Laboratory and physiological measurements before and after transfusion
| High-haematocrit group | Low-haematocrit group | |||||
|---|---|---|---|---|---|---|
| Pretransfusion | Post-transfusion | p* | Pretransfusion | Post-transfusion | p* | |
| Haemoglobin, g/dl | 13.6 (1.0) | 16.3 (1.6) | <0.0001 | 9.1 (1.4)† | 13.1 (1.4)‡ | <0.0001 |
| Haematocrit, % | 39 (7) | 48 (5) | <0.0001 | 27 (4)† | 38 (4)‡ | <0.0001 |
| RBC count, ×106/μl | 4.1 (0.7) | 5.4 (0.6) | <0.0001 | 2.9 (0.5)† | 4.2 (0.6)‡ | <0.0001 |
| Reticulocyte count, ×103/μl | 53 (20) | 62 (19) | 0.412 | 53 (16) | 61 (21) | 0.586 |
| Blood lactic acid, mmol/l | 1.1 (0.2) | 0.7 (0.1) | <0.0001 | 1.1 (0.2) | 0.9 (0.2) | 0.032 |
| Plasma erythropoietin, mU/ml | 16 (6) | 14 (6) | 0.596 | 16 (7) | 14 (5) | 0.609 |
| Cardiac output, ml/min per kg | 291 (98) | 277 (91) | 0.402 | 301 (101) | 253 (66) | 0.048 |
| Arterial oxygen content, ml/dl | 16 (2) | 20 (3) | <0.0001 | 12 (2)† | 17 (2)‡ | <0.0001 |
| Oxygen consumption, ml/min per kg | 8.1 (1.5) | 8.1 (1.1) | >0.99 | 10.0 (1.7) | 9.0 (1.1) | 0.279 |
| Systemic oxygen transport, ml/min per kg | 44 (7) | 57 (12) | 0.004 | 33 (4)† | 41 (5)‡ | 0.001 |
| Fractional oxygen extraction | 0.20 (0.08) | 0.17 (0.08) | 0.250 | 0.31 (0.11)† | 0.24 (0.12)‡ | 0.003 |
| Mean FiO2 | 0.31 (0.09) | 0.32 (0.10) | 0.561 | 0.32 (0.11) | 0.31 (0.12) | 0.055 |
| Mean oxygen saturation, % | 96 (3) | 96 (3) | 0.563 | 96 (3) | 95 (2) | 0.333 |
| Mixed venous O2 content, ml/dl | 13 (2) | 17 (2) | <0.0001 | 8 (2)† | 13 (3)‡ | <0.0001 |