Rollo 1995.

Study characteristics
Methods	Design: RCT, parallel four‐arm, single‐centre study Setting: specialist orthopaedic hospital, Philadelphia, PA, USA Recruitment: June 1991 to February 1992 Maximum follow‐up: 48 hours postoperatively
Participants	153 participants undergoing primary total hip arthroplasty were randomised to one of four groups: Group 1(intraoperative and postoperative cell salvage (Haemonetics)) (Cell salvage/intervention group): N = 35. M:F 19:16. Mean (range) age 68 (50 to 86) Group 2(postoperative cell salvage (Solcotrans)) (Cell salvage/intervention group): N = 40. M:F 24:16. Mean (range) age 68 (28 to 87) Group 3(standard drain (Hemovac)) (Control/no cell salvage group): N = 38. M:F 20:20. Mean (range) age 64 (39 to 85 years) Group 4 (no drainage system): N = 38. M:F 20:18. Mean (range) age 61 (38 to 86) There were no differences between the groups at baseline.
Interventions	Group 1(intraoperative and postoperative cell salvage (Haemonetics)) (Cell salvage/intervention group): cell salvage group (Haemonetics system) had intraoperative salvage of red blood cells performed with the Haemonetics Cell Saver. A paediatric bowl was used for the processing of salvaged, shed blood. This collection was continued after surgery through two medium drains while the participant remained in the recovery room. A closed‐suction standard Hemovac drain was placed when salvage was discontinued. Group 2(postoperative cell salvage (Solcotrans)) (Cell salvage/intervention group): cell salvage group (Solcotrans system) were treated with a Solcotrans drainage infusion system at the completion of surgery. This system consists of a 500 mL collection canister with 260 µm pre‐transfusion filter for collection and a 40 µm filter for transfusion. A minimum of 300 mL of blood had to be collected within a 4‐hour period. Total collection/infusion time could not exceed 6 hours. A maximum of 2 units could be reinfused. After the completion of the transfusions, the Solcotrans unit was discarded and replaced with a closed‐suction drain. Group 3(standard drain (Hemovac)) (Control/no cell salvage group): control group (Hemovac drainage system) were treated with a standard 400 mL Hemovac closed‐suction drain. Group 4 (No drainage system): control group did not receive drains at the completion of surgery.
Outcomes	Outcomes reported: amount of allogeneic and/or autologous blood transfused, number of participants transfused allogeneic blood, adverse events, thigh circumference measures, wound drainage
Notes	Transfusion protocol: all decisions for allogeneic blood transfusion were based on the clinical condition of the participant. The absolute value of the haemoglobin or haematocrit was not considered in isolation. Participants who were able to donate at least 2 units of autologous blood preoperatively were included in the study. Prospective registration status: the study was published prior to 2010. Ethical approval: it is not clear whether the study was approved by an ethics committee or institutional review board. Language of publication: English Study groups: for the purpose of our review, we have included the specific group comparisons within our subgroup analyses of cell salvage timing. Group 1 versus Group 3 has been included in the intraoperative and postoperative cell salvage subgroup. Group 2 versus Group 3 has been included in the postoperative cell salvage subgroup. Trial funding: not reported Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Randomised by month of birth
Allocation concealment (selection bias)	High risk	No concealment due to allocation by month of birth
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	No transfusion protocol in place
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	High risk	No mention of blinding; allocation not concealed (not properly randomised). No transfusion protocols or other definitions for other outcomes
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	No mention of blinding; allocation not concealed (not properly randomised). No transfusion protocols or other definitions for other outcomes
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	All participants randomised are accounted for in the reported outcomes; appears to be ITT, though authors admit that not all measures taken in all participants.
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Unclear risk	No obvious baseline imbalance. Funding and conflicts not reported