OBJECTIVES: Primary nosocomial bloodstream infections (BSI) (5-15% of all infections) are associated with increased length of stay and additional hospital costs. Propofol infusions, commonly used for sedation in intensive care units (ICU), are formulated in lipid emulsion which promotes microbial growth. The present study aimed at identifying the probabilities and costs of contamination of syringes of propofol in critically ill patients, and subsequently determining the best strategy for administering propofol. METHODS: Costs of propofol-related infection and the different strategies of administration of propofol were computed according to the literature and microcosting method. The additional length of stay in ICU due to major infections related to propofol administration was estimated using the disability model, assuming a cost of CHF 2’118/intensive care unit day (local cost). The cost of each strategy was estimated based on all costs and on the probability of major infections related to propofol administration. RESULTS: According to the links found in the literature by genotyping bacteria (syringe-patient), we assumed that a patient has a mean 22.6% risk of developing an infection by a contaminated preparation of propofol. Thus, the ready-to-use syringe and syringes drawn from vials have an infection probability of 0.0014 [0.0009 – 0.0038] and 0.0118 [0.0056 – 0.0181] respectively. Probability of infection and the extended length of stay were the cost-drivers of this analysis. Ready-to-use syringes of propofol saved money, decreasing the cost by at least CHF 251 per sedation. Ready-to-use syringes remained a cost saving strategy when the propofol related infection rate probability according to the literature was as high as 0.38%. CONCLUSIONS: Ready-to-use syringes of propofol save money by preventing major infections related to its administration.