Search terms

1.       random$:ab,ti 2.       placebo:ab,ti 3.       (singl* OR doubl* OR trebl* OR tripl*) AND (blind* OR mask*) 4.      ' cross over$' OR crossover$ 5.       'randomized controlled trial'/exp OR 'randomized controlled trial' 6.       'phase 2 clinical trial'/exp OR 'phase 2 clinical trial' 7.       'phase 3 clinical trial'/exp OR 'phase 3 clinical trial' 8.       'double blind procedure'/exp OR 'double blind procedure' 9.       'single blind procedure'/exp OR 'single blind procedure' 10.   'crossover procedure'/exp OR 'crossover procedure' 11.   'latin square design'/de OR 'latin square design' 12.   'placebo'/exp 13.   'multicenter study'/exp OR 'multicenter study' 14.   or/1‐13 15.   14# AND [humans]/lim 16.   thromb$ 17.   fibrin$ 18.   occlu$ 19.   block$ 20.   infect$ 21.   stenos$ 22.   or/16‐21 23.   'central venous' 24.   cva$:ab,ti 25.   jugular$:ab,ti AND subclavian$:ab,ti 26.   jugular$:ab,ti AND femoral$:ab,ti 27.   subclavian$:ab,ti AND femoral$:ab,ti 28.   or/23‐27 29. 15# AND 22# AND 28#