Heiss 1997.

Methods	Design: Randomised controlled trial. Setting: Germany.
Participants	N = 56 patients undergoing colorectal surgery with a primary diagnosis of colorectal cancer that was potentially curable (resectable). NB: No demographic data provided Inclusion criteria: Diagnosis of colorectal cancer that was potentially curatively resectable and were eligible for autologous blood donation.
Interventions	PAD (n = 29) Control (n = 27) Timing of autologous blood collection/retransfusion: PAD group donated blood on the seventh and tenth day before surgery. Patients received their autologous units (packed red cells, buffy coat poor) and additional allogeneic blood units if necessary. Volume of autologous blood collected/retransfused: 2 units per donation. Iron supplementation: No supplementation reported. Use of transfusion threshold: Blood transfusions were given when the Hb value declined to less than 9.0 g/dL. Length of surgery: Not reported.
Outcomes	Outcomes reported: Number of patients exposed to allogeneic blood (n), modulation of immune responses (IL‐2 receptor serum levels, TNF‐alpha serum levels, TNF‐alpha and IL10 serum levels, Tetanus‐immunoglobulin titre, Serum cytokine responses)
Notes	Period of study: From 1992 to 1996. Length of study: Not reported. A priori sample size: Not reported. Baseline comparability: No statistically significant difference between the study groups.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	No information.
Allocation concealment?	Unclear risk	No information.
Blinding? All outcomes	Unclear risk	No information.
Intention‐to‐treat analysis?	Low risk	Data were analysed on an intention‐to‐treat basis.