Table 1.
Characteristics and outcomes of subjects in the control arm, stratified by median fHb ratio (N=110)
| Overall (n=110) | fHb ratio ≤2.23 (n=55) | fHb ratio >2.23 (n=55) | p | |
|---|---|---|---|---|
| Age, years | 47.50 [43.25, 53.75] | 46.00 [42.50, 50.00] | 49.00 [45.00, 56.50] | 0.021 |
| Males | 42 (38.2) | 21 (38.2) | 21 (38.2) | 1 |
| BMI, kg/m2 | 22.04 [20.43, 24.08] | 22.04 [20.44, 23.93] | 22.03 [20.38, 24.20] | 0.816 |
| Diagnosis | 0.207 | |||
| Rheumatic valve disease | 104 (94.5) | 54 (98.2) | 50 (90.9) | |
| Congenital valve disease | 2 (1.8) | 0 (0.0) | 2 (3.6) | |
| Infective valve disease | 4 (3.6) | 1 (1.8) | 3 (5.5) | |
| EUROscore II | 1.09 [0.90, 1.52] | 1.09 [0.90, 1.52] | 1.22 [0.90, 1.51] | 0.608 |
| Diabetes | 2 (1.8) | 1 (1.8) | 1 (1.8) | 1 |
| Baseline serum creatinine, mg/dL | 1.07 [0.97, 1.18] | 1.06 [0.98, 1.18] | 1.09 [0.97, 1.18] | 0.931 |
| Baseline eGFR, mL/min/m2 | 67.94 [61.71, 77.63] | 67.25 [62.39, 77.12] | 69.48 [60.21, 77.39] | 0.827 |
| Duration of CPB, min | 131.50 [111.25, 153.75] | 127.00 [109.50, 144.50] | 140.00 [120.00, 161.50] | 0.005 |
| Duration of cross-aortic clamping, min | 74.00 [62.25, 89.50] | 70.00 [60.50, 82.50] | 80.00 [67.00, 101.50] | 0.019 |
| ΔfHb, μM | 38.82 [24.38, 57.20] | 24.25 [11.75, 34.71] | 56.47 [45.27, 73.55] | <0.001 |
| fHb ratio | 2.23 [1.79, 2.99] | 1.78 [1.37, 1.97] | 2.99 [2.54, 3.62] | <0.001 |
| Days on vasoactive/inotropic drugs | 3.00 [2.00, 5.00] | 3.00 [0.50, 5.00] | 4.00 [2.50, 5.00] | 0.023 |
| AKI | 71 (64.5) | 27 (49.1) | 44 (80.0) | 0.001 |
| AKI stage | 0.001 | |||
| 0 | 39 (35.5) | 28 (50.9) | 11 (20.0) | |
| 1 | 60 (54.5) | 24 (43.6) | 36 (65.5) | |
| 2 | 5 (4.5) | 3 (5.5) | 2 (3.6) | |
| 3 | 6 (5.5) | 0 (0.0) | 6 (10.9) | |
| RRT | 6 (5.5) | 0 (0.0) | 6 (10.9) | 0.036 |
| Hours of ICU LOS | 65.29 [44.25, 81.23] | 66.16 [45.79, 85.71] | 62.42 [41.46, 69.08] | 0.064 |
| In-hospital mortality | 6 (5.5) | 0 (0.0) | 6 (10.9) | 0.036 |
Continuous data were presented as median with interquartile range (IQR, 25–75th percentiles) and compared with the Mann-Whitney U test. Categorical variables are presented as frequencies and compared with a chi-square test or Fisher exact test when appropriate. All analyses were two sided. BMI, body mass index; EUROscore II, European System for Cardiac Operative Risk Evaluation II; eGFR, estimated glomerular filtration rate; CPB, cardiopulmonary bypass; fHb, free hemoglobin; AKI, acute kidney injury; RRT, renal replacement therapy; ICU, intensive care unit; LOS, length of stay.