Prevalence, incidence and risk: a study of pressure ulcers at a rural base hospital

This project was conducted in an Australian rural base hospital. It compared the Norton and Waterlow pressure ulcer risk assessment scales with an informal nurse assessment via a prevalence and an incidence study of inpatients. This study, more a pilot study due to the small sample size, suggests that the pressure ulcer prevalence and incidence within this Australian hospital was comparable to national and overseas studies. Statistical analysis of the incidence data using the Kappa and McNemar tests showed that the Waterlow risk assessment scale performed better than both the Norton scale and the informal nurse assessment when identifying patients at risk of developing pressure ulcers. Corrine Charlier BN Intensive Care Unit Westmead Hospital Sydney NSW Tel: 0428 267 746 Introduction The hospital in which this research project was conducted is an 80 bed facility. Numbers of inpatients are progressively higher among the older population brackets, with an average length of stay of 4-5 days 1. Pressure ulcers, also known as decubitous ulcers, pressure sores, bed sores or pressure areas 2, 3, are defined as “any lesion caused by unrelieved pressure resulting in damage of underlying tissue” 4. Put simply, they are ischaemic ulcers due to pressure 2. They usually affect tissue over bony prominences 2, 4 such as the sacrum and coccyx, ischial tuberosities, greater trochanters, external malleoli, heels, occiput and elbows 2, 5. Pressure ulcers are graded according to their severity. The most common system for classifying pressure ulcers appears to be the 1995 AHCPR 4 definition, which classifies ulcers as Stage I-IV, according to the amount of tissue damage observed by the clinician. Although widely used, it is, however, open to limitations and error. For example, Stage I pressure ulcers, although the least severe in the staging system, may mask more significant damage. They may also be difficult to assess in skin of darker pigmentation 5. In addition, when assessing people with pressure ulcers of Stage II or more, any eschar present must be removed before the wound is assessed to minimise inaccuracies 2, 4. Pressure ulcers may be caused by anything that applies a force to tissue to the extent that the cells are deprived of an adequate level of oxygen to maintain perfusion 6. Any external compressing force that exceeds the mean blood pressure of 25mmHg in the capillary bed is enough to interrupt blood flow 7. If such a force is maintained or increased, it will begin to occlude larger vessels such as arterioles 7 or venules. Should this be maintained for over 2 hours, the combination of oxygen deprivation and the accumulation of metabolic end products will result in irreversible tissue damage. Pressure ulcers may occur over any part of the body, particularly those areas subjected to friction or shearing forces 7 which cause damage through sliding one layer of tissue over another 7. The angulation and the stretching of the vessels during the sliding process result in injury, such as trauma and bleeding, to the vessels concerned 7. These processes may be due to, or exacerbated by, illness, immobility 6 or forces such as those applied during repositioning or sliding down in an inclined bed 6, 7. Factors for risk Factors that may place a person at risk of developing pressure ulcers may be considered as intrinsic or extrinsic. Intrinsic • Mobility: the less mobile a person, the more they are exposed to prolonged periods of pressure. Corrine Charlier BN