Urine colour as an index of hydration in critically ill patients

In order to test the hypothesis that urine colour can be used as an index o f hydration in critically ill patients, we selected 40 intensive care and h igh-dependency patients and correlated urine colour (scored on an eight-poi nt scale) with various indices of hydration: urine:plasma sodium, osmolalit y and urea ratios, urine output and central venous pressure. In addition, w e compared the colour-chart score with scores made by intensive care nurses (without the benefit of a colour chart) in order to test subjective assess ment of urine colour. There were weak but statistically significant correla tions between urine colour and urine output (Spearman's r = - 0.555) and be tween urine colour and urine:plasma sodium ratio (Spearman's r= - 0.459). S ubjective assessment of urine colour appeared to be reliable. Thus, althoug h urine colour does vary with hydration in the critically ill, assessment o f urine colour adds little to the overall assessment of hydration in this g roup of patients.