Pressure by design: How to improve the consistency of pressure garments in the clinical environment and implement a simple method for gathering evidence to establish efficacy.

Pressure garments are used to treat scars after major trauma including burns. However, the ideal pressure for treatment is not known. Pressures exerted are not routinely measured and garments exert a wide range of pressures. Therefore, current treatment and its efficacy are variable. Pressure Garment Design Tools were introduced in 2012 but their application in hospitals has not been reported. A Garment Dimension and Pressure Calculator was used to audit pressures delivered by 8 pressure garments made for children using the hospital department's standard reduction factor. The tool was easy to use and showed that pressures exerted by standard garments ranged from 15 to 54 mmHg with highest pressures exerted on wrists. Results of our pilot study indicated that the Garment Dimension and Pressure Calculator was slightly quicker to use than our normal manual process for calculating garment dimensions and enabled easy auditing of past treatment. The Pressure Garment Design Tool was easy to use and calculated garments that exerted the mean target pressures of 15 mmHg and 25 mmHg, improving consistency. Pressures exerted by garments were difficult and time consuming to measure with the Picopress sensor. Pressure was not distributed evenly around the limbs and measurements were inaccurate on the smallest limbs.

Survey of lipoedema symptoms and experience with compression garments.

Lipoedema is an incurable chronic disease causing limb deformity, painful skin and excessive ecchymosis. Compression garments are frequently recommended to manage symptoms, but the existing products are not designed specifically for lipoedema, and are for other medical conditions. A structured questionnaire was prepared in Online Surveys in October 2018 to investigate lipoedema symptoms and the use of compression garments to manage them. Some 279 people with lipoedema completed the survey; 70% wore compression garments in all four compression classes, of which class 2 was most common (58% of wearers). The top three reasons for wearing compression garments were to feel supported (73%), reduce lipoedema pain (67%) and improve mobility (54%). Most people with lipoedema who wore compression garments found compression helpful in managing their symptoms, but overall satisfaction was low. Problems with existing compression garments were so severe in some cases that the garments were not worn at all or used less often. The information collected in this survey might be useful for the design and development of compression garments specifically for lipoedema.

Nanocomposite-Based Microstructured Piezoresistive Pressure Sensors for Low-Pressure Measurement Range.

Piezoresistive pressure sensors capable of detecting ranges of low compressive stresses have been successfully fabricated and characterised. The 5.5 × 5 × 1.6 mm³ sensors consist of a planar aluminium top electrode and a microstructured bottom electrode containing a two-by-two array of truncated pyramids with a piezoresistive composite layer sandwiched in-between. The responses of two different piezocomposite materials, a Multiwalled Carbon Nanotube (MWCNT)-elastomer composite and a Quantum Tunneling Composite (QTC), have been characterised as a function of applied pressure and effective contact area. The MWCNT piezoresistive composite-based sensor was able to detect pressures as low as 200 kPa. The QTC-based sensor was capable of detecting pressures as low as 50 kPa depending on the contact area of the bottom electrode. Such sensors could find useful applications requiring the detection of small compressive loads such as those encountered in haptic sensing or robotics.

How can the pressure in anti-embolism stockings be maintained during use? Laboratory evaluation of simulated 'wear' and different reconditioning protocols.

BACKGROUND: Deep vein thrombosis is a major global health issue, responsible for thousands of deaths each year. While thrombi can form under a variety of circumstances, lack of mobility significantly increases risk and therefore non-ambulant patients are frequently fitted with anti-embolism stockings on admission to hospital, to aid blood flow, prevent pooling and thus clotting. Anti-embolism stockings are the most widely used non-invasive medical device on the market and are believed to reduce the risk of deep vein thrombosis by 40%. Despite their widespread use in hospitals world-wide, there is remarkably little research addressing their use or reconditioning and a wide variety of different reconditioning protocols are used in hospitals. OBJECTIVE: The objective of this study was to establish the impact of different wear and reconditioning protocols on the pressure delivering ability of anti-embolism stockings. DESIGN/METHODS: A laboratory investigation was undertaken to evaluate the pressure delivering ability of 2 major global brands of anti-embolism stockings over 5-8days of simulated wear (extension on static cylinders) and 4 different reconditioning protocols. 1 set of samples was continuously 'worn' for 8days without reconditioning, 1 set of samples was 'worn' for 5days with a day of relaxation between each day of 'wear', 1 set was 'hand washed' and 1 set was machine washed and then allowed to relax between each day of 'wear'. The pressure was measured at the beginning and end of each period of 'wear'. SETTING: This study was undertaken in a conditioned textile testing laboratory that complies with BS EN ISO 139:2005+A1:2011. RESULTS: The pressure exerted by anti-embolism stockings reduced by between 15 and 24% after 24h of wear, it reduced by between 21 and 32% when worn continuously for 8days. Allowing stockings to rest for a day between days of wear allowed them to recover slightly but this recovery was only temporary. Washing stockings regenerated their pressure delivering potential significantly and machine washing allowed some to recover to exert more pressure than they had when new. CONCLUSIONS: Different brands of anti-embolism stockings exert different pressures on the same size of leg, when correctly fitted. The pressure exerted by anti-embolism stockings decreases with use but the correct pressure gradient is maintained if correctly fitted. Washing stockings after 24h of wear is effective in restoring their pressure delivering abilities and in some cases can surpass their 'as new' pressure delivering ability.

Impact of Moisture on the Pressure Delivering Potential of Pressure Garments.

Pressure garments are the main method of treatment and prophylaxis for hypertrophic burn scars. The pressure they exert on the scarred skin prevents contractures forming, reduces the itchiness and pruritus associated with active hypertrophic scars, and is believed, by many, to hasten normalization of the scar tissue. The pressure exerted is believed to be critical to treatment success and can be predicted based on laboratory measurement of the fabric's tension profile. All previous research on the pressures delivered by pressure garments has been undertaken using dry fabrics in either laboratory or clinical conditions. However, many patients have complained of increased perspiration when wearing pressure garments, and many burn victims live and work in hot conditions where high levels of perspiration may be expected. This article investigated the impact of moisture content on fabric tension and thus the pressure exerting ability of pressure garments. Four different fabrics currently used in the construction of pressure garments were evaluated in seven different states of "wetness" from completely dry to completely saturated in water or artificial perspiration. Standard laboratory methods were used to measure the initial tension in fabrics and the tension after 11 cycles of extension. Pressures that would be exerted by these fabrics were calculated using the Laplace law. The results of this study showed that the tension, and therefore pressure delivering ability, of fabrics used in pressure garments was significantly reduced when they were wet but that the amount or type of "wetness" did not have a significant effect on pressure delivering ability.

Pressure garment design tool to monitor exerted pressures.

Pressure garments are used in the treatment of hypertrophic scarring following serious burns. The use of pressure garments is believed to hasten the maturation process, reduce pruritus associated with immature hypertrophic scars and prevent the formation of contractures over flexor joints. Pressure garments are normally made to measure for individual patients from elastic fabrics and are worn continuously for up to 2 years or until scar maturation. There are 2 methods of constructing pressure garments. The most common method, called the Reduction Factor method, involves reducing the patient's circumferential measurements by a certain percentage. The second method uses the Laplace Law to calculate the dimensions of pressure garments based on the circumferential measurements of the patient and the tension profile of the fabric. The Laplace Law method is complicated to utilise manually and no design tool is currently available to aid this process. This paper presents the development and suggested use of 2 new pressure garment design tools that will aid pressure garment design using the Reduction Factor and Laplace Law methods. Both tools calculate the pressure garment dimensions and the mean pressure that will be exerted around the body at each measurement point. Monitoring the pressures exerted by pressure garments and noting the clinical outcome would enable clinicians to build an understanding of the implications of particular pressures on scar outcome, maturation times and patient compliance rates. Once the optimum pressure for particular treatments is known, the Laplace Law method described in this paper can be used to deliver those average pressures to all patients. This paper also presents the results of a small scale audit of measurements taken for the fabrication of pressure garments in two UK hospitals. This audit highlights the wide range of pressures that are exerted using the Reduction Factor method and that manual pattern 'smoothing' can dramatically change the actual Reduction Factors used.

Do anti-embolism stockings fit our legs? Leg survey and data analysis.

BACKGROUND: Anti-embolism stockings are commonly used worldwide to prevent the development of thrombosis in hospitalised patients. Patients are typically measured for, and fitted with, anti-embolism stockings during extended periods of non-ambulation. Anti-embolism stockings must critically fit the leg to achieve optimum blood flow and thus success of prophylaxis. Therefore, hospitals endeavour to maintain stock of anti-embolism stockings that fit the majority of their patients. OBJECTIVES: The objective of this study was to establish whether popular styles/brands of anti-embolism stockings "fitted" the legs of convenience sampled volunteers. DESIGN/METHODS: Volunteer's legs were measured at ankle, calf and thigh following guidance from British nurses and in accordance with brand instructions. Leg measurements were subsequently compared to the size charts of 10 anti-embolism stocking styles made by 4 different manufacturers. "Fit" is defined as a volunteer's leg measurements matching any stocking size in a range at all measurement points. SETTINGS: Volunteers were measured in different settings around Scotland, including private homes, work places and shopping centres. PARTICIPANTS: A convenience sample of 471 volunteers (283 female, 188 male) were recruited on the basis of willingness to participate and being over 16 years old. Volunteers ranged from 17 years to 82 years old with an average age of 35. RESULTS: The 10 different styles of anti-embolism stockings, made by 4 different brands, examined for this paper had a size match coefficient ranging from 0% to 100% for our volunteer's legs. The size match coefficient is strongly influenced by the Brand's sizing policy. CONCLUSIONS: The proportion of legs that "fit" a particular brand of anti-embolism stockings can be increased through: (1) the reduction of the number of leg measurement points that need to be matched to the size chart of the stockings; (2) the use of open-ended size ranges; (3) the use of increased size range width and (4) the use of increased overlap between sizes. However, all but the last of these measures can have a potentially deleterious impact on the ability of the stocking to deliver the optimum graduated pressure profile to all legs that "fit" the stocking, resulting in important implications to the efficacy of prophylaxis.

New calibration method for I-scan sensors to enable the precise measurement of pressures delivered by 'pressure garments'.

Accurate measurement of the pressure delivered by medical compression products is highly desirable both in monitoring treatment and in developing new pressure inducing garments or products. There are several complications in measuring pressure at the garment/body interface and at present no ideal pressure measurement tool exists for this purpose. This paper summarises a thorough evaluation of the accuracy and reproducibility of measurements taken following both of Tekscan Inc.'s recommended calibration procedures for I-scan sensors; and presents an improved method for calibrating and using I-scan pressure sensors. The proposed calibration method enables accurate (±2.1 mmHg) measurement of pressures delivered by pressure garments to body parts with a circumference ≥30 cm. This method is too cumbersome for routine clinical use but is very useful, accurate and reproducible for product development or clinical evaluation purposes.

The impact of design variables and aftercare regime on the long-term performance of pressure garments.

We sought to establish the impact of pressure garment design variables, moisturizer use, and laundry method on the ability of pressure garments to maintain their pressure delivering potential, indicated here by garment tension, over time and use. Twenty-six sets of three replicate pressure garment sleeves were constructed from four powernet fabrics, using three reduction factors and six sleeve dimensions. These pressure garment sleeves were extended for 23 hours on static cylinder models followed by hand or machine laundry up to 28 times. Some sleeves were additionally exposed to moisturizers during their extension. Garment tension and dimensions were measured before and during the simulated wear and wash period to indicate each garment's ability to maintain its tension and therefore pressure throughout a period of "use." The results of the investigation were analyzed in groups where each group contained only 1 variable, thereby allowing the variables with the most significant impact on tension degradation to be identified. The investigation confirmed that all pressure garments lost tension and therefore pressure delivering ability over time and use. It further revealed that pressure garments designed to exert greater pressures degraded faster than those designed to exert lower pressures. Contact between pressure garments and moisturizers accelerated tension degradation, and machine-washing pressure garments tended to prolong their pressure-delivering properties compared with hand-washing them. To maintain the initial pressure delivered by pressure garments, powernet fabrics should be prestressed before being designed/constructed and they should be machine-washed by patients.

Designing pressure garments capable of exerting specific pressures on limbs.

Pressure garments have been used prophylactically and to treat hypertrophic scars, resulting from serious burns, since the early 1970s. They are custom-made from elastic fabrics by commercial producers and hospital staff. However, no clear scientifically established method has ever been published for their design and manufacture. Previous work [2] identified the most commonly used fabrics and construction methods for the production of pressure garments by hospital staff in UK burn units. These methods were evaluated by measuring pressures delivered to both cylinder models and to human limbs using I-scan pressure sensors. A new calibration method was developed for the I-scan system to enable measurement of low interface pressures to an accuracy of +/-2.5 mmHg. The effects of cylinder/limb circumference and pressure garment design on the pressures exerted were established. These measurements confirm the limitations of current pressure garment construction methods used in UK hospitals. A new method for designing pressure garments that will exert specific known pressures is proposed and evaluated for human thighs. Evaluation of the proposed design method is ongoing for other body parts.

Pressure garments for use in the treatment of hypertrophic scars--a review of the problems associated with their use.

Pressure garments have been the mainstay of hypertrophic scar treatment since the 1970s. However, there are many problems associated with their use. This is the first in a series of papers on pressure garments that will review the literature published to date on the origins of pressure garments for hypertrophic scar treatment and the problems associated with current pressure garment use.

Pressure garments for use in the treatment of hypertrophic scars -- an evaluation of current construction techniques in NHS hospitals.

The purpose of this investigation was to establish the variety of pressure garment construction methods and materials used in UK hospitals. This paper reports an investigation conducted in two parts. First, a survey of pressure garment practitioners was conducted and second, 15 of the fabrics currently used in UK hospitals were tested. The results showed that the pressures exerted by pressure garments constructed in UK hospitals were likely to range from ineffectively low to dangerously high.