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Table 5 Renal function and metabolism

From: A perioperative infusion of sodium bicarbonate does not improve renal function in cardiac surgery patients: a prospective observational cohort study

  Total cohort Control - no bicarbonate Intervention - bicarbonate Significance, P-value
Number 584 304 (52.1%) 280 (47.9%)  
Diuresis and fluid balance
Postoperative diuresis within 24 h, ml 2,844 (2,744, 2,944) 2,723 (2,564, 2,881) 2,977 (2,861, 3,092) 0.012
Postoperative cristalloid fluid balance, ml -124 (-225, -22) -133 (-295, 30) -114 (-231, 4) 0.855
Postoperative surgical drainage, ml 927 (887, 968)] 933 (875, 991) 921 (865, 978) 0.782
Postoperative colloidals - drainage fluid balance, ml 549 (480, 618) 471 (374, 569) 633 (536, 731) 0.022
Postoperative diuretics, number of patients
Furosemide 280 (47.9%) 142 (46.7%) 138 (49.3%) 0.590
Torasemide 462 (79.1%) 242 (79.6%) 220 (78.6%) 0.838
HCT 200 (34.2%) 102 (33.6%) 98 (35.0%) 0.779
Other diuretics 34 (5.8%) 20 (6.6%) 14 (5.0%) 0.524
Renal function
Creatinine baseline, μmol/L 81 (79, 83) 81 (78, 84) 82 (78, 84) 0.787
Creatinine maximum*, μmol/L 93 (90, 96) 93 (88, 97) 93 (89, 97) 0.785
Creatinine at discharge*, μmol/L 82 (80, 87) 84 (80, 88) 80 (80, 87) 0.153
Maximum relative increase in creatinine*     
< 25% 369 (63.2%) 204 (67.1%) 165 (58.9%) 0.217
> 25% 123 (21.1%) 57 (18.8%) 66 (23.6%)  
> 50% 56 (9.6%) 25 (8.2%) 31 (11.1%)  
> 100% 36 (6.2%) 18 (5.9%) 18 (6.4%)  
eGFR baseline, ml/min 82 (80, 84) 81 (78, 84) 83 (80, 87) 0.434
eGFR minimum*, ml/min 69 (67, 71) 69 (66, 72) 70 (66, 73) 0.744
eGFR at discharge*, ml/min (n = 566) 82 (79, 85) 81 (77, 86) 83 (79, 86) 0.586
AKI grading according to creatinine changes (new RRT = grade 3), number patients     
Grade 1 85 (14.6%) 38 (12.5%) 47 (16.8%) 0.478
Grade 2 7 (1.2%) 3 (1.0%) 4 (1.4%)  
Grade 3 74 (12.7%) 39 (12.8%) 35 (12.5%)  
AKI grading according to diuresis** (new RRT = grade 3), number patients     
Grade 1 14 (2.4%) 11 (3.6%) 3 (1.1%) 0.135
Grade 2 1 (0.2%) 0 (0.0%) 1 (0.4%)  
Grade 3 45 (7.7%) 21 (6.9%) 24 (8.6%)  
AKI grading, total**, number patients     
Grade 1 90 (15.4%) 44 (14.5%) 46 (16.4%) 0.753
Grade 2 8 (1.4%) 3 (1.0%) 5 (1.8%)  
Grade 3 75 (12.8%) 39 (12.8%) 36 (12.9%)  
New RRT     
Patients (%) 45 (7.7%) 22 (7.2%) 23 (8.2%) 0.774
Duration of treatment, h 144 (114, 196) 153 (110, 196) 125 (76, 227) 0.892
Intraoperative metabolism
Blood glucose max, mg/dl 193 (189, 202) 189 (184, 193) 197 (193, 204) 0.005
Blood glucose min, mg/dl 92 (91, 93) 91.5 (89, 94) 92 (91, 94) 0.181
pH max 7.45 (7.44, 7.45) 7.45 (7.45, 7.45) 7.45 (7.44, 7.45) 0.034
pH min 7.32 (7.32, 7.32) 7.32 (7.31, 7.32) 7.32 (7.32, 7.33) 0.157
Lactate max, mmol/L 1.7 (1.6, 1.8) 1.6 (1.5, 1.7) 1.8 (1.6, 1.9) 0.005
Lactate min, mmol/L 0.6 (0.6, 0.6) 0.6 (0.6, 0.7) 0.7 (0.6, 0.7) 0.594
Postoperative metabolism
Blood glucose max, mg/dl 169.0 (166.0, 172.0) 163.5 (161.0, 167.0) 173.5 (170.12, 177.88) 0.0015
Blood glucose min, mg/dl 90.09 (88.68,1.51) 89.70 (87.73, 91.67) 90.53 (88.48, 92.57) 0.566
pH max 7.46 (7.46, 7.47] 7.46 (7.45, 7.46) 7.47 (7.46, 7.48) 0.001
pH min 7.32 (7.31, 7.32) 7.32 (7.31, 7.32) 7.32 (7.31, 7.33) 0.165
Lactate max, mmol/L 2.00 (1.90, 2.10) 1.90 (1.70, 2.00) 2.10 (2.00, 2.20) 0.010
  1. Fluid balance, diuretics, metabolism, and renal function are shown for patients undergoing elective on-pump cardiac surgery with or without a perioperative infusion of bicarbonate. HCT: hydrochlorothiazide; eGFR: estimated glomerular filtration rate: modifications of diet in renal disease formula; AKI: acute kidney injury; CVVH: continuous-veno-venous hemofiltration; max: maximal; min: minimal. Data are given as absolute numbers (percentage) for nominal variables, median (95% confidence interval) for non-normally distributed data, and mean (95% confidence interval) for normally distributed variables. *Changes in plasma creatinine levels and derived variables were calculated after exclusion of patients treated with renal replacement therapy. **AKI grading was performed according to Acute Kidney Injury Network recommendations (9) on the basis of changes in plasma creatinine, need for new renal replacement therapy and time course of diuresis (within 48 h after surgery).