Accuracy of the New Injury Severity Score in Evaluating Patients With Blunt Trauma

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

The goal of this prospective observational study is to evaluate the predictive utility of the New Injury Severity Score (NISS) in determining mortality outcomes among blunt trauma patients admitted to the Emergency Department of Kadhimiya Educational Hospital, Iraq.

The main questions it aims to answer are:

How accurately does NISS predict mortality in blunt trauma patients? What is the performance of NISS in predicting secondary outcomes, such as the need for intensive care and length of hospital stay?

Participants will:

Be assessed using the NISS score upon their admission to the emergency department.

Have their clinical outcomes, including mortality, need for intensive care, and hospital stay, monitored throughout their hospitalization.

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.

Research Gap and Study Rationale Although the benefits of NISS over ISS are well-documented globally, there is a lack of localized research evaluating its utility in predicting clinical outcomes in blunt trauma patients in Iraq. Existing studies primarily focus on high-income countries with established healthcare infrastructure, leaving a gap in understanding how such scoring systems perform in resource-limited and post-conflict settings like Iraq.

This study seeks to address this gap by evaluating the predictive accuracy of NISS for blunt trauma patients within Iraq. By assessing the sensitivity, specificity, and overall utility of NISS in the Iraqi healthcare context, this research aims to provide evidence-based recommendations to improve trauma care protocols and patient outcomes. The findings could inform policy development and foster the adoption of standardized trauma assessment tools, thereby strengthening Iraq's healthcare system.

Inclusion Criteria:

• Trauma patients admitted to the emergency department, presenting with blunt trauma, such as from motor vehicle accidents, falls, or assaults.
• Patients with adequate documentation of anatomical injuries and physiological parameters required for NISS calculation.
• Injury assessment and NISS calculation completed within the first 6 hours of arrival to ensure accuracy and consistency in trauma evaluation.

Exclusion Criteria:

• Patients under 18 years, pregnant women, or those with pre-existing medical conditions that may alter trauma scoring accuracy or management outcomes.
• Patients presenting with medical emergencies, terminal illnesses, or conditions unrelated to blunt trauma to ensure focus on trauma-specific evaluations.
• Patients declared dead on arrival or who do not receive active treatment in the emergency department.
• Patients or their families refusing participation or withdrawing consent at any stage of the study.
• Patients transferred from or to another facility or those previously treated elsewhere, as this may affect data collection and scoring reliability.