Nagaraja 2018.

Methods	Parallel RCT Ethics committee: approved by the ethics committee Informed consents: written informed consents obtained Site: Departments of Cardiac Anaesthesiology and CTVS, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India Setting: university hospital Dates of data collection: not reported Funding: departmental/institutional Registration: unspecified
Participants	50 participants undergoing cardiac surgery; mean age 47.5 years; sex distribution: 22 females and 28 males Inclusion criteria Adult elective cardiac surgical patients underwent median sternotomy Exclusion criteria Emergency surgery; left main coronary artery disease Left ventricular ejection fraction < 40% Spinal abnormalities; blood or cerebrospinal fluid tap during the procedure Failed blocks Patient on anticoagulants; bleeding diathesis Patients who expired before extubation
Interventions	Interevention Epidural analgesia (N = 25) Comparator Bilateral erector spinae plane block (N = 25) Standardized general anaesthesia Surgery: CABG through median sternotomy
Outcomes	Relevant to this review Tracheal extubation Pain scores Others Intensive care unit length of stay Lung function
Notes	Correspondence: email sent 18 November 2018; no reply Conflict of interest: none DOI: 10.4103/aca.ACA_16_18
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomization was performed to two groups of 25 each using the closed envelope method"
Allocation concealment (selection bias)	Low risk	"Randomization was performed to two groups of 25 each using the closed envelope method"
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Groups well balanced