Lei 2022.

Methods	Participants undergoing Caesarean section were randomised at a 1:1 ratio into one of two groups. The method of the 1:1 randomisation is not described. The method of allocation concealment is not described. The blinding status of participants, study personnel, and outcome assessors is not described.
Participants	130 participants undergoing Caesarean section were recruited and randomised to one of two groups: Intraoperative cell salvage (ICS) (Autotransfusion group): N = 65. Mean (SD) age 33 (1). Number (%) of emergency Caesarean sections included = 13 (12.31%) Control group: N = 65. Mean (SD) age 32 (1). Number (%) of emergency Caesarean sections included = 27 (41.54). Study participants underwent Caesarean section for elective and emergency indications. Results are presented for the mixed population, with no subgrouping for elective and emergency surgery groups.
Interventions	Intraoperative cell salvage (ICS) group: an XTRA Autotransfusion System (LivaNova, UK) was installed before the operation. After delivery and placental separation, an anticoagulant solution (25,000 IU of heparin per 1000 mL of 0.9% NaCl) was dripped into the operation field and mixed with the maternal blood. Blood mixed with anticoagulant saline solution in the surgical field was sucked into the collection reservoir and centrifuged to separate RBCs from other components in the XTRA Autotransfusion SysteM. RBCs were then washed and suspended with 0.9% saline, passed through a white blood cell filter, and infused back into the participant's own circulation as soon as possible. If the participant's haemoglobin was still less than 80 g/L, allogeneic RBCs were provided to increase the haemoglobin level to 80 g/L. Control group: participants in the control group were transfused with allogeneic RBCs.
Outcomes	Outcomes reported: blood loss, allogeneic RBC transfusion volume, volume of recollected and retransfused ICS, infusion volume of other blood products, adverse events, surgical complications, infections. Postoperative haemoglobin level, complete blood count, haematocrit level blood gas analysis, electrolytes, liver and kidney function, and coagulation tests were performed at 24 hours and 3 days.
Notes	Transfusion protocol: during the operation, ICS or allogeneic RBCs were given to the participants who had a haemoglobin level < 80 g/L to achieve a haemoglobin level ≧ 80 g/L at the end of surgery. Prospective registration status: the registration status of the study is not clear. Ethical approval: the study received ethical approval from the Ethics Committee of Haidian Maternal and Child Health Hospital, Beijing, China. Language: the study is published in English. Reason for awaiting classification status: study participants underwent Caesarean section for elective and emergency indications. Results are presented for the mixed population, with no subgrouping for elective and emergency surgery groups.