Wei et al reported a model for predicting postoperative urinary retention for a patient undergoing thoracic surgery. This can help to identify a patient who may benefit from more aggressive management. The authors are from the University of Alabama at Birmingham.
Outcome: postoperative urinary retention
Parameters:
(1) age in years, from 20 to 90
(2) preoperative serum creatinine in mg/dL, from 1 to 8
(3) sex
(4) preoperative COPD
(5) postoperative patient-controlled analgesia (PCA)
(6) procedure
points for age in years =
= (1.37 * (age)) - 24.72
points for creatinine =
= (10.54 * (creatinine)) - 2.23
|
Parameter
|
Finding
|
Points
|
|
sex
|
female
|
0
|
|
|
male
|
32
|
|
preoperative COPD
|
no
|
0
|
|
|
yes
|
14
|
|
PCA
|
no
|
0
|
|
|
yes
|
33
|
|
procedure
|
chest wall
|
40
|
|
|
neck
|
40
|
|
|
lobectomy or segmentectomy
|
34
|
|
|
mediastinum
|
31
|
|
|
diaphragm
|
31
|
|
|
wedge resection
|
27
|
|
|
esophagus
|
13
|
|
|
other
|
0
|
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 433.2
• The higher the score the greater the risk of postoperative urinary retention.
value of X =
= ( 0.03398* (score)) - 5.576
probability of urinary retention =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve for the derivation cohort was 0.77 vs 0.72 for the validation cohort.
