Reduction of broad-spectrum antibiotic use with computerized decision support in an intensive care unit

Objective. To implement and evaluate the effect of a computerized decision support tool on antibiotic use in an intensive care unit (ICU). Design. Prospective before-and-after cohort study. Setting. Twenty-four bed tertiary hospital adult medical/surgical ICU. Participants. All consecutive patients from May 2001 to November 2001 (N = 524) and March 2002 to September 2002 (N = 536). Intervention. A real-time microbiology browser and computerized decision support system for isolate directed antibiotic prescription. Main outcome measures. Number of courses of antibiotic prescribed, antibiotic utilization (defined daily doses (DDDs)/100 ICU bed-days), antibiotic susceptibility mismatches, and system uptake. Results. There was a significant reduction in the proportion of patients prescribed carbapenems [odds ratio (OR) = 0.61, 95% confidence interval (CI) = 0.39-0.97, P = 0.04], third-generation cephalosporins (OR = 0.58, 95% CI = 0.42-0.79, P = 0.001), and vancomycin (OR = 0.67, 95% CI = 0.45-1.00, P = 0.05) after adjustment for risk factors including Apache II score, suspected infection, positive microbiology, intubation, and length of stay. The decision support tool was associated with a 10.5% reduction in both total antibiotic utilization (166-149 DDDs/100 ICU bed days) and the highest volume broad-spectrum antibiotics. There were fewer susceptibility mismatches for initial antibiotic therapy (OR = 0.63, 95% CI = 0.39-0.98, P = 0.02) and increased de-escalation to narrower spectrum antibiotics. Uptake of the program was high with 6028 access episodes during the 6-month evaluation period. Conclusions. This tool streamlined collation and clinical use of microbiology results and integrated into the daily ICU workflow. Its introduction was accompanied by a reduction in both total and broad-spectrum antibiotic use and an increase in the number of switches to narrower spectrum antibiotics.