Hybrid Equation/Agent-Based Model of Ischemia-Induced Hyperemia and Pressure Ulcer Formation Predicts Greater Propensity to Ulcerate in Subjects with Spinal Cord Injury

Pressure ulcers are costly and life-threatening complications for people with spinal cord injury (SCI). People with SCI also exhibit differential blood flow properties in non-ulcerated skin. We hypothesized that a computer simulation of the pressure ulcer formation process, informed by data regarding skin blood flow and reactive hyperemia in response to pressure, could provide insights into the pathogenesis and effective treatment of post-SCI pressure ulcers. Agent-Based Models (ABM) are useful in settings such as pressure ulcers, in which spatial realism is important. Ordinary Differential Equation-based (ODE) models are useful when modeling physiological phenomena such as reactive hyperemia. Accordingly, we constructed a hybrid model that combines ODEs related to blood flow along with an ABM of skin injury, inflammation, and ulcer formation. The relationship between pressure and the course of ulcer formation, as well as several other important characteristic patterns of pressure ulcer formation, was demonstrated in this model. The ODE portion of this model was calibrated to data related to blood flow following experimental pressure responses in non-injured human subjects or to data from people with SCI. This model predicted a higher propensity to form ulcers in response to pressure in people with SCI vs. non-injured control subjects, and thus may serve as novel diagnostic platform for post-SCI ulcer formation. © 2013 Solovyev et al

Development of a model to demonstrate the effects of friction and pressure on skin in relation to pressure ulcer formation

© 2017 The Authors Pressure ulcers are a common injury of the skin which leads to pain and potential infection for patients and financial burden to the healthcare providers across the global due to treatment costs, litigation and extended hospital stays. The current study focuses on one of the causes of pressure ulcer formation, ischemia. Blood vessels are deemed to be deformed and blood flow restricted when skin is subjected to external mechanical loads including friction, pressure and the combination of both. Hence, normal oxygen delivery to cells or metabolic waste removal are locally stopped which causes cells deaths and ultimately pressure ulcers. The current study proposes a 3D finite element analysis model which is capable of demonstrating the effect of friction, pressure and the combination of both to the deformation of blood vessels. The results of simulation suggested that applied pressure collapsed the blood vessels while friction opened up the blood vessels. However, as a combination effect of pressure and friction, the cross-sectional areas of blood vessels were reduced significantly. This model is clinically and physiologically relevant in terms of loading regime and blood vessels structures. The model with further development can be adopted to be an effective tool to evaluate the effects of medical devices to the possibility of pressure ulcer formation

Mathematical Modelling of Different Types of Body Support Surface for Pressure Ulcer Prevention

Pressure ulcer is a common problem for today’s healthcare industry. It occurs due to external load applied to the skin. Also when the subject is immobile for a longer period of time and there is continuous load applied to a particular area of human body, blood flow gets reduced and as a result pressure ulcer develops. Body support surface has a significant role in preventing ulceration so it is important to know the characteristics of support surface under loading conditions. In this paper we have presented mathematical models of different types of viscoelastic materials and also we have shown the validation of our simulation results with experiments

Pressure ulcer management

Pressure ulcers are usually the result of sustained pressure on parts of the body such as the heels, trochanteric and sacral areas. The main risk factors contributing to pressure ulcer formation are acute illness, injury or sedation. The two main groups of patients most susceptible of sustaining pressure ulcers are frail older patients and patients with spinal cord injuries. Frail older patients have thinner skin, are more likely to have a lower body mass index, and may be malnourished and immobile due to various neurological and musculoskeletal pathologies. Because of the phenomenon of an ageing population, pressure ulcers are becoming increasingly prevalent.peer-reviewe

Enhancement of heat and mass transfer between human body and hospital mattress to reduce pressure ulcer formation

A pressure relieving mattress has been developed along with multilayered functional bed cover to reduce the magnitude, direction and/or duration of pressure and temperature, thereby avoiding excessive tissue distortion on vulnerable parts of the body. The interface pressure and temperature between body and mattress are measured and analyzed using the parameters, such as deformation index and pressure gradient. The pressure relieving mattress developed reduces the interface pressure by 30-60%, and reduces the heat generated by ~ 3° C. Hence, the new mattress developed along with the cover sheet reduces the chance for pressure ulcer formation and improves the comfort of the patients

A Review on Pressure Ulcer: Aetiology, Cost, Detection and Prevention Systems

Pressure ulcer (also known as pressure sore, bedsore, ischemia, decubitus ulcer) is a global challenge for today’s healthcare society. Found in several locations in the human body such as the sacrum, heel, back of the head, shoulder, knee caps, it occurs when soft tissues are under continuous loading and a subject’s mobility is restricted (bedbound/chair bound). Blood flow in soft tissues becomes insufficient leading to tissue necrosis (cell death) and pressure ulcer. The subject’s physiological parameters (age, body mass index) and types of body support surface materials (mattress) are also factors in the formation of pressure ulcer. The economic impacts of these are huge, and the subject’s quality of life is reduced in many ways. There are several methods of detecting and preventing ulceration in human body. Detection depends on assessing local pressure on tissue and prevention on scales of risk used to assess a subject prior to admission. There are also various types of mattresses (air cushioned/liquid filled/foam) available to prevent ulceration. But, despite this work, pressure ulcers remain common.This article reviews the aetiology, cost, detection and prevention of these ulcers

Apelin/APJ signaling suppresses the pressure ulcer formation in cutaneous ischemia-reperfusion injury mouse model

学位記番号：医博甲1849

Implementing a Hospital-Acquired Pressure Ulcer Prevention Program

Objective: To implement a Hospital-Acquired Pressure Ulcers (HAPU) prevention program utilizing an assessment tool to identify patients at risk, and intervene with a sacral Mepilex® dressing. Our aims are to determine if a change in nursing knowledge and change in nursing behavior after implementing our program. Background: HAPUs are a significant problem in patient care and healthcare organizations must implement prevention protocols to reduce HAPU prevalence. Guidelines for implementing HAPU prevention programs suggest use of a validate risk assessment tool and initiating preventive interventions. One intervention found in the literature is the adjunctive use of prophylactic Mepilex® dressings to sacral skin. Design: Descriptive study with a prospective one-group pre and post-test design, followed by a retrospective medical record review. Methods: A HAPU education was disseminated to TriHealth nurses who voluntarily participated in a 15-question test before and after the HAPU educational didactic. A paired t-test was performed to determine a difference in mean pre/post-test scores. After completion of the educational didactic, units with 65% completion were included in a medical record review to determine adherence to nursing clinical behaviors relating to the new policy. Results: 1,182 nurses completed the pre-test and 1,514 completed the post-test. Paired t-test analysis determined a difference in mean scores before and after our educational intervention, indicating change in nursing knowledge. 65 medical records were reviewed from 5 units at TriHealth. The mean percent completion of required documentation was 62.2%, and an analysis of variance determined a difference in mean percent completion scores between hospitals, but not unit location. Nurses correctly identified at-risk patients in 50.8% of medical records and used a prophylactic Mepilex® dressing; however 16.9% of at-risk patients were missed. The most identified Mepilex® application criteria included age \u3e65 years, mechanical ventilator use, surgical procedures lasting ≥4 hours, and Braden Scale scores \u3c13. Conclusion: A change in nursing knowledge was evident after our educational didactic, however, our medical record review indicates a failure to consistently follow the HAPU protocol to identify, intervene, and maintain pressure ulcer prevention practices for patients at-risk. Relevance to Clinical Practice: This HAPU prevention protocol may be successful at changing nursing knowledge, but had variable impact on changing nursing behaviors. Additional program evaluation is needed to identify areas to support our nurses for long-term sustainability