Pneumonia After Trauma Risk Factors

Risk factors for early onset pneumonia (from logistic regression analysis):

(1) combined severe thoracic and abdominal trauma (thorax AIS > 4, abdomen AIS > 9)

(2) age > 40 years

(3) mechanical ventilation < 24 hours during the first 4 days of hospitalization

where:

• I am not sure how one gets an AIS of 9 for the abdomen. The maximum regional score would be a 6, which is a fatal lesion. A moderate injury is graded 2 and a severe injury is graded 3.

• One option is that they are referring to the square of the regional value. The injury severity score combines the square of the highest regional injuries.

• A second option is that they are combining multiple abdominal injuries.

• The only thing that makes sense is that they are referring to the squared value for the regional injury. "Thorax AIS > 4" would refer to regional injuries graded 3, 4 or 5. "Abdominal AIS > 9" would refer to regional injuries graded 4 or 5.

Risk factors for late onset pneumonia (from logistic regression analysis):

(1) abdominal AIS > 4

(2) mechanical ventilation for > 5 days

where:

• The abstract refers to an AIS > 4, but the text on page 226 says >=4. If they are using the square of the regional injury grade then "> 4" would refer to a regional injury of 3 to 5.