MEASURING INJURY SEVERITY - TIME FOR A CHANGE

Background: The Injury Severity Score (ISS) doss not take irate accoun t multiple injuries in the same body region, whereas a New ISS (NISS) may provide a more accurate measure of trauma severity by considering the patient's three greatest injuries regardless of body region. The p urpose of this study was to evaluate the ISS and NPSS in patients with blunt trauma. Methods: Consecutive individuals treated from January o f 1992 to September of 1996 at one institution were included if they h ad sustained blunt trauma and satisfied triage standards (n = 2,328). For each patient, we computed the ISS and the NISS to determine how of ten the two scores were identical or discrepant. Discrepant casts were then further analyzed, using receiver operating characteristic curves to determine which score better predicted short-term mortality. Resul ts: The mean ISS was 25 +/- 13, and the mean MSS was 33 +/- 18. The tw o predictive scores were identical in 32% of patients and discrepant i n 68% of patients. Patients with identical scores had a lower mortalit y rate than patients with discrepant scores (10% vs. 13%; p < 0.02). I n patients with discrepant scores, the area under the receiver operati ng characteristic curves was greater for the NISS than the ISS (0.852 vs. 0.799: p < 0.001), and greater amounts of discrepancy were associa ted with increasing rates of mortality (p < 0.001).Conclusions: The NI SS often increases the apparent severity of injury and provides a more accurate prediction of short-term mortality. The benefit associated w ith using the NISS rather than the ISS must be weighed against the dis advantages of changing a scoring system and the potential far still gr eater improvements.