1. Can sensors help determine pressure ulcer risk
Can sensors help determine pressure ulcer risk? Frank Knoefel1,2,3,4 Stephanie Bennett3 Louise Carreau4 Ambika Dewan4 Rafik Goubran1,3 1Bruyère Research Institute 2University of Ottawa 3Carleton University 4Bruyère Continuing Care
BACKGROUND
RESULTS
• Ongoing pressure applied to the skin can cause capillary compression, decreased oxygenation, and skin breakdown, leading to significant morbidity and mortality
Reduced mobility and pre-existing vascular and skin conditions are associated with pressure ulcers
The prevalence of pressure ulcers in Canadian acute care settings is estimated at 25%1, and each ulcer can cost up to $90,000 to treat2
Pressure-sensitive mat sensors provide continuous monitoring of pressure3
Infra-red (IR) thermal cameras can identify micro-circulation patterns4
Preliminary results from a 70-year old female with diabetes, heart disease, peripheral vascular disease, dialysis, and high risk of pressure ulcers (MDS 2.0 – PU Risk Scale score: 4)
Pressure data was collected over one night (October 26, 2015); the images were taken on the morning of October 27, 2015
This participant typically slept with her left foot rotated externally
Pressure-sensitive mat data confirmed a larger pressure area around the left lateral malleolus
IR comparisons of the lateral malleoli of the left and right feet showed a significant temperature difference (28 C vs. 31 C)
OBJECTIVE
To explore the use of two sensor technologies; the pressure-sensitive mat and IR thermal cameras (Figure 1.), and to determine the pressure ulcer risk in complex continuing care patients
Right Foot
Left Foot
METHODS
• Observational pilot study
Saint-Vincent Hospital, Bruyère Continuing Care, Ottawa, Canada
Seven (7) participants at high-risk for pressure ulcers
Primary outcomes:
Continuous pressure on body parts (pressure-sensitive mats)
Blood circulation (IR thermal camera)
Formation or worsening of pressure ulcer
Technology used:
Pressure-sensitive mats (fiber-optic pressure sensor arrays embedded in polymer foam, manufactured by S4 Sensors Inc.) placed under the mattress, below the feet
IR camera (FLIR Systems Inc.) used to capture morning heel skin temperature bi-weekly
The pressure-sensitive mat data was continuously collected and converted to mean sum of pressures (SoP) and standard deviation (SD)
Left Foot
Figure 3. Contour plots of the patient ‘s heels and corresponding temperature (C˚)
Figure 4. Average exerted pressure and level of overnight movement at the heels. Both figures had low and high bound sensor values of 400 and 1000, respectively
Figure 3: The thermal images were transformed into heat maps by calculating contours representative of each 1°C between the temperature range of 15°C to 32°C, as well as the area of skin (measured by number of pixels) at these specified temperatures
Figure 4: Average exerted pressure by the patient’s heels and level of overnight movement by the patient’s heels, for one night (9pm - 8am) with sensor value bounds of 400 and 1000
DISCUSSION
• We found a relationship between consistent pressure and little pressure relief on the lateral foot, and reduced skin temperature
We believe that we are the first to combine these two sensors to suggest that immobility results in decreased microcirculation in the context of pressure ulcer risk
If replicated, using pressure-sensitive mat sensors may provide a novel automated way of measuring pressure ulcer risk
Our next step is to complete analyses on all 7 participants
ACKNOWLEDGEMENTS
We gratefully acknowledge the collaboration of patients, the clinical expertise of Ankica Jovan, Jessica Singh and Sara Owusu‐Sarfo, the research support of Courtney Lord and
Caroline Gaudet, as well as the administrative support of Jodie Taylor and Nancy Mieleszko. This work was supported by AGE-WELL NCE Inc., a member of the Networks of Centres of Excellence program, as well as the Bruyère Academic Medicine Organization Incentive Fund.
REFERENCES
1) Woodbury MG, Houghton PE. Prevalence of pressure ulcers in Canadian healthcare settings. Ostomy Wound Manage. 2004;50(10): 22-4, 26, 28, 30, 32, 34, 36-8.
2) Chan B, Ieraci L, Mitsakakis N, Pham B, Krahn M. Net costs of hospital-acquired and pre-admission PUs among older people hospitalized in Ontario. J Wound Care.
2013;22(7):341-2,344-6.
3) Barnett, R. I., & Ablarde, J. A. (1995). Skin vascular reaction to short durations of normal seating. Archives of physical medicine and rehabilitation, 76(6): 533‐540.
4) Lahiri, B. B., Bagavathiappan, S., Jayakumar, T., & Philip, J. (2012). Medical applications of infrared thermography:a review. Infrared Physics & Technology, 55(4): 221‐235.
Figure 1. Equipment (A) and thermal imaging set-up (B)
Figure 2. Participant’s feet
Contact
Dr. Frank Knoefel can be contacted at