Trauma is one of the most common causes of mortality [1,2]. The World Health Organization has reported that more than nine people die every minute from injuries or violence. The common causes of casualties in trauma include road traffic accidents, railway accidents, natural disasters, industrial and accidental injuries, terror and other criminal acts, and international or political wars [3].

Head injury (traumatic brain injury) is one of the most common presentations of patients admitted to trauma departments worldwide [1]. The global trauma-related costs are very high and include lost lives, lost family source of income, medical expenses, compensation and costs. It is considered a severe public health issue [4]. Proper evaluation of trauma patients from the onset is crucial for triage, management, and mortality prediction. Physiological scoring systems have gained universal approval for all emergency trauma care patients.

The present study was restricted to the revised trauma score (RTS) [5] and the Glasgow coma scale-age-pressure (GAP) [6] scores to predict trauma mortality. RTS and GAP scores do not include the trauma mechanism or the mode of injury, so they do not vary with the type of injury, i.e., head injury or abdominal injury, and hence can be applied to predict survival in any form of trauma in patients presenting to the hospital. This study was conducted to determine which physiological scoring system was better.

This study aimed to compare the probability of survival of head trauma cases (traumatic brain injury) using the RTS [Glasgow coma scale (GCS) + systolic arterial pressure + respiratory rate] and GAP score (GCS + systolic arterial pressure + age score) from admission to discharge/death.

We believe this study will improve the assessment and management of patients with trauma and help to plan strategies to reduce the burden of trauma.

A prospective observational study was conducted at a tertiary care referral center in a metropolitan city in India. The study included 500 consecutive patients with traumatic brain injury presenting to the Emergency Department over 6 months. The study included patients with head injury who were above 12 years of age, the upper age limit was not determined, and patients with polytrauma. The study excluded patients who were less than 12 years of age, patients with head injury (which scored GCS 13-15) without polytrauma, referred patients, and previously intubated patients. However, in the patient population who attended the tertiary care referral trauma center, the age given may not necessarily be reliable as the exact age was not always known.

The RTS is age independent and a more suitable system based on physiological variables than using GAP scores which is an age-dependent physiological trauma score.

All the patients were primarily admitted to the Trauma Intensive Care Unit. The on-duty trauma registrar performed a detailed clinical examination. Investigators recorded the patient’s vital parameters including their pulse rate, blood pressure (BP), respiratory rate, and GCS at admission. All 500 patients underwent evaluation by both RTS (Table 1) and GAP trauma scoring systems (Table 2). The mode of trauma, type of head injury based on computed tomography, surgical intervention needed for the head injury, and associated injuries were recorded. Patients were assessed and managed as per Advanced Trauma Life Care protocols. Primary assessment and definitive management proceeded concurrently in all cases, the urgency of either dictated by the magnitude of trauma.

The data was collected using an interview schedule with the patient, if the patient was not conscious relatives, policemen, or bystanders were interviewed (if available to give the details of the patient and the mode and mechanism of injury). A standardized proforma maintained the complete record, and the cases were followed up for 7 days. Management of the patient’s care was not altered. Investigators recorded the investigations and treatments given to the patient to rule out any complications related to the outcome, and used these factors in the final analysis. Investigators ascertained the patient’s survival status at 4 intervals (Day 1, Day 2, Day 7, and at discharge) so that patients were assessed immediately at the time of trauma, and once they were stabilized by Day 7, and at the time of discharge. The mortality rates were calculated using the available records. The patient's outcome was recorded as surviving and discharged or expired.

The investigators plotted the Receiver Operating Characteristic (ROC) curves for the scores and survival. The Area Under the Curve and its 95% confidence intervals were calculated. The investigators also assessed the equality of 2 ROC curves. Survival and mortality were calculated based on the above data, and the RTS and GAP scores were calculated for admission, and ROC curves were plotted using the chi-square test and 95% confidence intervals.

The statistical analyses were performed where a p < 0.05 was considered statistically significant. Stata Version 13 (StataCorp, College Station, Texas, USA) was used for analysis.

The following results were derived based on observation and analysis of 500 head trauma patients. The mean age of the study group was 34.1 years. Head trauma was common in the younger age group 21-30 years, however, survival was also better at a young age (Table 3). Survival decreased with increasing age. There was 100% mortality above 60 years of age in our study (Table 4). There were 459 (91.8%) patients who were male, and 41 (8.2%) were female (Table 3).

Road traffic accidents were the most common mode of head trauma (35.6%) observed at this center, closely followed by railway accident (34%), and fall from height (27%). Assault and other modes of head trauma comprised only 3.4% of total head trauma patients (Table 3).

The most common type of head injury (traumatic brain injury) based on computed tomography findings was hemorrhagic contusion (45.4%), followed by subarachnoid hemorrhage (36.3%), subdural hematoma (33%), extradural hematoma (22.5%), diffuse axonal injury (2.45%), and others (7.6%). Only 28.2% of patients required surgical intervention. The rest of the patients required conservative management. Associated injuries were noted in 34.4%. The rest of patients (65.6%) had isolated head injuries (Table 3).

Most patients had a GCS score ranging between 3 and 12 with a mean of 7.232, a SD of ± 3.35, and a variance of 11.25. The vital parameters showed massive variations. The pulse rate was recordable in 492 patients. The results varied between 54 bpm to 150 bpm (the mean pulse rate was 99 bpm). In the remaining eight patients, the peripheral pulse was not palpable. The observed systolic BP ranged from 60 to 200 mmHg (The mean systolic BP was 111 mmHg). The systolic BP was not recordable in 17 patients (Table 3).

The respiratory rate ranged from 8 per minute (gasping) to 44 per minute (hyperventilation; the mean respiratory rate was 23 breaths per minute. When comparing the mortality related to the respiratory rate, mortality was highest at extremes of respiratory rates, i.e., below 12 and above 24 breaths per minute (Table 3).

The RTS was calculated from the data above. The score ranged from a minimum of 0.87 to a maximum of 7.84 (the mean RTS reading was 5.54 with a standard deviation of 1.40 (Table 5).

The GAP score, was subsequently calculated. The score varied between 4 and 23 (with a mean of 14.31 and a standard deviation of 3.71; Table 5).

The survival at 24 hours post admission was 82.8% (414 out of 500), at 48 hours it was 74.6% (373 out of 500), and on Day 7 only 53% (265 out of 500). Out of 500 patients, 289 (57.8%) patients survived and were discharged, and the remaining 211 (42.2%) patients expired.

A comparison of individual RTS and GAP scores revealed that as the RTS increases, mortality decreases. There was 100% mortality for RTS at scores of 0-2 and 0% mortality at 7. There was 100% mortality for GAP scores less than 8. A decreasing trend in mortality existed as the GAP score increased. Above a GAP score of 21, the mortality was 0% (Figures 1-3).

At 24 hours post admission, RTS was better in predicting survival at 24 hours compared with the GAP score (p = 0.0441). At 48 hours, a better prediction of survival by RTS was observed when compared with the GAP score (p = 0.0485). At 7 days, RTS was not better than the GAP score at predicting survival (p = 0.2401). At the final outcome, RTS was not better than the GAP score at predicting survival (p = 0.3730; Table 6).

We conducted the study to compare the GAP and RTS systems during the hospital stay at the Trauma Centre as a predictor of mortality or survival. The GAP and RTS scores benefitted multiple institutes as a triage tool. Russell et al [5] advocated for using the Mechanism- GAP score, while Kondo et al [6] observed that the GAP score is a better predictor and more generalizable scoring system to be applied easily in the Emergency Department.

Though our sample may be relatively small (as it is a single center study that comes from a relatively short duration) for statistical comparison with data from other studies [5-7] (which have a larger study population and data that has been collected over a longer period). The results from this study were still comparable with these studies (Table 7 [6-8]).

In the present study, the younger age group of less than 20 years of age showed a mortality of 40%, and the 21-30, 31-40 and 41-50 years age-groups showed mortality slightly lower than the mortality rate of the 51-60 years age-group. For patients more than 60 years of age, mortality rates were very high. These were comparable with most other studies conducted in the last 15 years, which show proportionately increased mortality as age advances [9]. Age is a crucial factor that influences the possibility of head trauma and the impact of this trauma. Young people are more likely to suffer from head trauma but equally strong to fight this trauma and survive. Elderly patients have very little chance of surviving severe head trauma and associated comorbidities. Patients whose values for pulse rate, systolic BP, and respiratory rate were within the normal range fared well. Extreme values for these parameters were associated with poor outcomes.

The high proportion of males in this study can be attributed to the cultural practices in our region, where generally males go out to work and earn a livelihood for the entire family, whilst women predominantly stay at home to manage the family and house, which translated into males having 11.5 times higher risk of sustaining head trauma than females.

Since ours was a tertiary referral center, we receive a lot of patients who had severe injuries which are difficult to manage at peripheral centers and hence referred to us, which was reflected as a mean GCS of 7.23 in our study which was also the reason for high case fatality and mortality in our study.

The data for the GAP score was categorized as per the Kondo et al paper [6] and compared to our results. In both cases, the probability calculated using Fisher's exact test was < 0.0005, implying statistically significant outcomes. Comparison of the RTS data from this study to the study by Kondo et al [6] (REF), showed that the RTS-based prediction of survival value was statistically significant in both studies as determined by Fisher's exact test (p < 0.0005).

RTS is an age-independent predictor of in-hospital mortality. It is a tool to assess a patient with injury on admission. It determines the survival possibilities of patients and helps in resource allocation for patient management strategies. GAP score is a practical predictor of survival in cases of head trauma which is age-dependent. Higher GAP scores were associated with improved chances of survival. Likely, a higher RTS was related to decreased mortality. RTS and GAP scores were similar at predicting survival on the 7^th day and RTS turned out to be a better predictor of survival for head injury patients at 24 and 48 hours.

Thoracic and Abdominal injuries (associated injuries) may have influenced our study results (as only 65.6% of patients had isolated head injuries). Pre-existing comorbidities may also affect study results. RTS and GAP scores do not include the mechanism of trauma or the mode of injury, and they do not vary with the type of injury, i.e., head injury or abdominal injury. RTS and GAP scores may also be affected by the primary treatment received by the patient at the previous center or in an ambulance, as also the pre-hospital delay before reaching the tertiary center.

As time progresses from the event of trauma, irrespective of the mode of injury, the type of injury incurred, or the management given, the chances of survival decrease. The need for a better trauma assessment and management protocol is thus evident.

The present sample size is too small which limits this study. It cannot be compared with the study by Kondo et al [6]. RTS and GAP scores were both quick assessors of survival. Despite these factors, RTS appears to be a better predictor for survival.

Age is an important factor for head trauma; younger patients are more likely to suffer from trauma but are stronger and more likely to survive. Elderly patients have a lower chance of surviving severe head trauma due to the greater incidence of comorbidities and increased likelihood that these patients are physically weaker. RTS is an age-independent useful predictor of in-hospital mortality. It is also a useful tool to assess a patient with traumatic head injury on admission. It also helps to determine a patient’s survival probability which can be used for better preparedness and resource allocation towards patient management in the future. RTS was a better early predictor for mortality (within 48 hours of admission) compared with the GAP score.