Wang et al reported a nomogram for predicting acute kidney injury in a patient undergoing on-pump cardiac surgery. This can help to identify a patient who may require closer monitoring of renal function. The authors are from Sichuan University, Zhejiang University, and affiliated hospitals in China.
Patient selection: on-pump cardiac surgery, age >= 18 years
Exclusions: serum creatinine before surgery > 176 µmol/L, on renal replacement, emergency surgery
Parameters:
(1) age in years
(2) serum urea in mmol/L
(3) RBC transfusion in units
(4) serum creatinine in µmol/L
(5) RBC count in 10^12/L
(6) operation time in hours
(7) serum cystatin C in mg/L
(8) cardiopulmonary bypass time in minutes
(9) gender
(10) hypertension
|
Parameter |
Finding |
Points |
|
age in years |
< 40 years |
0 |
|
|
40 to 50 years |
4.9 |
|
|
50 to 60 years |
10.3 |
|
|
60 to 70 years |
19.6 |
|
|
> 70 years |
33.3 |
|
serum urea |
< 3 mmol/L |
0 |
|
|
3 to 6 mmol/L |
4.8 |
|
|
6 to 9 mmol/L |
9.0 |
|
|
9 to 12 mmol/L |
10.5 |
|
|
> 12 mmol/L |
21 |
|
RBC transfusion |
< 2 |
7.3 |
|
|
2 to 4 |
14 |
|
|
4 to 6 |
0 |
|
|
> 6 |
26.3 |
|
serum creatinine |
< 21 µmol/L |
100 |
|
|
21 to 77 µmol/L |
7.2 |
|
|
77 to 110 µmol/L |
0 |
|
|
> 110 µmol/L |
9.8 |
|
RBC count |
< 3 * 10^12/L |
14.9 |
|
|
3 to 4 * 10^12/L |
8.8 |
|
|
4 to 4.6 * 10^12/L |
3.5 |
|
|
> 4.6 * 10^12/L |
0 |
|
operation time |
< 3 hours |
0 |
|
|
3 to 6 hours |
25 |
|
|
6 to 9 hours |
34.2 |
|
|
> 9 hours |
64.3 |
|
serum cystatin C |
< 1.1 mg/L |
0 |
|
|
> 1.1 mg/L |
12.3 |
|
CPB time |
< 60 minutes |
0 |
|
|
60 to 120 minutes |
17.5 |
|
|
120 to 180 minutes |
29.8 |
|
|
180 to 240 minutes |
41.2 |
|
|
> 240 minutes |
64.5 |
|
gender |
female |
0 |
|
|
male |
12.1 |
|
hypertension |
no |
0 |
|
|
yes |
7 |
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 355.7
value of X for Stage III AKI =
= (0.0425 * (score)) - 8.694
value of Y for Stage II or III AKI =
= (0.04241 * (score)) - 7.724
probability of Stage III AKI =
= 1 / (1 + EXP((-1) * X))
probability of Stage II or III AKI =
= 1 / (1 + EXP((-1) * Y))
Performance:
• The area under the ROC curve for Stage III was 0.80
• The area under the ROC curve for Stage II was 0.73.
