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Control of air-cell mattress for preventing pressure ulcer based on approximate anthropometric model
Abstract
Air mattress is now used widely to prevent the pressure ulcer by reducing the localized pressure peaks. In this paper an air-cell mattress and its pressure control method based on an approximate anthropometric model are presented. The air-cell mattress has eighteen cylindrical air cells made of porous material allowing air leakage to contribute in reducing the development of pressure ulcer by lowering the pressure peak, temperature and humidity. To determine an optimal air-cell pressure appropriate for each user, we divide the parts of the body into four sections such as head, trunk, hip, and leg. Then, the pressure of each section is independently calculated from the weight of each part based on the individual body height and weight and the approximate anthropometric model. Air supply system for the air-cell mattress is implemented by using four electronic solenoid valves and an air compressor, and it is driven by a real-time micro-controller. The experimental results for seven subjects shows that the proposed air-cell mattress is effective for the prevention of the pressure ulcer.
... pressures [15], [31], while others monitor and distribute pressure across large regions of the body [29]. Similarly in the academic literature, Moon et al. [33] developed an air mattress consisting of 18 air tubes where the mattress was divided into four main sections including the head, trunk, hip, and legs and the pressure in each section was controlled to be less than 32 mmHg. However, it was unclear if it was possible to select specific sites (e.g., not across large body areas) to offload the pressure. ...
... A few research studies have attempted to monitor different risk factors associated with PUs such as pressure [41], [69]- [85], temperature [111], [112], humidity [113], blood flow [114], or a combination [33], [57], [115]- [123] to alert healthcare professionals if the individual is at the risk of developing a PU [124]. Some of these studies have used machine learning (ML) and artificial intelligence (AI) techniques to either detect/classify patient's posture and identify pressure distribution under the body, or perform ulcer tissue classification using image processing techniques and identify ulcer severity [125] which are further described in the following. ...
... z hip, and the legs. For each body part, we use the anthropometric data given in [33] ...
Patients with limited body movement ability are subject to the development of pressure ulcers (PUs), especially when confined to a bed. Pressure relief and frequent repositioning help to mitigate complications associated with PUs. Manually moving a patient is a physically-demanding task that can lead to musculoskeletal disorders for the caregivers and skin abrasion for patients. The first study in this thesis reviewed devices (commercially-available or published research) that are meant to address patient pressure relief, repositioning and/or transfer while in a bed. The review findings indicated that current technologies have limitations such as design complexity, high cost, bulkiness, unidirectional patient transfer, and the need for a caregiver’s intervention.
Inspired by waves in nature such as water waves that can carry objects, a proposed solution in the literature for patient transfer is to create traveling ways on a bed surface for multidirectional
patient transfer and to minimize the caregiver’s physical effort for constant patient readjustment on the bed. Inspired by this idea, the second study in this thesis built upon prior work in the literature and presented the design requirements for moving a human body using traveling waves on a bed surface. Particularly, through kinematic analysis and simulation of traveling waves, this study explored how various wave parameters such as the wavelength, amplitude, frequency, and number of wave-generating actuators would affect human transportation speed and movement
smoothness. Results are summarized into a set of design guidelines for the development of actuation systems to physically realize a traveling wave that can move a body on a bed.
... According to the design requirements and the national standard of adult body dimensions in China, the body dimensions of standing and sitting posture of P5, P50, P95, and P99 are for men aged 36 to 60 years and females aged 36 to 55 years. e physiological status of the elderly changes significantly with age [27], such as loss of height and weight [28]. At present, research on body dimensions of the elderly has not been widely conducted in China; and since body dimensions of the elderly tend to stabilize after reaching the age of 65 [29], there is no need for further subdivision of body dimensions of the elderly. ...
... Based on the study of a standard human mannequin by D.A. Winter [30] and the study of general human body measurement data by Inhyuk Moon [28] and others using an approximate mannequin, in this design, the human body is divided into five parts: head, shoulder and back, waist and hip, legs, and feet, i.e., i � head, shoulder and back, waist and hip, legs, and feet. w i A i can be calculated from anthropometric data and approximate mannequin data, so the body pressure P i of the i part of the body can be Computational Intelligence and Neuroscience 7 minimized by increasing w i . ...
Pressure ulcers are a type of injury that causes tissue ischemia, a deficiency of nutrition and oxygen to the tissues, and, eventually, tissue necrosis when an area of skin is placed under constant pressure for an extended length of time. With the acceleration of the aging process, the problem of providing care for pressure ulcers for the bedridden elderly becomes increasingly urgent. This study conducts a field survey based on the research status of 221 disabled elderly in 16 communities on 7 typical streets in Beijing, focusing on the problem of pressure ulcer complications caused by bedridden. An automatic inflatable airbag mattress is designed according to anthropometric dimensions of bedridden elderly, pressure ulcer-prone areas, and the decompression standard, so that the airbag mattress can reduce the pressure in its initial shape. To achieve accurate control of the pressure in the pressure-prone areas of an airbag, air pressure control system is proposed which can control airbags individually and link multiple airbags, evaluating the safety of pressure ulcer points based on the data from sensors and making corresponding air pressure changes to reduce the possibility of generating pressure ulcers. The proposed pressure ulcer preventing system will be an efficient healthcare tool for families who had elderly bedridden patients, patients with chronic degenerative disease side effects, and terminal and postsurgical patients, as well as femur fractures, in their homes.
... Ways to manage the development of pressure ulcers are not new to healthcare providers. Risk factors for developing pressure ulcers are divided into intrinsic and Healthcare 2021, 9,1701 2 of 9 extrinsic [6]. While intrinsic factors are hard to manage mechanically due to the fact they lie within the body, extrinsic factors are often dealt with mechanically. ...
... Bedsore wound management and prevention has been under the scope of researchers and scientists; due to this fact, multiple solutions have been developed. Mechanical or pneumatic tools emerged to aid healthcare practitioners such as mattresses and overlays that are divided into different design cells filled with gas or water [9,10] cushions designed on anatomical bases [11] and wedges to support limbs [12]; or a combined dynamic system of electrical sensors and mechanical components [13,14]. According to Marchione et al. 2015, the most used techniques to prevent and manage pressure ulcers are by monitoring pressure. ...
Bedsores, also known as pressure ulcers, are wounds caused by the applied external force (pressure) on body segments, thereby preventing blood supply from delivering the required elements to the skin tissue. Missing elements hinder the skin’s ability to maintain its health. It poses a significant threat to patients that have limited mobility. A new patented mattress design and alternative suggested designs aimed to reduce pressure are investigated in this paper for their performance in decreasing pressure. A simulation using Ansys finite element analysis (FEA) is carried out for comparison. Three-dimensional models are designed and tested in the simulation for a mattress and human anthropometric segments (Torso and Hip). All designs are carried out in solidworks. Results show that the original design can redistribute the pressure and decrease it up to 17% less than the normal mattress. The original design shows better ability to decrease the absolute amount of pressure on the body. However, increasing the surface area of the movable parts results in less pressure applied to the body parts. Thus, this work suggests changing the surface area of the cubes from 25 to 100 cm2.
... Therefore, to prevent pressure ulcers, it is necessary to measure, monitor and evaluate the pressure incident on the patient [5,6]. Hence, in previous research, an alternative pressure mattress that can reduce the pressure on a patient by measuring and controlling it was proposed [7,8]. ...
... In previous research, operation algorithms of the alternative pressure mattress that can reduce the pressure on a patient were proposed. For example, Moon et al. [8] proposed a method to reduce the pressure by maximizing the supporting surface using the body height and weight of the patient. Misaki et al. [7] proposed a method to prevent the concentration of pressure by adjusting the air cells according to the site-specific body pressure data, making the bed surface fit the supine position of the patient. ...
Pressure ulcers are caused by tissue damage, which occurs when the blood supply to an area of skin is diminished because of sustained or concentrated pressure on a patient from the mattresses of a bed. One action that concentrates the pressure is a bed head elevation operation. Recently, a control system known as the alternative pressure mattress has been proposed to prevent the concentration of pressure. However, the challenge with this controlled system is that it has a slow response because it uses air cells. The slow response causes controlling the air cells to lag behind the change in pressure during the bed head elevation operation. Therefore, this system cannot adequately prevent the concentration of pressure on a patient. To address this issue, we need to predict the change in pressure during the bed head elevation operation and control the pressure based on this prediction. In the current work, we focus on predicting the pressure distribution. This prediction is high-dimensional. We regarded the pressure distribution as an image and predicted the change in pressure by applying a deep neural network. To the best of our knowledge, this paper is the first to propose the body pressure predictive model.
... Bu çalışmada sunulan matematiksel modelin doğruluğunun değerlendirilebilmesi amacıyla bir insan vücudunun farklı bölgelerine göre basınç, nem, sıcaklık ve ıslaklık değerleri aşağıda verildiği gibi rastgele üretilmiştir. Tablo 2'de gösterilen basınç değerleri, [16]' daki örnek basınç değerleri baz alınarak hesaplanmıştır. [16]' da insan vücudu 4 bölümde incelemiş, her bir bölüm için yüzey alanı ve ağırlık katsayılarına göre denekler üzerinde baş, sırt, gövde ve bacaklar için basınç değerleri hesaplanmıştır. ...
... Tablo 2'de gösterilen basınç değerleri, [16]' daki örnek basınç değerleri baz alınarak hesaplanmıştır. [16]' da insan vücudu 4 bölümde incelemiş, her bir bölüm için yüzey alanı ve ağırlık katsayılarına göre denekler üzerinde baş, sırt, gövde ve bacaklar için basınç değerleri hesaplanmıştır. Ayrıca bu çalışmada önerilen ıslaklığın etkisinin detaylı olarak gösterilebilmesi için Şekil 6'da yer alan grafik çizilmiştir. ...
Basınç ülseri, yatan hastalarda hareketsizlikten dolayı oluşan yaraya denilmektedir. Tüm dünyada yatan hastaları tehdit eden ciddi bir sorundur. İleri boyutlara gelindiğinde tedavisi imkansız hale gelmektedir. Bu nedenle basınç ülserinin önlenmesi için çalışmalar yapılmaktadır. Bu çalışmada, yatak yaralarının önlenmesi veya oluşumunun geciktirilmesi amacıyla yara oluşmasında etkili olan basınç, nem ve sıcaklık parametrelerinin yanı sıra ıslaklık parametresi de göz önünde bulundurularak bir şilteye ait matematiksel model geliştirilmiştir. Geliştirilen matematiksel model ve simülasyondan elde edilen veriler kullanılarak her bir şilte hücresi için yatak yarası oluşma riski hesaplanmıştır. Bu model sayesinde ülkemizde önemli bir sağlık problemi olan basınç ülserlerinin önlenmesine katkı sağlanması ve bu sayede hastaların basınç ülserlerine bağlı hastanede yatma sürelerinin kısaltılması hedeflenmektedir. Abstract-Pressure ulcers are called contusion caused by inactivity of hospitalized patients. It is a serious problem that threatens hospitalized patients all over the world. When it reaches advanced size, its treatment becomes impossible. Therefore, studies are conducted for the prevention of pressure ulcers. In this study, in order to prevent or delay the formation of pressure ulcers, a mathematical model based on not only the pressure, moisture and temperature parameters but also on the wetness was developed. Using developed mathematical model and the data obtained from a performed simulation, the risk of bed sores for each cell of the mattress was calculated. With the help of this model we aimed to, contribution to the works about prevention of pressure ulcers that is an important health problem in our country and also to reduce the time of stay in the hospital that depends on pressure ulcers.
... Evaluation of interface pressure on pressure ulcers prevention with pressure sensors [12] proved that body turning or repositioning, either voluntarily [17] or based on continuous pressure measurements, could reduce the risks of developing pressure ulcers. Air-filled mattresses [29] are commonly used for relieving applied pressure on the body and have been shown effective [30]. However, the actuation (filling/releasing air) is typically performed either randomly or based on a simplified human model [29]. ...
... Air-filled mattresses [29] are commonly used for relieving applied pressure on the body and have been shown effective [30]. However, the actuation (filling/releasing air) is typically performed either randomly or based on a simplified human model [29]. It does not determine the potential risk locations associated with a lying posture or the risk of developing pressure ulcers at those locations. ...
Pressure ulcers are a common problem among patients with limited mobility, such as those bed-bound and wheelchair-bound. Constant and prolonged applied pressure is one of the extrinsic factors contributing to the development of pressure ulcers. Analyzing lying postures together with interface pressure measurements from a pressure sensitive bed helps revealing pressure hot spots that can potentially lead to pressure ulcer development. We propose an intelligent system that features lying posture classification with pressure hot spots identification based on interface pressure measurements to possibly identify potential pressure ulcer risk and to provide effective preventive measures. Experimental outcomes correctly classify different lying postures with an accuracy of up to 93%. The proposed system is expected to assist caregivers to detect risk evidence and to provide timely and appropriate interventions for effective pressure ulcer prevention.
... To distribute pressure and alleviate the risk of pressure ulcers, proper positioning of the patient or the use of an overlay, such as an Alternating Pressure Air Mattress (APAM) or seat cushion, is necessary. These commercially available devices feature air cells that inflate and deflate, effectively redistributing pressure [6][7][8][9][10][11]. However, these devices operate based on the present system defined by the manufacturer and lack the ability to sense high-pressure areas. ...
Patients who are unable to help themselves and sleep on a regular mattress face an increased risk of pressure ulcers, especially elderly and bedridden patients. The external contact pressure on the mattress can lead to injuries when blood pressure exceeds that of the capillaries, disrupting blood supply to the capillary network and resulting in pressure ulcers. This occurs due to inadequate force distribution and poor air circulation between the skin and the mattress. This research focuses on developing an intelligent air mattress prototype based on commercially available alternating pressure air mattresses to prevent pressure ulcers. Force-sensitive resistors (FSRs) are installed under each air cell to measure interface pressure values occurring at different parts of the body. These collected values are then used to create pressure maps, indicating areas of high overpressure. The prototype incorporates a smart pneumatic control system divided into seven functional areas: head, back, waist, buttocks, thighs, calves, and heels. All operations are performed using LabVIEW software. Furthermore, all instruments have been calibrated and verified. To obtain the optimal pattern for cell expansion, inflation times in each cell were experimentally adjusted using a human model before conducting real human trials. Attention was primarily given to adjusting the growth rate in the back, buttocks, and calves, as these areas experience higher pressure compared to other parts of the body.
... To improve sleep quality, various mattresses have been designed in existing studies [25][26][27]. In a few studies, a thermal controlling device was applied to the developed mattress to improve the sleep quality of the users [28][29][30][31]; others studies have determined the relation between sleep quality and the rigidity of a mattress [27,32,33]. Furthermore, several studies have varied the materials used to design the mattress and have modified its structure [34][35][36]. ...
Several studies, wherein the structure or rigidity of a mattress was varied, have been conducted to improve sleep quality. These studies investigated the effect of variation in the surface characteristics of mattresses on sleep quality. The present study developed a mattress whose rigidity can be varied by controlling the amount of air in its air cells. To investigate the effect of the variable rigidity of the air mattress on sleep quality, participants (Male, Age: 23.9 ± 2.74, BMI: 23.3 ± 1.60) were instructed to sleep on the air mattress under different conditions, and their sleep quality was subjectively and objectively investigated. Subjectively, sleep quality is assessed based on the participants’ evaluations of the depth and length of their sleep. Objectively, sleep is estimated using the sleep stage information obtained by analysing the movements and brain waves of the participants during their sleep. A subjective assessment of the sleep quality demonstrates that the participants’ sleep was worse with the adjustment of the air mattress than that without; however, the objective sleep quality results demonstrates an improvement in the sleep quality when the rigidity of the air mattress is varied based on the participant’s preference. This paper proposes a design for mattresses that can result in more efficient sleep than that provided by traditional mattresses.
... Excessive pressure between human buttock and seating surface is generally recognized as the principal cause of the occurrence of PUs [8]. IP involves mapping using sensors to quantify the pressure between two contacting objects, such as a person and their support surface. ...
... Excessive pressure between human buttock and seating surface is generally recognized as the principal cause of the occurrence of PUs [8]. IP involves mapping using sensors to quantify the pressure between two contacting objects, such as a person and their support surface. ...
... If this pressure is continued it can cause tissue necrosis [7].The factors causing PU is complex phenomenon and according to various researchers, they mainly include the pressure under bony prominences, shear forces, temperature, moisture, nutrition, seating position and daily life routine [8][9][10]. Excessive pressure between human buttock and seating surface is generally recognized as the principal cause of the occurrence of PUs [11]. IP involves mapping using sensors to quantify the pressure between two contacting objects, such as a person and their support surface. ...
IDENTIFYING LOCATION OF MAXIMUM INTERFACE PRESSURE IN BEDRIDDEN PATIENT –A COMPARATIVE STUDY, www.ijates.com Volume No.03, Special Issue No. 02, February 2015 ISSN (online): 2348 – 7550 ,P a g e 113-121
... Interface pressure involves mapping using sensors to quantify the pressure between two contacting objects, such as a person and their support surface. It is commonly used by clinicians and by researchers investigating the surface, risk factors for ulceration and ulcer prevention protocols [5], [6]. Fredrick Shelton [7] com-pared different surfaces for elderly people (65-70 years) mannequins with Tekson 5315 system in his test. ...
Patients who have limited body movement ability need assistance with frequent repositioning and transfers from their caregivers. These common manual tasks are physically strenuous for caregivers. To minimize caregiver physical effort, several assistive devices have been proposed. However, most devices have complex designs, are expensive, can only move the patient in one direction, or still need the caregiver's intervention. Inspired by natural waves such as water waves that can carry objects, this study presents actuator-agnostic design guidelines for moving a body on a bed surface using traveling waves as an alternative solution. Specifically, this study explores how transportation speed and movement smoothness are affected by wave parameters such as the wavelength, wave amplitude, number of the actuators used to create the wave profile, and their movement pattern. Additional requirements for moving an elastic object, such as a human body, were also established to minimize the stiffness of the interface layer between the body and wave particles. Results suggest that transportation speed is linearly proportional to wave frequency and horizontal displacement of the wave actuators. Maximizing the number of actuators while minimizing wave amplitude and wavelength will increase the smoothness. Meanwhile, the wavelength must be at least half of the object length to ensure motion stability while also exceeding a critical value to guarantee that feasible waves are achieved in practice. Additionally, the wavelength, wave amplitude, and number of actuators will determine the minimum required stiffness of the interface layer.
Purpose:
Pressure ulcers (PUs) are prevalent among immobile bed or wheelchair-reliant individuals who experience prolonged sedentary positions. Pressure relief and frequent repositioning of body posture help to mitigate complications associated with PUs. Adherence with regular repositioning is difficult to maintain due to nursing labour shortages or constraints of in-home caregivers. Manual repositioning, transferring, and lifting of immobile patients are physically demanding tasks for caregivers. This review aimed to explore and categorize these devices, discuss the significant technical challenges that need addressing, and identify potential design opportunities.
Materials and methods:
In this review, a literature search was conducted using PubMED, Science Direct, Google Scholar and IEEE Xplore databases including studies from 1995 until Feb 2023 with keywords such as pressure ulcer, assistive device, pressure relief, repositioning, transfer, etc. Both commercial and research-level devices were included in the search.
Results:
142 devices or technologies were identified and classified into four main categories that were further subcategorized. Within each category, the devices were investigated in terms of their mechanical design, actuation methods, control strategies, sensing technologies, and level of autonomy. Limitations of current technologies are design complexity, lack of patient comfort, and a lack of autonomy requiring caregivers frequent intervention.
Conclusions:
Several devices have been developed to help with prevention and mitigation of PUs. There remain challenges that hinder the widespread accessibility and use of current technologies. Advancements in assistive technologies for pressure ulcer mitigation could lie at the intersection of robotics, sensors, perception, user-centered design, and autonomous systems.
Numerical simulation of magnetic nanoparticle hyperthermia for cancer treatment has been investigated in this study. The presented simulation did account for the effects of fluid flow, mass flow, and heat transfer during the MNP hyperthermia. The tumor was assumed to be a porous slab, 30% of which had been necrosed previously, with two capillaries, where magnetic nanoparticles were added into the bloodstream and distributed in the tumor by blood flow through capillaries. Fluid flow, mass transfer by capillaries, and interstitial tissues have been coupled in this study. Furthermore, tumor tissue damage has been calculated using a thermal damage indicator. The goal of this research is to find an optimum injection duration and exposure time in order to maximize hyperthermia treatment effectiveness using the BOBYQA optimization method. At the end of the 1-h time hyperthermia treatment, most of the non-necrotic tissue of the tumor were damaged. Moreover, the fraction of damaged tissue increased to more than 90% in some parts of the tumor. Results of this study indicate that MNP hyperthermia with the proposed setup can effectively damage the tumor in just one session, making it more susceptible to complementary therapies such as radiotherapy or chemotherapy.
Taking zonal spring mattress as the research object, the paper studied the effect of spring mattress zonal changes on spine alignment and mattress comfort through the methods of mattress sinkage measurement and body pressure distribution test. The results showed that, the back and waist clearance of four types of spring mattresses was in the range of 2–3 cm, and the ratio of back to hip sinkage was in the range of 0.6 to 0.8. the ratio of back to hip sinkage of men subjects in the four types of spring mattresses was larger than women subjects’. The back clearance of men subjects was larger than women subjects’ on zonal spring mattress, which had a certain relationship with male and female body shape. Reasonable zonal spring mattress could get better body pressure distribution parameters than non-zonal spring mattress. More zonal number could live up to requirements of human body on mattress elasticity distribution. Research results provided the basis for zonal mattress design.
This study discussed the spinal alignment and lying comfort for the subjects within different height ranges when lying on zonal spring mattresses by indentation measurement and body pressure distribution measurement. Nine healthy female subjects were instructed to lay on three kinds of zonal spring mattresses. The height ranges of subjects were from 150 to 170 cm. The results indicated that the ratio of back to buttock sinkage of different height subjects laying on mattresses is in the range of 0.6 to 0.8, the distance of waist and back of different height subjects laying on mattresses is 20–30 mm. Height difference on mattress sinkage of three kinds of five zonal spring mattresses has no significant effect. Tall subjects got better pressure distribution on the mattress with more length in back zone and short subjects on the mattress with less length in buttock zone. It’s a matter with height of subjects.
The incidence and costs for pressure ulcer (PU) treatment remain high even though preventive methods are applied. Approaches that use software to support the prevention of PU are presented in the literature to make it more effective.
Identify the state of art of the approaches that use software to support the prevention of PUs.
A systematic literature review was performed to analyze approaches that use software to support the prevention of PU. ACM, IEEE, PubMed, Scopus, CINAHL and Embase databases have been searched with a predetermined search string to identify primary studies. We selected the ones that met the established inclusion criteria.
Thirty-six articles met the inclusion criteria. To support prevention, most approaches monitor the patient to provide information about exposure to pressure, temperature level, humidity level and estimated body position in bed providing risk factor intensity charts and intensity maps. The main method to perform patient's monitoring is using sensors installed on the mattress, but recently, alternative methods have been proposed such as electronic sensors and tactile sensory coils. Part of the approaches performs automated management of the risk factors using ventilation tubes and mattresses with porous cells to decrease body's temperature and movable cells to automatically redistribute the pressure over the body. Matters as cost of the approach, patient comfort and hygiene of the monitoring equipment is only briefly discussed in the selected articles. No experiments have been conducted to evidence the approached may reduce PU incidence.
Currently, approaches that use software to support the prevention of PU provide relevant information to health professionals such as risk factor intensity charts and intensity maps. Some of them can even automatically manage risk factors in a limited way. Yet, the approaches are based on risk factor monitoring methods that require patient's contact with the monitoring equipment. Therefore, some matters need to be considered such as patient's comfort and the hygiene or replacement of the equipment due to the risk of infection. With the emergence of new alternative methods of monitoring, new technologies that do not require contact could be explored by new researches. Randomized Control Trials could also be conducted to verify which approaches are really effective to reduce PU incidence.
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Mattress, as a sleep platform, its types and physical properties has an important effect on sleep quality and rest efficiency. In this paper, by subjective evaluations, analysis of sleeping behaviors and tests of depth of sleep, the relationship between characteristics of the bedding materials, the structure of mattress, sleep quality and sleep behaviors were studied. The results showed that: (1) Characteristics of the bedding materials and structure of spring mattress had a remarkable effect on sleep behaviors and sleep quality. An optimum combination of the bedding materials, the structure of mattress and its core could improve the overall comfort of mattress, thereby improving the depth of sleep and sleep quality. (2) Sleep behaviors had a close relationship with sleeping postures and sleep habits. The characteristics of sleep behaviors vary from person to person.
Today, the number of elderly people in Japan is increasing, and the number of families who have members in need of nursing care is also increasing. A home care is promoted by Japanese government, but there is a big problem of a pressure ulcer. Accordingly, many types of antidecubitus aids have been developed. However, these aids are not enough for controlling the body pressure. To address this problem, we developed novel active air mattress, which has soft pressure sensor sheet and can control its air cells independently. In this paper, we analyze the characteristics of the air cell and the relationship between value of the sensors and states of the mattress. As a result, we demonstrate that the condition of the mattress can be estimated from sensor values.
Pressure ulcers are of great cost to both the patient and the healthcare system. Devices have been developed with the goal of pressure ulcer prevention, but many available technically complex devices have been shown to be no more effective than low pressure overlays or mattresses. This paper proposes a subject dependent algorithm capable of automatically detecting when and where pressure points have been relieved from underneath a supine subject, without any user inputs or assumptions. Pressure sensitive mats, associated software, a laptop and a video camera were used to measure and collect pressure signals generated by a supine subject performing 3 movements: the subject rolling to one side of the body, then to the other side, and the subject attempting to roll without lifting any pressure points off the mattress. The data was zeroed, baseline values were found, differences in sensor score from baseline were calculated, and instances during which a valley on one side coincided with a peak on the other, were recorded. Examination of these results indicated that the algorithm was capable of determining when and where pressure points underneath the sacrum and foot regions were lifted off the bed, but not capable of determining if a scapula pressure point was relieved. These results suggest that the proposed algorithm is effective for some, but not all regions of the body. Future work will therefore focus on detection of all pressure points, and the adjustment of the algorithm for subject independence.
In this study, a new alternating-pressure air cushion (APAC) is designed and fabricated to render, for pressure ulcer prevention, a sufficient rest for the skin tissue in contact with the user's body pressure. The APAC designed comprises six cylindrical air bags and conforms to human factors or ergonomics. The inflation/ deflation system adopts a microcontroller IC chip to drive the pump and four associated electromagnetic valves. The software code renders a full control on the system parameters, such as the period, inflation duration, deflation duration, air-withholding duration, and so on, to enable the user to adjust or readjust the parameters so as to achieve an optimal status for his or her most satisfactory comfort while using the proposed device. The actual field tests indicate that the proposed system, indeed, exhibits a significant effect in reducing pressure for pressure ulcer prevention and treatment.
With the increased demands on sleeping quality, the zoned pocket spring mattress (PSM) designed and manufactured using ergonomic principles is getting popular. This study investigated the pressure distribution of buttocks and shoulder zones of pocket spring mattresses using a body pressure distribution measure system. Test results indicated that pocket spring type and cushioning material type, and people sleeping positions had the influences on body pressure distribution. A soft PSM had a lowest peak pressure in the buttocks zone, and a medium elastic PSM had a lowest peak pressure in the shoulder zone. Based on the experimental results, an optimal design scheme for zoned pocket spring mattresses was proposed.
The classic book on human movement in biomechanics, newly updated. Widely used and referenced, David Winter's Biomechanics and Motor Control of Human Movement is a classic examination of techniques used to measure and analyze all body movements as mechanical systems, including such everyday movements as walking. It fills the gap in human movement science area where modern science and technology are integrated with anatomy, muscle physiology, and electromyography to assess and understand human movement. In light of the explosive growth of the field, this new edition updates and enhances the text with: Expanded coverage of 3D kinematics and kinetics. New materials on biomechanical movement synergies and signal processing, including auto and cross correlation, frequency analysis, analog and digital filtering, and ensemble averaging techniques. Presentation of a wide spectrum of measurement and analysis techniques. Updates to all existing chapters. Basic physical and physiological principles in capsule form for quick reference. An essential resource for researchers and student in kinesiology, bioengineering (rehabilitation engineering), physical education, ergonomics, and physical and occupational therapy, this text will also provide valuable to professionals in orthopedics, muscle physiology, and rehabilitation medicine. In response to many requests, the extensive numerical tables contained in Appendix A: "Kinematic, Kinetic, and Energy Data" can also be found at the following Web site: www.wiley.com/go/biomechanics.
A comparison of pressure reducing properties of alternating air, static air, and water mattress overlays was conducted with 57 patients in a surgical intensive care unit. Sacral and heel pressures in both recumbent and semi-Fowler's positions were tested for each surface using a repeated measures design. Mean pressures for the alternating air mattress were significantly higher than pressures with other surfaces, regardless of position or site. There were significant main effects for position and site, with higher pressures in the semi-Fowler's position and at the sacral site. A significant interaction between surface, site, and position was found. Pressure sores developed in eight patients, but the incidence was not significantly different across groups. A pressure measuring device constructed from available clinical materials proved to be both sensitive and reliable. The findings suggest alternating air overlays should be avoided, and that positioning and periodic position change to reduce sacral pressures for patients requiring prolonged upper body elevation is important.
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[6] http://www.cape.co.jp