Adults with insertion of a nontunneled , nonantimicrobial-impregnated double-lumen DC for an expected duration greater than @ hours , to perform renal-replacement therapy or plasma exchange , were randomly allocated ( @:@ ) to receive a @-minute catheter lock with either @ % wt/wt ethanol solution ( ethanol group ) or @ % saline solution ( control group ) at the end of DC insertion and after each renal-replacement therapy or plasma exchange session .