Clinician’s recommendations on wheelchair pressure reliefs in the context of the high prevalence of pressure ulcers that
occur in people with spinal cord injury is not supported by strong experimental evidence. Some data indicates that
altered tissue perfusion and oxygenation occurring under pressure loads, such as during sitting, induce various
pathophysiologic changes that may lead to pressure ulcers.
Pressure causes a cascade of responses, including initial tissue hypoxia, which leads to ischemia, vascular
leakage, tissue acidification, compensatory angiogenesis, thrombosis, and hyperemia, all of which may lead to tissue
damage. We have developed an advanced skin sensor that allows measurement of oxygenation in addition to perfusion,
and can be safely used during sitting. The sensor consists of a set of fiber optics probes, spectroscopic and Laser Doppler
techniques that are used to obtain parameters of interest. The overriding goal of this project is to develop the evidence
base for clinical recommendations on pressure reliefs.
In this paper we will illustrate the experimental apparatus as well as some preliminary results of a small clinical
trial conducted at the National Rehabilitation Hospital.