Study of skin–fabric interactions of relevance to decubitus: friction and contact-pressure measurements

Background/purpose: Prolonged pressure as well as friction and shear forces at the skin–textile interface are decisive physical parameters in the development of decubitus. The present article describes the contact phenomena at the skin–textile interface and the development of a purpose-built textile friction analyser (TFA) for the tribological assessment of skin–fabric interactions, in connection with decubitus prevention.
Methods: Interface pressure distributions were recorded in the pelvic and femoral regions between supine persons and a foam mattress. Fabrics made of various natural and synthetic yarns were investigated using the TFA. A vertical load of 7.7 kPa was applied to the swatches, simulating high interface pressures at the skin–fabric interface and clinical conditions of bedridden persons. Fabrics were rubbed in reciprocating motions against a validated skin-simulating material to determine static as well as dynamic friction coefficients (COFs).
Results: Maximum contact pressures ranged from 5.2 to 7.7 kPa (39–58 mmHg) and exceeded the capillary closure pressure (32 mmHg) in all investigated bedding positions. For both COFs, a factor of 2.5 was found between the samples with the lowest and highest values. Our results were in a similar range to COFs found in measurements on human skin in vivo . The results showed that our test method can detect differences of 0.01 in friction coefficients.
Conclusion: TFA measurements allow the objective and reliable study of the tribology of the skin–textile biointerface and will be used to develop medical textiles with improved performance and greater efficacy for decubitus prevention.