Comparison of quantitative methodologies to define chronic pressure ulcer measurements

The objective of this study was to evaluate and compare various methodologies of measuring the characteristics of pressure ulcers. This prospective, four-week, follow-up study consisted of 20 patients, of whom 17 completed the study. Each patient had at least one full-thickness pressure ulcer (surface area between 1.2 and 61.6 cm2) that had been present for at least four weeks. The ulcers were assessed weekly for four weeks using the following techniques: direct measurement (length, width, and depth), tracing of the ulcer outline onto transparent material, standard photography, and volume measurement. Computer-assisted planimetry from the tracings and photographs, and calculations from the direct measurements determined ulcer areas. Each technique estimating ulcer area gave similar results; however, the areas obtained from the direct measurements slightly over-estimated the areas when compared with the areas obtained by computer-assisted planimetry (mean difference of about 1.5 cm2). Areas obtained from the photographs were more variable than the other measurement techniques. Volumes calculated from bedside measurements were consistently larger than those calculated by jeltrate impression (mean difference of 4.0 cm3). While all the measurement methodologies gave similar and reproducible results, the areas obtained from the photographs were more variable than the areas obtained from the other measurement techniques. The photographic measurements could be improved either by tracing the ulcer outline at the bedside onto the photograph shortly after being taken, or by drawing an outline of the ulcer margin directly on the patient's skin just before taking the photograph.