Pressure mapping for mobility chairs and wheelchairs

Pressure Mapping for Mobility Chairs and Wheelchairs: Preventing Pressure Sores and Enhancing Seating Solutions

Wed Dec 13 2023

For individuals with limited mobility who rely on mobility chairs or wheelchairs, the risk of pressure sores is a common concern. Pressure sores, also known as pressure ulcers, can be painful, debilitating, and even life-threatening if not properly managed. In this article, we will look into the risks associated with pressure sores, the signs to watch out for, preventative measures, and possible solutions, such as specialist seating, with a focus on pressure mapping technology.

Understanding the Risk of Pressure Injuries

Pressure sores are a result of prolonged pressure on the skin, leading to reduced blood flow and, consequently, oxygen deprivation in affected areas. Both skin and muscle tissues need oxygen to remain healthy, and when this essential supply is compromised, it can have serious consequences. This is particularly common among individuals who spend extended periods seated, as it reduces blood flow and restricts the flow of oxygen to vital tissues.

In addition, individuals with reduced sensation or limited mobility are at an elevated risk of skin breakdown due to their inability to receive feedback from the body or change positions easily. When blood flow is restricted due to compression (resulting from continuous sitting, pressure on the prominent edge of a bone, or uneven weight distribution), increased moisture due to reduced thermoregulation and sweating, and shear forces (caused by sliding, spasms or vibrations through a chair), redness may develop on the skin. This redness is the body's way of attempting to reoxygenate the affected area. It's important to note that if this redness doesn't subside within half an hour, it is the first sign of a pressure sore.

The severity of pressure injuries can vary, ranging from uncomfortable, persistent redness to open wounds that can be life-threatening. In the later stages of pressure sores, complete offloading through bedrest is often the primary course of action. However, this can be frustrating and extremely limiting to those afflicted, reducing their quality of life significantly. However, there are preventative measures that can be taken to avoid this entirely. 

Preventing Pressure Sores and Solutions

Preventing pressure sores is a top priority for individuals with limited mobility. The following daily activities can promote skin integrity and help prevent the development of pressure sores:

Keeping Hydrated: Staying well-hydrated is crucial for overall skin health. Proper hydration helps maintain the elasticity and strength of skin tissues.

Good Nutrition: A balanced diet rich in essential nutrients is vital for tissue health and repair. Adequate protein, vitamins, and minerals support the body's natural healing processes.

Incorporating Pressure-Relieving Materials into Seating: Specialised cushions and seating materials designed for pressure relief can help distribute pressure evenly, reducing the risk of pressure sores. These materials often include memory foams, gel, and air cushions.

Regular Position Changes: Implementing a routine for offloading pressure by lifting up out of or re-adjusting one's position in a chair to allow blood flow back to vulnerable body prominences is crucial. Depending on an individual's skin condition and mobility, preventative offloading should occur at a minimum of every 1-3 hours.

The Importance of Pressure Offloading - Wheelchair position 

Effective offloading is a key strategy in preventing pressure sores. Tilt-in-space wheelchairs are valuable tools for redistributing pressure from the bottom to the back without the need for transferring. This feature is particularly beneficial for individuals who have difficulty adjusting their own position to offload pressure, allowing them to do so independently, even while on the move.

Seating Solutions and Cushions for Pressure Sores

Seating solutions play a crucial role in preventing pressure sores. Pressure is calculated as force divided by area, meaning that to reduce pressure, it's essential to maximise the contact surface area between the body and the seat. 

There are two primary ways to achieve this: through cushion shape and materials.

Cushions with higher contouring are associated with increased pressure relief and more stable positioning. Stability in sitting can help minimise shear forces, while contouring allows weight redistribution across the entire buttocks and thighs rather than isolating pressure on the ischial tuberosities (ITs). Some advanced cushion designs even offer custom moulding to maximise tailored support and pressure relief.

Pressure-relieving seating utilises various materials, including memory foam, gel, and air. It's not uncommon to use a combination of these materials, with the most immersive cushioning located under high-risk bony prominences like the ITs or the spine. These materials work on the same principle - the immersion of the body into these soft materials maximises all available contact points between a wheelchair user and their seat. The most unstable material (air) will be the most immersive and offer the highest pressure relief. In high-risk cases, closed air cell technology or custom moulding can be used to completely offload a pressure site. Different fabric covers can also be employed to help with thermoregulation and maintain moisture levels at a minimum.

The Role of Pressure Mapping

Pressure mapping technology has evolved significantly in recent years, using an array of highly sophisticated sensors to precisely measure the amount and location of pressure. This numerical and visual data is a great investigative tool to tell us what some wheelchair users can’t and for others, can help to return a degree of autonomy back to wheelchair users in their own healthcare management. 

Comparing data from different cushions and set ups offers a more comprehensive understanding of pressure distribution. A bank of data can even be built up over time to monitor the effectiveness of seating and the impacts on daily living. 

At Wheelfreedom, we offer pressure mapping to our customers. The data from this and our special analysis tools offer invaluable insights to enhance product design, manufacturing, quality, and research.

The significance of proper chair setup cannot be overstated, as it helps protect posture, reduce shear forces, and optimise pressure distribution. Pressure mapping provides valuable data to fine-tune seating configurations, ensuring optimal comfort and pressure relief for each individual.

How does pressure mapping work?

Pressure mapping technology involves the use of sensors and software to measure the interface pressure between a person's body and a seating surface. These sensors are typically embedded within a cushion or seat, and they collect data on pressure distribution at various points of contact. This data is then transmitted to a computer or mobile device for analysis. Here are some key aspects of the technology:

Sensor Types: Pressure mapping systems use various types of sensors, including resistive, capacitive, and piezoelectric sensors. Resistive sensors rely on changes in electrical resistance when pressure is applied, while capacitive sensors measure changes in capacitance. Piezoelectric sensors generate electrical charges when pressure is applied. Each sensor type has its advantages and is chosen based on the specific application and requirements.

Data Collection: The sensors collect data on pressure distribution, often in real-time. This data is represented graphically, allowing healthcare professionals, researchers, and seating specialists to assess the pressure points and make informed decisions regarding seating adjustments or customised solutions.

Analysis Software: Advances in pressure mapping technology have brought about sophisticated analysis software. This software interprets the data collected by the sensors, providing insights into the distribution of pressure across the body's contact points with the seating surface. It also allows for the visualisation of high-pressure areas, helping professionals identify potential problem spots.

Wireless Connectivity: Many modern pressure mapping systems are equipped with wireless connectivity, allowing for greater flexibility in data collection. Users can view real-time pressure data on tablets or computers, making on-the-spot adjustments to seating arrangements as needed.

Long-Term Monitoring: Some pressure mapping systems are designed for long-term monitoring, making them suitable for assessing the effects of seating and positioning over extended periods. This feature is particularly valuable for tracking changes in pressure distribution and comfort over time.

Recent advances in pressure mapping technology have focused on enhancing the accuracy, portability, and usability of these systems. Some notable developments include:

Integration with Smart Devices: Pressure mapping technology can now be integrated with smartphones and tablets, making it more accessible and user-friendly. Users can view and analyse pressure data on their mobile devices, enabling immediate adjustments for better comfort and pressure relief.

Wireless Sensors: Some pressure mapping systems feature wireless sensors that can be easily transferred between different seating surfaces. This flexibility allows for a more comprehensive assessment of various seating options. - repeated from above?

Pressure Mat Systems: Pressure mats have become popular for dynamic pressure mapping. These thin, flexible mats can be placed on different seating surfaces, such as wheelchairs, mattresses, or chairs, to assess pressure distribution during various activities and positions. They are particularly useful for evaluating pressure while sitting, lying down, or transitioning between positions.

Cloud-Based Data Storage: Cloud-based storage solutions enable healthcare professionals to access and analyse pressure data remotely, ensuring seamless collaboration and the ability to track long-term changes in pressure distribution.

Pressure-Relieving Recommendations: Advanced analysis software can now provide personalised recommendations based on pressure mapping data. These recommendations may include adjustments to seating configurations, cushion types, or wheelchair features, leading to more tailored and effective solutions.

The Impact of Footplate Positioning

One often overlooked factor in pressure distribution is the positioning of footplates - On average, 15-20% of our body weight is loaded through the feet. If footplates are too low, that weight that would be taken through the feet is usually displaced behind the knees. Over a prolonged period,with the body seeking stability is commonly observed in conjunction with sacral sitting as a compensatory posture. If footplates are too high, the weight that would have been loaded across the whole femur is instead taken primarily through the sitting bones (ITs). Both the sacral area and the ITs are considered high risk pressure areas, so redistributing pressure away from these and loading through areas with more soft tissue is highly desirable. 


In summary, pressure mapping, alongside proper seating and offloading techniques, can play a pivotal role in preventing pressure sores for individuals with limited mobility. By understanding the risk factors, recognising early signs, and implementing preventative measures, we can significantly improve quality of life and minimise the discomfort and risks associated with pressure injuries. 

Meanwhile, pressure mapping technology continues to advance, offering a more nuanced understanding of pressure distribution and facilitating the development of innovative seating solutions. These technological developments have the potential to enhance the quality of life for individuals with limited mobility by reducing the risk of pressure sores and optimising comfort and support. As technology continues to evolve, pressure mapping will likely play an increasingly vital role in improving the well-being of those in need of specialised seating solutions.

Book Your Seating Assessment

If you or a loved one are living with reduced mobility and are concerned about pressure sores or seating solutions, don't hesitate to reach out to us for a seating assessment. At Wheelfreedom, we are trusted, knowledgeable, impartial, dependable, and progressive. With thousands of 5-star reviews, you can feel reassured that you will receive a service tailored to your individual needs.

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