The clinical applicability of sensor technology with body position detection to combat pressure ulcers in bedridden patients

Introduction: Pressure Ulcers (PUs) are a major healthcare issue leading to prolonged hospital stays and decreased quality of life. Monitoring body position changes using sensors could reduce workload, improve turn compliance and decrease PU incidence. Method: This systematic review assessed the clinical applicability of different sensor types capable of in-bed body position detection. Results: We included 39 articles. Inertial sensors were most commonly used (n = 14). This sensor type has high accuracy and is equipped with a 2–4 hour turn-interval warning system increasing turn compliance. The second-largest group were piezoresistive (pressure) sensors (n = 12), followed by load sensors (n = 4), piezoelectric sensors (n = 3), radio wave-based sensors (n = 3) and capacitive sensors (n = 3). All sensor types except inertial sensors showed a large variety in the type and number of detected body positions. However, clinically relevant position changes such as trunk rotation and head of bed elevation were not detected or tested. Conclusion: Inertial sensors are the benchmark sensor type regarding accuracy and clinical applicability but these sensors have direct patient contact and (re)applying the sensors requires the effort of a nurse. Other sensor types without these disadvantages should be further investigated and developed. We propose the Pressure Ulcer Position System (PUPS) guideline to facilitate this.</p

The clinical applicability of sensor technology with body position detection to combat pressure ulcers in bedridden patients

Introduction: Pressure Ulcers (PUs) are a major healthcare issue leading to prolonged hospital stays and decreased quality of life. Monitoring body position changes using sensors could reduce workload, improve turn compliance and decrease PU incidence. Method: This systematic review assessed the clinical applicability of different sensor types capable of in-bed body position detection. Results: We included 39 articles. Inertial sensors were most commonly used (n = 14). This sensor type has high accuracy and is equipped with a 2–4 hour turn-interval warning system increasing turn compliance. The second-largest group were piezoresistive (pressure) sensors (n = 12), followed by load sensors (n = 4), piezoelectric sensors (n = 3), radio wave-based sensors (n = 3) and capacitive sensors (n = 3). All sensor types except inertial sensors showed a large variety in the type and number of detected body positions. However, clinically relevant position changes such as trunk rotation and head of bed elevation were not detected or tested. Conclusion: Inertial sensors are the benchmark sensor type regarding accuracy and clinical applicability but these sensors have direct patient contact and (re)applying the sensors requires the effort of a nurse. Other sensor types without these disadvantages should be further investigated and developed. We propose the Pressure Ulcer Position System (PUPS) guideline to facilitate this.</p

Extending the Design Space of E-textile Assistive Smart Environment Applications

The thriving field of Smart Environments has allowed computing devices to gain new capabilities and develop new interfaces, thus becoming more and more part of our lives. In many of these areas it is unthinkable to renounce to the assisting functionality such as e.g. comfort and safety functions during driving, safety functionality while working in an industrial plant, or self-optimization of daily activities with a Smartwatch. Adults spend a lot of time on flexible surfaces such as in the office chair, in bed or in the car seat. These are crucial parts of our environments. Even though environments have become smarter with integrated computing gaining new capabilities and new interfaces, mostly rigid surfaces and objects have become smarter. In this thesis, I build on the advantages flexible and bendable surfaces have to offer and look into the creation process of assistive Smart Environment applications leveraging these surfaces. I have done this with three main contributions. First, since most Smart Environment applications are built-in into rigid surfaces, I extend the body of knowledge by designing new assistive applications integrated in flexible surfaces such as comfortable chairs, beds, or any type of soft, flexible objects. These developed applications offer assistance e.g. through preventive functionality such as decubitus ulcer prevention while lying in bed, back pain prevention while sitting on a chair or emotion detection while detecting movements on a couch. Second, I propose a new framework for the design process of flexible surface prototypes and its challenges of creating hardware prototypes in multiple iterations, using resources such as work time and material costs. I address this research challenge by creating a simulation framework which can be used to design applications with changing surface shape. In a first step I validate the simulation framework by building a real prototype and a simulated prototype and compare the results in terms of sensor amount and sensor placement. Furthermore, I use this developed simulation framework to analyse the influence it has on an application design if the developer is experienced or not. Finally, since sensor capabilities play a major role during the design process, and humans come often in contact with surfaces made of fabric, I combine the integration advantages of fabric and those of capacitive proximity sensing electrodes. By conducting a multitude of capacitive proximity sensing measurements, I determine the performance of electrodes made by varying properties such as material, shape, size, pattern density, stitching type, or supporting fabric. I discuss the results from this performance evaluation and condense them into e-textile capacitive sensing electrode guidelines, applied exemplary on the use case of creating a bed sheet for breathing rate detection

Development of a yarn capable of measuring localised temperature

In this research an electronic temperature sensor (ETS) yarn has been developed by embedding a commercially available thermistor chip into the fibres of a yarn. A polymer resin is used to encapsulate the thermistor creating a micro-pod which protects the thermistor from mechanical and chemical stresses during use, and also allows the ETS yarn to be washed. The thermistor micropod and interconnects were then encased within a warp knitted braid to from the ETS yarn. Temperature is the most widely measured physiological bio-marker in medicine. Temperature changes can indicate underlying pathologies such as wound infections or the formation of ulcers in diabetic patients. A temperature sensor capable of providing remote, continuous and localised (temperature at a given point) temperature measurements could provide clinicians with a powerful tool when handling such complications. Even though there are many flexible temperature sensors they lack true textile characteristics making them unsuitable in many situations. The existing textile-based temperature sensors are incapable of providing localised measurements and can suffer from hysteresis. At the start of the project a geometrical model of the ETS yarn was developed in-order to understand its design parameters. Then the crafting of the ETS yarn was achieved in three key stages. Hardware and software necessary to obtain temperature from the ETS yarn have been developed. Thereafter work has been conducted to characterise the behaviour of the thermistor and understand the design rules for the micro-pod. Theoretical models were created in COMSOL in-order to study the heat flow through the micro-pod and warp knitted braid, and the effect they have on the response and recovery times of the thermistor. The model has been validated using experiments. Results have shown that encapsulating the thermistor in a micro-pod and making it into a yarn has a minimal effect on the thermal time constant and that the resin of the micro-pod and fibres of the warp knitted braid have no significant impact on the accuracy of the temperature readings. The research into calibrating the ETS yarn has shown that the resistance-temperature conversion equation provided by the thermistor manufacturer provided the most accurate temperature measurement with 63 % of the readings being within ± 0.5 °C accuracy. Cyclic tests have been carried out on the ETS yarn to ensure that its performance is not effected by mechanical strain. Thereafter an evaluation of the response of the ETS yarn to operational conditions (ambient temperature, moisture content, wind speed) was studied. Finally, prototype temperature sensing garments have been produced using a network of ETS yarns. The necessary hardware and software to capture the temperature data from these prototypes has been developed. Finally, two prototypes have been created, a temperature sensing sock with five ETS yarn for detecting non-freezing cold injuries and a dressing with 16 ETS yarns to provide a temperature map of a wound. The temperature sensing sock was tested on volunteers. Both the wound dressing and the sock can provide remote, continuous and localised temperature measurements without compromising the textile characteristics of the fabric

The development of test procedures for controlling the quality of the manufacture of engineered compression stockings

A new technology platform known as 'Scan2Knit' was invented in the William Lee innovation Centre of the University of Manchester to engineer and manufacture compression stockings for the treatment of venous disease in a Welcome Trust funded research project. The intellectual property of the above technology has been licensed for commercial exploitation by the University.The graduated pressure profile that is necessary for the treatment of venous ulcers is generated with the engineered compression stocking, and will depend on the stitch length of the knitted fabric structure and an empirical pressure profile database. The 'Scan2Knit' technology was developed to produce an engineered compression stocking on a 18 gauge Stoll CMS computerised flat-bed knitting machine utilising a microprocessor controlled precision positive yarn delivery system to guarantee the delivery of a predetermined stitch length to the knitting needles. However, the licensee of the technology has decided to manufacture engineered compressions stockings by using 14 gauge Stoll CMS flat-bed knitting machines instead of gauge 18 machines due to commercial advantages. Therefore, the main aim of this work is to investigate the transfer of 'Scan2Knit' technology on to a coarse gauge manufacturing platform to produce engineered compression stockings. The investigation focuses on two vital requirements of 'Scan2Knit' technology; the analysis of the performance of the precision positive yarn delivery system on the new production platform and the evaluation of the functionality of the knitted structure produced with it. The objectives of the research are to develop test procedures for the evaluation of the three dimensional pressure characteristic of compression stockings manufactured on the new production platform, and the performance of the precision yarn delivery system. To produce the engineered compression stockings with the 'Scan2Knit' technology, it is essential to determine the interface pressure that the knitted structure would impart on a particular radius of curvature at a predetermined strain percentage which is attained with an empirical database. Hence, a key objective of this study is to develop a methodology, which is efficient and user friendly, for the generation of the empirical pressure profile database required to engineer the interface pressure profile of a compression stocking.It is envisioned that the manufacturer of the engineered compression stockings would benefit by the knowledge generated within this research, and develop their own quality assurance procedures to guarantee that the compression stockings are produced to deliver the graduated pressure profile prescribed by the clinician for the treatment of venous ulcers.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Smart Textiles Production

The research field of smart textiles is currently witnessing a rapidly growing number of applications integrating intelligent functions in textile substrates. With an increasing amount of new developed product prototypes, the number of materials used and that of specially designed production technologies are also growing. This book is intended to provide an overview of materials, production technologies, and product concepts to different groups concerned with smart textiles. It will help designers to understand the possibilities of smart textile production, so that they are enabled to design this type of products. It will also help textile and electronics manufacturers to understand which production technologies are suitable to meet certain product requirements

The Effects of Compression Wrapping Techniques and Primary Wound Dressings on Leg Skin Interface Pressure

Peripheral edema affects approximately 20% of people in the US over the age of 50 and is frequently encountered among individuals with conditions such as heart disease, prolonged immobility, and venous insufficiency.1 Compression is an established therapeutic tool utilized for the management of several chronic edema presentations including lymphedema and venous leg ulcers.2,3 Therapeutic efficacy of compressive applications can be evaluated by defining interface pressure (IP) and IP distributions associated with specific textile combinations.2 During compressive applications where an open wound is present, primary wound dressings should be used in combination with compressive wraps. Primary wound dressings provide a barrier and maintain a moist environment that promotes healing while compressive textiles applied over the primary wound dressing exert pressure on the wound and surrounding tissues. This pressure helps improve blood circulation and lymphatic drainage, reducing edema and promoting the delivery of oxygen and nutrients to the wounded area.4 This clinical study was conducted using 40 participants where each participant had three compressive textile combinations applied to their lower extremity. IP distribution data was collected for each textile combination immediately after application and following a brief exercise period. IP distributions resulting from the presence of primary wound dressings were evaluated in a separate benchtop study. Based on the results, the three compressive textile combinations evaluated in the clinical study and the three wound dressings evaluated in the benchtop study were shown to induce adequate amounts of pressure to improve circulation, promote wound healing, and reduce edema

Exploring Methods to Improve Pressure Ulcer Detection: Spectroscopic Assessment of the Blanch Response

Pressure damage in intact skin is difficult to detect, particularly in individuals with dark skin, because color changes and tissue blanching are masked by the skin's pigmentation. Tissue reflectance spectroscopy (TRS) may be able to detect the blanch response regardless of skin color by measuring the change in total hemoglobin (delta tHb) that occurs when pressure is applied to the skin. The objective of this dissertation was to examine the ability of TRS to detect the blanch response at sites at risk for pressure ulcer development in individuals with various levels of skin pigmentation. Three studies were conducted to address this objective. In Study 1, delta tHb was assessed at the heel and sacrum of light and dark-skinned healthy participants using a portable TRS system. Study 1 showed that a significant decrease (p less than 0.001) in tHb could be measured in both light and dark skinned-participants with good intra-rater reliability (ICC greater than or equal to 0.80) at the heel, but not at the sacrum. Study 2 was conducted to identify a reliable method of skin color description for use in subsequent studies of the spectroscopic blanch response. Two examiners (B and C) performed three skin color assessments at the volar forearm of ten healthy participants using Munsell color tile matching and colorimetry. Intra and inter-rater reliability was excellent for colorimetry (ICCs typically greater than or equal to 0.90). Reliability for Munsell color tile matching was highest for Munsell value within Examiner B (93% agreement, kappa 0.87-1.00), which was determined to be sufficiently high for use in subsequent studies. In Study 3, delta tHb was assessed at the heels of light, moderate, and dark-skinned elderly nursing home residents at risk for pressure ulcers. As in the pilot study, a significant decrease in tHb was observed in all skin color groups (p less than 0.05). Intra-rater reliability for delta tHb was moderate or greater (ICC greater than or equal to 0.61). In combination, the results of Study 1 and Study 3 demonstrated that a significant spectroscopic blanch response could be detected with moderate or greater intra-rater reliability at the heel regardless of age or pressure ulcer risk status