Evaluating dressing materials for the prevention of shear force in the treatment of pressure ulcers

Mechanical and contact characteristics of foam materials within wound dressings: Theoretical and practical considerations in treatment

In the treatment of acute and chronic wounds, the clinical performance of a given foam-based dressing, and, ultimately, the wound healing and cost of care outcomes are strongly influenced by the mechanical performance of the foam material/s within that dressing. Most aspects of the mechanical performance of foam materials, for example, their stiffness, frictional properties, conformability, swelling characteristics and durability, and the overall mechanical protection provided by a foam-based dressing to a wound strongly depend on the microstructure of the foam components, particularly on their microtopography, density and porosity. This article, therefore, provides, for the first time, a comprehensive, self-inclusive compilation of clinically relevant theoretical and practical considerations, based on published analytical and experimental research as well as clinical experience related to the mechanical performance of foams in foam-based wound dressings. The current bioengineering information is useful for establishing understanding of the importance of mechanical properties of foams in foam-based dressings among clinicians and researchers in industry and academia, and other potential stakeholders in the wound care field, for example, regulators and buyers. This information is also particularly important for the development of standardised test methods for the evaluation of foam-based wound dressings and resulting standard mechanical performance metrics for these dressings.

Dressings for preventing pressure ulcers: how do they work?

Pressure ulcers (PUs) negatively affect quality of life (QoL) and cause problems for patients, such as pain, distress and often specific difficulties with treatments used to manage the wound. Thus, it is important to implement appropriate prevention strategies in order to achieve high-quality care, thereby reducing the burden of PUs on patients, the healthcare system and society as a whole. PU development arises due to the adverse effects of pressure, shear, friction and moisture at the skin/surface interface. Preventive interventions typically include risk assessment, reducing pressure and minimising shear and friction. More recently, certain wound dressings, as a potential additional protective strategy for preventing PUs, have been introduced. This review explores the mechanisms of action of dressings for preventing PUs. Findings from the review indicate that decreasing frictional forces transmitted to the patient's skin is achieved by use of a dressing with an outer surface made from a low friction material. Furthermore, the ability of dressings to absorb and redistribute shear forces through good adhesion to the skin, high loft and lateral movement of the dressing layers is important in reducing shear forces. This is achieved when the dressing reduces pressure transmitted to the patient's tissues by the propriety of high loft/thickness and padding that allows a degree of cushioning of bony prominences. Further, dressings may reduce humidity at the skin/dressing interface, i.e., the dressing is absorbent and/or permits moisture to evaporate quickly. As part of an established PU prevention protocol, dressings may help decrease PU incidence.

Dressings, Topical Therapy, and Negative Pressure Wound Therapy

The current epidemic of diabetes has created a high demand for skilled wound-care professionals. Wound-care treatment begins with an appreciation of the cause of the ulceration and an adherence to the fundamental pillars of wound care. Also critical in the wound management paradigm is the optimization of the wound environment to facilitate the progression through the stages of healing. This can be accomplished through the use of different topical therapies and wound dressings to generate a favorable condition conducive to healing. This article summarizes the updated literature and best practices related to this topic.

The role of dressings in the prevention of pressure ulcers

Pressure ulceration is a significant global healthcare problem and represents a considerable burden on healthcare resources. Within the literature an increasing number of studies have examined the role prophylactic dressings play in redistributing pressure and helping to protect the skin from the effects of friction and shear. The use of dressings to prevent pressure ulcers may be considered a controversial issue, as previous opinion has been that dressings do not reduce the effects of pressure. This article will critically evaluate the literature to examine the role dressings play in the prevention of pressure ulceration.

Dressings for Preventing Pressure Ulcers: A Meta-analysis

The purpose of this analysis is to determine the effectiveness of dressing material in the prevention of pressure ulcers. Results showed that hydrocolloid, foam, and film were more effective than a standard care protocol in patients at risk for pressure ulcers.

Soft silicone foam dressing is more effective than polyurethane film dressing for preventing intraoperatively acquired pressure ulcers in spinal surgery patients: the Border Operating room Spinal Surgery (BOSS) trial in Japan

Preventing intraoperatively acquired pressure ulcers (IAPUs) in patients undergoing spinal surgery in the prone position using a Relton-Hall frame is challenging. We investigated the efficacy of soft silicone foam dressings in preventing IAPUs. A prospective dual-center sham study was conducted among patients undergoing elective spinal surgery in a general hospital and a university hospital in Japan. The incidence of IAPUs that developed when soft silicone foam dressings and polyurethane film dressings were used was compared on two sides in the same patient. IAPUs developed on the chest in 11 of 100 patients (11%). Polyurethane film dressings were associated with a significantly higher rate of IAPUs than soft silicone foam dressings (11 versus 3, P = 0·027). A multivariate logistic regression analysis revealed that a diastolic blood pressure of <50 mmHg (P = 0·025, OR 3·74, 95% confidence interval [CI] 1·18-13·08) and the length of surgery (by 1 hour: P = 0·038, OR 1·61, 95% CI 1·03-2·64) were independently associated with the development of IAPUs. The use of soft silicone foam dressings reduced the risk of IAPUs (P = 0·019, OR 0·23, 95% CI 0·05-0·79) and was more effective than film dressings for preventing IAPUs in spinal surgery patients.

Evaluation of Wound Healing Properties of Grape Seed, Sesame, and Fenugreek Oils

Background. Medicinal plants have proved at all times to be a powerful remedy for health care. Accordingly, grape seed, sesame, and fenugreek extracted oils with pharmacological properties are investigated as wound treatments. This study assesses the potential of our oils for healing wounds induced on rats. Methods. Phytochemical analyses of oils have involved: quality value, polyphenol, chlorophylls, carotene, and fatty acids. Antibacterial activity was carried out. Antioxidant activity was evaluated: the scavenging effect on DPPH radicals, the reducing power, and β-carotene discoloration. Uniform wound excision was induced on rats dorsum randomly divided into five groups: groups treated with "CICAFLORA®" and tested oils and untreated one. The posthealing biopsies were histologically assessed. Results. Wound biopsies treated with oils showed the best tissue regeneration compared to control groups. Groups treated with our oils and "CICAFLORA" had higher wound contraction percentage. Polyunsaturated fatty acids in oils act as inflammatory mediators increasing neovascularization, extracellular remodeling, migration, and cell differentiation. Wound healing effect was attributed to antibacterial and antioxidant synergy. Conclusion. According to findings, oils showed better activity in wound healing compared to "CICAFLORA" due to a phytoconstituents synergy. However, clinical trials on humans are necessary to confirm efficacy on human pathology.

Five-Layered Soft Silicone Foam Dressing to Prevent Pressure Ulcers in the Intensive Care Unit

BACKGROUND

In critically ill patients, prevention of pressure ulcers is a challenge because of the high risk for multiple comorbid conditions, immobility, hemodynamic instability, and increased use of medical devices.

OBJECTIVES

To compare the difference in incidence rates of hospital-acquired pressure ulcers (HAPUs) in critically ill patients between those treated with usual preventive care and a 5-layered soft silicone foam dressing versus a control group receiving usual care. Secondary goals were to examine risk factors for HAPUs in critically ill patients and to explicate cost savings related to prevention of pressure ulcers.

METHODS

A prospective, randomized controlled trial in the intensive care units at a 569-bed, level II trauma hospital. All 366 participants received standard pressure ulcer prevention; 184 were randomized to have a 5-layered soft silicone foam dressing applied to the sacrum (intervention group) and 182 to receive usual care (control group).

RESULTS

The incidence rate of HAPUs was significantly less in patients treated with the foam dressing than in the control group (0.7% vs 5.9%, P = .01). Time to injury survival analysis (Cox proportional hazard models) revealed the intervention group had 88% reduced risk of HAPU development (hazard ratio, 0.12 [95% CI, 0.02-0.98], P = .048).

CONCLUSION

Use of a soft silicone foam dressing combined with preventive care yielded a statistically and clinically significant benefit in reducing the incidence rate and severity of HAPUs in intensive care patients. This novel, cost-effective method can reduce HAPU incidence in critically ill patients.

Role of multi-layer foam dressings with Safetac in the prevention of pressure ulcers: a review of the clinical and scientific data

Background

Despite the implementation of prevention strategies, pressure ulcers (PUs) continue to be a challenging health problem for patients (and their carers), clinicians and health-care providers. One area of growing interest is the use of prophylactic dressings (which were originally designed for the treatment of PUs and other wound types) as a component of standard prevention measures. Over the past few years, a large amount of scientific and clinical data relating to this subject has been published in peer-reviewed journals and presented at international meetings and conferences. A substantial proportion of these data relate to one group of dressings: multi-layer foam dressings with Safetac, which are manufactured by Mölnlycke Health Care (Gothenburg, Sweden). This evidence pool has influenced the experts involved in updating the Clinical Practice Guideline, produced by the National Pressure Ulcer Advisory Panel, European Pressure Ulcer Advisory Panel and Pan Pacific Pressure Injury Alliance, on the prevention and treatment of PUs. The updated Guideline, published in 2014, recommends that, as part of their PU prevention regimens, clinicians should consider applying prophylactic dressings to bony prominences in anatomical areas that are frequently subjected to friction and shear.

Aims

A literature review was undertaken to identify clinical data from the entire evidence hierarchy, as well as scientific data from laboratory studies, on the use of multi-layer foam dressings with Safetac in the prevention of pressure ulceration.

Method

The MEDLINE (National Library of Medicine, Bethesda, US) and EMBASE (Elsevier BV, Amsterdam, Netherlands) bibliographic databases were searched. In addition, abstract books and proceedings documents relating to national and international conferences were scanned in order to identify presentations (i.e. oral, e-posters and posters) of relevance to the review.

Results

Clinical and health economic experts have undertaken numerous studies, including randomised controlled trials, to assess the efficacy and cost-effectiveness of using multi-layer foam dressings with Safetac as a component of standard PU prevention strategies. The results of these studies indicate that the application of multi-layer foam dressings containing Safetac can reduce the occurrence of PUs on anatomical locations such as the sacrum and the heel, and underneath medical devices. Scientists have also developed and used laboratory methods to gain a better understanding of how prophylactic dressings work. The results of these studies indicate that the composition of foam dressings containing Safetac (i.e. their multi-layer structure) sets them apart from other dressings due to their ability to mediate the effects of physical forces (i.e. pressure, friction and shear) and control microclimate, all of which contribute to pressure ulceration.

Conclusion

The evidence pool clearly indicates that the prophylactic use of multi-layer foam dressings with Safetac as a component of standard prevention measures is beneficial to the clinician, the health-care provider and the patient. It should be noted that the findings outlined in this review may not be transferable to other products as their makeup and components are likely to differ significantly from those of multi-layer foam dressings with Safetac. As the importance of evidence-based practice and the need for cost-effective care continues to grow, clinicians and provider should carefully consider this point when selecting prophylactic dressings for PU prevention.

The effect of concentration of tackifying agent on adhesive and skin-protective properties of ceramide 2-containing hydrocolloid dressings

OBJECTIVE

In the treatment of pressure ulcers and leg ulcers it is necessary to achieve an effective balance between adhesive and skin-protective properties. We speculated that addition of a tackifying agent (TA) to ceramide 2-containing hydrocolloid dressings would increase their adhesiveness under dry conditions and reduce their adhesiveness under wet conditions because dry tack converts to wet tack after water absorption.

METHOD

We prepared ceramide 2-containing hydrocolloid dressings with varying amounts of TA. Basic characteristics of the test ceraminde dressings, such as initial tack force and peeling force, were evaluated using standard methods. Peeling force and stratum corneum (SC) removal on healthy human skin were also evaluated at 20 minutes, 7 hours, and 72 hours. In addition, the effect of 10 repeated applications on transepidermal water loss (TEWL) was investigated on the skin of hairless mice under dry and wet conditions. Statistical analyses were performed using one-way analysis of variance followed by Dunnett's multiple comparison test. A p-value of <0.05 was considered statistically significant.

RESULTS

On a stainless steel substrate, initial tack force and 180° peeling force increased as TA content increased. Twenty minutes after application on human skin, peeling force and SC removal increased with increasing TA content. When TA contents were over 10%, significant differences in peeling force and SC removal were obtained compared with ceramide 2-containing hydrocolloid dressings without TA (p<0.05). However, a TA content-dependent increase in peeling force was not evident 7 hours and 72 hours after application. Under dry conditions, TEWL increased with repeated application and peeling. Conversely, no significant increases in TEWL were evident under wet conditions after 10 repeated applications and peelings.

CONCLUSION

Our data demonstrate that the initial attachment of ceramide 2-containing hydrocolloid dressings to the skin increases with addition of TA. Skin damage can be avoided by conversion of the adhesive system to wet tack with water absorption.

DECLARATION OF INTEREST

Masushi Kohta and Tetsuji IwasakI are employees of ALCARE Co., Ltd., Japan. This project was supported by an unrestricted grant from ALCARE.

Enhancing pressure ulcer prevention using wound dressings: what are the modes of action?

Recent clinical research has generated interest in the use of sacral wound dressings as preventive devices for patients at risk of ulceration. This study was conducted to identify the modes of action through which dressings can add to pressure ulcer prevention, for example, shear and friction force redistribution and pressure distribution. Bench testing was performed using nine commercially available dressings. The use of dressings can reduce the amplitude of shear stress and friction reaching the skin of patients at risk. They can also effectively redirect these forces to wider areas which minimises the mechanical loads upon skeletal prominences. Dressings can redistribute pressure based upon their effective Poisson ratio and larger deflection areas, providing greater load redistribution.

Taking the pressure off in the Emergency Department: evaluation of the prophylactic application of a low shear, soft silicon sacral dressing on high risk medical patients

Pressure injuries are key clinical indicators of care standard. In Australia, pressure injuries increase length of hospital stay by 4.31 and cost $285 million annually. This pilot study examined the effectiveness of sacral dressing in reducing the prevalence of pressure injuries in older, high-risk patients. A non randomised one-sample experimental design was used in this study comprising of four phases. Of the 51 patients recruited to the study, one patient developed a sacral pressure injury compared to six patients identified in a known group with similar demographics who were not approached to participate in the study. The results indicated that patients in the known group were 5.4 times more likely to develop a pressure injury than the intervention group. Findings suggest that applying a protective sacral dressing with a low shear backing as part of a simple standardised prevention injury prevention regime commencing in the Emergency Department was beneficial in the prevention of pressure injury in older 'at high risk' medical patients.

Tip anchor flap in decubital surgery

Anchoring a flap remains a key procedure in decubital surgery because a flap needs to be stable against shearing forces. This allows an early mobilization and undisturbed primary wound healing. This study evaluated a uniform group of eight paraplegic patients with sacral decubital ulcers and covered the lesions using gluteal rotation flaps with a deepithelialized tip to anchor the flap subcutaneously on the contralateral ischial tuber. Initial wound healing and recurrence after one year were evaluated. All but one flap showed uneventful wound healing, and all the flaps presented without any signs of recurrence or instability. The authors suggest that sufficient anchoring using a deepithelialized part of the flap helps to integrate and stabilize sacral rotation flaps.

Effects of skin wrinkles, age and wetness on mechanical loads in the stratum corneum as related to skin lesions

Finite element models of skin were developed to determine the effects of wetness, age, and wrinkles on mechanical strains and stresses in the stratum corneum (SC) as related to skin lesions. We modeled two geometries, young (0.12-mm-deep wrinkles) and aged (0.18-mm-deep wrinkles), and for each geometry, three loading conditions were applied (compression in a dry environment, compression and shear in dryness, and compression with shear in wetness). Effects of skin wrinkling were studied independently or while coupled with age-related mechanical property changes. For each simulation, we calculated the peak maximal shear strain and stress in the SC, peak shear stress on the skin surface, and volumetric exposure of the SC to potentially injurious shear stresses (<70 kPa). Compression and shear with wetness produced the highest skin surface loads. Volumetric exposure of aged skin to potentially injurious shear stresses was six times greater than in the young skin for these conditions. Deeper wrinkles caused elevated loads in the SC consistently for all outcome measures and independently of the age factor. Thinning and/or stiffening the SC increased both the surface and internal SC stresses. Our findings indicate that theoretically, wetness, skin aging, and/or skin wrinkling are all risk factors for skin lesions such as superficial pressure ulcers.

Observation of capillary flow in human skin during tissue compression using CCD video-microscopy

Recent technological advances of the CCD video-camera have made microscopes more compact and greatly improved their sensitivity. We newly designed a compact capillaroscopy which was composed with a CCD video-probe equipped a contact-type objective lens and illuminator. In the present study, we evaluated usefulness of the instrument for a bed-side human capillaroscopy to observe the capillary flow in various dermal regions. The influences of tissue compression on the dermal capillary blood flow were also investigated to confirm the utility for clinical applications. Our capillaroscopy visualized the nutritional capillary blood flow in almost all parts of skin surface. Our observations showed that a level of vertical stress similar to arterial pressure was required to stop the capillary flow. From these demonstrations the present CCD video-probe based capillaroscopy would be useful for clinical applications as a bed-side human capillaroscopy.

Friction coefficients in a longitudinal direction between the finger pad and selected materials for different normal forces and curvatures

This study investigated the effect of object curvature, normal force and material on skin friction coefficient. Twelve subjects slid their middle fingertip pad against a test object with small (11 mm), medium (18, 21 mm) or large (flat object) radii of curvature, while maintaining a normal force of 1, 10 or 20 N. Tested materials were aluminium and four rubber hoses. The average friction coefficient was 0.6 for aluminium and 0.9 for the rubber hoses. As normal force increased from 1 to 20 N, the average friction coefficient decreased 46%. Friction coefficient did not vary significantly with object curvature. The citation of friction coefficient data requires careful attention to normal force levels with which they are measured, but not so much to object curvature between 11 mm and infinity. This study provides skin friction coefficient data that are needed for design of objects that are manipulated with the hands. The investigation of the effect of object curvature on skin friction coefficient has important implications to ergonomics practices as many objects handled in everyday activities have curved surfaces.

A prospective clinical audit of a new dressing design for lower limb arthroplasty wounds

An audit of wound healing in patients undergoing total hip or knee arthroplasty in a Scottish hospital found that use of a barrier film made no difference to the effectiveness of a new Hydrofiber/hydrocolloid dressing combination.

Topical negative pressure therapy for para-ileostomal ulceration in a patient with Behçet's disease

BehCet's disease is a chronic, relapsing, inflammatory disorder. This case report describes how use of an improvised topical negative pressure (TNP) device in a patient with a non-healing para-ileostomal ulcer with Behçet's disease.

Treating the chronic wound: A practical approach to the care of nonhealing wounds and wound care dressings

Chronic wounds are a major healthcare problem costing the United States billions of dollars a year. The American Academy of Dermatology has underscored the significance of wound care in dermatological practice. It is critical for all dermatologists to understand the elements of diagnosis and therapy. We emphasize major aspects of diagnosis and present a simple classification of wound dressings with guidelines for usage and relative cost data.

LEARNING OBJECTIVE

After completing this learning activity, participants should be able to diagnose common types of chronic wounds, formulate a therapeutic plan, and describe the major classes of topical therapies and dressings for the chronic wound.

Evaluation of a new pressure ulcer preventive dressing containing ceramide 2 with low frictional outer layer

AIM

This paper is a report of an evaluation of the effectiveness of a newly developed dressing for preventing persistent erythema and pressure ulcer development and improving the water-holding capacity without increasing the skin pH in bedridden older patients.

BACKGROUND

Shear forces and skin dryness play important roles in persistent erythema and pressure ulcer development. To eliminate these risks, we developed a dressing to reduce shear forces and improve the water-holding capacity. However, the effects of this dressing in clinical settings remain unknown.

METHOD

An experimental bilateral comparison study was conducted at a hospital in Japan in 2004 with 37 bedridden older patients at risk of pressure ulcer development. The dressing was randomly applied to the right or left greater trochanter for 3 weeks. No dressing was applied to the opposite side as a control. The skin was monitored weekly during the 3-week application for persistent erythema and pressure ulcer development. Skin hydration and pH were also assessed during the intervention and for 1 week after dressing removal.

FINDINGS

The incidence of persistent erythema was significantly lower in the intervention area than the control area [P = 0.007, RR 0.18 (95% CI: 0.05-0.73) and NNT 4.11 (2.50-11.63) ]. No pressure ulcers occurred in either the intervention or control area. Skin hydration increased significantly during dressing application and remained high after removal (P < 0.001) relative to the control area. Skin pH decreased significantly during the application (P < 0.001) but returned to control levels after removal (P = 0.38).

CONCLUSION

This safe and effective dressing can be used for patients with highly prominent bones and dry skin to prevent pressure ulcers.