Thorlacius 2020.

Study characteristics
Methods	Study design: secondary analysis of randomised, controlled, parallel arm trial Setting: operating room and paediatric ICU of 2 tertiary children’s hospitals (university hospitals of Gothenburg, Sweden and Helsinki, Finland) Study start/end dates or study duration: October 2014 to April 2017 Funding sources: funds under the ALF agreement (grants from the Swedish state under the agreement between the Swedish government and county councils) Declarations of interest: authors have disclosed that they do not have any potential conflicts of interest
Participants	Sample size: 72 patients randomised Patient age (mean ± SD): levosimendan group 5.9 ± 2.9 months, milrinone group 5.6 ± 2.7 months Patient sex: 16 male and 16 female in the levosimendan group, 18 male and 20 female in the milrinone group Diagnosis/severity: all patients had biventricular physiology. RACHS‐Score 2: levosimendan group 25/32, milrinone group 30/38. RACHS‐Score 3: levosimendan group 7/32, milrinone group 8/38 Inclusion criteria: children aged 1 to 12 months undergoing corrective surgery for non‐restrictive ventricular septal defect or complete balanced atrio‐ventricular septal defect or tetralogy of fallot
Interventions	Intervention 1: starting in the operating room after the start of cardiopulmonary bypass: levosimendan bolus of 12 μg/kg, followed by infusion of 0.1 μg/kg/min. Infusion for 24 h plus 2 h weaning at 50% the prior infusion rate. An extra bolus dose of half the loading dose and/or increasing the infusion rate up to 0.16 μg/kg/min levosimendan was permitted. Intervention 2: starting in the operating room after start of cardiopulmonary bypass: milrinone, administered as a bolus dose of 48 μg/kg for 10 minutes, followed by infusion at a rate of 0.4 μg/kg/min. Infusion for 24 h plus 2 h weaning at 50% the prior infusion rate. An extra bolus dose of half the loading dose and/or increasing the infusion rate up to 0.67 μg/kg/min milrinone was permitted. Co‐interventions: anaesthesia with opioids, sevoflurane, and muscle relaxant. Diuretics, adrenergics, fluids at the discretion of the responsible physician.
Outcomes	Primary outcome(s): absolute value of serum creatinine data on postoperative day 1 Secondary outcome(s): Acute kidney injury according to the serum creatinine criteria of Kidney Diseases: Improving Global Outcomes Acute kidney injury with serum creatinine corrected for fluid balance Plasma neutrophil gelatinase‐associated lipocalin Cystatin C Urea Lactate Haemodynamic variables Use of diuretics in the paediatric ICU Need for dialysis Length of ventilator therapy Length of paediatric ICU stays
Notes	Intention‐to‐treat analysis: no Trialists contacted: yes Unpublished information received: lactate levels, central venous oxygen saturation, arterial oxygen saturation, urine output, incidences of hypokalaemia, anaemia, hypocalcaemia, MCS, heart transplantation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"To allocate the patients to the parallel groups, the QMinim computer program was used."
Allocation concealment (selection bias)	Low risk	"An external randomizer informed the drug‐preparation staffs which group the patient in question was allocated to. Neither the randomizer nor the drug preparation staffs were involved in providing other care for the patient or compiling study documentation. Additionally, the medical and the study‐documentation staffs were blinded to the drug."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"The medical and the study‐documentation staffs were blinded to the drug. The study drug [...] was prepared in a concealed syringe attached to a concealed line into the patient."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"An external randomizer informed the drug‐preparation staffs which group the patient in question was allocated to. Neither the randomizer nor the drug preparation staffs were involved in providing other care for the patient or compiling study documentation. Additionally, the medical and the study‐documentation staffs were blinded to the drug."
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data suspected.
Selective reporting (reporting bias)	Low risk	All outcomes of interest listed in the methods section reported.
Other bias	Low risk	No other bias suspected.