Predictive validity of pressure risk assessment scales in a private sector trauma intensive care unit

Abstract

Background. Risk assessment scales are considered essential tools in pressure ulcer prevention, but none of them have been tested for predictive validity (sensitivity, specificity and positive and negative predictive value) in intensive care, especially in the South African context. Purpose. To compare the sensitivity, specificity and predictive value of a pressure ulcer risk assessment scale developed for intensive care unit patients (research scale) with the one that was currently being used in the research unit (control scale). Method. Sixty-six patients were assessed over a period of 3 months. Pressure ulcer risk was calculated on a weekly basis using both assessment scales. Predictive risk was compared with the actual outcome (pressure ulcer development) in order to determine the sensitivity and specificity of each scale. Results. Twenty-five (38%) of the sampled patients developed pressure ulcers. There was significant asymmetry (p < 0.05) between the two scales, with the control scale having a tendency to classify more patients as being at risk. The two scales matched well for sensitivity, but the research scale had a higher specificity (71% v. 29%) and positive predictive value (63% v. 44%). Conclusion. It was concluded that the research scale is superior to the control scale, as it was able to predict risk with more accuracy.