Temperature-modulated pressure ulcers: a porcine model.

OBJECTIVE A reliable porcine model was developed to facilitate investigations of pressure ulcer formation, healing, and prevention. In the present study, it was specifically used to study the relationship between applied temperature, applied pressure, and time of application in the formation of cutaneous and deep tissue injuries. DESIGN An apparatus and procedure were created to simultaneously apply 12 metal discs (each with a diameter of 51mm) on the dorsal aspect of the swine, all at an equal pressure of 100mmHg, for a 5-hour period, while servo-controlling disc temperatures at either 25, 35, 40, or 45 degrees C. RESULTS The severity of the resultant tissue injuries correlated with an increase in applied temperature. No damage was observed in the superficial or deep tissues underlying the sites of the 25 degrees C pressure applicators. In general, only deep tissue damage resulted from the application of a 35 degrees C temperature, whereas the application of higher temperatures caused both cutaneous and subdermal damage (the extent of necrosis being greater at the 45 degrees C sites). There was a high degree of reproducibility of these results among a large population of sites per temperature (n = 64) and number of animals investigated (n = 16). Furthermore, subsequent healing (monitored up to 4 weeks) was uniform for the degree of induced damage. Insights into pressure ulcer formation were also sought via systematic examination of histological sides and postmortem visual assessment over the 4-week period. CONCLUSION It was concluded that this animal model of temperature-modulated pressure ulcers has the potential for significant use in all major areas of this field, ie, wound formation, healing, and prevention.