Peristomal Skin Complications Are Common, Expensive, and Difficult to Manage: A Population Based Cost Modeling Study

BACKGROUND: Peristomal skin complications (PSCs) are the most common post-operative complications following creation of a stoma. Living with a stoma is a challenge, not only for the patient and their carers, but also for society as a whole. Due to methodological problems of PSC assessment, the associated health-economic burden of medium to longterm complications has been poorly described. AIM: The aim of the present study was to create a model to estimate treatment costs of PSCs using the standardized assessment Ostomy Skin Tool as a reference. The resultant model was applied to a real-life global data set of stoma patients (n = 3017) to determine the prevalence and financial burden of PSCs. METHODS: Eleven experienced stoma care nurses were interviewed to get a global understanding of a treatment algorithm that formed the basis of the cost analysis. The estimated costs were based on a seven week treatment period. PSC costs were estimated for five underlying diagnostic categories and three levels of severity. The estimated treatment costs of severe cases of PSCs were increased 2-5 fold for the different diagnostic categories of PSCs compared with mild cases. French unit costs were applied to the global data set. RESULTS: The estimated total average cost for a seven week treatment period (including appliances and accessories) was 263€ for those with PSCs (n = 1742) compared to 215€ for those without PSCs (n = 1172). A co-variance analysis showed that leakage level had a significant impact on PSC cost from 'rarely/never' to 'always/often' p<0.00001 and from 'rarely/never' to 'sometimes' p = 0.0115. CONCLUSION: PSCs are common and troublesome and the consequences are substantial, both for the patient and from a health economic viewpoint. PSCs should be diagnosed and treated at an early stage to prevent long term, debilitating and expensive complications

Developments in silicone technology for use in stoma care

YesSoft silicone's flexibility, adhesive capacity and non-toxic, non-odourous and hypoallergenic nature have made it an established material for adhesive and protective therapeutic devices. In wound care, silicone is a component of contact layer dressings for superficial wounds and silicone gel sheeting for reducing the risk of scarring, as well as of barriers for incontinence-associated dermatitis. Regarding stoma accessories, silicone is established in barrier films to prevent contact dermatitis, adhesive removers to prevent skin stripping and filler gels to prevent appliance leaks. Until recently, silicone has not been used in stoma appliances flanges, as its hydrophobic nature has not allowed for moisture management to permit trans-epidermal water loss and prevent maceration. Traditional hydrocolloid appliances manage moisture by absorbing water, but this can lead to saturation and moisture-associated skin damage (MASD), as well as increased adhesion and resultant skin tears on removal, known as medical adhesive-related skin injury (MARSI). However, novel silicone compounds have been developed with a distinct evaporation-based mechanism of moisture management. This uses colloidal separation to allow the passage of water vapour at a rate equivalent to normal trans-epidermal water loss. It has been shown to minimise MASD, increase wear time and permit atraumatic removal without the use of adhesive solvents. Trio Healthcare has introduced this technology with a range of silicone-based flange extenders and is working with the University of Bradford Centre for Skin Sciences on prototype silicone-based stoma appliance flanges designed to significantly reduce the incidence of peristomal skin complications, such as MARSI and MASD. It is hoped that this will also increase appliance wear time, reduce costs and improve patient quality of life

Characterisation of Interaction between Combustion Dynamics and Equivalence Ratio Oscillations in a Pressurised Combustor

In regular operation, all gas turbine combustors have a significant spontaneous noise level induced by the turbulent high power flame. This noise is characteristic for the operation as it is the result of the interaction between turbulence and combustion. Pressure fluctuations may also be generated by thermoacoustic instabilities induced by amplification by the flame of the acoustic field in the combustor. This paper focuses on the characterisation of the latter process, the combustion dynamics, in a pressurized premixed natural gas combustor. In order to predict the thermo-acoustically unstable operating ranges of modern gas-turbines with the use of an acoustic network model, it is essential to determine accurately the flame transfer function. This transfer function gives the relationship between a perturbation upstream of the flame and its combustion response, leading to acoustic forcing. In this paper, the flame transfer function is obtained by experimental means in a combustor test rig. This test rig was built in the framework of the European DESIRE project, and has the ability to perform thermo-acoustic measurements up to an absolute pressure of 5 bars. The maximum power of the setup is 500 kW. The paper presents a method to determine the flame transfer function by factorizing it in six subfunctions. Systematically these subfunctions are determined. With the method presented, acoustic measurements on the steady, unperturbed flame and on the unsteady, actively perturbed flame are performed. The effect of pressure is investigated. The steady measurements are used to provide an acousto-combustion finger print of the combustor. In the unsteady measurements, the flame transfer function is reconstructed from the measured acoustic pressures. These flame transfer functions are compared to transfer functions obtained from a numerical experiment in CFD. Good agreement is obtained

Experimental study and velocity scaling of the tip-leakage noise generated by low-speed axial flow-fans

The present paper reports of an experimental study of the broad band and the tip leakage noise generated by axial flow fans employed for automotive cooling systems. Two operating points and three different configurations, with and without tip leakage flow, have been considered. The measurements have been taken in a hemi-anechoic chamber at constant rotational speed and during speed ramps, and the problem of the scaling of the different noise components has been faced. The acoustic response function of the test configuration, computed by means of the spectral decomposition method, has been compared with the SPL at constant Strouhal number. The comparison has shown that the acoustic response strongly affects the trend of the SPL spectra and results in a complicated dependence on the rotational speed. However, the analysis of the acoustic propagation function demonstrates that the broad band noise and the tip leakage noise scale with different power laws but are both affected by the same propagation effect. The scaling law also depends on the operating point