Laszczyca 2015.

Study characteristics
Methods	Design: RCT, parallel two‐arm, single‐centre study Setting: university teaching hospital, Katowice, Poland Recruitment: January 2013 to February 2014 Maximum follow‐up: duration of hospital stay
Participants	101 patients undergoing total knee replacement were randomised to one of two groups: Re‐transfusion group (RTF and RTF2 group) (Cell salvage/intervention group): N = 44. Mean age 70.9 Drainage group (DRN and DRN2 group) (Control/no cell salvage group): N = 57. Mean age 70.5 There was a higher proportion of males < 60 years old but does not state in which group. Groups were otherwise reported as balanced.
Interventions	Re‐transfusion group (RTF and RTF2 group) (Cell salvage/intervention group): RTF group (cell salvage group) were scheduled to receive postoperative autotransfusion of salvaged blood via a HandyVac ATS (Unomedical) retransfusion set. Blood was collected and re‐infused in‐line with the manufacturers instructions. RTF2 represents those participants that received their drainage blood. Drainage group (DRN and DRN2 group) (Control/no cell salvage group): DRN group (control group) received a standard drain. DRN2 represents all participants that did not receive drainage blood.
Outcomes	Outcomes reported: intraoperative blood loss, postoperative blood loss, amount of blood re‐transfused, amount of fresh frozen plasma (FFP) transfused, amount of packed red blood cells transfused, duration of hospital stay
Notes	Transfusion protocol: the postoperative indication to transfuse was the onset of hypovolaemic shock symptoms, general weakness and increasing symptoms of ischaemic disease. The trigger for transfusion was a haemoglobin < 8 g/dL, a decrement > 5 g/dL or < 9.5 g/dL with symptomatic anaemia or bleeding. Prospective registration status: the study was not prospectively registered with a trials registry. Ethical approval: the study was not approved by a Research Ethics Committee or Institutional Review Board. Language of publication: English and Polish Trial funding: not reported Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation methods not stated
Allocation concealment (selection bias)	Unclear risk	The method of allocation concealment is not described and so there is insufficient information to make a judgement.
Blinding of participants and personnel (performance bias) Objective outcome: mortality	Low risk	No objective outcomes reported (mortality unlikely to be affected by blinding if reported in future publications)
Blinding of participants and personnel (performance bias) Subjective: transfusion protocol	High risk	Authors state indications for transfusion in the methods section, but also state that decision to give allogeneic blood was made on 'individual basis' so it is not clear how robust / rigid the transfusion protocol was.
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	Unclear risk	Blinding of study personnel and participants is not described and so there is insufficient information to make a judgement. No attempt suggested in terms of intraoperative blinding of surgeons until end of procedure, as has been done in other studies
Blinding of outcome assessment (detection bias) Objective outcomes: mortality and transfusions	Low risk	No objective outcomes reported (mortality unlikely to be affected by blinding if reported in future publications)
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Blinding of study personnel and participants is not described and so there is insufficient information to make a judgement. No attempt suggested in terms of intraoperative blinding of surgeons until end of procedure, as has been done in other studies. Outcomes measures not adequately defined
Incomplete outcome data (attrition bias) All outcomes	High risk	Six participants from intervention group were moved to control group because they did not receive an autotransfusion
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Unclear risk	Difference in group sizes included in analysis e.g. 38 RTF group versus 55 in drainage only group. Baseline characteristics table has not been provided ‐ difficult to assess whether the groups were truly homogenous at baseline. Conflicts of interest statement / funding sources have not been provided.