A Randomized Trial of Low-Air-Loss Beds for Treatment of Pressure Ulcers

OBJECTIVE: To assess the effectiveness of low-air-loss beds for the treatment of pressure ulcers in nursing homes. DESIGN: Prospective, randomized, clinical trial. SETTING: Three teaching nursing homes in Los Angeles, Calif. SUBJECTS: Eighty-four nursing home residents with trunk or trochanter pressure ulcers (Shea stage > or = 2). INTERVENTIONS: Subjects were randomly assigned to use either a low-air-loss bed (n = 43) or a 10-cm corrugated foam mattress (n = 41) throughout the healing of their ulcers. OUTCOME MEASURES: Ulcers were assessed twice weekly using surface area and two observational scales (median follow-up, 37.5 days; range, 4 to 571 days). RESULTS: Groups were similar with respect to demographics, medical variables, wound care, and early dropouts. Results indicate more than a threefold improvement in median rate of healing for low-air-loss beds compared with foam mattresses (9.0 vs 2.5 mm2/d; P = .0002). This finding was true for deep as well as superficial ulcers (deep ulcers, 9.9 vs 0.7 mm2/d; P = .02; superficial ulcers, 9.0 vs 3.2 mm2/d; P = .004). Cox regression models revealed that the bed, ulcer depth, and fecal continence had independent effects on healing. After controlling for fecal continence, the deep and superficial subgroups using low-air-loss beds remained 2.5 times more likely to heal in a given length of time compared with those using foam mattresses (combined cure probability ratio, 2.66; 95% confidence interval, 1.34 to 5.17; P < .004). CONCLUSION: Low-air-loss beds provide substantial improvement compared with foam mattresses despite other factors in pressure ulcer healing.