Nichols et al used 2 models in 1984 to predict the risk of infection after penetrating abdominal trauma. Patients at high risk for infection may benefit from more aggressive antimicrobial therapy. The study was done at Tulane University in New Orleans and the University of California in San Francisco.
Method 1: Utilization of Risk Factors
score for predicting risk =
= (0.076 * (age in years)) - (2.516 * (ostomy points)) + (0.049 * (number of blood products used)) + (1.050 * (number of organs injured)) - 2.892
where:
• ostomy points = 1 if ostomy formed at surgery; = 2 if no ostomy formed
risk of infection =
= 1 / (1 + EXP((-1) * (score for predicting risk)))
goodness of fit chi square = 3.99, with 9 degrees of freedom, P = 0.912
Method 2: Utilization of the Modified Trauma Index
Organ systems scored in the modified trauma index:
(1) respiratory
(2) cardiovascular
(3) abdominal
(4) skin and subcutaneous tissue
Scoring - from 0 (no injury) to 7 (fatal injury)
modified trauma index score =
= SUM(scores for the 4 organ systems)
where:
• minimum index score: 0
• maximum index score: 28
score for predicting risk =
= (0.425 * (modified trauma index score)) - 6.048
risk of infection =
= 1 / (1 + EXP((-1) * (score for predicting risk)))
goodness of fit chi-square = 3.56, with 7 degrees of freedom, P = 0.828
Limitation:
• A fatal injury is unlikely to be associated with infection risk.
