Excluding significant intra-abdominal trauma on the basis of clinical evaluation is a lost art in the realm of zero-miss. Nowhere is this more important than in a pediatric population, considering the small, but real, potential from harms due to exposure to ionizing radiation from CT.
This is the Blunt Abdominal Trauma in Children (BATiC) score, derived in 2009 by a Swiss group. This rule promotes use of clinical exam, ultrasonographic findings, and laboratory results to determine need for CT. In this study, authors from the Netherlands retrospectively applied the rule to 216 pediatric trauma patients presenting in a four-year span between 2006 and 2010. All told, this cohort contained 18 patients for whom intra-abdominal injury were identified, and a BATiC score cut-off of 6 would have a sensitivity of 100% and specificity of 87%, with an AUC of 0.98. So, this all sounds splendid.
But, only 34 of these patients even received a CT scan as part of their evaluation – and, with the standard outcome definition being injuries diagnosed on CT or as part of hospitalization, there is potential for a fair number of missed diagnoses. A reasonable case may be made whether any missed injuries were clinically significant, given lack of observed morbidity, but it would be difficult to have confidence based on such as small sample. Furthermore, just as a simple cultural issue, trauma surgeons in the U.S. tend to feel any injury is clinically significant.
Then, 18.5% of observations used to validate this rule were missing from the retrospective data collection and required imputation. The extent of this missing data further degrades the reliability of the observed diagnostic characteristics. No confidence intervals are presented along with their results – but, rest assured, they are quite wide. Ultimately, this decision-instrument may indeed be valid – but requires specific prospective evaluation.
As an interesting Costs of Care side note, the additional charge for a such a trauma encounter including a CT scan in the Netherlands? A mere 148 euros.
“External validation of the Blunt Abdominal Trauma in Children (BATiC) score: Ruling out significant abdominal injury in children”
http://www.ncbi.nlm.nih.gov/pubmed/24747461