Abstract
OBJECTIVE: We compared the shear forces exerted over the heel between a pressure ulcer preventive dressing and a thin-film dressing in a clinical setting. Interface pressures were measured as well.
DESIGN: Quasi-experimental clinical trial.
SETTING AND SUBJECTS: Participants were 30 elderly patients (5 men, 25 women; mean age, 86.4 +/- 8.0 years) hospitalized in a geriatrics hospital in Japan; all had a Braden score of less than 14 (mean, 10.1 +/- 1.1). Informed consent was obtained from all the patients.
A shear force and pressure sensor including a strain gauge, and an oval airbag-type pressure sensor were used.
METHODS: The sensor was attached to one heel using double-sided tape; then the target dressing was applied over the sensor and on the opposite heel to avoid the influence of the opposite heel on the shear force measurement. Interface pressures were measured with the patient in a stationary supine position; shear force was then measured at 0.2-second intervals, while the sheet was manually pulled at a velocity of around 5 cm/second. Shear force was determined by averaging the stable shear force lasting for 10 measurement points.
RESULTS: The mean interface pressures with the PPD and the film dressings were 70.7 +/- 16.5 and 70.2 +/- 15.2 mmHg, respectively; this difference was not statistically significant. The shear force produced during the pulling of the sheet was 2.2 +/- 1.4 and 11.7 +/- 5.8 N, respectively (P < .001, Wilcoxon signed-rank test).
CONCLUSIONS: The results of this study suggest that a dressing with a low-friction external surface (such as the pressure ulcer preventive dressing) can significantly reduce shear force. However, results also suggest that external dressings do not significantly reduce interface pressures and cannot be used as a substitute for heel elevation in an immobile patient.