Prieto 2013.

Study characteristics
Methods	Prospective, randomised study Run‐in period: between March and June 2009 Study date: 2013 Number of study centres and location: single centre.Hospital Universitario La Princesa, Madrid, Spain
Participants	Fifty‐seven patients were prospectively randomised to undergo cardiac surgery without (n = 28) or with a cell saver (n = 29). Mean age: 64.7 years Sex (female/male ratio): 31.6% Low‐risk patients Inclusion criteria: first‐time, nonemergency cardiac surgery with the use of CPB Exclusion criteria: age over 80 years, redo or emergency surgery, aortic or pericardial disease, endocarditis, need for triple‐valve surgery, refusal of blood products, logistic EuroSCORE > 10%, and a high risk of bleeding (Cr > 2.2 mg/mL, liver insufficiency (Child‐Pugh B or C), severe lung disease, body surface area < 1.6 m2, preoperative Hb < 13 g/dL in males or < 12 g/dL in females, Plt count < 50,000/mL or any Plt disorder, coagulation disorder, intake of aspirin 3 days before surgery or clopidogrel 7 days before surgery)
Interventions	Intervention group: all remaining blood inside the circuit was recovered and concentrated by the cell saver and transfused to the participants using a 200‐m filter (Venisystem; Hospira, USA). Cardiotomy suction was applied when the participant was heparinised. This blood was re‐infused into the participant continuously during ECC. Control group: all blood in the surgical field was aspirated using only cardiotomy suction. All blood aspirated before starting heparin administration and after protamine administration was lost.
Outcomes	Complete blood count, proinflammatory cytokines (IL‐8, p40 subunit of IL‐12, IL‐6, IL‐1β, INF‐γ, IL‐23), and clinical outcomes Blood samples for inflammatory marker assays were collected from the arterial line on induction of anaesthesia, at the end of CPB, 1 hour after surgery, and 24 hours after surgery. Clinical data were also recorded on the day of discharge. All participants were interviewed in person or by telephone 30 days after the procedure.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Patients were randomised using a statistical program the day before surgery. There were no significant differences between the two groups for baseline characteristics.
Allocation concealment (selection bias)	Unclear risk	No allocation concealment method described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No mention of blinding of participants and personnel
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No mention of blinding of outcomes assessment
Incomplete outcome data (attrition bias) All outcomes	Low risk	No trial group changes, no withdrawals, and no losses to follow‐up were reported, but no ITT analysis. Data from all the patients were included in the final analysis.
Selective reporting (reporting bias)	Low risk	All expected outcomes were reported properly.
Other bias	Low risk	This research received no specific grant from any funding agency in the public, commercial, or not‐for‐profit sectors. No conflict of interest