Sintes 2009.

Methods	Participants undergoing total knee arthroplasty were randomised in a prospective randomised study of postoperative blood salvage using a reinfusion drain. The method of randomisation and allocation concealment are not described. The blinding status of study participants, personnel, and outcome assessors is not described.
Participants	100 participants undergoing total knee arthroplasty with regional anaesthesia were randomised. There were 50 male and 50 female participants recruited to the study. No further demographic data are available.
Interventions	The intervention assessed was the use of the Redax Drentech Surgical postoperative blood recovery system. This is a wound drain used postoperatively which collects blood for reinfusion to the patient. The comparator and intervention groups are not clear.
Outcomes	Outcomes reported: mean haemoglobin concentration of recovered blood, requirement of additional transfusion of heterologous blood, mean haemoglobin concentrations, post‐transfusion coagulation, volume transfused The abstract reports results of an interim analysis only.
Notes	Transfusion protocol: a transfusion protocol is not described in the abstract. Prospective registration status: it is not clear whether the study was registered prospectively. Ethical approval: it is not clear whether the study was approved by an ethics committee or institutional review board. Language: the abstract is published in English. Reason for awaiting classification status: there is a lack of detail regarding intervention and comparison methods.