Analysis of skin temperature changes on compressed area for pressure sores using animal models

For immobile patients, pressure sores are one of the most severe diseases. When such people must continuously lay or sit in the same posture, pressure sores can from as a result. However, the mechanism that causes pressure sores is not fully understood. In this study, we examined the skin surface temperature (SST) under pressure loading and relief in rabbits, and discussed the influence of ambient temperature on SST at the ischemic area. When the pressure load duration was changed, SST at the compressed area was compared. Animals were healthy rabbits whose ears were compressed with a local external pressure of 40 kPa for 10, 120 or 240 min. As the ambient temperature was controlled constantly within 20.0-30.0°C, the SST was determined by a thermocouple. The results revealed that the SST of the complete localized ischemic area changed due to the different average of ambient temperature under the same pressure loading and relief. Under the optional ambient temperature, the SST at the compressed area increased during the initial 30 min under pressure loading. It was shown that the recovery time of the SST at the compressed area when released from pressure loading became longer the lower the ambient temperature and the longer the duration of pressure loading. In order to prevent pressure sores, it is necessary to analyze not only the ischemic area released from pressure loading, but also physiological factors including SST.