Momeni 2011.

Methods	Randomised controlled trial.
Participants	41 (20 intervention, 21 control), aged under five years, undergoing corrective surgery for congenital heart defects using CPB and in need of inotropic support.
Interventions	Intervention: 0.05 µg/kg/min of levosimendan, started at onset of CPB, allowed to be doubled, for a maximum of 48 hours. Control: 0.4 µg/kg/min of milrinone, started at onset of CPB, allowed to be doubled, for a maximum of 48 hours.
Outcomes	Recorded until 48 hours after admission to paediatric ICU: 1. Lactate level at four hours postoperatively. 2. Biologic markers and haemodynamic data (heart rate, mean arterial pressure, lactate, difference between arterial and mixed venous oxygen saturations, troponin, creatinine, alanine aminotransferase, aspartate aminotransferase).
Notes	One patient (control group) excluded who did not receive study medication because of modification of the surgical plan, two patients (1 intervention group, 1 control group) excluded because they required extracorporeal membrane oxygenation at the end of CPB, two patients (1 intervention group, 1 control group) excluded because of intraoperative death.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random code.
Allocation concealment (selection bias)	Low risk	Allocation code was concealed in an envelope opened by the study nurse in charge of preparing the medication.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Syringes and tubing system covered with aluminium foil, both drugs administered at same infusion rates.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Syringes and tubing system covered with aluminium foil, both drugs administered at same infusion rates.
Incomplete outcome data (attrition bias) All outcomes	High risk	Two patients (1 intervention group, 1 control group) excluded because they required extracorporeal membrane oxygenation at the end of CPB, two patients (1 intervention group, 1 control group) excluded because of intraoperative death.
Selective reporting (reporting bias)	Low risk	No incomplete reporting suspected.
Other bias	Low risk	No other bias suspected.