The relationship between pressure ulcer incidence and buttock-seat cushion interface pressure in at-risk elderly wheelchair users

Objective: To investigate the relation between pressure ulcer incidence and buttock-wheelchair seat cushion interface pressure measurements. Design: Secondary analysis of data from a randomized clinical trial. Setting: Skilled nursing facility. Patients: Thirty-two elderly patients (age, greater than or equal to 65 yr), with Braden score less than or equal to 18 and Braden mobility and activity subscale score less than or equal to 5, who used wheelchairs greater than or equal to 6hr/d, were free of existing sitting-induced pressure ulcers, and weighed less than or equal to 250lb. Interventions: Generic foam seat cushion or pressure-reducing seat cushion. Main Outcome Measures: The incidence of sitting-induced pressure ulcers over a 1- to 12-month period was compared with pressure measured between patients' buttocks and wheelchair seat cushions. A flexible pad with a 15 X 15 pressure sensor array was used to measure interface pressure. Results: Interface pressure measured on wheelchair seat cushions was higher (p less than or equal to .01 for both peak pressure and average of highest 4 pressures) for patients who developed sitting-acquired pressure ulcers compared with those patients who did not. Conclusions: Results indicated that higher interface pressure measurements are associated with a higher incidence of sitting-acquired pressure ulcers for high-risk elderly people who use wheelchairs.