Changes in physiological dead space (VD/VT) from before to after transfusion for each group: cells saver (CS), washed allogeneic erythrocytes, and unwashed allogeneic erythrocytes. Data are mean ± SD, with “n” for each group shows at the base of the bars. VD/VT in the CS group changed significantly with transfusion (P = 0.034) but did not change in the washed allogeneic (P = 0.53) or the unwashed allogeneic (P = 0.62) transfusion groups. There were no differences among groups for changes from before to after transfusion (P = 0.28).