Use of a Shear Reduction Surface for Prehospital Transport: A Randomized Crossover Study

OBJECTIVE: To compare the effectiveness of an antishear mattress overlay (ASMO) with a standard ambulance stretcher surface in reducing pressure and shear and increasing patient comfort. METHODS: In this randomized, crossover design, adults in three body mass index categories served as their own controls. Pressure/shear sensors were applied to the sacrum, ischial tuberosity, and heel. The stretcher was placed in sequential 0°, 15°, and 30° head-of-bed elevations with and without an ASMO. The ambulance traveled a closed course, achieving 30 mph, with five stops at each head-of-bed elevation. Participants rated discomfort after each series of five runs. RESULTS: Thirty individuals participated. Each participant had 30 runs (15 with an ASMO, 15 without), for a total of 900 trial runs. The peak-to-peak shear difference between support surfaces was −0.03 N, indicating that after adjustment for elevation, sensor location, and body mass index, peak shear levels at baseline (starting pause) were 0.03 N lower for the ASMO than for the standard surface (P = .02). The peak-to-peak pressure difference between surfaces was −0.16 mm Hg, indicating that prerun peak-to-peak pressure was 0.16 mm Hg lower with the ASMO versus standard surface (P = .002). The heel received the most pressure and shear. Discomfort score distributions differed between surfaces at 0° (P = .004) and 30° (P = .01); the overall score across all elevations was significantly higher with the standard surface than with the ASMO (P = .046). CONCLUSIONS: The ASMO reduced shear, pressure, and discomfort. During transport, the ambulance team should provide additional heel offloading.