| Methods |
Between May 2005 and December 2005, 178 patients were entered into the study. All patients over 55 years with osteoarthritis and/or inflammatory arthritis of the knee, and awaiting total knee replacement (TKR), were considered for the study. In a pre‐assessment clinic patients were randomly assigned into two groups by sealed envelopes. |
| Participants |
178 patients undergoing total knee replacement were randomised to one of two groups:
Group 1 (Autologous retransfusion group): n=92, M/F=43/49, mean (range) age = 70.3 (55.2‐88.5) years Group 2 (Control group): n=86, M/F=39/47, mean (range) age = 70.4 (57.9‐87.1) years
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| Interventions |
Group 1: Autologous retransfusion group (Bellovac ABT autotransfusion sytem) had the blood collection suction bellows connected to an autologous transfusion bag with a 200mm filter and a one‐way valve. The transfusion bag was connected to a transfusion set with a 40um filter. The drain was opened 20 minutes after tourniquet release. The shed blood was returned to the patient after collecting up to 500mls and no later than 6 hours after surgery. A maximum of 1200mls was re‐transfused. Group 2: Control group (standard vacuum drain) had blood collected in the vacuum drains discarded. |
| Outcomes |
Outcomes reported: number of patients transfused allogeneic blood, hospital length of stay, adverse events. |
| Notes |
Transfusion threshold: allogeneic blood transfusion was given if the haemoglobin level was less than 8.0g/dL. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Method used to generate allocation sequences was not described. |
| Allocation concealment (selection bias) |
High risk |
Sealed envelopes were used to conceal treatment allocation. |
| Blinding (performance bias and detection bias)
All outcomes |
High risk |
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