Support surfaces affect tissue by managing pressure, shearing, heat, and moisture. However, the support surface must also keep the patient safe as they ingress, egress, and roll, to prevent entrapment and patient falls.

This poster describes a pilot study using laboratory simulation to measure the stability of the edges of 5 different mattress technologies: visoelastic foam, standard foam, air-filled, air-filled with air-filled bolsters, and air-filled with foam-filled bolsters.   The two studies simulated sitting on the edge of a mattress, and rolling toward the edge of the mattress. 

In edge-sitting, a wooden mold of buttocks and thighs were loaded with 125# and lowered onto the edge of the mattress.  A force gauge at approximate knee height measured the force pushing the mold off of the bed.

In rolling, a mannequin simulating a 6'0” and 167# man was laid in the center of the mattress.  Using an over-the-bed rig, we bent the mannequin's knees and rolled it toward the edge of the bed to simulate the supine-to-sit motion.  The point of edge-collapse was marked by two measures – the distance from the center of the mattress that the mannequin traveled, and the amount of pressure the mannequin was exerting at the point of collapse.

The five mattress technologies behaved very differently in both tests.  The air-filled with foam-filled bolsters was significantly more stable in both edge sitting (first graph) and in rolling (second graph).  In addition, 4 of the mattress configurations collapsed well before the edge was reached, indicating that the patient could not utilize the full width of the mattress safely. However, on the air-filled with foam-filled bolsters mattress the full width was safe to use.

These tests will help the clinician choose mattresses that address the patient's skin and the patient's safety.