Belino, N.J.R.1, Geraldes, M.J.O. 1, Figueiredo, M.N. 1, Ferreira, P.A.R.C.2, Pimenta, N.2, Cardoso, F.2, Matos, J. L.3
1University of Beira Interior, Textile Department Covilhã, PORTUGAL 2
INOV– Instituto de Novas Tecnologias, Lisboa, PORTUGAL 3QSC– Quinta de S. Cosme, Lda. , Vila Nova de Tázém, PORTUGAL
Corresponding author: Nuno Belino,[email protected]
Abstract: Pressure ulcers are skin lesions that seriously affect the patient’s quality of life. This pathology is
caused by low pressure application during a long period of time over a bone prominence or also due to high pressure application for a short period. This paper describes the initial prototype of a textile based technological solution to perform real time control of the anatomical position of bedridden patients suffering from pressure ulcers. For this purpose, the authors developed an electrotextile system with an integrated sensing system that captures the anatomical position of the body along time and communicates with a PC to inform healthcare personnel about the necessity of changing and relieving pressure.
Key words: Pressure ulcers; prophylaxis; Smart Textiles; Electrotextiles; Remote Sensing; Medical Textiles;
1. INTRODUCTION
Pressure ulcers (Hereafter, PU) come from local tissue ischemia caused by pain reflex change in patients with medulla injuries (tetraplegics, paraplegics or hemiplegics) or debilitated patients, elderly or chronically ill. In patients with medulla trauma there is an injury of the afferent nociceptive fibers, responsible for pain stimulus for decubitus change and, on the second patient group, these signs are ignored(1).
The pressure sores etiology is not yet completely enlightened, but it is well known that continuous pressure on the skin takes to ischemic phenomena associated to nutrients deficit and consequently tissue necrosis (4). PU can develop in areas where pressure is exerted over bone prominences like sacral, ischium, trochanter or less frequently calcaneus, occipital region, instep, malleolus and patella(2).
Studies indicate that pressures between 60 and 580 mmHg in a 1 to 6 hour period can cause PU. Besides pressure, shear and friction stresses can act in synergy on a wound development in malnourished, incontinent, bedridden or mentally disturbed patients.
PU can develop within 24 hours or take up to 5 days to arise. All medical professionals responsible for patients’ monitoring should be familiar with the main risk factors. This way, it is vital to observe prophylactic measures in order to eliminate continuous pressure, shear or friction forces, preventing sores formation.
PU incidence in hospital environment is extremely high, with variations from 2.7% to a maximum of 29.5% (3). Tetraplegics (60%) and elderly with femur neck fracture (66%)(4)reach the highest rates of complications, followed by critically ill patients (33%). Generally, 40% of medulla injured patients that accomplish treatment will develop pressure sores(5). UP are direct causes of death in paraplegics, with 7 to 8%(6) incidence. The economic impact of pressure sores treatment is huge.
Recent treatment cost (clinic and surgical) estimates of PU have revealed a hospital average cost of US$21675. Besides, when femur neck fracture patients develop pressures sores, hospital expenses increase US$10986 average by patient (7). On surgical patients, the main internment cost
impact seems to be the presence or not of postoperative complications, which can significantly change the internment period and consequently its costs(8).
2. METHODOLOGY
The innovation areas in which the authors intend to evolve (biomedical textiles) are the ones with greatest impact and business potential. Technologies and processes to be used are relatively recent and constitute relevant scientific advances, of wide application in many engineering areas. The present project introduces some innovative aspects (nationally and internationally) that should be highlighted, and may allow the development of function and optimization of textile structures with integration of electronic devices with both medical and human health application. It is important to underline the commitment and funding volume that the European Union has granted when financing transnational and national projects within this thematic, and has successively supported and incentivized through the 5th, 6th and 7th framework programmes, e.g. the Wealthy, WearIT@work, My Heart, Mermoth, Avalon, Biotex, Acteco, Proetex, Stella, Ofseth, Inteltex, Polytect projects, etc... The research team has two entities from the public Portuguese Scientific System UBI working on all the textile solutions and INOV-INESC which will be dealing with the electronic and telecommunications issues. The Centro Hospitalar da Cova da Beira (Hospital) will be responsible for all the medical essays and clinical methodology.
The present research can be subdivided into two main phases: The electrotextile system development and the clinical study.
2.1 - Production and optimization of the electroactive textile structure
The electroactive textile system consists of a textile composite structure, with the same length, thickness and shape of a normal mattress. The textile material specifications were conceived in order to allow an easy industrial scalable product with reduced production costs. Of the several tested technological solutions we chose to develop a composite structure constituted by three layers. The first and third layers (external) were constructed with a nonwoven felt, 100% wool, mechanically consolidated. The intermediate layer (second) is the sensing layer, which also consists of the aggregation of three different layers: a vertically conductive layer, a separation layer (foam) and a horizontally conductive layer, as seen on figure 1. Woolen yarns and wool/inox yarns were used to produce the conductive layers. The integrated sensing system was placed in predetermined areas, corresponding to the great anatomic zones of the human body. The selected areas were: the torso, hip, legs, arms, neck and head zone.
Fig. 1– Schematic representation of the sensing layer
2.2– Sensing and communication system
The overall system (electrotextile system) is constituted by a matrix of positioning sensors integrated into an electroactive textile structure and by a control centre (CC - Server). Each
electrotextile device has an associated CPM (collection and processing module) as seen on figure 2, which allows data acquisition and wireless communication to the CC.
Fig. 2– Ilustration of the collection and processing
module
The sensing unit is comprised by a positioning sensor network (maximum of 64) and by a data unit (Data Collection Module – DCM) as seen on figure 3,) which reads the sensors status continuously and individually. The CPM is connected to the DCM which in its turn is connected to the electroactive textile system. The collected and processed data are sent to the CC. The CPM module also permits the generation of local alarms through light indicators or sound alarm. The communication module (CM) seen on figure 4, serves as the communication interface (wireless) between the CC and the electrotextile device.
Fig. 3 - Ilustration of the Data Collection Module Fig. 4 - Ilustration of the communication module
The CPM is connected to the DCM which in its turn is connected to the electroactive textile system. The collected and processed data are sent to the CC. The CPM module also permits the generation of local alarms through light indicators or sound alarm. The communication module (CM) seen on figure 4, serves as the communication interface (wireless) between the CC and the electrotextile device.
2.3– Clinical study
A normal control group of an age similar to that of the patient groups was selected from the CHCB. This normal control group is assessed by two Physicians in order to exclude other pathologies. A group of patients with pressure ulcers is also selected. Both groups are assessed by the physicians of the team in order to confirm the diagnosis and to evaluate the wound stage. Regarding the location of PU, the following regions will be evaluated: sacrum, ischium, trochanter, calcaneus, knee, occipital region, instep, ankle, shoulder, chest, leg, back and occipital region. The measurement of ulcers in their largest diameter (cm) will be jointly conducted. The treatment will be evaluated through the success rate and the rate of PU recurrence on the basis of the best practices with local presence / absence of the electrotextile device. In parallel, a survey to the professional nursing will be produced in order to investigate the advantages/disadvantages of this new technological solution. The survey will also deal with the degree of convenience and comfort that it might provide to patients under
treatment. An inquiry about treatment quality will also be presented to the control and to the patients’ groups.
3. RESULTS
The project MEDTEX has already carried out much of the predicted work so far. The electroactive textile structure is fully achieved, tested and validated, as seen on figure 5.
Fig. 5– Sensing layer and prototype view
The developed electrotextile structure possesses a good breathing and water vapor permeability, and also excellent isolating and thermal regulation characteristics. The clinical study is an ongoing task. A prospective case-control study about the benefits of the electrotextile device usage is being prepared. The selection and characterization of the population under study, the preparation of standardized inquiries for wound assessment, the delivery and filling of the informed consent form, and the methodology definition have already been done, and the same applies to the process control software which has also been fully tested as shown on figure 6.
Fig. 6– Control software -
View of a patient status
4. CONCLUSIONS
Based on initial results we may consider that the idea beyond this research work presents an elevated sucess potential. It is intended to prevent the progression of PU for more advanced stages and, consequently, diminishing hospitalization times and the resource to more expensive techniques such as the chirurgical treatment. We predict that the PU treatment costs will decrease dramatically. Simultaneously, the quality of life of the patients is significantly improved. Nursery care will also be facilitated. The second layer (sensing layer) will be patented at the end of this research work. This project has already been the object of 6 ongoing PhD thesis
5. REFERENCES
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[3] Stevenson TR, Pollock RA, Rohrich RJ, Craig AV. The gluteus maximus musculocutaneous island flap: refinements in design and appplication. Plast Reconstr Surgery 1987; 79:761-8.
[4] Yarkony Gm. Pressure ulcers: a review. Arch Phys Med Rehabil1994; 75: 908-17.
[5] National Pressure Ulcer Advisory Panel. Pressure ulcers: incidence, economics, risk assessment. Consensus Development Conference Statement, West Dundee Illinois, S-N Publications Incorporated, 1989.
[6] Dinsdale SM. Decubitus ulcer: role of pressure and friction in causation. Arch Phys Med Rehabil 1974; 55:147-52.
[7] Bours, Gerrie JW- Pressure Ulcers, Prevalence measurements as a tool for improving care, ISBN 9052783837, University of Maastricht, Maastricht, 2003.
[8] Brooks, R. G.; Thomson, J. S.-“The economics of preventing and treating pressure ulcers: a pilot