Gabriel A, Shores J, Bernstein B, de Leon J, Kamepalli R, Wolvos T, Baharestani MM, Gupta S. A Clinical Review of Infected Wound Treatment with Vacuum Assisted Closure ® (V.A.C. ®) Therapy: Experience and Case Series. ABSTRACT Over the last decade Vacuum Assisted Closure ® (KCI Licensing, Inc., San Antonio, TX) has been established as an effective wound care modality for managing complex acute and chronic wounds. The therapy has been widely adopted by many institutions to treat a variety of wound types. Increasingly, the therapy is being used to manage infected and critically colonized, difficult-to-treat wounds. This growing interest coupled with practitioner uncertainty in using the therapy in the presence of infection prompted the convening of an interprofessional expert advisory panel to determine appropriate use of the different modalities of negative pressure wound therapy (NPWT) as delivered by V.A.C. ® Therapy and V.A.C. Instill ® with either GranuFoam ™ or GranuFoam Silver ™ Dressings. The panel reviewed infected wound treatment methods within the context of evidence-based medicine coupled with experiential insight using V.A.C. ® Therapy Systems to manage a variety of infected wounds. The primary objectives of the panel were 1) to exchange state-of-practice evidence, 2) to review and evaluate the strength of existing data, and 3) to develop practice recommendations based on published evidence and clinical experience regarding use of the V.A.C. ® Therapy Systems in infected wounds. These recommendations are meant to identify which infected wounds will benefit from the most appropriate V.A.C. ® Therapy System modality and provide an infected wound treatment algorithm that may lead to a better understanding of optimal treatment strategies.

Prompt diagnosis and treatment of necrotizing fascitis reduces the morbidity and mortality rates of this devastating disease. To examine the clinical outcomes of using negative pressure wound therapy in the adjunctive management of wounds secondary to necrotizing fascitis, a retrospective review of medical records was conducted. Participants included 11 consecutive patients (16 wounds) with a diagnosis of necrotizing fascitis admitted to a teaching hospital between 2000 and 2005 and treated on an inpatient basis with negative pressure wound therapy. The patients included seven men, four women (average age 54 years; range 18 to 82 years). Variables abstracted from the medical records and consultation notes included: demographic information, tissue and blood bacteriological data, wound history, wound healing outcomes, duration of negative pressure wound therapy, length of hospital stay, and mortality and morbidity information. Variables were entered into an electronic database and analyzed. Operative tissue biopsies were obtained and all participants received serial surgical debridements as well as infection, nutrition, and hemodynamic support. Negative pressure wound therapy was applied to the wound(s) at 125 mm Hg continuous negative pressure until reconstructive closure could be performed. Most wounds (10) were on lower extremities, seven patients presented with sepsis, and beta-hemolytic Streptococcus was identified in nine wounds. Mean number of negative pressure wound therapy treatment days was 25 (range: 7 to 74), mean length of stay was 67 days (range: 21 to 186). All wounds were successfully closed ĝ€" 73% received split-thickness skin grafts, 27% required flaps, 100% limb salvage was achieved, and all patients survived. No negative pressure wound therapy or dressing-associated complications were observed. Negative pressure wound therapy was found to be a viable adjunctive treatment in the management of wounds associated with necrotizing fascitis.

Bakgrund: Undertrycksbehandling eller Negative Pressure Wound Therapy (NPWT) är en sårbehandling som ofta används när andra behandlingar inte lyckats med läkningen av det kroniska såret. Flera forskningsstudier stödjer metodens effektivitet gällande sårläkning och bildande av granulationsvävnad, men behandlingens påverkan på patienten och dennes upplevelse av att använda behandlingen är bristfällig.Syfte: Syftet med studien var att beskriva patientens upplevelse av att genomgå undertrycksbehandling av ett sår och om behandlingen påverkar patientens livskvalitet.Metod: Litteraturstudie baserad på kvalitativa artiklar som svarade på huvudsyftet och kvantitativa artiklar som svarade på frågeställningen.Resultat: Informanterna upplevde att NPWT-enheten var ett fokus i behandlingen. Behandlingen var smärtsam och påverkade det dagliga livet och informantens självbild. Informanterna upplevde en brist på information och stöd och en inkonsekvens i vårdpersonalens kunskap och kompetens. Ingen signifikant skillnad i livskvaliteten påvisades vid jämförelse av NPWT och standard sårbehandling.Konklusion: NPWT-behandlingen upplevdes som en krävande sårbehandling där patienten utmanades både fysiskt och psykiskt. Behandlingen innebar mycket eget ansvar, var starkt förknippad med smärta och oro och ångest överskuggade målet med behandlingen. / Background: Negative Pressure Wound Therapy (NPWT) is a wound therapy, often used, when other therapies fail to heal the chronic wound. Several research studies support the effectiveness of the method regarding wound healing and granulation tissue formation, but the effect of treatment on the patient and his experience of using the treatment is lacking. Aim: The aim of the study was to describe the patient´s experience of undergoing negative pressure wound therapy and if the treatment affects the patient´s quality of life. Method: Literature review based on qualitative articles that responded to the main objective and quantitative articles that answered the research question. Results: The informants felt that the NPWT device was a focus in the treatment. The treatment was painful and affected the daily life and the informant´s self-image. The informants experienced a lack of information and support, and an inconsistency in the nursing staffs knowledge and skills. No significant difference in the quality of life were proved by comparing NPWT and standard wound treatment.Conclusion: NPWT treatment was perceived as a demanding wound treatment where the patient was challenged both physically and mentally. Treatment entailed a lot of own responsibility, was highly associated with pain and worry and anxiety overshadowed the goal of treatment.

Bakgrund: Sårvård medför höga kostnader för samhället och bidrar till sänkt livskvalitet för den drabbade individen. Det är viktigt med en effektiv och personcentrerad sårvård för att patienten ska kunna bibehålla en god livskvalitet. Vakuumassisterad sårbehandling är en metod som har blivit allt vanligare för behandling av sår. Syfte: Syftet med studien var att beskriva patienters erfarenheter av vakuumassisterad sårbehandling. Metod: Studien genomfördes som en allmän litteraturstudie av åtta kvalitativa artiklar. Resultat: Fyra teman identifierades: att delta i en ny spännande behandlingsmetod, att vara begränsad i sin vardag, att ha smärta och att ha behov av kunskap och stöd. Konklusion: Patienterna såg fram emot att delta i en ny spännande behandlingsmetod. Patienterna upplevde att de begränsades fysiskt, psykiskt och socialt samt hade behov av stöd. Genom att beskriva patienters erfarenheter av vakuumassisterad sårbehandling identifieras områden som sjuksköterskan behöver vara medveten om för att kunna ge en personcentrerad och god evidensbaserad vård. / Background: Wound care entails high costs for society and contributes to a reduced quality of life for the affected individual. Effective and person- centered wound care is important for the patient to be able to maintain a good quality of life. Negative pressure wound therapy is a method that has become increasingly common for the treatment of wounds. Purpose: The purpose of the study was to describe patients' experiences of negative pressure wound therapy. Method: The study was conducted as a general literature study of eight qualitative articles. Results: Four themes were identified: participating in a new exciting treatment method, being limited in everyday life, having pain and needing knowledge and support. Conclusion: The patients looked forward to participating in a new exciting treatment method. The patients felt that they were limited physically, psychologically and socially and had a need for support. By describing the patients' experiences of negative pressure wound therapy, areas are identified that the nurse needs to be aware of in order to provide person- centered and good evidence-based care.

INTRODUCTION: Negative pressure wound therapy (NPWT) has proved to be a powerful tool in facilitating the healing of difficult wounds of a variety of etiologies. The pediatric experience with NPWT has been limited because of concerns about vascular compression and pain associated with treatment. METHOD: A retrospective review (2004-2014) was conducted at Shriners Hospital for Children-Boston to evaluate the therapeutic effect of NPWT on children with difficult wounds due to burns or soft-tissue trauma. Information was collected on patient demographics, wound size and depth, burn injury etiology, length of hospital stay, number of operating room visits, and other treatment procedures. NPWT was instituted in the operating room under general anesthesia using a commercially available system. NPWT was not initiated until all necrotic material had been removed from the wounds. A negative pressure varying between -50 and -125 mmHg was applied to the wound as continuous suction, with younger children being prescribed the lower negative pressures. NPWT dressings were changed every 5-7 days in the operating room. When wounds were clean and granulated, they were closed with split-thickness skin grafts. RESULTS: Twenty-nine children with an average age of 9.43 +/- 1.95 years (range 2 months to 18 years) were treated with NPWT. The average total wound size was 24.8 +/- 8.9% (range 0%-95%) of the body surface in patients who had suffered burns and non-burn injuries. Injury mechanisms were categorized as hot liquid (2 children), contact with hot object (4 children), electricity (7 children), flame (9 children), and other non-burn injuries such as abrasion and degloving (7 children). Over 90% of the patients required central venous or bladder catheters. Perceived benefits of the treatment included reduced numbers of dressing changes and more rapid wound granulation. There were no episodes of bleeding associated with NPWT. All patients healed their wounds, were successfully grafted, and survived. CONCLUSION: NPWT has a useful role in the pediatric burn unit in facilitating wound healing and improving quality of life. A significant correlation between the size of third-degree burn wounds and the number of negative pressure therapies suggests that NPWT may be more effective in treating complicated burn wounds. Overall, NPWT appears safe and effective when applied to well-debrided wounds, and the treatment does not seem to be associated with excessive bleeding or discomfort in children.

An experimental study was carried out on a single-ply low-slope roof using a series of different underlayment layers to test and understand distributional characteristics of negative air pressure throughout the roof assembly, when subjected to suction pressure corresponding to different wind speeds. Various underlayments were tested at the Research & Demonstration Facility at Virginia Polytechnic Institute and State University to develop design guidelines for the installation of recently developed omni-directional roof vent on low slope membrane roofing systems. The newly designed and patented low-pressure roof vent works on Bernoulli and Venturi air flow principals and helps prevent uplift and detachment of the roofing membrane during storm or high wind conditions by creating a negative pressure zone underneath the roof membrane. The objective of this research is to further develop the Pressure Equalizing Vent System by testing the wind vent in combination with different underlayments and to determine the appropriate tributary area of each vent under dynamic wind conditions. The determined area of influence of each wind vent therefore serves as a guideline for appropriate spacing of the vents on the roof. It will also suggest the wind speed at which the pressure is lowered and its ability to weather storm events. The pressure sensors permanently installed beneath the membrane will continuously monitor the pressures in and around the wind vent. An additional objective of the research project is to understand the distributional characteristics of negative pressure in various layers of roof assembly in combination with varying underlayment membranes under different suctionals pressure to further develop the Pressure Equalizing Vent System. The proposal seeks to develop a cost effective roof assembly method, which can withstand the effect of extreme wind through improved understanding of air movement through different layers of roof assembly. The study explores the effect of various underlayments on spatial and distributional character of pressure field on the single ply flat roof deck in combination with omni-directional roof vent system. / Master of Science

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<p>Intermeshing counter-rotating twin screw extruders (ICRTSE) are used extensively in the polymer processing industry for pelletizing, devolatilization and extrusion of various plastic products. ICRTSE have better positive displacement ability and are more suitable for shear sensitive materials compared to other types of twin screw extruders.</p> <p>The objectives of this thesis are to understand the flow mechanism and the effects of screw geometries and processing conditions in the ICRTSE. First, a simple flow model based on a volume of the conveying element of ICRTSE was used to calculate flow rate. Since ICRTSE do not give complete positive displacement, the various leakage flows were identified and taken into account in the simple flow model. Although the simple flow model provided reasonable results in terms of flow rate, computer simulations were found necessary due to the limitations of simple flow model. Second, a 3D computer simulation of ICRTSE was developed for various screw geometries and processing conditions. Both Newtonian and non-Newtonian fluids were examined.</p> <p>It was shown the simple model based on geometrical parameters for pumping behaviour give reasonable prediction of flow rate. It was found that determination of negative pressure should be taken into account in numerical simulations. The pumping efficiency is influenced positively by the ratio of flight width-to-channel width but it is affected negatively by the screw pitch length. It is negligibly changed with screw speed. Finally, the dominant flow is shear flow in ICRTSE and therefore, dispersive mixing capacity is very limited due to a lack of elongational effects.</p> / Master of Applied Science (MASc)

Winds create forces on buildings, sometimes with disastrous results. Low-slope roofs are subjected to potentially high levels of suction pressure, especially when winds strike the corner of a building, creating vortices. Traditional methods of attaching roof membranes to substrates are prone to failure when the low pressure on the roof surface instigates a transfer of forces to the roof membrane. Existing pressure-equalized roof systems use the power of the wind to transmit low pressure to the space immediately beneath the roof membrane, pulling the membrane down to the roof surface. The object of this study is the design of a wind vent which, when coupled with a single-ply roof membrane in a complete roof assembly, will successfully equalize low pressure throughout the entire field of the roof. The proposed wind vent differs from existing equalizer valves in its use of the Bernoulli effect to create low pressure. Optimized for ease of manufacturing and installation, the vent is omni-directional and contains no moving parts. After the wind vent prototype is developed, future study will be required to determine the tributary area of each vent, the interaction with the insulation beneath the membrane, the response time of the system when subjected to dynamic wind loading, the effect on the vent of various weather conditions, and the permissible amount of infiltration into the roof system. Associated research will also investigate the benefits of incorporating the heat evacuating capacity of the pressure-equalizing roof vent system into a roof membrane containing an amorphous photovoltaic array. / Master of Science