RATIONALE: Ethanol rapidly eradicated experimental biofilm. Clinical studies of ethanol lock to prevent catheter-related infections (CRIs) suggest preventive efficacy. No such studies have been done in intensive care units (ICU).OBJECTIVES:To determine whether ethanol lock decreases the risk of major CRI in patients with short-term dialysis catheters (DCs).METHODS:A randomized, double-blind, placebo-controlled trial was performed in 16 ICUs in seven university hospitals and one general hospital in France between June 2009 and December 2011. Adults with insertion of a nontunneled, nonantimicrobial-impregnated double-lumen DC for an expected duration greater than 48 hours, to perform renal-replacement therapy or plasma exchange, were randomly allocated (1:1) to receive a 2-minute catheter lock with either 60% wt/wt ethanol solution (ethanol group) or 0.9% saline solution (control group) at the end of DC insertion and after each renal-replacement therapy or plasma exchange session. The main outcome was major CRI defined as either catheter-related clinical sepsis without bloodstream infection or catheter-related bloodstream infection during the ICU stay.MEASUREMENTS AND MAIN RESULTS:The intent-to-treat analysis included 1,460 patients (2,172 catheters, 12,944 catheter-days, and 8,442 study locks). Median DC duration was 4 days (interquartile range, 2-8) and was similar in both groups. Major CRI incidence did not differ between the ethanol and control groups (3.83 vs. 2.64 per 1,000 catheter-days, respectively; hazard ratio, 1.55; 95% confidence interval, 0.83-2.87; P = 0.17). No significant differences occurred for catheter colonization (P = 0.57) or catheter-related bloodstream infection (P = 0.99).CONCLUSIONS:A 2-minute ethanol lock does not decrease the frequency of infection of DCs in ICU patients. Clinical trial registered with www.clinicaltrials.gov (NCT 00875069).