| dc.description.abstract | Soft tissue breakdown occurs in association with biochemical changes that can be
attributed to a reduction in blood and lymph flow to a localised tissue area in response
to applied pressure. The resulting ischaemia can lead to a reduction in available oxygen
and accumulation of waste products. Tissue breakdown leading to the development of
pressure sores afflicts patients who are already debilitated, although not all patients
appear to be equally susceptible.
Measurement of sweat biochemistry and blood gas tensions may reflect the
biochemical process in the underlying tissues and provide a simple and non-invasive
method of investigating the status of soft tissues. The potential of specific sweat
metabolites to act as markers of soft tissue status during and following loading has
been investigated at a clinically relevant site in healthy volunteers, and in two clinically
relevant patient groups. A range of validation procedures were undertaken and a series
of parameters derived to investigate the temporal profile of sweat biochemistry, and
identify various modes of gas tension response.
Investigations at the loaded sacrum of healthy individuals showed a statistically
significant increase in sweat lactate, urea, urate and chloride concentrations which
were dependent upon the level of externally applied pressure. Mean increases of
between 10%-60% were demonstrated for sweat metabolite concentrations at the
loaded site compared to the control site for applied pressures in the range 40-120
mmHg. Similar increases were demonstrated in sweat collected from highly loaded
tissue areas within the stump socket of lower limb amputees.
A threshold value for P02 tension was identified, amounting to a 60% reduction
from the unloaded value, which was associated with elevated tissue carbon dioxide
levels as well as increased sweat metabolite concentrations in the loaded phase.
This finding may provide a useful predictor of soft tissue status during prolonged
loading.
No pessimist ever discovered the secrets of the stars, or sailed
to an uncharted land, or opened a new heaven to the human spirit.
Helen Adams | en_US |
