It is estimated that 10% of the population are people with disabilities. About 10% of the people with a disability require a wheelchair.
A wheelchair is appropriate when it meets the individual’s needs and environmental conditions; provides a proper fit and postural support based on sound biomechanical
One element of postural support is the wheelchair cushion. Wheelchair seat cushions are designed to provide comfort and aid against pressure injury development. To aid against pressure injuries, cushions are designed to reduce extrinsic risk factors known to increase the risk of pressure injuries, such as pressure and shear.
Manufacturers of wheelchair cushions should specify the an exact description of the intended purpose in the device’s instructions for use and should specify contraindications, warnings, and precautions.
Four commonly used wheelchair cushions are foam, foam/gel, interconnected air cell, and compartmented air cell cushions. Their instructions for use differ based on intended use/indications, expected lifetime, and precautions.
However, despite the clear instructions in the instructions for use of wheelchair cushions, there is still a risk that a wheelchair cushion can be misused with all the detrimental consequences that can result from misuse, primarily pressure injuries (PI’s), skeletal deformation, and loss of function.
Risks of misuse of a wheelchair cushion
Healthcare professionals, clinical educators, carers, but also patients must be aware of how to apply a medical device in accordance with the instructions for use and the potential risk of developing a Device Related Pressure
Injury (DRPI) if medical devices are not applied correctly. This is particularly important in the community setting. Devices should be carefully selected to ensure a good fit with the user’s anatomy and contours. It should also
be possible to be able to adjust them in response to changes in tissue characteristics, volume, and contours.
Misuse of a wheelchair cushion could also lead to accelerated aging or failure of the cushion.
Factors influencing misuse of a wheelchair cushion – disregarding the instructions for use
Wheelchair cushion manufacturers disclose in their instructions for use the maintenance of the cushion and when there is potential cushion failure. When an individual does not adhere to the instructions in the instructions
for use, this is considered to be misuse. Furthermore, these instructions for use instruct when and how to check for bottoming out, if an individual continues to use the cushion when bottoming out has occurred, this is also
considered as misuse and discouraged by wheelchair cushion manufacturers.
Continuing use while cushion shows fatigue
After 6 month of use, 70% of foam wheelchair cushions show signs of fatigue. When a foam cushion ages, interface pressure magnitudes tend to rise over time.
If a cushion is used after the cushion has started to show material fatigue, the user is at a higher risk of developing pressure injuries since the cushion age has an inverse
relationship with cushion performance.
One study found a PI incidence of 26.4% in wheelchair users with chronic Spinal Cord Injury (SCI) and reasoned that this might be due to prolonged use of a foam cushion.
Foam cushions are not durable and deteriorate over time, even without use, and therefore should be changed more frequently (e.g. every six months instead of yearly).
The study by Kovindha et al. is not the only study that found prolonged use of a foam cushion. A study by Sumiya et al. found that foam cushions can be used upwards of 4 years before being replaced. This means
that cushions that are profoundly deteriorated, are still being used, which could lead to unacceptably high interface pressures.
Over- or underinflation of air-filled cushions
Air-filled cushions, specifically rubber designed cushions with multiple air bladders, are at risk of over- or underinflation. When a wheelchair cushion is over-inflated, there is less immersion and envelopment, which
can lead to stability issues, higher interface pressures, and an increased risk of pressure injuries. When a wheelchair cushion is underinflated, this can lead to bottoming out, which also puts the user at a higher risk
of developing pressure injuries because tissue is not suspended in the material and hits the bottom of the wheelchair. Furthermore, the bladders of these cushions can be punctured or burned, rendering them useless.11 12
Unfortunately, there was very little literature on misuse. Therefore, we had to rely heavily on other search engines such as google scholar, but also on experts in
the fields. Despite all our efforts, we could include only seven studies in this review.
When we asked experts in the field for possible relevant literature, we were able to include fourteen articles to assess for eligibility based on the text.
Assess the incidence of misuse of a wheelchair cushion
Only one of the seven studies (Key et al.6) reported the incidence of misuse during a visit at the seating clinic. Of the 166 patients included and followed-up by Key et al., 4
patients were reported to misuse their cushion.
However, these incidents of misuse were only caught during a visit at the seating clinic. Therefore, incidents of misuse outside of the seating clinic were not caught, which could mean that the true incidence of misuse is
higher than Key et al. reported.
Anecdotal evidence corroborates this suggestion.
Several experts in the field reported about wheelchair users they met whose cushions were placed in the wrong orientation or even upside down and came to them complaining about discomfort. Therefore, the true
incidence of misuse remains unknown.
Assess the risk of misuse of a wheelchair cushion
We found one extensive review on device related pressure injuries (DRPI) which, although it was not specifically on wheelchair cushions, provided extensive evidence on increased risk of development of pressure injuries
when a device provides pressure and/or shear at the skin-device surface.7 We feel comfortable extrapolating these results to misused wheelchair cushions, since an offloading cushion that is sat upon whilst in the wrong
orientation, can possibly increase shear and compressive forces, leading to an increased risk of pressure injuries.
However, it can also lead to minor complications such as discomfort and backpain or neck pain resulting from poor posture.
Assess factors influencing misuse of a wheelchair cushion
This was the only aim that was somewhat satisfactorily met since we found the most literature on factors influencing misuse. Although the factors identified by these studies are very important and should be taken seriously, due to the low amount of data, this is probably not the complete picture. Experts in the field might be able to add factors to the list that are not identified in this review, but are encountered in their work.
All factors influencing misuse boil down to the same thing, not following the instructions for use as specified by the manufacturer
Therefore, this implies that a lot of incidents of misuse can be prevented by a sufficient understanding and following the instructions for use, especially the ‘use’ and ‘caution’sections of instructions for use, and in the case of foam cushions also the ‘expected lifetime’ section. However, there could be several reasons why an individual does not adhere to the instructions for use. Firstly, the instructions for use could have not been provided with the cushion. Secondly, the wheelchair user is unable to understand the instructions for use due to language barriers, intellectual disabilities, or learning disabilities. These reasons are very serious, and action should be undertaken to decrease the risk of misuse. Possible solutions could be graphic presentation of the steps one needs to undertake to correctly use the cushion, short video’s explaining how to use the cushion, or 1-on-1 instruction of the wheelchair user and/or caregiver.
There is very little literature regarding misuse of a wheelchair cushion. Since proper use is needed to achieve pressure and shear reducing properties, more scrutiny is needed regarding misuse.
Misuse or improper use of a wheelchair cushion can be a cause of the development of pressure injuries. Especially when the wheelchair user has both physical and intellectual disabilities. All Vicair cushions are provided with a Quick Installation Guide which depicts the installation steps, skin checks with pictures and a QR code linking to the user manual.
The Vicair 4 wheelchair cushion consists of four compartments of equal size. This cushion can be placed in the wheelchair in any orientation, even upside down, without affecting the pressure redistributing, positioning,
and microclimate control properties. Therefore, a Vicair 4 should be considered when there is a risk that the user will misuse their wheelchair cushion.
Larissa de Groot | 04-2021 | 02.12REV4.21