Experience at Rancho Los Amigos Hospital With Devices and Techniques to Prevent Pressure Sores

  • J. B. Reswick
  • J. E. Rogers
Part of the Strathclyde Bioengineering Seminars book series (BCSDA)


Since this paper is a contribution to a symposium dealing with many aspects of tissue trauma, we propose to limit our discussion to experience only at Rancho Los Amigos Hospital in Downey, California. We do not wish to imply that our methods are superior to all others but we hope that some different and useful ideas may obtain from our limited experience. The Tissue Trauma Group of the Rehabilitation Engineering Center has been actively involved in research, development and patient service for both the sitting and the recumbent (or prostrate) patient. The approaches to these two types of problem are fundamentally different for the following reasons:
  1. (i)

    The projected area of support of a prostrate human being, when divided into his body weight, yields an average pressure of around so mm Hg. This is below the 30-35 mm Hg usually accepted as necessary to cause ischaemia.

  2. (ii)

    The projected area of support, including the feet (but not the back) of a sitting person when divided into his body weight, yields an average pressure of about 50 mm Hg. This is above the 30-35 mm Hg ‘ischaemic pressure’.

The logic of reason (i) has led us to develop devices to attempt to distribute the support pressure of the recumbent patient as uniformly as possible, so that such patients may lie in any position in definitely (usually through the night) without being turned. This approach has resulted in the Rancho Flotation Bed (mud bed) and the Poly-Flotation Mattress to be described later. The problems of the seated patient suggested in reason (ii) have led to an approach that involves the development of optimum seat cushions, coupled with clinical service which relies on special pressure measurement techniques and procedures for custom modification of seat cushions and sit­ting positions. These will be discussed in detail. Research and development have focused on new instrumentation to indicate the potential for tissue damage, studies of various support material characteristics and the development of support systems, both passive (viscoelastic seat cushions with or without cutouts, and flotation systems) and active (devices requiring external power) systems.


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  1. Kosiak, M. (1959). Etiology and pathology of ischaemic ulcers, Arch. Phys. Med. Rehab. (Feb.), 62–69Google Scholar

Copyright information

© Bioengineering Unit, University of Strathclyde 1976

Authors and Affiliations

  • J. B. Reswick
  • J. E. Rogers

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