Logo for the Journal of Rehab R and D

Volume 46 Number 7, 2009
   Pages 945 — 956

Abstract — Thermodynamic rigid cushion loading indenter: A buttock-shaped temperature and humidity measurement system for cushioning surfaces under anatomical compression conditions

Martin Ferguson-Pell, PhD;1* Hideyuki Hirose, PhD;2 Graham Nicholson, PhD;3 Evan Call, MS4

1Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada; 2Research Institute, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan; 3ASPIRE Centre for Disability Sciences, Institute of Orthopaedics, University College London, Stanmore, United Kingdom; 4Weber State University, Ogden, UT

Abstract — A method is described for measuring the heat and water vapor dissipation characteristics of wheelchair cushions and seating systems while under simulated loading conditions. Thermal interaction between the body and seating surfaces can result in elevated tissue temperature and moisture build-up, which may increase the risk of pressure ulcers associated with prolonged ischemia or due to macerative damage. Both the materials and geometry of commercial seating systems are thought to influence the body-support surface microclimate. A thermodynamic rigid cushion loading indenter (TRCLI) has been developed to simulate the thermal and loading conditions of the body on seating surfaces. Results are reported for 32 commercially available wheelchair cushions. The results differentiate the cushions into clusters of comparable properties that offer the potential for classification of support surfaces based on their heat and water vapor dissipation performance. This study has shown that deducing the heat and water vapor dissipation characteristics of a seating system from material physical properties is of limited value because of the influences of particular design features of combinations of materials. Testing of individual products with the use of the TRCLI can, however, reliably differentiate wheelchair cushions by their ability to dissipate heat and water vapor.

Key words: anatomical loading, heat and water vapor dissipation, humidity, pressure ulcer, rehabilitation, seating, temperature, test method, thermal properties, wheelchair cushion.

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