Comments on the article "Development of test methods for evaluation of wheelchair cushions".

Vincent Palmieri : Development of Test Methods for Evaluation of Wheelchair Cushions. That article and a related paper on details of test equipment employed appear in this issue of The Bulletin of Pros-thetics Research. This issue of the Bulletin reports some very commendable efforts to measure the pressure and shear stresses that impinge on human flesh as a result of sitting in a wheelchair on one cushion or another. Other investigators have increased the sophistication of our ability to measure capillary bloodflow in tissues under pressure. Still others, engaged in the management of patients who lack sensation, have emphasized the value of intermittent relief of pressure by teaching the patient to lift himself or herself off the cushion at regular intervals, to compensate for the ischemia produced during sitting. While we warmly encourage every attempt to develop "cushion-ology" into a science and to record pressures and shear stress by numbers, we were particularly pleased to find authors Cochran and Palmieri warning against any move at this time to rate cushions as "acceptable" or "unacceptable"" as though we knew the answers to the problem of pressure sores. The problem seems to me to be even more complex than Cochran and Palmieri have indicated in their excellent analysis. Consider two factors that are individual to each patient that could change an apparently correctly prescribed "acceptable" cushion to "unaccep-table" in a particular case. The first of those factors is intermittency. Most patients are being advised today that, if they have to sit in a wheelchair for many hours, they should lift themselves off the seat support at regular intervals. This is because there seems to be no way in which even the best cushion can prevent some degree of ischemia on some parts of the patient's buttocks. With lifting at intervals, the tissues under bony prominences can get enough relief to last until the next lift. But lifting is a strenuous muscular effort, and that effort is multiplied if the cushion is so soft that the patient has sunk far into it. There are cushions that achieve their maximum pressure relief only when the patient sinks 3½ inches into the soft material. Thus the pressure is fully relieved only on a 3½" lift. That is very hard work and will rarely be accomplished frequently and completely. Really weak patients may hope to accomplish intermittent relief by only leaning forward to tilt their pelvis …