ChiCTR‐TRC‐10000822.

Methods	Randomised controlled trial
Participants	Older people undergoing orthopaedic surgery who meet the following criteria: American Society of Anesthesiologists classification 1‐2 good general condition Hct > 0.35 platelet count > 100 g/L with normal function normal coagulation no serious functional organ diseases (heart, liver, lung and kidney) no infectious fever or bacteraemia no haematopoietic system diseases
Interventions	Group 1: transfusion if Hct < 0.25 and maintain Hct 0.25‐0.30 Group 2: transfusion if Hct < 0.25 and continue transfusion even if Hct ≥ 0.30 Group 3: Hct never decrease to 0.30, transfusion Group 4: Hct never decrease to 0.30, no transfusion Group 5: transfusion if Hct < 0.35 and maintain Hct > 0.35
Outcomes	Haemoglobin Central venous pressure Blood pressure (mean arterial pressure) Oxygen saturation (SpO2) Electrocardiograph Airway pressure Infusion volume End tidal carbon dioxide (ETCO2) recovery 24‐hour drainage Heal of the incision Infection Hospital length of stay Cognitive function Complications (coagulation disorders, electrolytes disorders) Haematocrit
Notes	The trial was identified on the Chinese Clinical Trial Registry, but the record has not been updated since first added in 2010. We have been unable to find contact details for the named applicant (checked again 14 March 2013). The trial record states that the trial is due to close by 1 May 2015

Hct: haematocrit.