This study has shown that hospitalized trauma deaths constitute only 13.5% of all trauma deaths in Abu Dhabi. Eighty-two per cent (82%) of the deaths were in young males, and 85% occurred in either the ED or the ICU. Motor vehicle collisions, causing mainly head injuries or injuries to two body regions, and fall from height were the two predominant mechanisms in the patients who died. The in-hospital mortality rate of 1.5% is less than the 4.7% reported in the United States [10]. The low incidence of death in this study reflects our registry criteria, which allows for the inclusion of trauma patients with low ISS.
In the suggested classical trimodal distribution of trauma deaths in the USA, over 50% of the deaths occur in the first few minutes to hours before the patients reached the hospital [11]. The 86% prehospital death rate in our study is more than the reported range of 30–70% [12]. In the present study, most of the deaths in the ED were in patients with no vital signs on arrival. These patients could arguably be classified as prehospital deaths, thus further increasing the proportion of those who died in a prehospital setting. The high prehospital death rate may reflect the primary injury severity and prolonged transfer time. Increased injury severity rate, defined as the ratio of injury and fatality per 1000 road traffic accidents, has been previously reported in our setting [13]. A prolonged extrication and transfer time of injured patients to the hospital is also a possible reason. The current study did not look at the ambulance on-scene and transfer times. However, the geographical distribution of the trauma centres and the land mass of the Abu Dhabi Emirate, which represents 87% of the UAE land mass, may suggest that delayed transfer time is a contributory factor. This is mitigated by the good road network and the interventions provided by our EMS, which are limited to providing airway support and hemorrhage control, leading to a ‘scoop and run’ approach.
Gunst et al. described a bimodal distribution of deaths, where the first peak occurred in the prehospital phase, followed by a second peak several days later [14]. More recent studies have shown an early peak occurring within minutes and a few hours, followed by a gradual decrease in deaths over time without any peak [15]. The current study showed two definite in-hospital peaks; one in the ED, which was immediate, and a second in the ICU which occurred over several days. Rather than looking at trauma deaths as a function of time, which has been shown to be related to the time model used [16], we chose instead to look at the locations in the hospital where the deaths have occurred. This will help to identify where intervention measures and resource allocation can be most effective when patients arrive to the hospital. Our results show the ED (33.3%) and the ICU (51.7%) as the two areas where most of the deaths have occurred and where intervention measures could be directed.
In this study, head injuries accounted for over 45% of the deaths while hemorrhagic deaths (injuries to the abdomen, pelvis and, to some extent, the chest) constituted only 10%. This indicates head injury remains a major problem in our setting. Indeed, advances in trauma care across the globe have demonstrated a reduction in hospital trauma deaths due to hemorrhage but little change in death due to traumatic brain injury [17, 18]. Nonetheless, while primary brain injuries can only be mitigated by legislation and primary injury prevention measures, much can be done to prevent secondary brain injuries, such as targeted brain protection from hypoxia, hypercarbia and hypotension. These measures may improve survival in ICU deaths due to head injury, which is close to 50% in this study.
About 7% of the reported deaths in this study occurred in the ward. These were mainly elderly patients with extremity injuries and normal vital signs on arrival at the hospital. This reflects the high incidence of falls in old Emirati females with fractured neck femurs, as we have previously reported [19]. The median ED length of stay in these patients was the highest. The overall median ED length of stay was about two hours, which was close to double for those who died in the ward. Many studies have reported an increasing trend in trauma in the elderly [20–22]. We have also reported a similar trend in our setting [19]. Recognizing these high-risk patients will help focus on intervention measures such as preventing falls in the elderly and optimizing their care in the ED by reducing their ED length of stay and instituting measures to reduce injury complications.
There were significant differences in mortality rates in our trauma-receiving hospitals. Hospitals A and E each received over seven thousand trauma cases during the study period. This equates to more than 1000 trauma admissions per year. The two hospitals admitted close to 50% of all the trauma cases but accounted for only 25.8% of the total deaths. In contrast, three other hospitals received between three to five thousand cases representing 40% of the total trauma admission but accounted for almost 70% of the total deaths. This may be due to the differences in the setup at the different institutions and the trauma team development within each hospital. In addition, there were differences in the median ISS of the patients in the different hospitals, making further comparison difficult. Several studies have shown that the regionalization of trauma services leads to better patient outcomes by concentrating trauma resources and expertise in a few centers [23, 24]. The optimal annual trauma admissions that ensure a viable trauma centre with the maintenance of skills is unknown. However, it has been shown that volume leads to better outcomes in trauma care [24]. A system of hubs and spokes with agreed procedures with the EMS to bypass smaller hospitals and transfer trauma patients directly to the major trauma centres will ensure the maintenance of skills and improved patients’ outcome.
About 75% of those who died in the ward received no trauma code or only had a consultation. This suggests a significant level of under-triaging. Our results show that the median (IQR) age for the patients who died on the ward was 65.50 (31.75–82.21), indicating that they were elderly trauma patients. Appropriate triaging of elderly trauma patients is challenging. The American College of Surgeons Committee on Trauma (ACS-CoT) adult triage tool performs poorly in this age group. Many triage tools that modify the physiological thresholds have been developed to improve triage reliability. Still, elderly trauma patients continued to experience significant levels of under-triaging with the attendant impact on outcomes [25–27]. Adopting any of these new elderly trauma triaging tools in our settings may improve outcomes in our population.