Soleimani 2018.

Study characteristics
Methods	Single‐centre, prospective, randomised controlled trial Run‐in period: between August 2015 and April 2016 Registration date: 2014, Iranian Registry of Clinical Trials Database (IRCT2015040921669N1) Number of study centres and locations: single centre; authors from University of Mazandaran University of Medical Sciences, Sari, Iran
Participants	A total of 150 adults who were scheduled for elective CABG surgery using CPB were included. Mean age: 62 years Sex (female/male ratio): 0.83 Low‐risk patients (elective CABG) Inclusion criteria: elective CABG, both sexes (age, 35 years to 75 years) Exclusion criteria: history of previous cardiac surgery, prior treatment with antiarrhythmic medications (except beta‐blockers), a history of heart failure with EF < 30%, left atrium size > 55 mm, obstructive sleep apnoea, a need for more than 4 grafts, renal failure (serum Cr > 1.5 mg/dL on 2 consecutive tests), liver dysfunction (hepatic enzymes elevated over 1.5 times the normal value), a history of COPD, hyperthyroidism, grade II to III atrioventricular block, serum pH < 7.25 or > 7.55, or experienced MI after surgery
Interventions	Group A: after induction of anaesthesia, participants received IV NAC infusion at a dose of 50 mg/kg, diluted to a total volume of 50 cc of normal saline, over a period of 30 minutes. Furthermore, these participants received 2 IV doses of 50 mg/kg NAC (with each dose occurring over a period of 30 minutes) on days 1 and 2 after surgery. Group B: normal saline (as a placebo) with the same volume at the same time interval
Outcomes	Postoperative variations of hs‐CRP levels, the length of ICU and hospital stay, and the incidence of MACCEs, which was defined as the occurrence of any of the following complications during the perioperative period: AMI, nonfatal cardiac arrest, unstable angina pectoris, heart failure, postoperative stroke, and death Prior to and on the third day after the surgery, blood samples were obtained for evaluation of the hs‐CRP level.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random numbering system: "Patients who fulfilled the inclusion criteria were randomly divided into groups A and B (75 patients in each group) using a sealed envelope technique with a computer‐generated random numbering system with the help of a nurse anaesthetist who was blinded to the study groups."
Allocation concealment (selection bias)	Low risk	Use of opaque sealed envelopes: "using a sealed envelope technique"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Research staff was likely blinded to the intervention: "All pharmaceutical preparations were done by an anaesthesiology resident who was not involved in the conduct of the study."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not clearly described but plausible
Incomplete outcome data (attrition bias) All outcomes	High risk	Participants were excluded from the analysis if they developed cardiovascular instability, needed reoperation, or needed a pacemaker; as two of these factors could occur if participants developed postoperative AF, this could have introduced bias.
Selective reporting (reporting bias)	Low risk	Protocol available: all prespecified outcomes were reported.
Other bias	Low risk	Declaration of conflicts of interest present, and authors declare no conflicts of interest.