Risk assessment tools may over or underpredict risk. It is essential to understand their limitations and have confidence in our own clinical judgement, says Frances Healey
Last year my co-author and I concluded that tools claiming to predict patients’ likelihood of falling as “high” or “low” do not work well, with little evidence they are any more effective than nurses’ judgement (Oliver and Healey, 2009). In this week’s Practice Review, Professors Griffiths and Jull come to the same conclusions on scores intended to predict pressure ulcer risk. And these weaknesses are found in tools that have been carefully researched and widely tested.
When I was a new tissue viability nurse, I introduced a “modified” version of the Waterlow risk score, cheerfully ignorant of whether my well-intentioned tweaking had made it better or worse. In the same burst of enthusiasm the standard NHS brick-like foam mattresses of the era were replaced by higher specification foam mattresses, and each ward gained several alternating pressure mattresses or overlays. It would be easy to believe that introducing the modified Waterlow score was the cause of our subsequent reduced prevalence of pressure ulcers, but in hindsight I wonder if it was actually a very small part of the picture.
But should a good experience at the time a tool was introduced mean we should be complacent about continuing to use it? Tools which over- or under-predict risk are not just an abstract statistical issue, as every under-prediction represents a missed opportunity to prevent a fall or pressure ulcer, while every over-prediction means limited resources have been directed at patients who may never have needed them.
And there are alternatives to using a risk score, since nurses’ judgement can be just as effective as falls or pressure ulcer scores. I once witnessed a healthcare assistant move a new patient over to a high specification mattress before a student nurse had finished calculating his Waterlow score. Asked by the student how she had known he would need one, she replied: “Just looked at him, pet.” She had a point – the patient was emaciated, had poor colour, and had been admitted for terminal care. Registered nurses are even better placed to apply “intuition” (which is not a psychic power, but the subconscious use of knowledge and experience) to assessing patients’ risk.
For falls, another alternative is to proceed straight to identifying and acting on individual risk factors such as poor balance, vision problems, sedative medication, delirium or incontinence - the emphasis is not on attributing a score to each of these, but on doing something about them. And ethically it makes sense – we could not, for example, ignore unsafe footwear just because a patient is “low risk”. For pressure ulcer prevention, an opt-out - rather than opt-in - approach may be appropriate given the increasing age, frailty and level of acute illness in inpatients.
So where now for nursing by numbers? As an absolute minimum, nurses should assess how well any scoring tool they use works for their patient group. This is not a complex process – a simple spreadsheet to calculate this can be found in the falls prevention area here. If you understand the limitations of the tools you use, you can appreciate just how important it is to use them to supplement clinical judgement, rather than replace it. Perhaps even more importantly, assessment is only ever a means to an end, not an end in itself, and the point where we truly benefit patients is when we follow up with appropriate interventions.
FRANCES HEALEY is head of patient safety (medical specialties), National Patient Safety Agency
Oliver D, Healey F (2009) Falls risk prediction tools for hospital inpatients: do they work?Nursing Times; 105: 7, 18–21.