Zheng et al reported a model for predicting the risk of severe hemorrhage in a patient undergoing nephrolithotomy for nephrolithiasis. The authors are from Guangzhou Medical University in China.
Patient selection: adult >= 18 years, with renal stone >= 2 cm, undergoing mini percutaneous nephrolithotomy
Parameters:
(1) number of tracts (not defined; possibly number of percutaneous needle tracts = punctures)
(2) hydronephrosis
(3) congenital anomalies of the urinary tract
(4) urinary tract infection
(5) operation time in minutes
(6) renal stone peak Hounsfield unit (HU)
Parameter
Finding
Points
number of tract
0.7829 * (number)
hydronephrosis
none
1.1620
mild
1.1620
moderate to marked
0
congenital anomalies
no
0
yes
1.1334
urinary tract infection
no
0
yes
0.3915
operation time
0.0101 * (time)
renal stone peak HU
0.0008 * (peak HU)
value of X =
= SUM(points for all of the parameters) - 6.7068
risk of hemorrhage =
= 1 / (1+EXP((-1) * X))
Performance:
• The C-index is 0.73.
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