Fluid-Filled Pod Cushion for Pressure Redistribution
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Solution Overview
Problem
Conventional cushioning devices fail to effectively prevent pressure ulcers due to localized pressure buildup, instability, and inadequate conformance to the body, leading to tissue necrosis and increased hospital stays or amputation risks.
Innovation Solution
A portable support assembly with fluid-filled pods and pads that redistribute pressure through a layered system, including an inner pad, outer pad, and outer shell, to prevent bottoming out and provide adjustable, conformable support to high-risk areas like the sacrum and trochanter, using incompressible fluids or gases to reduce pressure below 4.3 kPa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional foam or spring cushioning devices are used, then the cushion can deform and conform to the patient's body, but the cushion typically bottoms out such that the patient's body contacts the underlying platform and localizes pressure onto the body
Solution Approach 1:
The cushion is divided into multiple independent fluid-filled bladders arranged in an array, where each bladder can independently deform to contact the patient's body. This segmentation prevents bottoming out because the fluid bladders can conform to body contours without the entire cushion structure collapsing to the platform level.
Solution Approach 2:
The invention uses fluid-filled bladders instead of traditional foam or spring materials. The fluid (liquid or gas) within each bladder provides continuous conformability to body surfaces while the incompressibility of the fluid prevents the bladders from bottoming out, thereby eliminating localized pressure points.
2Stress or pressure
If fluid-filled bladders are used to prevent bottoming out, then pressure distribution improves, but the cushion sacrifices stability and requires significant volume of fluid beneath the patient
Solution Approach 1:
Multiple smaller fluid-filled bladders are arranged in an array rather than using a single large bladder. This segmentation maintains stability because the individual bladders are less prone to excessive displacement and bottoming out, while collectively providing adequate pressure distribution across the seating surface.
Solution Approach 2:
The invention changes the physical parameters of the fluid system by using incompressible fluids (liquids or gases) within constrained bladder volumes. This allows the bladders to maintain stable positions while still deforming to conform to body surfaces, achieving both pressure distribution and stability.
3Stress or pressure
If the amount of fluid in the bladder is increased to prevent bottoming out, then pressure distribution improves, but this requires significant volume of fluid beneath the patient and specialized bedding
Solution Approach 1:
The total fluid volume is distributed across multiple smaller bladders rather than requiring a single large volume. Each bladder contains a modest amount of fluid, but collectively they provide adequate pressure distribution without requiring significant fluid volume or specialized bedding infrastructure.
Solution Approach 2:
Instead of increasing fluid volume in the vertical dimension (which would require more space beneath the patient), the invention distributes fluid across multiple bladders in the horizontal plane, achieving pressure distribution through spatial arrangement rather than volume increase.
4Stability of the object's composition
If fluid-filled membranes are made thick to provide support, then stability improves, but the hammocking that occurs in the regions of high protrusions prevents adequate pressure relief
Solution Approach 1:
The membrane is segmented into multiple independent fluid-filled bladders rather than using a single thick membrane. Each bladder can independently deform to eliminate hammocking in high-protrusion regions while maintaining overall structural stability through the array configuration.
Solution Approach 2:
The invention uses flexible fluid-filled bladder membranes that can thin and deform in regions of high body protrusions to eliminate hammocking effects, while the overall cushion structure maintains stability through the distributed bladder array and outer shell.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces pressure on sensitive areas, preventing tissue necrosis and reducing the occurrence of pressure ulcers by distributing pressure evenly and maintaining support, as demonstrated by a 43% average reduction in pressure measurements.
Implementation Method 1
Each of the pods may be filled with a fluid or gas or a combination of both. The one or more fluid filled pods may thus support the body portion... The amount of compression of the pods themselves may be controlled by the inner pad which envelopes the pods... The presence of the surrounding outer pad may further transmit and redistribute the induced pressure
Implementation Method 2
The outer shell may be made from materials including plastics such as polypropylene, ABS, PVC, polyethylene, nylon, acrylic, polycarbonate, etc. The outer shell may also be fabricated from other materials such as polymers, carbon fiber, light weight metals, elastomeric materials, rubbers, foams, etc.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
Apparatus and methods for adjusting a support to a body are described in which a portable support assembly may be worn or used by a bed-stricken or wheel-chair restricted individual around particular regions of the body where pressure ulcers tend to form. The portable support assembly may generally include adjustable supports which conform the assembly to the patient's body and which also help to distribute one or more fluid pad assemblies relative to the body. The support assembly may be incorporated into a design for a wheelchair or a bed.