A Prospective Evaluation of the New Injury Severity Score's Accuracy in Blunt Trauma Patients

Trauma is the leading cause of death among individuals under 45 years of age, who represent the most productive population of society. According to the World Health Organization, trauma will remain a major driver of years of productive life lost by the end of this decade. Blunt trauma, a common form of injury, typically results in solid organ damage rather than hollow organ injuries.

Trauma management protocols play a vital role in reducing mortality. For example, standardized resuscitation protocols have been shown to decrease mortality by 15% in severely injured patients. The Airway, Breathing, Circulation, Disability, Exposure (ABCDE) approach is a clinically proven framework for managing trauma patients, improving patient outcomes, optimizing team performance, and saving time during life-threatening emergencies. In addition to standardized protocols, scoring systems play a critical role in evaluating the severity of trauma and predicting patient outcomes.

The Injury Severity Score (ISS), introduced in 1974, is one of the most widely used anatomical scoring systems. It evaluates the severity of injuries by dividing the body into six regions: head and neck, face, thorax, abdomen, extremities (including pelvis), and external. Each injury is assigned a score using the Abbreviated Injury Scale (AIS), but only the highest AIS score from each region is used. The ISS is then calculated as the sum of the squares of the top three AIS scores, with a maximum value of 75. Patients with an AIS score of 6 in any region are automatically assigned the maximum ISS score.

However, ISS has limitations. By considering only the most severe injury per body region, which may underestimate the severity of trauma in patients with multiple injuries in the same region. To address this, Osler et al. developed the New Injury Severity Score (NISS) in 1997. Unlike ISS, NISS accounts for the total of squares of the three most severe injuries, regardless of their location in the body, providing a more comprehensive assessment of trauma severity. Studies have shown that NISS often results in higher scores compared to ISS, offering better predictions of patient outcomes in multiple trauma cases.

In addition to anatomical scoring systems like ISS and NISS, physiological scoring systems have been developed to predict outcomes in trauma patients. The Revised Trauma Score (RTS) evaluates physiological parameters, incorporating the Glasgow Coma Scale, systolic blood pressure, and respiratory rate to assess trauma severity and predict mortality.