Arguments for (pro) and against (con) a policy to implement universal white cell reduction of all transfused cellular blood components for the purpose of preventing postoperative infection caused by the purported deleterious immunomodulatory effects of allogeneic blood transfusion
| Pro26 27 . | Con27 . |
|---|---|
| 1. An increase in the incidence of postoperative infection attributable to an immunomodulatory effect of allogeneic WBCs is supported by at least one single-blind and correctly designed and analyzed RCT conducted by van de Watering et al.6 | 1a. The RCT of van de Watering et al6 did not detect a TRIM effect in the intention-to-treat analysis; only when the 2 control (WBC-reduced) arms were combined was a marginally significant (P = .06) difference demonstrated between the recipients of buffy-coat–reduced and WBC-reduced RBCs. 1b. The RCT of van de Watering et al6 enrolled patients having open heart surgery, and an allogeneic blood transfusion effect detected in the setting of cardiac surgery may not apply to other surgical settings. |
| 2. Four3,5-7 of 5 RCTs3,5-7 22investigating the relationship between WBC-containing (versus non–WBC-containing) allogeneic blood transfusion and postoperative infection show at least a trend toward an increase in the incidence of postoperative bacterial infection in association with the transfusion of allogeneic WBCs. | 2. The 2 RCTs by Jensen et al35 reported an implausibly large allogeneic blood transfusion effect, and, if these 2 studies35 were excluded from the analysis, the OR of postoperative infection in the allogeneic transfusion (compared with the control) arm across the remaining RCTs6,7 22 would no longer be statistically significant and would be sufficiently modest to be attributed to chance.5-150 |
| 3. It is unlikely that further RCTs examining the relationship between allogeneic blood transfusion and postoperative infection will be reported in the foreseeable future. Even if more studies are conducted in the future, it is unlikely that such future RCTs will be large enough to be definitive. | 3. If a policy decision is made to implement universal WBC reduction based on the evidence that is currently available, it will be impossible to rescind this policy in the future if further studies establish that universal WBC reduction does not decrease the incidence of postoperative infection. |
| 4. In the future, research into the purported deleterious immunomodulatory effects of allogeneic blood transfusion can continue, by means of observational studies comparing the incidence of postoperative infection between patients having transfusion before or after the implementation of universal WBC reduction. | 4. Such future observational studies are bound to have at least some of the flaws of their predecessors,19 making it impossible to attribute any observed difference between patients having transfusion before or after the implementation of universal WBC reduction to the receipt of WBC-containing allogeneic blood transfusion. |
| 5. The receipt of WBC-containing allogeneic blood transfusion is associated with increased postoperative mortality in the RCT of van de Watering et al.6 | 5a. The RCT of van de Watering et al6 was not designed to investigate mortality as an outcome variable. 5b. The association between WBC-containing allogeneic blood transfusion and increased postoperative mortality reported by van de Watering et al6 has not been corroborated by another RCT. |
| Pro26 27 . | Con27 . |
|---|---|
| 1. An increase in the incidence of postoperative infection attributable to an immunomodulatory effect of allogeneic WBCs is supported by at least one single-blind and correctly designed and analyzed RCT conducted by van de Watering et al.6 | 1a. The RCT of van de Watering et al6 did not detect a TRIM effect in the intention-to-treat analysis; only when the 2 control (WBC-reduced) arms were combined was a marginally significant (P = .06) difference demonstrated between the recipients of buffy-coat–reduced and WBC-reduced RBCs. 1b. The RCT of van de Watering et al6 enrolled patients having open heart surgery, and an allogeneic blood transfusion effect detected in the setting of cardiac surgery may not apply to other surgical settings. |
| 2. Four3,5-7 of 5 RCTs3,5-7 22investigating the relationship between WBC-containing (versus non–WBC-containing) allogeneic blood transfusion and postoperative infection show at least a trend toward an increase in the incidence of postoperative bacterial infection in association with the transfusion of allogeneic WBCs. | 2. The 2 RCTs by Jensen et al35 reported an implausibly large allogeneic blood transfusion effect, and, if these 2 studies35 were excluded from the analysis, the OR of postoperative infection in the allogeneic transfusion (compared with the control) arm across the remaining RCTs6,7 22 would no longer be statistically significant and would be sufficiently modest to be attributed to chance.5-150 |
| 3. It is unlikely that further RCTs examining the relationship between allogeneic blood transfusion and postoperative infection will be reported in the foreseeable future. Even if more studies are conducted in the future, it is unlikely that such future RCTs will be large enough to be definitive. | 3. If a policy decision is made to implement universal WBC reduction based on the evidence that is currently available, it will be impossible to rescind this policy in the future if further studies establish that universal WBC reduction does not decrease the incidence of postoperative infection. |
| 4. In the future, research into the purported deleterious immunomodulatory effects of allogeneic blood transfusion can continue, by means of observational studies comparing the incidence of postoperative infection between patients having transfusion before or after the implementation of universal WBC reduction. | 4. Such future observational studies are bound to have at least some of the flaws of their predecessors,19 making it impossible to attribute any observed difference between patients having transfusion before or after the implementation of universal WBC reduction to the receipt of WBC-containing allogeneic blood transfusion. |
| 5. The receipt of WBC-containing allogeneic blood transfusion is associated with increased postoperative mortality in the RCT of van de Watering et al.6 | 5a. The RCT of van de Watering et al6 was not designed to investigate mortality as an outcome variable. 5b. The association between WBC-containing allogeneic blood transfusion and increased postoperative mortality reported by van de Watering et al6 has not been corroborated by another RCT. |
WBC indicates white blood cell; RCT, randomized controlled trial; TRIM, allogeneic blood transfusion–associated immunomodulation; RBC, red blood cell; OR, odds ratio.
The OR of postoperative infection in recipients of buffy-coat–reduced6,22 or standard7 RBCs, as compared with recipients of WBC-reduced RBCs, was 1.20 (95% confidence interval for the OR, 0.78-1.85; P > .05). These 3 studies6,7 22 are sufficiently homogeneous to permit meta-analysis (P > .05 for the Q test statistic).