Avoidance of Damage Accumulation to Minimize the Risk of Deep Tissue Injury: An Investigative Protocol of Double Loading Episodes

摘要

Pressure ulcer is local tissue damage due to prolonged excessive loading acting on the skin. Evidence show that injuries can happen in the deep muscles before clinical signs on the skin. However, such deep tissue injuries if unattended could in time become massive lesions all the way to the skin. It is known that immediate muscle damage can occur as a direct mechanical insult under high enough loading. It is also known that damage can further build-up upon unloading due to subsequent reperfusion oxidative stresses and inflammation responses. Those loading-unloading tissues responses, if not appropriately relieved, can render the involved tissues more vulnerable to subsequent loadings, leading to a process of damage accumulation. In this presentation, we introduce an experimental protocol of double loading episodes to study the vulnerability of the involved tissues to such damage accumulation. A second loading episode is adopted in order to highlight the adequacy, or the inadequacy, of the preceding relief after the 1~(st) loading episode and the vulnerability of those myofibers to further injury as a result of the 2~(nd) loading episode. Given the load-duration of each episode and by varying the time between the two loading episodes, one may study using this approach how long it would take before the involved tissues can tolerate a 2~(nd) loading episode - an issue that is clinically relevant to the design of pressure relief strategies for long-term bed-confined patients and for wheelchair-hound subjects with spinal cord injury.