In this multicenter trial , we randomly assigned nontunneled central venous catheterization in patients in the adult intensive care unit ( ICU ) to the subclavian , jugular , or femoral vein ( in a @:@:@ ratio if all three insertion sites were suitable -LSB- three-choice scheme -RSB- and in a @:@ ratio if two sites were suitable -LSB- two-choice scheme -RSB- ) .