Patient selection: Pediatric patients from birth to 15 years of age. Injuries were related to motor vehicle accidents, bicycle accidents or falls.
Indications for CT scan - one of the following:
(1) hemodynamically unstable
(2) AST > 450 IU/L
(3) ALT > 250 IU/L
NOTE: One of the references cited by Puranik et al is the paper of Hennes et al from 1990, which gave essentially the same decision levels. For Hennes et al the upper limits for the normal references ranges were < 35 IU/L (page 88, Hennes et al).
Observations about serum transaminase levels above the thresholds given:
(1) The level of elevation did not correlate with injury severity.
(2) The level of elevation did not correlate with the need for surgery.
(3) The level of elevation did not predict outcome.
Performance:
• 1 patient out of 32 patients with serum transaminases below the cutoff levels had liver injury seen on CT scan.
• All 14 patients with serum transaminases above the cutoff levels had liver injury.
• The sensitivity for liver injury was 92.9%, specificity 100%, positive predictive value 100%, and negative predictive value 96.8%.
Limitation:
• The authors did not define the upper limit of the normal reference range for the analytic method given, nor was the method of determination stated. A multiple of the upper limit of normal would be a more transportable measure.
• Since children are involved, the reference range needs to be age-adjusted.
• The mean value for the AST in patients without liver injury seen on CT scan was about 100 IU/L, while the ALT was about 50 IU/L. For most analytic methods the upper limit of the reference range for ALT and AST is about 50 IU/L. Thus, it would appear that some patients who did not have hepatic injury visible on CT scan did have some nonvisible injury.
