Multilayer Foam Research Articles

Silicone adhesive multilayer foam dressings to prevent hospital-acquired sacrum pressure ulcers: An economic evaluation based on a publicly funded pragmatic randomized controlled trial linked with real-world data

ObjectivesTo estimate the cost-effectiveness of sacrum multilayer silicone foam dressings as an adjuvant prophylactic therapy compared to standard pressure ulcer prevention in a hospital population at high risk for pressure ulcer development. MethodsAn economic evaluation is performed from a healthcare payer's perspective. This evaluation is based on a Belgian publicly funded pragmatic randomized controlled trial (RCT), linked with real-world data from administrative claims database and a Belgian cost analysis. A cost-consequences analysis with a one-year time horizon is performed. ResultsThe RCT has shown that the risk of developing a new pressure ulcer on the sacrum was statistically significantly reduced by 41 % in the treatment group (RR = 0.59, 95 % CI 0.35–0.98, p = 0.04). The absolute risk reduction of 2.0 % (95 % CI -0.1–4.1 %) coincides with a number needed to treat of 50.0 to prevent one new pressure ulcer of category II or worse. The evolution of quality of life is on average negative for patients who developed a pressure ulcer before day 3, while it is positive for patients without pressure ulcers. In a scenario with conservative assumptions, i.e. without inclusion of price discounts for the multilayer silicone foam dressings and only including costs during the hospitalization, pressure ulcer prevention with dressings on the sacrum was already cost-neutral. ConclusionsThe preventive use of silicone adhesive multilayer foam dressings on the sacrum for a population similar to the pragmatic trial population can be supported both from a clinical and economic point of view.

Aerogel‐like biodegradable acoustic foams of bacterial cellulose

AbstractWe report the first work on the development of biodegradable acoustic foams from self‐grown bacterial cellulose (BC) from kombucha solution and green processing techniques. Kombucha BC‐agar and kombucha BC‐polyvinyl alcohol foams were fabricated by using slurries of BC pellicles mixed with the additives, froze for 24 h, and recast into foams using the freeze‐drying method. The foams were aerogel‐like with a density 20 kg/m3, thermally stable upto 220 °C, and crystallinity ~74%. Morphological analysis revealed macropores with coarse walls in agar‐based foams, whereas the PVA‐based foams comprised a polydisperse pore network with coarse walls. A broadband absorption was observed with a maximum of 0.4 for the 2.5‐mm‐thick single‐layer foams and 0.9 for the 12‐mm‐thick multilayer foams. The sound absorption was found to be on par with the biodegradable foams of agar and other cellulose‐rich materials such as agricultural residue, yet with a lightweight. Being largely porous, the foams had little transmission loss. As the densities and the crystallinities of these foams are tunable by the addition of other polymers, the results from this study provide scope to explore BC‐based lightweight materials for large‐scale fabrication suitable for sound absorption over specific regimes.

CUSTO-EFETIVIDADE DE DUAS COBERTURAS NA PREVENÇÃO DE LESÃO POR PRESSÃO EM PACIENTES DE TERAPIA INTENSIVA

ABSTRACT Objective: to analyze the cost-effectiveness of using silicone adhesive multilayer foam and transparent polyurethane film in preventing pressure injuries in patients admitted to an Intensive Care Unit. Method: this is an economic cost-effectiveness study, developed with public domain data and a rapid literature review, which included three studies developed in Canada, the United Kingdom, Italy and the United States. The searches were carried out in the PubMed, Cochrane and Scopus databases. The population was patients admitted to the Intensive Care Unit. The perspective was from the Brazilian Health System, with a time horizon of less than one year. Data was collected and analyzed between March and June 2022. A decision tree model was developed using TreeAge Pro® 2017 software to project economic outcomes of incremental cost and effectiveness, incremental cost per effectiveness, and cost per percentage increase in preventing the development of pressure injuries. Sensitivity analysis was also performed. The Consolidated Health Economic Evaluation Reporting Standards and the Methodological Guideline for Economic Evaluation of the Brazilian Ministry of Health recommendations were adopted. Results: multilayer foam reduces the occurrence of pressure injuries at a lower cost when compared to film, promoting an average saving of R$ 278.78 (US$ 1,393.90) for each patient. Conclusion: multilayer foam was the most cost-effective technology in preventing pressure injuries in Intensive Care Unit patients in the Brazilian Health System.

Examining the Clinical Outcomes of a Soft Silicone Multilayer Foam Dressing for Exudate Management in US Hospitals: It Is Time to Optimize Dressing Change Frequency

Background. Acute and chronic wounds in the acute hospital setting are commonly managed with soft silicone multilayer foam dressings (SSMFDs). While many SSMFDs are indicated for wear time of up to 7 days, they are often changed more frequently. Objective. To use real-world data on dressing change practices and clinical outcomes to examine whether a built-in indicator on a proprietary SSMFD could reduce unnecessary dressing changes. Materials and Methods. Health care professionals (HCPs) were screened and recruited from a health care research panel to complete per wound data capture forms. Outcomes reported included dressing wear time, healing rates, dressing change frequency, user satisfaction, and adverse events. Outcomes were reported as an aggregated data set. Results. A total of 53 wounds were analyzed. The mean treatment period was 23.83 days, which included dressing changes every 2 to 3 days on average. Of the 53 cases analyzed, the unique change indicator on the SSMFD was used to guide dressing change frequency 98% of the time. Overall, 21% of wounds completely healed (n = 11), 70% (n = 37) showed improvement, 9% (n = 5) were static, and 0% deteriorated. Conclusion. Real-world data on use of the proprietary SSMFD in an acute setting indicates that the SSMFD can allow for the optimization of dressing change protocols to enable appropriate dressing change frequency, allowing for undisturbed healing and maximizing HCP and dressing resources.

Exploring the mechanical properties of 3D-printed multilayer lattice structures for use in accommodative insoles

Full-contact insoles fabricated from multilayer foams are the standard of care (SoC) for offloading and redistributing high plantar pressures in individuals with diabetes at risk of plantar ulceration and subsequent lower limb amputation. These devices have regional variations in total thickness and layer thickness to create conformity with a patient's foot. Recent work has demonstrated that metamaterials can be tuned to match the mechanical properties of SoC insole foams. However, for devices fabricated using a multilayer lattice structure, having regional variations in total thickness and layer thickness may result in regional differences in mechanical properties that have yet to be investigated. Three lattices, two dual-layer and one uniform-layer lattice structure, designed to model the mechanical properties of SoC insoles, were 3D-printed at three structure/puck thicknesses representing typical regions seen in accommodative insoles. The pucks underwent cyclic compression testing, and the stiffness profiles were assessed. Three pucks at three structure/puck thicknesses fabricated from SoC foams were also tested. Initial evaluations suggested that for the latticed pucks, structure thickness and density inversely impacted puck stiffness. Behaving most like the SoC pucks, a dual-layer lattice that increased in density as structure thickness increased demonstrated consistent stiffness profiles across puck thicknesses. Identifying a lattice with constant mechanical properties at various structure thicknesses may be important to produce a conforming insole that emulates the standard of care from which patient-specific/regional lattice modulations can be made.

Optimal design of 3D macro-structures for multi-layer foams achieving ultra-broadband microwave absorption properties and high retention after immersion in brine

A novel flexible microwave absorbing material (C–MCM–FAS) with a cone-shaped sandwich structure is proposed, which is constructed by carbonyl iron-carbon nanotubes/PDMS foams and SiC–morchella biochar/PDMS film. To enhance broadband absorption properties, a three-level scale design has been creatively introduced into C–MCM–FAS, encompassing millimeter, micron and nano scales. The rational structural parameters of C–MCM–FAS are determined by CST simulation, leading to the preparation of C–MCM–FAS with an impressive minimum reflection loss (RLmin) of −43.26 dB and an effective absorption band (EB) covering the entire C2, X, and Ku bands at 11.79 GHz. Encouragingly, the measured results are basically consistent with the simulation results (an RLmin of −35.78 dB and an EB of 14.68 GHz), which verifies the accuracy of the theoretical simulation and the feasibility of the method. It holds great significance that the investigation of the adsorption retention rate of C–MCM–FAS after immersing it in 3.5 wt% NaCl solution for 21 days. The measured RLmin reaches −48.41 dB with a retention rate of 111.9 %, and the EB reaches 8.56 GHz with a retention rate of 72.6 %. This work presents a groundbreaking concept for designing structural absorbers, expecting the C–MCM–FAS to become a strong contender for application in special environments like microwave detection in the nautical field.

Underwater impulsive response of sandwich structure with multilayer foam core

Abstract The coupling between fluid-solid interaction and structural response is a crucial factor in understanding the resistance of sandwich structures to underwater blasts. In this study, we present a theoretical model that predicts the dynamic response of multilayer foam core sandwich beams subjected to underwater impulses. We carried out a time-scale intercoupling analysis by considering the compressible core in both incident impulse and structural response. In the incident impulse coupling phase, the one-dimensional fluid-structure interaction in terms of cavitation evolution is conducted to obtain the incident pressure profile. A four inter-stages response model is proposed for further analyze the structural response coupling phase and its coupling with core strength. Explicit finite element calculations are performed to verify the theoretical results in terms of the velocity profile, transverse deflection, and core compression. The results suggest that the interaction between the four stages of the dynamic response is significantly influenced by the impulsive intensity and core strength, and the sandwich beam does not undergo all the four stages. The equivalent core strength used in the theoretical analysis is confirmed accurate to predicts impact resistance of the corresponding graded core sandwich beam, which is inferior to the sandwich beam with uniform cores, despite having the same areal mass.

The incidence of intraoperatively acquired pressure injuries in the park-bench position was reduced by applying soft silicone multilayer foam dressings.

The Park-Bench Position (PBP) is associated with a high incidence rate of intraoperatively acquired pressure injuries (IAPIs). Preventive measures must be established to prevent the development of IAPIs. We investigated the risk factors for PBP by applying a soft silicone multilayered foam dressing (SMD) under core temperature management to prevent IAPIs. We conducted a prospective, single-centre, open-label observational study of patients undergoing elective neurosurgery operations using PBP in a university hospital in Japan. The incidence rate of IAPIs in this study was compared with that in our two previous studies, in which a film dressing was applied and core temperature management was not performed. IAPIs developed in 90 patients (6.7%); in the lateral thoracic region in five patients and the iliac crest region in one patient. The operative time (every 1 h: p = 0.0001, OR: odds ratio 3.62, 95% CI: confidence interval 1.73-11.42) was significantly associated with the incidence of IAPIs. In our two previous studies, the incidence rate of IAPIs was 11.0% and 24.1%, respectively, when film dressing was used. SMD may weaken the involvement of risk factors in IAPIs.

Multifunctional melamine-based multilayer foam with heterogeneous alternating structure towards electromagnetic interference shielding

With the rapid development of 5G technology, there is an urgent need to endow electromagnetic interference (EMI) shielding materials multifunctionality to cope with various harsh environments. Herin, a multifunctional melamine-based EMI shielding composite with heterogeneous alternating multilayer structure were fabricated through the layer-by-layer stacking method, consisting of Ni coated melamine foam (MF@Ni) layers, Fe3O4@polydimethylsiloxane dipped MF layers (Fe3O4@PDMS/MF) and metallized polyimide fabric layer (PI@Ni). The synergistic electromagnetic loss and interfacial polarization loss formed by the selectively distributed conductive Ni coating and magnetic Fe3O4 nanoparticles result in a high EMI shielding effectiveness (SE) of 54.20 dB with an absorption (A) value of 0.51 for the multilayer MF-based composite. Moreover, since the micro/nano porous structure, the nonflammability of MF, the functional Ni coating and Fe3O4@PDMS filling, the multilayer foam owns thermal insulation and flame retardancy. This work provides a viable strategy for designing absorption-based EMI shielding materials with thermal insulation and flame retardancy, which accords with the next generation of multifunctional EMI shielding materials.

Pressure Injury Prevention in Patients in Prone Position With Acute Respiratory Distress Syndrome and COVID-19.

In patients with acute respiratory distress syndrome, prone positioning improves oxygenation and reduces mortality. Pressure injuries occur frequently because of prolonged prone positioning in high-risk patients, and preventive measures are limited. This article describes 2 patients who developed minimal pressure injuries despite several prone positionings. Prevention strategies are also described. A 64-year-old man and a 76-year-old woman were admitted to the hospital with respiratory insufficiency. Due to acute respiratory distress syndrome, both patients were intubated and received mechanical ventilation and prone positioning. Both patients had positive test results for SARS-CoV-2 and a diagnosis of acute respiratory distress syndrome. Patient 1 was in prone position for 137 hours during 9 rounds of prone positioning; patient 2, for 99 hours during 6 rounds of prone positioning. The standardized pressure injury prevention bundle for prone positioning consisted of skin care, nipple protection with a multilayer foam dressing, a 2-part prone positioning set, and micropositioning maneuvers. For both patients, 2-cm-thick mixed-porosity polyurethane foam was added between skin and positioning set in the thoracic and pelvic areas and a polyurethane foam cushion was added under the head. Patient 1 developed no pressure injuries. Patient 2 developed category 2 pressure injuries on the chin and above the right eye during deviations from the protocol. For both patients, the additional application of polyurethane foam was effective for preventing pressure injuries. These case reports support the addition of polyurethane foam to prevent pressure injuries in patients placed in the prone position.

Dynamic Response of Components Containing Polymer Composites in the Resonance Region for Vibration Amplitudes up to 5g.

This paper focuses on high-speed-operation textile machines with the aim of increasing the rotational speed by operating within the resonance region to vibration amplitudes up to 5g. The native design does not allow keeping the vibration amplitude under 5g, which is a safe operation mode, for revolutions more than 120,000 min-1. The innovative modification of the design was made by the incorporation of polymer composite materials with carbon dust, glass hollow microspheres, and silica sand fillers to the rotor-bearing casing; moreover, through the incorporation of a multilayered foam composite structure and particle damper to the pressure plate of the mechanical machine system. By using the approach of supplementing with high-damping composites, the existing native design can be used, thus avoiding the costly production of new components and subassemblies with modified shapes and dimensions. Twelve possible combinations of mentioned modifications were tested, evaluated and compared with the native design made of steel, as standard structure material in mechanical engineering. The average vibration amplitudes were evaluated in the region before the resonance peak and in the range of the resonance peak, i.e., 120,000-135,000 min-1. Significant vibration amplitude reductions in the range from 30 to 70% of the average vibration amplitude were obtained. The vibration amplitude reduction results were evaluated considering the mass through the amplitude reduction efficiency coefficient.

Preparation and Properties of Epoxy/Multiwalled Carbon Nanotube Nanocomposite Foams with an Alternating Layer Structure.

Multilayered epoxy/multiwalled carbon nanotube (EP/MWCNT) composite foams with a density of 0.713 g/cm3 were prepared through the chemical foaming of laminated epoxy sheets in a mold with a fixed cavity. The difference in cell morphology and properties between adjacent layers in the multilayer foams (two- and four-layer) was tuned by MWCNT or chemical foaming agent (CFA) concentration. It was found that the storage modulus and microwave-absorbing ability of the multilayered EP/MWCNT foams were strongly associated with the loading direction, the thermal diffusivity was slightly direction-dependent, and the electromagnetic interference (EMI) shielding effectiveness (SE) was direction-independent. In addition, as the layer number increased, the mechanical, thermal, and electrical conductivity properties and EMI shielding performances of the multilayered composite foams showed different change tendencies. These results indicated that the effect of the multilayer structure on the properties of composite foams was different when they underwent force, heat, or electromagnetic microwave, and the underlying reasons were investigated in detail.

Silicone adhesive multilayer foam dressings for preventing facial pressure injuries in COVID-19 patients in prone position.

The development of facial pressure injury (PI) during prone position is frequently described. During the COVID-19 pandemic, the number of patients with facial PIs increased. This quality improvement project describes the effectiveness of using silicone adhesive multilayer foams for preventing facial PIs in COVID-19 patients in need of prone position therapy. After introduction of foam dressing on chin and forehead to the standard protocol procedures for PI prevention, the decrease in number of patients developing facial PIs was statistically significant. Based on these results, the use of silicone adhesive multilayer foam will be implemented as a standard procedure for facial PIs prevention.

X-band full absorbing multi-layer foam with lightweight and flexible performance

A novel absorbing material with a flexible sandwich structure (S121) was designed and assembled using light-weight foams of Polydimethylsiloxane (PDMS) to achieve a full X-band absorption. The PDMS foams based on the composites of hollow polyaniline and MWCNTs (HPC) were prepared by means of impregnation technology selecting sugar cubes as a template. For the construction of sandwich S121, the upper and lower layers were HPC-PDMS foams (d foam = 1.0 mm) and the middle layer was HPC-PDMS film (d film = 0.5 mm). The SEM results revealed plentiful pores existed in S121, which would endow S121 with the traits of light-weight and lower density. The absorption performance of S121, single-layer HPC-PDMS foam (S1) and single-layer HPC-PDMS film (S2) had been characterized. Of importance, S121 achieved full absorption in X-band and its minimum reflection loss (RL min ) reached −32.65 dB at 9.5 GHz. In contrast, the RL min of S1 and S2 were only −15.42 dB and −11.72 dB. The frequency regions with RL < −10 dB of S1 and S2 were surprisingly narrow, which were 1.5 GHz and 0.4 GHz, respectively. The results indicated that the design of S121 demonstrated a synergistic effect of foams and film, which was helpful to enhance absorption and realize an X-band full absorption. Of great significance, due to the excellent flexibility of S121, after bending and compressing many times, RL min value is nearly identical to that of original S121, and the effective bandwidth is also full coverage of X-band. The results showed that the proposed S121 design is feasible for applications in X-band. • A flexible sandwich was designed and assembled based on PDMS foam and film. • The sandwich was constructed by filtering, absorbing and reverse interference layers. • The sandwich achieved a full X-band absorption and the RL min of −32.65 dB at 9.5 GHz. • The sandwich still kept admirable EM absorption after bending and compressing tests.

Use of multilayer silicone foam dressings as adjuvant therapy to prevent pressure injuries.

Despite progress in the prevention of pressure injuries (PIs), they remain a challenging public health problem because of their frequency and morbidity. Protection of the skin by multilayer silicone foam dressings may be an adjuvant measure to prevent PIs in high-risk patients. Despite the available clinical data and published recommendations on this measure, caregivers face difficulties in identifying patients who would benefit from this adjuvant measure. The objective of this work was to define the profiles of high-risk patients who would benefit optimally from this measure in combination with basic preventive procedures. This consensual expert opinion was drawn up using two methods: the Nominal Group Technique with eight medical and paramedical experts, and the Delphi process with 16 experts. The bases for this expert consensual opinion were a formal search and analysis of the published literature regarding evidence on the prevention of PIs using multilayer silicone foam dressings. The consensual expert opinion reported here addresses five proposals mostly intended to define patients who would benefit from the use of a multilayer silicone foam dressing (≥4 layers) to prevent PIs (sacrum and heels).

Low-velocity impact response of multilayer foam core sandwich panels with composite face sheets

This paper focuses on the analytical and experimental investigations on the low-velocity impact response of multilayer foam core sandwich panels with composite face sheets. Taking into account the reinforcement of face sheets by foam cores, an energy-based analytical model for multilayer sandwich panels was developed to predict contact force, impactor displacement and energy absorption. The predictions were validated by experimental results. The impact resistance of the multilayer sandwich panel is superior to that of monolayer one with the same mass under the low-velocity impact. Adjusting the local stiffness close to the top face sheet can further improve the energy absorption of multilayer sandwich panels; however, the maximum contact force will be increased. This finding suggests that the design of multilayer foam core sandwich panels needs to carefully consider the requirements according to the cases in engineering applications.

Effects of loading and prophylactic dressings on the sacral and heel skin: An exploratory cross-over trial.

Pressure ulcers/injuries are caused by sustained loading and deformation of skin and underlying soft tissues. Prophylactic dressings are recommended as an adjunct to other preventive measures such as repositioning and offloading. The aim of this study was to investigate the effects of prophylactic soft silicone multi‐layered foam dressings on the skin structure and function of the two most common pressure areas, sacrum and heel, with and without loading. An exploratory randomised cross‐over trial using intra‐individual comparisons was conducted. Eight healthy volunteers (mean age 27.5 years) were assigned to three groups and either spent 2.5 hours on a standard hospital mattress lying in supine position with and without dressings or spent 2.5 hours with dressings applied but without loading. Skin temperature, stratum corneum, and epidermal hydration increased in all groups irrespective of wearing a dressing and/or loading. Mean roughness decreased at the heels. Reactive hyperaemia and the release of interleukin 1 alpha were associated with loading only. Results suggest that the occlusive effects of dressings are similar or only slightly greater than those observed with non‐loading or loading without dressings. Thus, a dressing does not cause additional irritation or skin changes during loading but it may reduce the inflammatory response.

Effect of multi-layer prosthetic foam liner on the stresses at the stump–prosthetic interface

The prosthetic liner plays a significant role in the redistribution of the pressure between the stump and the socket, as it adding a cushioning layer between the stump and the socket which relieves pain and makes the prosthesis more comfortable. This study employed nonlinear finite element analyses to investigate the peak pressure and shear stress at stump–prosthetic interface in the case of multi-layer prosthetic foam liner, this liner having an inner polymeric foam layer Surrounded by another type of polymeric foam layer, we used three different types of foams in different order to define this liner (flexible polyurethane foam, polyurethane-shape memory polymer foam, and natural rubber latex foam). That’s allows comparing 6 deferent configuration of multi-layer prosthetic foam liner.

Silicone adhesive multilayered foam dressings for pressure ulcer prevention.

Silicone adhesive multilayered foam dressings for pressure ulcer prevention.

A prospective, randomized, controlled, crossover study comparing three multilayered foam dressings for the management of chronic wounds.

Aim: Compare foam dressings- Mepilex Border Flex (MxBF), Allevyn Life (AL) and Optifoam Gentle EX (OGEX) -in treatment of chronic wounds. Materials & methods: Prospective, randomized, controlled trial (crossover design). Subjects received one dressing for 2weeks, then comparator dressing for following 2weeks. Wound/periwound characteristics evaluated weekly at dressing change. Primary endpoint: dressing durability (incidence of exudate strikethrough). Results: Higher incidence of intact dressings (no strikethrough) at Day 7 (Week1) with MxBF (6/17; 35.3%) compared with AL (1/18; 5.6%), and with MxBF (7/16; 43.8%) compared withOGEX (2/16; 12.5%;p<0.05). No significant differences between groups regarding wound size reduction. Conclusion: MxBF had statistically greater durability than AL/OGEX during first critical week of treatment.