Critical care nursing service costs: Comparison of the top-down versus bottom-up micro-costing approach in Brazil.

Abstract

To estimate the nursing service costs using a top-down micro-costing approach and to compare it with a bottom-up micro-costing approach. Accurate data of nursing cost can contribute to reliable resource management. We employed a retrospective cohort design in an adult intensive care unit in São Paulo. A total of 286 patient records were included. Micro-costing analysis was conducted in two stages: a top-down approach, whereby nursing costs were allocated to patients through apportionment, and a bottom-up approach, considering actual nursing care hours estimated by the Nursing Activities Score (NAS). The total mean cost by the top-down approach was US$1,640.4±1,484.2/patient. The bottom-up approach based on a total mean NAS of 833±776 points (equivalent to 200±86hr of nursing care) yielded a mean cost of US$1,487.2±1,385.7/patient. In the 268 patients for whom the top-down approach estimated higher costs than the bottom-up approach, the total cost discrepancy was US$4,427.3, while for those costed higher based on NAS, the total discrepancy was US$436.9. The top-down methodology overestimated costs for patients requiring lower intensity of care, while it underestimated costs for patients requiring higher intensity of care (NAS >100). The top-down approach may yield higher estimated ICU costs compared with a NAS-based bottom-up approach. These findings can contribute to an evidence-based approach to budgeting through reliable costing methods based on actual nursing workload, and to efficient resource allocation and cost management.