foam cushions

8/19/2019 Foam Cushions

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Foam cushions

Foam technology has come a long way. No longer just the soft, airy stuff of the past,

foam now comes in a range of densities and with varying degrees of "memory,"

holding its shape as you sit, contributing to your stability. The new foams can adapt toany shape, and still provide even support, spreading pressure across the sitting

surface. Different foams are often used in combination, layered for their various

properties of softness, even support, and memory.

Foam is relatively inexpensive, and it is easy to cut. therapist can experiment with

shapes free of financial ris!. f you have an area of s!in that is bro!en down or on the

verge, pressure can easily be reduced by cutting out a portion of the cushion. #$ou

should not do this on your own, though, because only a doctor or therapist can

identify the changes in your cushion that will help relieve pressure while still

maintaining appropriate support.%

&n the downside, foam wears out faster than other materials and loses its shape, but

because of its lower price, this might not concern you. f you choose a foam cushion,

be sure to replace it when its time is up. &ld foam that is compressed can allow

pressure points to form that can lead to a sore.

f you choose a gel or air flotation cushion for daily use, it is a good idea to have a

bac!up foam cushion since gel and air flotation cushions can lea!.

Gel cushions

'el cushion designs attempt, in effect, to replace the consistency and support of

atrophied muscle tissue. (ighly engineered gel fluids are placed in pouches and

usually attached to a foam base, so that the cushion conforms to the pressures placed

on it. s a result, gel cushions provide excellent pressure distribution and are very

comfortable. )any gel products also offer supplemental inserts to stabili*e your legs.

$our !nees might tend to fall together #adduction% or apart #abduction%, so such an

accessory can help !eep your legs straight which also aids your overall posture.

+nfortunately, gel cushions are much heavier than other types, which can cancel out

some of the benefits of your lightweight wheelchair. 'el suppliers such as ay and

Flofit offer lighter, active-use designs, but these might not be appropriate for you ifyou are unable to do your own pressure-relief lifts.

f you bounce up and down curbs, or commonly experience similar impact in your

chair, a gel cushion might not be ideal. hen you sit in a gel cushion, there is no

further "cushiness" to absorb impact, a concept !nown as impact loading. &ther

cushion types are better able to absorb impact.

nother drawbac! to gel cushions is the possibility of them "bottoming-out" as the

gel is pushed aside by your weight. $ou can help prevent this distribution problem by

!neading your gel cushion once a day, !eeping the fluids loose and spread evenly.

/oo! for a design that divides the gel portion into several sections so that all of the gel

cannot push to the sides.


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There is also the chance of the gel lea!ing. hile cushions arrive with patching !its,

patches are ineffective when the breach is at a seam, which is often the case. lea!

might be very minor, or it could be an extremely messy affair.

Air or dry floatation cushions

ir floatation cushions support the body entirely on air. typical example is the 0oho

cushion, designed with a group of small, interconnected rubber balloons arranged in

rows. 1ressure is balanced by air shifting out to surrounding balloons, spreading

pressure evenly against your s!in. The whole system is closed so air floatation

cushions can2t bottom out the way gel cushions can.

f you have a pressure sore, you can tie off individual balloons to reduce contact under

that area, allowing you to spend more time sitting as the sore heals. The 0oho

3uadtro allows the user to inflate four 4uadrants separately for optimal positioning.

ir cushions are relatively lightweight, and are waterproof, allowing for double duty

in the bathtub or on a boat.

5rown Therapeutics, ma!er of the 0oho cushions, also offers air floatation products

for the wheelchair bac!, supplemental lumbar or sacral support, full bed cushions, and

even a product for a standard toilet seat. ll are inflatable to adjust to your needs.

longtime presence in disability maga*ines has been an ad for the "6ye-6ye

Decubiti" cushion. t is inflatable, comes in many different si*es and shapes, is made

of heavy duty rubber, and--although different from the 0oho balloon design--is

uni4uely formed to minimi*e pressure at the bony protrusions on which we sit.

ir cushions can be less stable for those who move around a lot in their chair, but

recent designs offer either low profile or 4uadrant options that minimi*e this problem.

The balloons used in air cushions can be punctured, of course, and lea!s do occur,

although a fairly heavy duty rubber is used. 6ut patching them is easier than with the

gel design. The hard part is submerging the cushion under water to find the lea! #loo!

for escaping air bubbles%.

The biggest drawbac! to air cushions is that they re4uire more maintenance. t is

necessary to chec! the pressure fre4uently, especially if you have pressure sores.

Urethane honeycomb cushions

Thermoplastic urethane honeycomb cushions are the most recent development in the

world of cushions. 6ecause there are many individual cells--li!e a beehive--these

cushions are able to distribute weight evenly, but there is no ris! of lea!ing gel or of

an air bladder being punctured. The many open spaces in the beehive structure of the

cushion allow air to travel more effectively. This design helps to protect against s!in

brea!down because your s!in is !ept cooler and moisture is prevented from

collecting.

+rethane honeycomb cushions are very light, absorb shoc!, and a low profile cushion

can provide significant support. These cushions can even be thrown into your washingmachine and dryer, ma!ing them attractive for people with incontinence problems


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where the cushion will be soiled from time to time despite best efforts at bowel and

bladder management.

7upracor of 7an ose, 5alifornia, ma!es several honeycomb cushions based on their

patent. &ne type uses multiple layers of varying stiffness to allow your sit bones to

sin! into the cushion while deeper layers provide overall support and weightdistribution. nother type is contoured to provide adduction and abduction, plus a rear

dish for pelvic positioning. There is not much of a trac! record for urethane

honeycomb cushions because of their recent development, but there appears to be

good prospects for this type of cushion to evolve and become more widely used.

Comparison of Main Types of Cushions

Cushion type Advantages Disadvantages

Foam nexpensive.8ery lightweight.5omes in range of densities.(olds shape #memory%.1rovides even support.5an be cut to relieve sores.

Nothing to lea!

ears out faster./oses its shape.&ld, compressed foam could lead to asore.

'el 9xcellent pressure distribution.8ery comfortable.

)ay have supplemental inserts tostabili*e legs.

(eavy.5hance of lea!age.

/ess able to absorb impact.7ome designs allow gel to push out to

sides.

ir floatation /ightweight.9ven pressure distribution.ill not bottom out if properlyinflated.5an be modified to relieve pressure sores.

7ome models inflate to user2sspecific needs.aterproof.

/ess stable.5hance of puncture:lea!age.(igh maintenance; need to chec! pressure fre4uently.

+rethanehoneycomb

8ery lightweight./ow profile in appearance.Distributes weight evenly.'ood support.bsorbs shoc!.


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Wheelchair Cushion Differencesby Stephen Sprigle, Ph.D., PT Understanding the materials used to make wheelchair cushions can help you choose your

best seat and back.

Materials used for wheelchair cushions have come a long way. You now have quite a

choice based on your individual need. Cushions protect skin from damage that can

lead to pressure ulcers, and they affect many functional activities such as reaching,

transfers and wheelchair propulsion.

Many researchers and clinicians who have studied cushions have developed a common

conclusion: !o one cushion is best for all people". #ecause so many cushions are

available commercially, wheelchair users should be able to find one that adequately

meets their needs.

$ow do you do that% &irst you need to understand the materials used to makecushions. Cushions are designed to distribute body weight over its surface or to re'

distribute pressure away from areas considered (at risk( for pressure ulcer formation.

Many different materials and combination of materials are used in cushions, all of

which have both positive and negative characteristics. )n addition, several terms are

used to describe cushions.

#ecoming familiar with the words used to describe materials and construction will help

you select the right product. *hese definitions are used by the +aralyed -eterans of

merica and by the /ehabilitation 0ngineering and ssistive *echnology 1ociety of

!orth merica. few of these terms are:

Foam or flexible matrix: a lightweight, fle2ible cellular material used in

support surfaces.

Viscoelastic foam or matrix: a compressible cellular material that has both

elastic 3spring'like4 and viscous 3time'dependent4 properties. -iscoelastic foam is

different from regular foam by having time'dependent behaviors such as creep, stressrela2ation, and hysteresis. *his type of foam is sometimes called memory foam"

because it maintains the shape of an indentor 3like your hand4 before springing backto its original shape. !1 invented the first visco'elastic foam, *'foam, about 56

years ago.Non-deforming foam or matrix: a support material that does not compress,

deflect, or deform under sitting forces7 often'used in cushion bases 3Sunrise MedicalQuicie !a"# $tto %oc Cloud &sho'n here(cushions use non'deforming foam

bases4.

%onded foam: adhesion of foam material including different foams being

glued together 3*he )nvacare Ultimate cushion is made with bonded foam4Viscoelastic fluid: a relatively incompressible substance with viscous

properties7 viscous fluids do not flow as readily as water and include maple syrup and

grease. 3$tto %oc Floam) Sunrise Medical Quicie !a"Flo are viscoelastic fluids.4*ir cushion: a cushion with an impermeable 3air'tight4 membrane containing

air. 3Cro'n +nhancer &sho'n here(4

Water cushion: a cushion with an impermeable membrane containing water.

,el or solid elastomer: solid rubber'like, relatively incompressible material.

Segmented cushion: a cushion whose surface is divided into separate and

distinct segments. 3San *mericas /014

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Con2oluted cushion: cushion surface composed of conve2 protrusions

separated by depressions or sulci7 often called egg'crate". 31pan merica4Contoured: shaped to fit or reflect the form or shape of the body, specifically,

the buttocks. 3)nvacare Ultimate4Cut-out cushion: surface having a disruption or removal of material to alter

the load bearing characteristics of the surface.

Certain characteristics can be used when 8udging the appropriateness of supportsurfaces. /ecently, a anel of health care rofessionals, researchers and

industry representatives identified nine characteristics that impact efficacy and should

be considered when selecting support surfaces 39rouskop van /i8swi8k, ;


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per volume. &oams used in wheelchair cushions have medium stiffness in the range of

56 to @6 )&A 3)ndentation &orce Aeflection is a standard measure of foam stiffness

with a higher number indicating a stiffer foam4 while bed overlays can be softer 3B6

)&A4 because loads are less when lying down since your weight is distributed over a

larger area. &oams that are appropriate for a mattress will be too soft for use in

sitting. Egg-crate mattresses and other foam mattresses should never be cut into pieces for use as wheelchair cushions. &oams used as support surfaces should have a

higher density 3thicker and more difficult to compress4 than non'supportive foams and

be classified as high resilience 3$/4 foams.

+roper stiffness, density and resilience help ensure adequate support and an effective

lifespan. &oam envelops the buttocks well, but can be hot and is damaged by moisture

and light, so a protective cover should be used. Covers made from fabric that does not

stretch and is fitted tight around a cushion tend to negate the compressive benefits of

foam.

&oam absorbs impact loads well, so it can help absorb the shock of going over bumps

or obstacles.

,els and 2iscous fluids are heavier than foams and, therefore, are often used in

combination with foams. *hese materials are good at minimiing heat and are

typically encased by a protective cover so are easily cleaned. #ecause of their

incompressible nature, viscous fluid and gel cushions often use a contoured non'

deforming foam base or a flat, compressible foam base to better enable the cushion to

conform around the body. els and fluids absorb vibration but cannot absorb impact

well. *herefore, these materials can absorb the vibrations that one might e2perience

in a car, but not the impact one gets when bumping over a curbcut.

*ir is highly compressible and would make an e2cellent support surface, e2cept for its

requirement of an impermeable membrane. *herefore, the efficacy of air cushions is

directly related to the design of its container and proper inflation. 1ome encompass

the body well while others do not. 1ome dissipate heat well, all can handle moisture

without harm and most will absorb impact loads. #ecause air cushions are ad8ustable,

they can be inflated to meet the needs of the user, but this ad8ustability also means

that they must be maintained properly. n improperly inflated air cushion can be

either too hard or two soft, and both are potentially damaging situations. )f an air

cushion is right for you, be sure to read the instructions so you inflate the cushion

properly.

)n summary, many characteristics must be considered before you select a cushion.

*hese include cushion materials as well as other design characteristics. *his article

cannot tell you which material is best for you, but it can act as a source of

information. ll the cushion materials described in the article have positive and

negative features. #y better understanding these features, you"ll be better able to

make choices about your wheelchair cushion. nytime you decide to change

wheelchair cushions, a clinician e2perienced in wheelchair seating should evaluate

you and allow you to try out a few sample cushions, as well.

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Seat Cushions are designed to offer:

• Comfort

•

+ressure management• +ositioning

• )ncreased sitting stability

)ndeed, there are many wheelchair cushions available ' including foam, gel, and air

technologies ' and in understanding the benefits and limitations of each one, you can

decide which is best for you.

Cushion Varieties• &oam Cushions

• el Cushions

• ir Cushions

Other Cushion Resources• *ips for 1electing Maintaining a Cushion

Foam Cushions

&oam cushions are the most basic cushion, ideal for those wishing simplicity at minimal

cost. Dhile some foam cushions are a single'density 3firmness4, others feature contoured

bases with multiple layers of foam, designed for enhance pressure management and

positioning.

Eay #asic Dheelchair Cushion

* foam cushion ma" be best for "ou if "ou need:• ?ow maintenance

• Minimal cost

• very stable seating surface

• ?ow to mid'range positioning

• ?ight weight

* foam cushion ma" not be best for "ou if "ou need:

• 02ceptional pressure relief

• dvanced positioning characteristics

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Gel Cushions

el cushions are specifically designed to optimie pressure relief by allowing one(s pressure

points to FimmerseF into a gel pack, reducing pressure. dditionally, gel cushions typically

feature a contoured base, with advanced positioning characteristics.

*rulife /ela2 +leer0lite Dheelchair Cushion

* gel cushion ma" be best for "ou if "ou need:

• Gptimal pressure relief

• dvanced positioning

• very stable seating surface

• ?ow maintenance

* gel cushion ma" not be best for "ou if "ou need:

• ?ight weight

• ?ow cost

Air Cushions

s the name suggests, air cushions are filled with air, and by ad8usting the air pressure,

the cushion(s firmness can be ad8usted. ir cushions typically offer reduced stability and

positioning by comparison to foam and gel cushions, but are e2ceptional in the area of

pressure relief, allowing pressure points to FsinkF into the cushion. ir cushions are

commonly available in HF and 5F heights, with the HF offering a low'profile, more stable

surface, and the 5F offering ma2imum pressure relief.

/G$G ?*- 1eat Cushion

*n air cushion ma" be best for "ou if "ou need:

• 02ceptional pressure relief

• d8ustable firmness

•

?ight weight• ?ow maintenance

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*n air cushion ma" not be best for "ou if "ou need:

• ?ow maintenance 3air cushions require regular monitoring of air pressure, and can

develop leaks4

• dvanced positioning characteristics

• Utmost seating surface stability

• ?ow cost

Selecting & Maintaining a Cushion• seat cushion(s sie should be matched e2actly to the wheelchair(s seat sie

• /emember that a seat cushion(s height adds to the wheelchair(s seat'to'floor

height, so a taller cushion will cause you to sit taller, accordingly 3which can be an issue

fitting under tables and desks4

• )f there(s a chance that the cushion will be e2posed to fluids, an incontinence cover

should be used 3incontinence covers come included with many cushions4

• )nspect the cushion regularly for degraded materials or damaged foam

• Dith air cushions, confirm proper inflation daily

•

Most cushions have an optimal use life span of two to three years, so for properperformance, replace a cushion when needed

foam cushions

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