Antimicrobial use in a critical care unit: a prospective observational study.

OBJECTIVE

The purpose of this study was to describe antimicrobial utilization, consumption, indications and microbial resistance in a medical-surgical-trauma intensive care unit (ICU) of a teaching hospital to identify potential targets for antimicrobial stewardship.

METHODS

This was a 30-day prospective observational study enrolling adults admitted to the ICU for at least 24 h and having received antimicrobial therapy. Primary endpoints included utilization as percentage use of antimicrobials by class and agent, consumption measured as days of therapy per 1000 patient days (DOT/1000PD), indications for use and prescriber. Secondary endpoints included reasons for modifications to therapy and microbial resistance.

KEY FINDINGS: Eighty-three patients were screened and 61 enrolled, receiving 133 courses of antimicrobial therapy, mainly intravenously and prescribed by ICU staff. The most frequently prescribed agents were piperacillin/tazobactam (20%), cefazolin (17%) and vancomycin (13%). The indications for therapy were empirical (50%), directed (27%) and prophylactic (23%). Overall consumption was 1368.54 DOT/1000PD and was mainly attributed to empirical therapy (734.25). Prolonged durations were noted for carbapenems and for surgical prophylaxis. There were 86 therapy modifications involving indication (36), efficacy (25), safety (18) and route (7). Suboptimal or excessive dosing were common contributors to efficacy and safety modifications, respectively. Infections due to microorganisms with notable resistance included methicillin-resistant Staphylococcus aureus (5), Pseudomonas aeruginosa (1) and Streptococcus pneumoniae (1).

CONCLUSIONS

Antimicrobial utilization and consumption based on DOT/1000PD were prospectively determined providing a comparator for other ICUs. Potential targets identified for antimicrobial stewardship initiatives include empirical therapy, treatment duration, dosing and route.