity of 84% and a sensitivity of 48%. Models incorporating axial length were less successful, suggesting peripheral retinal irregularity is a better biomarker for retinal detachment than axial length. Mid-peripheral retinal irregularity can identify eyes that have experienced a retinal detachment.

Retinal Shape-Based Classification of Retinal Detachment and Posterior Vitreous Detachment Eyes.

INTRODUCTION: Retinal detachment is a sight-threatening emergency, with more than half of those affected suffering permanent visual impairment. A diagnostic test to identify eyes at risk before vision is threatened would enable exploration of prophylactic treatment. This report presents the use of irregularities in retinal shape, quantified from optical coherence tomography (OCT) images, as a biomarker for retinal detachment. METHODS: OCT images were taken from posterior and mid-peripheral retina of 264 individuals [97 after a posterior vitreous detachment (PVD), 99 after vitrectomy for retinal detachment and 68 after laser for a retinal tear]. Diagnoses were taken from history, examination and OCT. Retinal irregularity was quantified in the frequency domain, and the distribution of irregularity across the regions of the eye was explored to identify features exhibiting the greatest difference between retinal detachment and PVD eyes. Two of these features plus axial length were used to train a quadratic discriminant analysis classifier. Classifier performance was assessed by its sensitivity and specificity in identifying retinal detachment eyes and visualised with a receiver operating characteristic (ROC) curve. RESULTS: Validation set specificity was 84% (44/52 PVD eyes correctly labelled) and sensitivity 35% (23/64 retinal detachment eyes identified, p = 0.02). Area under the ROC curve was 0.75 (95% confidence intervals 0.58-0.85). Retinal detachment eyes were significantly more irregular than PVD eyes in the superior retina (0.70 mm versus 0.49 mm, p < 0.05) and supero-temporal retina (1.12 mm versus 0.80 mm, p < 0.05). Lower sensitivity (16/68, 24%) was seen for eyes with a retinal tear without detachment, that were intermediate in size between retinal detachment and PVD eyes. Axial length on its own was a poor classifier. Neither irregularity nor classification were affected by surgery for retinal detachment or the development of PVD. CONCLUSIONS: The classifier identified 1/3 of retinal detachment eyes in this sample. In future work, these features can be evaluated as a test for retinal detachment prior to PVD.

Predicting rupture locations of ascending aortic aneurysms using CT-based finite element models.

Accurate rupture risk assessment of ascending aortic aneurysms is important for reducing aneurysm-related mortality. More recently, computational models have been shown to better predict rupture risk than diameter-based measurements. However, it remains unclear whether finite element (FE) models of the ascending aorta can predict rupture location, and over what timeframe those predictions are reliable. The aim of this study was to evaluate FE models of the ascending aorta generated from computed tomography (CT) scans in predicting rupture location. Pre- and post-rupture CT scans were obtained of 12 patients who underwent emergency surgical repair for ascending aorta rupture with varying time intervals between scans (20 days - 6 years). A rigid iterative closest point (ICP) registration was used to overlay post-rupture aortic geometries with pre-rupture FE models and directly compare predicted regions of high equivalent strain with actual rupture. The FE model predicted the rupture location in the 5 patients with the shortest time intervals between the pre- and post-rupture scans (20 days - 2 years, 3 months). However, rupture location was not predicted in the 4/5 patients with greater than 3 years between scans. Achieving a physiological equivalent strain distribution in the FE model was highly dependent on the resolution of the pre-rupture scan and whether contrast agent was present. The results suggest there may be a time interval beyond which FE predictions of rupture location may not be reliable. The results in this study may help clinical validation of FE models of ascending aortic aneurysms predicting rupture risk.

Portable Colorimetric Device with Commercial Microplates for Quantitative Detection of Urine Biomarkers: Design, Development, and Clinical Evaluation.

Urine biomarkers are important in monitoring diseases related to human kidney function. The current processes for measuring biomarker levels in urine samples require patients to regularly visit clinical facilities, which is inconvenient and sometimes impossible for patients in rural areas. Therefore, portable analysis devices for the measurement of urine biomarkers are urgently requested. In this study, a portable platform using colorimetry, a common and simple-to-operate chemical analysis technique, was developed to measure urine biomarkers. The device, using commercial test kits as recognising reagents and a 96-well microplate as a solution container, provides quantitative measures of biomarker concentration. Moreover, the proposed device introduces a calibration method to minimise the dependence of regular maintenance. The device's performance was evaluated with urine from 73 renal patients and its results matched with clinical results well. The device has the potential for measuring urine creatinine, in addition to performing a variety of commercial assays for biomarker detection in human body fluids in general.

Relationships between tibial articular cartilage, in vivo external joint moments and static alignment in end-stage knee osteoarthritis: A micro-CT study.

Biomechanical factors (e.g., joint loading) have a significant role in the progression of osteoarthritis (OA). However, some relationships between in vivo joint loading indices and tibial cartilage thickness are conflicting. This study investigated relationships between pre-operative in vivo external knee joint moments, joint alignment and regional tibial cartilage thickness using micro-CT in subjects with end-stage knee OA. Tibial plateaus from 25 patients that underwent knee replacement for OA were micro-CT scanned (17 µm/voxel). Prior to surgery, subjects underwent gait analysis to calculate external knee moments. The mechanical axis deviation (MAD) was obtained from pre-operative radiographs. Cartilage thickness (Cart.Th) was analyzed from micro-CT images, in anteromedial, anterolateral, posteromedial and posterolateral subregions of interest. Medial-to-lateral Cart.Th ratios were also explored. Relationships between Cart.Th and joint loading indices were examined using Pearson's correlations. Significant correlations were found between Cart.Th and joint loading indices, positive anteromedially with the first peak knee adduction moment (r = 0.55, p < 0.01) and external rotation moment (ERM; r = 0.52, p < 0.01), and negative with MAD (r = -0.76, p < 0.001). In the lateral regions, these correlations had opposite signs. The medial-to-lateral Cart.Th ratio correlated strongly with ERM (r = 0.63, p = 0.001) and MAD (r = -0.75, p < 0.001). Joint loading indices correlated with regional cartilage thickness values and their medial-to-lateral ratios in end-stage knee OA subjects, with higher regional loads corresponding to thinner cartilage. These relationships have the opposite sign compared to the subchondral bone microarchitecture found in our previous study on the same specimens, which may suggest a complementary bone-cartilage interplay in response to loading.

Optical-Based Biosensors and Their Portable Healthcare Devices for Detecting and Monitoring Biomarkers in Body Fluids.

The detection and monitoring of biomarkers in body fluids has been used to improve human healthcare activities for decades. In recent years, researchers have focused their attention on applying the point-of-care (POC) strategies into biomarker detection. The evolution of mobile technologies has allowed researchers to develop numerous portable medical devices that aim to deliver comparable results to clinical measurements. Among these, optical-based detection methods have been considered as one of the common and efficient ways to detect and monitor the presence of biomarkers in bodily fluids, and emerging aggregation-induced emission luminogens (AIEgens) with their distinct features are merging with portable medical devices. In this review, the detection methodologies that use optical measurements in the POC systems for the detection and monitoring of biomarkers in bodily fluids are compared, including colorimetry, fluorescence and chemiluminescence measurements. The current portable technologies, with or without the use of smartphones in device development, that are combined with optical biosensors for the detection and monitoring of biomarkers in body fluids, are also investigated. The review also discusses novel AIEgens used in the portable systems for the detection and monitoring of biomarkers in body fluid. Finally, the potential of future developments and the use of optical detection-based portable devices in healthcare activities are explored.

Exaggerated ventilatory drive estimates from epiglottic and esophageal pressure deflections in the presence of airway occlusion.

Esophageal and epiglottic pressure deflections are widely used to quantify ventilatory effort during sleep in patients with obstructive sleep apnea (OSA). However, changes in upper airway patency will fundamentally alter pressure gradients across the respiratory system with different airflow and volume-dependent effects on esophageal versus epiglottic pressure. The magnitude of these obstruction effects on ventilatory effort assessed from pressure deflections has not been systematically investigated. This study sought to quantify the direct effect of airway occlusion on esophageal and epiglottic pressure deflections during sleep in patients with OSA compared with predictions based on classic respiratory mechanics. Pneumotachograph airflow and volume, and esophageal, epiglottic, mask, and gastric pressures were measured throughout a nonoccluded breath before and the first occluded breath after repeated external airway occlusions during sleep in 13 patients with OSA on constant positive airway pressure (CPAP). Inspiratory pressure deflections were approximately doubled with epiglottic pressure, and increased by around 40% with esophageal pressure on the occluded compared with the preoccluded breath. Differences in pressure between pre- and occluded breaths showed strong dependence on volume and flow, in line with theoretical models of respiratory mechanics. A relatively simple correction factor could account for these effects to provide more consistent measures of ventilatory effort from pressure, independent from measurement site and changing airflow conditions. These finding have important implications for interpreting ventilatory effort and arousal threshold measurements and for understanding the relationships between underlying ventilatory drive and pressure deflections in the presence of airway obstruction during sleep.NEW & NOTEWORTHY Esophageal and epiglottic pressure deflection measurements are widely used as gold-standard measures of ventilatory effort without consideration of differential obstruction effects between measurement sites. This study is the first to quantify the effect of airway occlusion on pressure recordings during sleep. The findings of substantial acute effects of occlusion itself on pressure deflections are important to consider in the planning, analysis, and interpretation of studies that make inferences regarding inspiratory effort.

Preliminary Analysis of a Wireless and Wearable Electronic-Textile EASI-Based Electrocardiogram.

Background: With cardiovascular disease continuing to be the leading cause of death and the primary reason for hospitalization worldwide, there is an increased burden on healthcare facilities. Electronic-textile (e-textile)-based cardiac monitoring offers a viable option to allow cardiac rehabilitation programs to be conducted outside of the hospital. Objectives: This study aimed to determine whether signals produced by an e-textile ECG monitor with textile electrodes in an EASI configuration are of sufficient quality to be used for cardiac monitoring. Specific objectives were to investigate the effect of the textile electrode characteristics, placement, and condition on signal quality, and finally to compare results to a reference ECG obtained from a current clinical standard the Holter monitor. Methods: ECGs during different body movements (yawning, deep-breathing, coughing, sideways, and up movement) and activities of daily living (sitting, sitting/standing from a chair, and climbing stairs) were collected from a baseline standard of normal healthy adult male using a novel e-textile ECG and a reference Holter monitor. Each movement or activity was recorded for 5 min with 2-min intervals between each recording. Three different textile area electrodes (40, 60, and 70 mm2) and electrode thicknesses (3, 5, and 10 mm) were considered in the experiment. The effect of electrode placement within the EASI configuration was also studied. Different signal quality parameters, including signal to noise ratio, approximate entropy, baseline power signal quality index, and QRS duration and QT intervals, were used to evaluate the accuracy and reliability of the textile-based ECG monitor. Results: The overall signal quality from the 70 mm2 textile electrodes was higher compared to the smaller area electrodes. Results showed that the ECGs from 3 and 5 mm textile electrodes showed good quality. Regarding location, placing the "A" and "I" electrodes on the left and right anterior axillary points, respectively, showed higher signal quality compared to the standard EASI electrode placement. Wet textile electrodes showed better signal quality compared to their dry counterparts. When compared to the traditional Holter monitor, there was no significant difference in signal quality, which indicated textile monitoring was as good as current clinical standards (non-inferior). Conclusion: The e-textile EASI ECG monitor could be a viable option for real-time monitoring of cardiac activities. A clinical trial in a larger sample is recommended to validate the results in a clinical population.

Tibial cartilage, subchondral bone plate and trabecular bone microarchitecture in varus- and valgus-osteoarthritis versus controls.

This preliminary study quantified tibia cartilage thickness (Cart.Th), subchondral bone plate thickness (SBPl.Th) and subchondral trabecular bone (STB) microarchitecture in subjects with varus- or valgus- malaligned knees diagnosed with end-stage knee osteoarthritis (OA) and compared them to controls (non-OA). Tibial plateaus from 25 subjects with knee-OA (undergoing knee arthroplasty) and 15 cadavers (controls) were micro-CT scanned (17 µm/voxel). Joint alignment was classified radiographically for OA subjects (varus-aligned n = 18, valgus-aligned n = 7). Cart.Th, SBPl.Th, STB bone volume fraction (BV/TV) and their medial-to-lateral ratios were analyzed in anteromedial, anterolateral, posteromedial and posterolateral subregions. Varus-OA and valgus-OA were compared to controls. Compared to controls (1.19-1.54 mm), Cart.Th in varus-OA was significantly lower anteromedially (0.58 mm, -59%) and higher laterally (2.19-2.47 mm, +60-63%); in valgus-OA, Cart.Th was significantly higher posteromedially (1.86 mm, +56%). Control medial-to-lateral Cart.Th ratios were around unity (0.8-1.1), in varus-OA significantly below (0.2-0.6) and in valgus-OA slightly above (1.0-1.3) controls. SBPl.Th and BV/TV were significantly higher medially in varus-OA (0.58-0.72 mm and 37-44%, respectively) and laterally in valgus-OA (0.60-0.61 mm and 32-37%), compared to controls (0.26-0.47 mm and 18-37%). In varus-OA, the medial-to-lateral SBPl.Th and BV/TV ratios were above unity (1.4-2.4) and controls (0.8-2.1); in valgus-OA they were closer to unity (0.8-1.1) and below controls. Varus- and valgus-OA tibia differ significantly from controls in Cart.Th, SBPl.Th and STB microarchitecture depending on joint alignment, suggesting structural changes in OA may reflect differences in medial-to-lateral load distribution upon the tibial plateau. Here we identified an inverse relationship between cartilage thickness and underlying subchondral bone, suggesting a whole-joint response in OA to daily stimuli.

The relationship between tibiofemoral geometry and musculoskeletal function during normal activity.

BACKGROUND: The effect of tibiofemoral geometry on musculoskeletal function is important to movement biomechanics. RESEARCH QUESTION: We hypothesised that tibiofemoral geometry determines tibiofemoral motion and musculoskeletal function. We then aimed at 1) modelling tibiofemoral motion during normal activity as a function of tibiofemoral geometry in healthy adults; and 2) quantifying the effect of tibiofemoral geometry on musculoskeletal function. METHODS: We used motion data for six activity types and CT images of the knee from 12 healthy adults. Geometrical variation of the tibia and femoral articular surfaces were measured in the CT images. The geometry-based tibiofemoral motion was calculated by fitting a parallel mechanism to geometrical variation in the cohort. Matched musculoskeletal models embedding the geometry-based tibiofemoral joint motion and a common generic tibiofemoral motion of reference were generated and used to calculate joint angles, net joint moments, muscle and joint forces for the six activities analysed. The tibiofemoral model was validated against bi-planar fluoroscopy measurements for walking for all the six planes of motion. The effect of tibiofemoral geometry on musculoskeletal function was the difference between the geometry-based model and the model of reference. RESULTS: The geometry-based tibiofemoral motion described the pattern and the variation during walking for all six motion components, except the pattern of anterior tibial translation. Tibiofemoral geometry had moderate effect on cohort-averages of musculoskeletal function (R2 = 0.60-1), although its effect was high in specific instances of the model, outputs and activities analysed, reaching 2.94 BW for the ankle reaction force during stair descent. In conclusion, tibiofemoral geometry is a major determinant of tibiofemoral motion during walking. SIGNIFICANCE: Geometrical variations of the tibiofemoral joint are important for studying musculoskeletal function during normal activity in specific individuals but not for studying cohort averages of musculoskeletal function. This finding expands current knowledge of movement biomechanics.

Dermal thickness and echogenicity using DermaScan C high frequency ultrasound: Methodology and reliability testing in people with and without primary lymphoedema.

BACKGROUND: DermaScan C high frequency ultrasound was investigated for image capture and analysis of dermal measures in people with and without primary lymphoedema. METHOD: Three repeated images were taken at six sites in people without lymphoedema (NLO). Intra-rater reliability was assessed by taking three sets of measures on images from 10 people and inter-session reliability by capturing three images, lifting the probe from the skin in between. Methods were adjusted, and repeated images from four sites were taken in people with primary lymphoedema (PLO) and reliability re-assessed. RESULTS: Intra-rater reliability in NLO and PLO for echogenicity measures were excellent (NLO ICC(3,1) : .989; PLO .997) across all sites and specific to each site (calf: ICC(3,1) : .989; and foot: ICC(3,1) : .999, respectively). Inter-session reliability was moderate for NLO (ICC(3,1) : .727), improving after method modifications for PLO (ICC(3,1) : .916). When investigated by site, inter-session reliability was good in the foot (ICC(3,1) : .811) and moderate in the calf (ICC(3,1) : .616). Mean thickness analysed by site resulted in good inter-session reliability only in the foot (ICC(3,1) .838). CONCLUSION: Intra-rater reliability was excellent using the DermaScan C for dermal measures in people with primary lymphoedema. Inter-session reliability required particular attention to method and gain settings.

Safety and Clinical Outcomes of Hospital in the Home.

OBJECTIVES: The aim of the study was to evaluate clinical outcomes and adverse events (AEs) experienced by patients treated within the Hospital in the Home (HITH) service of a major metropolitan hospital in South Australia. METHODS: A retrospective case note audit of 100 HITH episodes among adults who received continuous intravenous antimicrobial therapy via an elastomeric or electronic infusion device was undertaken. Age- and sex-adjusted binomial logistic regression analyses were undertaken to identify factors associated with major and minor AEs. RESULTS: Of the 100 patients included, 71 were male and the mean (SD) patient age was 62.8 (17.19) years. Elastomeric infusion devices were used for 98 patients. The mean (SD) HITH treatment duration was 20.1 (11.9) days. Overall, 130 AEs were documented for 72 patients (72%), of whom 12 patients experienced a major AE and 68 patients experienced a minor AE. There were 45 occasions among 23 patients where an infusion administered through an elastomeric device did not run to completion. Fifteen patients were readmitted to hospital. Minor AEs were more likely among people with more vascular line days (adjusted odds ratio [aOR] = 1.05; 95% confidence interval (CI) = 1.01-1.10 per day increase) and females (aOR = 4.43; 95% CI = 1.14-17.17). An increased number of vascular line days was associated with an increased likelihood of an incomplete infusion (aOR = 1.05; 95% CI = 1.01-1.09). Hospital readmission was more likely with increasing age (aOR = 1.06; 95% CI = 1.01-1.11 per year increase). CONCLUSIONS: Adverse events need to be monitored carefully when HITH treatment is provided for extended periods.

Electronic textile-based electrocardiogram monitoring in cardiac patients: a scoping review.

OBJECTIVE: The objectives of this scoping review were to explore, organize and present the existing research literature on the use of electronic textile (e-textile)-based resting, signal-averaged, ambulatory or exercise electrocardiogram (ECG) monitoring to evaluate the application of e-textile technologies for ECG cardiac monitoring. INTRODUCTION: E-textile-based ECG monitoring of cardiac patients offers a possible new alternative for in-hospital monitoring and post-discharge monitoring during cardiac rehabilitation. INCLUSION CRITERIA: Studies that included patients (inpatients or outpatients) who qualified for cardiac rehabilitation programs or continuous ambulatory ECG monitoring were considered. The key concepts that were addressed included resting, signal-averaged, ambulatory or exercise ECG monitoring based on e-textile technologies or e-textile-based cardiac rehabilitation. Studies were excluded if they focused only on specific aspects of the e-textile ECG system rather than a complete ECG system. METHODS: Research reports, dissertations or books that evaluated e-textile-based ECG monitoring of cardiac patients in a hospital or at home, written in English, and published between January 2000 and March 2018 were considered for inclusion. Published and unpublished literature was located through databases including Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed Central (PMC), Institute of Electrical and Electronics Engineers (IEEE Xplore), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Database of Systematic Reviews, Web of Science, Scopus, Expanded Academic ASAP, ProQuest Dissertations and Theses Global, SPORTDiscus, and ENGINE-Australian Engineering Database (Informit). Two independent reviewers screened citations for inclusion while the third reviewer resolved any discrepancies. Meta-data from each study were extracted, and a narrative summary was used to present the results. Furthermore, 38 study authors were contacted to request missing or additional data as required, with 16 responding within eight weeks. RESULTS: Of the 207 studies that were eligible for full-text review, only 8% (n = 17) were included in the final study. Eighty-eight percent (n = 15) of included studies were conducted with an adult population, and 11 studies reported an in-hospital application. Only three groups of researchers reported e-textile integration beyond the textile electrodes, mostly in the form of wiring and custom-made printed circuit boards. Eight studies utilized two ECG sensors, while single-lead ECG was the most common configuration, used in 10 studies. ECG result was the primary parameter reported across the included studies. Resting ECG was the most common form of ECG acquired (n = 10), followed by exercise ECG (n = 6) and ambulatory ECG (n = 5). Eight studies addressed the issue of power requirements, and seven studies used Bluetooth for wireless communication. The primary problem reported across all studies was noise from motion artifact. CONCLUSIONS: The recent advances in signal quality and noise reduction for e-textile-based ECG applications are promising. However, the use of a 12-lead, personalized, home-based cardiac rehabilitation monitor system containing fully textile-integrated electronics with diagnostic capability is yet to be reported. Therefore, there is potential for future research in this area. Additionally, motion artifact continues to be a challenge.

A Modular Hybrid Exoskeletal-Soft Glove for High Degree of Freedom Monitoring Capability.

In this paper, we present a hybrid exoskeletal-soft glove for the application of on-axis angle sensors that can be placed close to the center of rotation of the digit joints. 3D printed exoskeletal digit segments that run medially on most digits connect to low friction bearings. Exoskeletal segments and bearings provide rigid fixation points for a variety of traditional angle sensors, while a combination of textile and rigid structure fixate exoskeletal digits to the digits and hand. Exoskeletal digits are designed modularly so that only required digits are used and to reduce difficulty in donning and doffing. On-axis measurement may prove useful in control or assessment tasks in rehabilitation. The articulation of the digits while wearing the glove is demonstrated, albeit without sensors, showing little restriction at an early stage of the design process. Exoskeletal metacarpophalangeal joints of the 3rd and 4th digits require more work as the flexion/extension joint axis is inaccessible and moves when he digits are articulated. The proposed device must be customized for an individual and will facilitate an alternative approach to existing hand posture monitoring techniques.

Flow rate accuracy of ambulatory elastomeric and electronic infusion pumps when exposed to height and back pressures experienced during home infusion therapy.

Background: Elastomeric infusion pumps are widely used in the delivery of parenteral medications in the home, but real-life conditions may not match calibration or standardised testing conditions. This study investigated the impact of changes in infusion pump height and/or back pressure on infusion pump function. Methods: Volume delivered after one day, infusion duration, average and peak flow rates and time spent within stated accuracy were determined for four elastomeric and one electronic pump using gravimetric technique. Experiments were repeated after altering the height of the pump relative to the output (±40cm, ±20cm) and/or adding a back pressure (10-30mmHg) to the output of an attached catheter. Results: Under ideal operating conditions, the flow rate deviated from that specified by the manufacturer and between 88.5% and 99% of the total infusion volume was delivered. Varying the height or applying back pressure led to further changes in average flow rates and the volume of infusion solution delivered by the elastomeric pumps, but had little effect on the electronic pump. Conclusions: Clinicians should consider potential impact on drug delivery, safety and therapeutic effect for home infusion patients given variations in infusion pump performance observed in this study.

Quantification of human bone microarchitecture damage in press-fit femoral knee implantation using HR-pQCT and digital volume correlation.

Primary press-fit fixation of femoral knee prostheses is obtained thanks to the inside dimensions of the implant being undersized with respect to the bone cuts created intra-operatively, dictated by a press-fit specified by the implant design. However, during prostheses press-fit implantation, high compressive and shear stresses at the implant-bone interface are generated, which causes permanent bone damage. The extent of this damage is unknown, but it may influence the implant stability and be a contributing factor to aseptic loosening, a main cause of revisions for knee arthroplasty. The aim of this ex-vivo study was to quantify, using high-resolution peripheral quantitative computed tomography (HR-pQCT) imaging and Digital Volume Correlation (DVC), permanent bone deformation due to press-fit femoral knee implantation of a commonly used implant. Six human cadaveric distal femora were resected and imaged with HR-pQCT (60.7 µm/voxel, isotropic). Femurs were fitted with cementless femoral knee implants (Sigma PFC) and rescanned after implant removal. For each femur, permanent deformation was examined in the anterior, posterior-medial and posterior-lateral condyles for volumes of interest (VOIs) of 10 mm depth. The bone volume fraction (BV/TV) for the VOIs in pre- and post-implantation images was calculated, at increasing depth from the bone surface. DVC was applied on the VOIs pre- and post-implantation, to assess trabecular bone displacements and plastically accumulated strains. The "BV/TVpost/BV/TVpre ratio vs. depth" showed, consistently among the six femurs, three consecutive points of interest at increasing bone depth, indicating: bone removal (ratio<100%), compaction (ratio>100%) and no changes (ratio = 100%). Accordingly, the trabecular bone displacement computed by DVC suggested bone compaction up to 2.6 ±â€¯0.8 mm in depth, with peak third principal strains of -162,100 ±â€¯55,000 µÎµ (mean absolute error: 1,000-2,000 µÎµ, SD: 200-500 µÎµ), well above the yield strain of bone (7,000-10,000 µÎµ). Combining 3D-imaging, at spatial resolutions obtainable with clinical HR-pQCT, and DVC, determines the extent of plastic deformation and accumulated compressive strains occurring within the bone due to femoral press-fit implantation. The methods and data presented can be used to compare different implants, implant surface coatings and press-fit values. These can also be used to advance and validate computational models by providing information about the bone-implant interface obtained experimentally. Future studies using these methods can assist in determining the influence of bone damage on implant stability and the subsequent osseointegration.