New smartphone-based system provides at-home access to pressure-mapping data

Predicting and preventing pressure ulcers in people with spinal cord injury (SCI) is an ongoing challenge, with life-threatening and costly consequences for wheelchair users with SCI. Undetected cushion failures, caregiver turnover or inexperienced caregivers are among the list of factors that can increase the incidence of pressure ulcers.

Mayo Clinic's seating clinic receives about 900 patient visits annually, and about 54 percent of those visits are associated with pressure ulcers. Up to 95 percent of adults with SCI experience at least one advanced pressure ulcer during their lifetimes. When sepsis occurs, which occurs in 25 percent of nonhealing ulcers, the mortality rate is 50 percent. In addition to their significant impact upon mortality and morbidity, pressure sores among SCI patients also account for $6.3 billion in added medical expenses in the U.S.

These grim statistics moved a team from Mayo Clinic's seating clinic to explore new ways to address this common problem. Seat interface pressure mapping is one tool that has helped reduce patients' risk of pressure sores. Existing systems are designed for use in the clinical setting, with expensive components and complex data displays. So the Mayo team's first goal was to figure out how to develop a prototype pressure-mapping system that would provide patients with in-home access to relevant information that is easily understood.

Led by Tamara L. Vos-Draper, O.T., an occupational therapist at Mayo Clinic's campus in Minnesota, the team working on this project included a registered nurse, a physical therapist, a physiatrist, engineers and designers. The project had several facets that needed to be addressed upfront: how to work around the known limitations of pressure sensors, identifying available methods by which to wirelessly transmit and display the pressure image on a smartphone, and developing a patient-friendly, appropriate user interface.

The resulting prototype system that the Mayo team developed consists of a thin and flexible pressure mat that wirelessly transmits data to a smartphone via a Web-based application. Using this system, patients can view their average pressure and dispersion index in real time or send the data to a seating clinic specialist at Mayo Clinic for analysis.

Vos-Draper and her team recently conducted preliminary testing on the prototype system with a group of five wheelchair users with SCI. Three of the group members were manual wheelchair users, and two were power wheelchair users. Each of the five users tested the prototype during three separate three-hour sessions to help establish the skin safety of the mat and the repeatability of the average pressure and dispersion index. Patient feedback was sought during a focus group discussion.

User feedback

  • Users deemed battery rechargeability, equipment durability, comfort (for all-day use), portability and affordability to be the most critical features.
  • Four of the five users had smartphones and expressed a desire to watch their maps in real time on their phones as needed during the day.
  • Users want the map to function on a variety of surfaces, including shower or commode, car seat, arm cycle, and other seating surfaces.
  • Users want the ability to scan pressure-map data recorded throughout the day to watch for problems, save data, forward data to their seating clinic therapist for review, and use the map to assist their caregivers in positioning them correctly in their chairs.

None of the patients experienced any adverse reaction of the skin to the mat, and the dispersion index showed good consistency across trials.

Vos-Draper and her colleagues are encouraged by these preliminary results, but they recognize that additional research is needed to determine if patients using this tool will then make the behavior changes needed to prevent pressure sores.

"We have an ongoing study that's looking at whether patients using the system and receiving the visual feedback it provides will move more and make the necessary seating adjustments," says Vos-Draper.