CINAHL, EBSCOhost S1	(MM "Heart Surgery+") OR (MM "Cardiopulmonary Bypass+") OR CABG OR ((coronary or heart or cardiac* OR cardio* or valve) N3 (surg* or graft* OR bypass OR shunt or plasty or replacement)))	63,212
S2	(MM "Analgesia, Epidural+") OR (MM "Anesthesia, Epidural+") OR (MM "Epidural Analgesia Administration (Iowa NIC)") OR (epidural* OR peridural* OR extradural* OR subarachnoid* OR neuraxial*)	18,984
S3	(MH "Placebos") OR ( (MM "Randomized Controlled Trials") OR (MM "Random Assignment") OR (MH "Prospective Studies") OR (MH "Multicenter Studies") OR (MH "Clinical Trials") OR (MH "Single‐Blind Studies") OR (MH "Triple‐Blind Studies") OR (MH "Double‐Blind Studies") ) OR ( placebo* or multicenter or prospective or ((random* or control*) and trial*) )	755,253
S4	S1 AND S2 AND S3	103
S5	S1 AND S2 AND S3 Published: 2012‐2018	42