The new injury severity score: A more accurate predictor of need ventilator and time ventilated in trauma patients than the injury severity score

Objectives: This study validates the accuracy of the injury severity score (ISS) and the new injury severity score (NISS) systems for prediction of need for intubation (NI), need for mechanical ventilation (NMV) and duration of MV (DMV) in intensive care unit (ICU) trauma patient admissions. Design: On the day of admission, data were collected from each patient to compute the ISS and NISS. Setting: Prospective cohort study. Materials and Methods: One hundred and ten nonselected trauma patients were included in our study in a consecutive period of six months. Results: The predictive accuracies of the ISS and the NISS were compared using receiver operator characteristic (ROC) curves and Hosmer-Lemeshow (H-L) statistics for the logistic regression model of ICU admission. For prediction of NI, the best cut-off points were 22 for ISS and 27 for NISS. The positive prediction value was 91.6% in NISS and 87.8% in ISS. The Youden index had best cut-off points at 0.47 for NISS and 0.57 for ISS. The area under ROC curve was 0.79 in the ISS and 0.86 in the ISS. There were statistical differences among NISS with ISS in terms of Youden Index and the area under the ROC curve (P<0.05). For the prediction of NMV, NISS yielded significantly better results in the area under the ROC curve and Youden index than those of ISS (P<0.05). None of the two scoring systems provided good discrimination in prediction of more than three or five days assisted-ventilation under MV. Conclusions: For prediction of NI or NMV, the NISS has better accuracy than ISS.