V. H. Mouli1, J. W. Scott2, M. R. Hemmila2, R. Jean2, B. W. Oliphant3 1University Of Michigan, Medical School, Ann Arbor, MI, USA 2University Of Michigan, Department Of Surgery, Ann Arbor, MI, USA 3University Of Michigan, Department Of Orthopaedic Surgery, Ann Arbor, MI, USA
Introduction:
The Injury Severity Score (ISS) and New Injury Severity Score (NISS) are known predictors of outcomes such as mortality, ICU admission, and hospital length of stay. However, these calculations only use the three highest Abbreviated Injury Scale (AIS) scores, and they do not include any other information about injuries that the patient may have. While ISS and NISS have been validated, it is unclear if incorporating the total count of the patient’s injuries would help in predicting post-discharge utilization (e.g., discharge to rehabilitation). Also, certain body region injury categories (e.g., musculoskeletal) might affect this type outcome more than others. In this study, we quantified the number of patient injuries that were not included in the NISS calculation and evaluated whether the total number and type of injuries predicts the discharge destination.
Methods:
Data from a statewide trauma quality improvement program from 1/1/2015-12/31/2022 was utilized. Adult patients (≥ 18yrs) were included, and those that died during their admission were excluded. The number of injuries in each AIS body region subcategory (e.g., head and neck, extremity, etc.) was counted. We assessed the number of injuries for each patient that were not included in the NISS calculation and an ANOVA to assess the number of injuries not included across NISS categories. A multivariable logistic regression, controlling for NISS and other trauma related covariates, was performed to evaluate the likelihood of a patient being discharged to a rehabilitation facility.
Results:
There were 211,949 patients that met inclusion criteria with a mean of 1.33±2.5 injuries not included after the NISS was calculated. With increasing NISS categories, there was a significant increase in the mean number of injuries not included (NISS 5-15: 0.62 injuries ± 1.36; NISS 16-24: 2.57±2.81; NISS 25-35: 4.24±4.31; NISS>35: 6.05±4.73, p<0.001). The number of extremity, abdominal, chest, and head and neck injuries and higher NISS categories were associated with an increased likelihood of being discharged to a rehabilitation facility. (Table)
Conclusion:
We found that an ample number of injuries are not included nor accounted for after the NISS is calculated. Additionally, patients with higher injury severity scores had more injuries. Specifically, musculoskeletal injuries appear to better predict a rehabilitation discharge destination than other body regions. There is an abundance of injury information that is not included in standard injury severity scores that might better predict post-discharge needs. More nuanced approaches to scoring trauma patients that incorporates all the data available should be explored.
