Thirty-one RCTs (n=2,282 patients) were included in meta-analyses. The sample size ranged from 16 to 266. The median Jadad score was 2 points (ranging from 1 to 5).
Transfusion outcomes: Compared with no cell saver use during cardiac surgery, use of a cell saver apparatus was associated with a significant reduction in: patient exposure to any allogeneic blood product (OR 0.63, 95% CI 0.43 to 0.94; 14 RCTs); patient exposure to red blood cells (OR 0.60, 95% CI 0.39 to 0.92; 12 RCTs); the volume of total allogeneic blood products transfused per patient (WMD −256mL, 95% CI −416 to −95; six RCTs). Significant heterogeneity was observed in all these outcomes (I2>60%). There were no significant differences in the number of patients requiring fresh frozen plasma, and the number of patients requiring platelet transfusions between cell saver and no cell saver groups.
Clinical complications: No significant differences were found in hospital mortality, postoperative stroke or transient ischaemia attack, atrial fibrillation, renal dysfunction, infection, or the number of patients requiring reoperation for bleeding between the two groups. There was no significant heterogeneity in these outcomes.
Sensitivity analyses showed that trial quality significantly affected the results (p=0.03); higher quality trials reported more conservative effects in the reduction of patient exposure to red blood cells. There was no evidence of publication bias.
Subgroup analyses assessing the effects of surgery type and different methods of cell saver were also reported.