Analysis of sweat during soft tissue breakdown following pressure ischaemia.

This paper examines the nature of tissue metabolites collected in thermally induced sweat following the application of different loading regimes on the soft tissues of able-bodied subjects. Loading was produced by 1) external application on the forearm via both a tourniquet and a uniaxial indenter system, and 2) ischial support on a wheelchair and sacral support on an examination bed. In each case sweat pads were attached to the tissue areas of a group of able-bodied subjects and interface pressures were recorded. After a prescribed period, the pads were removed and a quantitative analysis of a range of metabolites was performed. Results indicated that tissues subjected to pressure ischemia produced a general increase in concentrations of lactate, chloride, urea, and urate associated with a decreased sweat rate. In the reperfusion phase, some of these metabolites returned to unloaded levels. It is proposed that specific metabolites may be used as an indicator of soft tissue damage.