Preoperative risk factors:
(1) gunshot wounds to the abdomen
(2) blunt abdominal trauma
(3) not using prophylactic antibiotics
(4) Revised Trauma Score (RTS) <= 7.8 (since the RTS only gives whole number results, I will use < 8 for the implementation)
(5) Abdominal Trauma Index (ATI) > 24
(6) Injury Severity Score (ISS) > 20
Intraoperative and postoperative risk factors:
(1) systolic hypotension (< 90 mm Hg for >= 1 hour)
(2) contamination of the abdominal cavity
(3) red blood cell transfusion (increased with any amount, with risk increasing as number increases)
(4) duration of operation > 2 hours
(5) insertion of drains
(6) requirement for an ostomy
(7) splenectomy
(8) abdominal packing
(9) damage control surgery
(10) abdomen left open at the end of surgery
(11) admission to the ICU
A multivariate model was developed based on:
(1) Abdominal Trauma Index (ATI) > 24
(2) admission to the ICU
(3) contamination of the abdominal cavity
|
Parameter
|
Finding
|
Points
|
|
ATI
|
<= 24
|
0
|
|
|
> 24
|
1
|
|
admission to ICU after surgery
|
no
|
0
|
|
|
yes
|
1
|
|
contamination of abdominal cavity
|
absent
|
0
|
|
|
present
|
1
|
X =
= (0.97 * (points for ATI)) + (2.13 * (points for ICU admission)) + (0.96 * (points for contamination of the abdominal cavity )) - 3.67
probability of intra-abdominal infection =
= 1 / (1 + EXP((-1) * X))
Limitations:
• While the multivariate model adjusts well and predicts 91% of events, it should not be used for prediction of the individual patient. It explains only 30% of the variability in the outcome and the residuals show a scattered distribution (page 1282).
