Washed cell salvage in surgical patients : a review and meta-analysis of prospective randomized trials under PRISMA

Background: Cell salvage is commonly used as part of a blood conservation strategy. However concerns among clinicians exist about the efficacy of transfusion of washed cell salvage. Methods: We performed a meta-analysis of randomized controlled trials in which patients, scheduled for all types of surgery, were randomized to washed cell salvage or to a control group with no cell salvage. Data were independently extracted, risk ratio (RR), and weighted mean differences (WMD) with 95% confidence intervals (CIs) were calculated. Data were pooled using a random effects model. The primary endpoint was the number of patients exposed to allogeneic red blood cell (RBC) transfusion. Results: Out of 1140 search results, a total of 47 trials were included. Overall, the use of washed cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 39% (RR = 0.61; 95% CI 0.57 to 0.65; P < 0.001), resulting in an average saving of 0.20 units of allogeneic RBC per patient (weighted mean differences [WMD] = -0.20; 95% CI -0.22 to -0.18; P < 0.001), reduced risk of infection by 28% (RR = 0.72; 95% CI 0.54 to 0.97; P = 0.03), reduced length of hospital stay by 2.31 days (WMD = -2.31; 95% CI -2.50 to -2.11; P < 0.001), but did not significantly affect risk of mortality (RR = 0.92; 95% CI 0.63 to 1.34; P = 0.66). No statistical difference could be observed in the number of patients exposed to re-operation, plasma, platelets, or rate of myocardial infarction and stroke. Conclusions: Washed cell salvage is efficacious in reducing the need for allogeneic RBC transfusion and risk of infection in surgery