any form or any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval without prior written permission from the author, or, when appropriate the publishers of the papers.Niets uit deze uitgave mag worden verveelvoudigd en/of openbaar gemaakt worden door middel van druk, fotokopie, microfilm of enige andere wijze, noch opgeslagen worden in een retrieval-systeem noch vertaald worden in welke taal dan ook, zonder schriftelijke toestemming van de auteur.
ColofonCover design: Dirk Franssens, huisarts te Dordrecht Layout & production: Optima Grafische Communicatie ISBN / EAN: 978-94-92683-10-6 Prevention of pressure ulcers in nursing homes, a big challenge
81Chapter 7 General discussion 99
Chapter 8 Valorisation 117Summary 123 Samenvatting 131 Dankwoord 139
About the author 145List of publications and presentations 149
6Prevention of pressure ulcers in nursing homes, a big challenge
7Prevention of pressure ulcers in nursing homes, a big challenge Chapter 1
General Introduction 8Prevention of pressure ulcers in nursing homes, a big challenge
9Prevention of pressure ulcers in nursing homes, a big challenge which may contribute in the development of a PU will be explained below.
General introduction
10Pressure and shear are the most mentioned direct causes of a pressure ulcer. 7,8,9,10 Pressure is defined as the amount of force/load applied perpendicular per unit area of application. 10 A force applied over a small area will produce a greater pressure than the same force over a larger area. Two aspects of pressure are important: intensity and duration. The intensity is defined as the amount of external pressure on the skin and the deeper tissue layers. Duration is the time that a certain pressure is exposed to a surface. A short period of high pressure or a longer period of a lower pressure may both result in a PU.Shear is often used to abbreviate the terms shear stress and shear force. Friction is no longer mentioned in the description of PU development in the last NPUAP/EPUAP/PPPIA guideline, but there is a close association with shear. Friction is defined as the force that resists the relative motion of two adjacent objects, like skin and support interface. Often friction potentiates shear stress.
12Prevention of pressure ulcers in nursing homes, a big challengeIf pressure and shear are applied to the skin, particularly over a bony prominence, it causes changes of the skin and the underlying tissue. This may result in tissue distortion, compression of blood vessels, stretching and narrowing of the capillary beds, disturbance of the cell metabolism and even cell death. A sufficient high level of shear stresses for a period of 4 hours will result in muscle death. The skin can resist the same type of stress for more than 12 hours. 12 This is one of the reasons why PUs may already have developed before skin breakdown is visible.
Other Contributing factorsThe development of a PU cannot be fully explained by the effects of pressure and shear stress only. Another...