A multi-center prospective randomized trial of buffy coat depleted- and leukocyte filtered erythrocyte transfusions in vascular- and gastrointestinal oncologic surgery

Association of RBC Transfusion With Mortality in Patients With Acute Lung Injury

BACKGROUND

RBC transfusion has been associated with increased morbidity and mortality in a variety of clinical settings. We assessed the effect of RBC transfusion on in-hospital mortality in patients with acute lung injury (ALI).

METHODS

Cohort study of 248 consecutive patients with ALI. RBC transfusion was evaluated as both dichotomous and continuous variables, with outcome being in-hospital mortality adjusted for clinical confounders and length of total hospital stay.

RESULTS

Overall in-hospital mortality rate was 39.5%. Of these patients, 207 of 248 patients (83.5%) received > or = 1 U of packed RBCs. The transfusion of any packed RBCs was associated with an increased risk of death (adjusted odds ratio [OR], 3.12; 95% confidence interval [CI], 1.28 to 7.58; p < 0.001). The overall OR per unit was 1.06 (95% CI, 1.04 to 1.09; p < 0.001) in the complete multivariable model. Transfusion after ALI onset was associated with an adjusted OR of 1.13 (95% CI, 1.07 to 1.20; p < 0.001), while transfusion before ALI onset was not associated with higher risk. The adjusted OR per unit of nonleukoreduced RBC transfused was 1.14 (95% CI, 1.07 to 1.21; p < 0.001), while the adjusted OR for leukoreduced cells per unit transfused was 1.06 (95% CI, 1.03 to 1.09; p < 0.001).

CONCLUSIONS

Transfusion of RBCs in patients with ALI was associated with increased in-hospital mortality. This risk occurred with RBC transfusion after the onset of ALI, and was greater for nonleukoreduced than for leukoreduced RBCs. Aggressive transfusion strategies in patients with established ALI should be questioned, pending further study.

Perioperative blood transfusion and outcome

PURPOSE OF REVIEW

As a result of advances in pathogen testing and transfusion standards over the last decade, the risk of disease transmission through allogeneic blood transfusions has decreased markedly. The effects of allogeneic blood transfusions on the immune system, however, have received more attention, as they appear to influence outcome. The following review summarizes the effects of allogeneic blood transfusions on selected outcome parameters and the influence of white blood cell reduction on these parameters.

RECENT FINDINGS

Adverse effects of allogeneic blood transfusions on outcome variables such as postoperative infection, cancer recurrence, pulmonary function, length of stay, and mortality have been shown in multiple trials, but most were not randomized or blinded. One proposed approach to reduce unwanted side-effects is to reduce the donor's white blood cell count before transfusion. This can be done either by individual bedside filtration or by pre-storage (or post-storage) universal white blood cell reduction. Studies investigating this approach have yielded conflicting results.

SUMMARY

Although the results of a number of studies suggest a negative impact of allogeneic blood transfusions on immune function and consequently outcome parameters, this has not been proven in rigorously controlled randomized trial, or in meta-analyses. Reduction of white blood cells might be beneficial in selected patient populations, but at this time does not appear warranted in the general surgical population. As universal white blood cell reduction is a very costly process, it probably should not be implemented until such a benefit is proven.

Transfusion of leukoreduced red blood cells may decrease postoperative infections: two meta-analyses of randomized controlled trials

PURPOSE

To evaluate the efficacy and effectiveness of red blood cell leukoreduction in reducing postoperative infection, mortality and cancer recurrence, two meta-analyses of randomized controlled trials (RCTs) were conducted.

METHODS

A systematic search of the scientific literature was conducted. The pooled relative risk ratio (RR) of developing an adverse postoperative outcome with either leukoreduced or non-leukoreduced blood was calculated using a random effects model. To better estimate the efficacy of leukoreduction, a second analysis of transfused patients only was conducted.

RESULTS

Ten RCTs met inclusion criteria and eight provided separate data for patients randomized and transfused. The mean percentage of patients randomized but not transfused was 34%. For postoperative infection, the overall pooled RR was 0.76 [(95% confidence interval (CI): 0.54-1.08] for the "all patients randomized" analysis. For the "only patients transfused" analysis, the pooled RR became clinically and statistically significant (RR = 0.60 (95% CI: 0.38-0.93). For mortality, the pooled RR for the "all patients randomized" analysis was 0.71 (95% CI: 0.45-1.13) and 0.61 (95% CI: 0.36-1.04) for the "only patients transfused" analysis. When analyzing either all patients randomized or all patients transfused, there was no statistically significant difference in cancer recurrence rates (one study only).

CONCLUSION

We demonstrated that patients who were transfused leukoreduced red blood cells might benefit from a decrease in postoperative infections. A decrease in mortality may have been realized if more patients had been enrolled in the various randomized trials. Including all patients randomized, regardless of whether or not they were actually transfused diluted the observed clinical benefit of leukoreduction.

White blood cell-containing allogeneic blood transfusion, postoperative infection and mortality: a meta-analysis of observational 'before-and-after' studies

BACKGROUND AND OBJECTIVES

An association of white blood cell (WBC) reduction with decreased mortality was reported by one observational, before-and-after study. A meta-analysis was undertaken to examine whether this finding is supported by all the evidence currently available from before-and-after studies, and whether these studies support an association of WBC reduction with a decreased risk of postoperative infection.

MATERIALS AND METHODS

Observational, before-and-after studies were retrieved that reported on postoperative infection and/or mortality between January 1997 and June 2003. Six studies met the criteria for meta-analysis. Unadjusted summary odds ratios (ORs) of postoperative infection or mortality in patients transfused after (compared with before) WBC reduction were calculated across the studies if the hypothesis of homogeneity was not rejected. Adjusted summary ORs were calculated across three studies that had reported multivariate analyses.

RESULTS

There was an unadjusted association of WBC reduction with a decreased risk of postoperative infection [summary OR = 0.93; 95% confidence interval (95% CI), 0.88-0.99; P < 0.01] that did not persist following adjustment for confounding factors (summary OR = 0.94; 95% CI, 0.85-1.04; P > 0.05). There was neither an unadjusted nor an adjusted association of WBC reduction with decreased mortality (summary OR = 0.94; 95% CI, 0.71-1.23; P > 0.05; and OR = 0.92; 95% CI, 0.80-1.05; P > 0.05, respectively).

CONCLUSIONS

An association of WBC reduction with decreased mortality was not detected across the results available from all before-and-after studies. An unadjusted association of WBC reduction with a decreased risk of postoperative infection exists, but this was not detected across the three studies that reported multivariate analyses.

WBC-containing allogeneic blood transfusion and mortality: a meta-analysis of randomized controlled trials

BACKGROUND

An association between allogeneic blood transfusion (ABT) and mortality was reported by one team of investigators from randomized controlled trials (RCTs) comparing recipients of non-WBC-reduced versus WBC-reduced RBCs in open-heart surgery. A meta-analysis was undertaken to examine whether this finding can be generalized across clinical settings and/or transfused RBC components.

STUDY DESIGN AND METHODS

RCTs reporting on adverse immunomodulatory effects of ABT between January 1992 and August 2002 were retrieved. Fourteen studies had recorded mortality as a primary or secondary outcome and met all other criteria for meta-analysis. Summary ORs of mortality in a treatment arm receiving WBC-containing allogeneic RBCs versus a control arm receiving autologous or WBC-reduced allogeneic RBCs were calculated across studies, for groups of studies in which the hypothesis of homogeneity was not rejected.

RESULTS

There was no association between ABT and mortality across 14 RCTs reporting on short-term mortality (summary OR, 1.20; 95% CI, 0.87-1.65) or across 3 RCTs reporting on long-term mortality (summary OR, 0.87; 95% CI, 0.64-1.19). In subgroup analyses, RCTs using autologous blood or conducted in abdominal or vascular surgery showed no difference in mortality, but short-term mortality differed across 3 RCTs conducted in open-heart surgery (summary OR, 2.26; 95% CI, 1.31-3.90; p < 0.05) and 7 RCTs comparing recipients of non-WBC-reduced versus WBC-reduced allogeneic RBCs filtered before storage (summary OR, 1.45; 95% CI, 1.00-2.11; p >/= 0.05).

CONCLUSIONS

An association between ABT and either short-term or long-term mortality was not detected across clinical settings and transfused RBC components, but subgroup analyses suggest that an association between WBC-containing ABT and short-term mortality may exist in open-heart surgery and in settings where WBC-reduced allogeneic RBCs filtered before storage are administered.