Date Presented 03/28/20
Occupational contexts are sparse in studies examining sitting-interface pressures of wheelchair users. This study evaluated 48 adults’ peak and average pressures in a manual wheelchair while they completed four functional tasks in a kitchen environment based on random assignment. Statistically significant differences occurred in the tasks with different reaching patterns. The findings inform practitioners when appraising the occupational influences on sitting-interface pressures for wheelchair users.
Primary Author and Speaker: Leslie Jackson
Additional Authors and Speakers: Allie Custer, Marissa Imondi, Anita Kolodich, Megan McMaster
PURPOSE: Wheelchair users with spinal cord injuries, degenerative conditions, or congenital disabilities have an increased risk of developing pressure injuries (Stockton, Gebhardt, & Clark, 2009). To manage this risk, wheelchair users require effective strategies and equipment while performing occupations, including those at home. Occupational therapists assist in pressure care by assessing function and posture, prescribing and fitting equipment, and training clients and caregivers (Macens, Rose, & Mackenzie, 2011).
Prior research has included isolated reaching and weight shifts while evaluating sitting interface pressure with pressure-mapping technology (Sonenblum, Vonk, Janssen, & Sprigle, 2014). However, occupational contexts are lacking in the methodologies of scholarly literature. Research is needed to determine how wheelchair users’ sitting interface pressures are impacted by occupations and their associated reaching and weight shift patterns. This study’s aim was to determine if differences in sitting interface pressures occur during functional tasks completed by adults sitting in manual wheelchairs.
DESIGN: This quantitative study used a repeated measures design to evaluate differences of sitting interface pressures among four functional tasks completed by healthy adults who were at least 18 years old. Participants were recruited with convenience sampling. Researchers structured the tasks to ensure consistent performance in a home environment lab located on a university campus. Four tasks incorporated different reaching and weight-shift patterns: washing dishes, sweeping floor debris, retrieving a pan, and retrieving a water bottle from a refrigerator. Using an XSENSOR® pressure mapping system, researchers recorded participants’ (n=48) peak pressures, overall average pressures, and times as they completed the tasks from a manual wheelchair. Two Silver Sport II wheelchairs accommodated different sizes of participants: an 18" x 16" manual wheelchair and a 22" x 18" Heavy Duty manual wheelchair.
RESULTS: Nonparametric alternatives to a repeated measures ANOVA were used for statistical analyses. A Kruskal-Wallis test indicated no order effects. The Friedman’s test indicated statistically significant differences for peak pressures among the task conditions, χ2 (3) = 29.425, p < .0005. Overall average pressures were statistically significant, χ2(3) = 53.700, p < .0005. Time differences were also statistically significant for task conditions, χ2(3) = 129.319, p < .0005. Regarding effect size, task condition led to 13% of peak pressure’s variability, followed by 31% for overall average pressure, and 78% for time. Wilcoxen Signed-Ranks tests revealed statistically significant differences for peak pressure for two comparisons: Pan-Sweep and Pan-Fridge. All comparisons were statistically significant for overall average pressure, except the Fridge-Sweep pair. With the exception of the Pan-Fridge task pair, all comparisons were statistically significant for time. Only BMI and overall average pressure had a moderate, positive association, rs
(46) = .59, p < .0005. However, BMI did not provide a significant interaction effect when α = .008 for a Bonferroni correction, p=.113
CONCLUSION: The results supported the hypothesis that sitting interface pressures differ between the four functional tasks based on their associated reaching and weight shift patterns. Tasks with contrasting & multidirectional weight shifts and time led to greater variability in pressures. This study is important to occupational therapy practice as the findings indicate occupational influences on sitting interface pressures. Understanding these influences can assist clinicians with prescribing strategies for mitigating pressure injury risk among wheelchair users.
References
Macens, K., Rose, A., & Mackenzie, L. (2011). Pressure care practice and occupational therapy: Finding of an exploratory study. Australian Occupational Therapy Journal, 58, 346-354. doi: 10.1111/j.1440-1630.2011.00962
Sonenblum, S. E., Vonk, T. E., Janssen, T. W., & Sprigle, S. H. (2014). Effects of wheelchair cushions and pressure relief maneuvers on ischial interface pressure and blood flow in people with spinal cord injury. Archives of Physical Medicine & Rehabilitation, 95(7), 1350-1357. doi: 10.1016/j.apmr.2014.01.007
Stockton, L., Gebhardt, K. S., & Clark, M. (2009). Seating and pressure ulcers: Clinical practice guideline. Journal of Tissue Viability, 98-108. doi: 10.1016/j.jtv.2009.09.001
