Fluid filled cushions are subjected to puncture. Open cell foam cushions needs a good water-proof covering to prevent body fluid infiltration. All the above increases the difficulty in using and maintaining a cushion. A lot of poor regions in world are hot and humid. Foam is a good insulator and trapped heat between the body and the cushion causes sweating.
Shear stress is produced when a foam cushion deforms to conform to body shape.
Sweating and shear are contributing factors of tissue damage. Low shear and low heat built-up are desirable properties of a cushion, especially for use in hot and humid climate. Tree leaves as a potential candidate For low cost, the cushion material has to be available locally as well as of low commercial value. In this regard, materials with high commercial value, such as fur and silk may not be appropriate even if available locally. Tree leaves are good potential candidates because they are in abundant supply and usually has no commercial value.