Maintenance and modifications: two key factors to remember when working with fluid cushions. Maintenance is easy peasy. Modifications are multiple. Let's dive in to discuss!
Let's start with what a fluid cushion is. Fluid cushions have a foam base (above left) to provide support and stability to the femurs and a contoured well in which a fluid insert sits (above centre) to provide pressure management at the pelvis. The cushion cover provides the final layer of pressure management protection (above right).
The fluid in the insert is a non-Newtonian fluid like petroleum jelly – whereas a Newtonian fluid has greater flow like water or air. Some people erroneously call a fluid cushion a "gel" cushion. The two are not the same. Whereas gel is a semisolid1 material, fluid allows for immersion into the cushion and displacement of the fluid around the boney prominences to provide pressure management.
Many cushion owner's manuals recommend monthly cleaning and maintenance to help extend the life of the cushion. Maintenance for a fluid cushion is easy. First, check the cover for tears or excessive wear and replace if ripped, torn, or otherwise not fully functional. Then inspect the fluid pad for punctures or any other abnormalities. If the fluid pad feels firmer in one area, knead the fluid back into its original consistency (or contact a local authorized supplier). Also, check the foam base to ensure foam consistency.2
While performing monthly maintenance, it's a good idea to knead the fluid pad to ensure even distribution of the fluid throughout the well. It takes less than a minute to knead the fluid, whether the cushion cover is on or off. Some individuals do this kneading daily – or even prior to every transfer onto the cushion – to ensure the even distribution of the fluid and to prevent "bottoming out." Bottoming out occurs when there is less than ½-inch of fluid under the "sit" bones and can be addressed through fluid modification, i.e., an overfill of fluid.
A modification to the volume of the fluid in the insert may be requested. This will affect the position of the pelvis within the well and the relative load distribution through the femurs. For example, a person with muscle atrophy at the buttocks may benefit from an overfill of the fluid volume to prevent "bottoming out." In this case, the additional fluid volume represents a replacement for the tissue the person may be lacking. The additional fluid volume prevents "bottoming out" (providing adequate maintenance is completed with the fluid pack) and helps to ensure that the load is distributed evenly through the length of the femurs along the foam base.
On the opposite end of the spectrum, a person with a lot of excess adipose tissue at the buttocks may benefit from an underfill of fluid volume if the femurs are not fully supported on the foam base. Without an underfill in this example, the person with excess tissue may be perched "on top" of the well with loading through the distal aspect of the femurs. An underfill for a person with excess adipose tissue at the buttocks may facilitate optimal pelvic immersion into the well of the cushion and optimal pressure distribution through the length of the femurs.
Another modification to a fluid pack to affect skin protection is to request a heat seal to prevent fluid migration between segments. Fluid packs are segmented to reduce surface tension and enable optimal immersion into the fluid; however, migration of fluid between segments can occur. To control fluid migration, a heat seal can be made on the area at risk for skin breakdown, such as the sacral area.
Finally, another modification that can be requested to a fluid insert is an obliquity overfill or underfill. This alters the fluid volume on one side of the fluid pad to address positioning needs for a pelvic obliquity. If an individual needs more fluid volume to prevent bottoming out on one side of the cushion, an obliquity overfill should be used. An obliquity underfill is less commonly used but remains an option for individuals who require it to allow for optimal immersion and positioning of the pelvis when excess tissue and a pelvic obliquity are present.
Fluid cushions work well for pressure management as they allow for immersion and envelopment to occur. For some individuals, modification to the fluid insert may be required to obtain optimal results. Maintenance of the fluid cushion is recommended for all to extend the life of the cushion.
Originally written by Sheilagh Sherman and published on 30 March 2022.
- Glossary of Wheelchair Terms and Definitions. Version 1.0. December 2013. Retrieved from: https://www.pvanewengland.org/
- JAY® Fusion Cushion Owner's Manual. Retrieved from: https://www.sunrisemedical.ca/seating-positioning/jay/wheelchair-cushions/fusion-cushion#support