Economies of scale in British intensive care units and combined intensive care/high dependency units.

<bold>Objective: </bold>To estimate the relationship between size of intensive care unit and combined intensive care/high dependency units and average costs per patient day.<bold>Design: </bold>Retrospective data analysis. Multiple regression of average costs on critical care unit size, controlling for teaching status, type of unit, occupancy rate and average length of stay.<bold>Setting: </bold>Seventy-two United Kingdom adult intensive care and combined intensive care/high dependency units submitting expenditure data for the financial year 2000-2001 as part of the Critical Care National Cost Block Programme.<bold>Interventions: </bold>None.<bold>Measurements and Results: </bold>The main outcome measures were total cost per patient day and the following components: staffing cost, consumables cost and clinical support services costs. Nursing Whole Time Equivalents per patient day were recorded. The unit size variable has a negative and statistically significant ( p<0.05) coefficient in regressions for total, staffing and consumables cost. The predicted average cost for a seven-bed unit is about 96% of that predicted for a six-bed critical care unit.<bold>Conclusion: </bold>Policy makers should consider the possibility of economies of scale in planning intensive care and combined intensive care/high dependency units. [ABSTRACT FROM AUTHOR]