AN ANIMAL-MODEL AND COMPUTER-CONTROLLED SURFACE PRESSURE DELIVERY SYSTEM FOR THE PRODUCTION OF PRESSURE ULCERS

Pressure ulcers continue to be a major health care problem. This paper describes an animal model and surface pressure delivery system for th e production of experimentally derived pressure ulcers. A method for i nducing dermal pressure lesions on the fuzzy rat was developed using a computer-controlled displacement column which produced a constant tis sue interface pressure. The pressure column consists of a force transd ucer located between two 0.5-in (1.27-cm) diameter metal cylinders. Th e desired cutaneous pressure is maintained by a computer-controlled mi niature stepper motor which displaces the column with the aid of inter active software. The force transducer signal is converted from analog to digital form, amplified, and recorded. Blood perfusion is monitored using a laser Doppler flowmeter (located in the tip of the column) du ring the application of pressure. The application of 145 mmHg pressure for 5 consecutive 6-hr sessions resulted in a greater than 90% incide nce of pressure ulcers. The implications of our model and contribution s of earlier animal models are discussed. This model provides a tightl y controlled and measured environment making possible the scientific s tudy of ulcer development and the evaluation of potential preventative or curative compounds.