Risk factors for death of trauma patients admitted to an Intensive Care Unit

Objective: To analyze the risk factors for death of trauma patients admitted to the intensive care unit (ICU). Method: Retrospective cohort study with data from medical records of adults hospitalized for trauma in a general intensive care unit. We included patients 18 years of age and older and admitted for injuries. The variables were grouped into levels in a hierarchical manner. The distal level included sociodemographic variables, hospitalization, cause of trauma and comorbidities; the intermediate, the characteristics of trauma and prehospital care; the proximal, the variables of prognostic indices, intensive admission, procedures and complications. Multiple logistic regression analysis was performed. Results: The risk factors associated with death at the distal level were age 60 years or older and comorbidities; at intermediate level, severity of trauma and proximal level, severe circulatory complications, vasoactive drug use, mechanical ventilation, renal dysfunction, failure to perform blood culture on admission and Acute Physiology and Chronic Health Evaluation II. Conclusion: The identified factors are useful to compose a clinical profile and to plan intensive care to avoid complications and deaths of traumatized patients.

A total of 569 hospitalizations from January 1, 2013 to December 31, 2016 were selected and identified in the admission book with reasons for hospitalization of any injury due to external cause. The initial selection criteria were hospitalizations with mention of trauma, external cause and procedure related to trauma care. After analysis of each hospitalization, the study excluded hospitalizations related to procedures not related to trauma management (101), with incomplete records (31) and occurring in children under 18 years (9). Trauma related to burns (3) and poisoning (8) was also excluded, in order to make the sample homogeneous, since these are considered specific types of trauma, requiring differentiated intensive care.
The study sample totaled 417 individuals. Rev. Latino-Am. Enfermagem 2020;28:e3236. those of the lower level, and the proximal ones, which directly predict death ( Figure 1). This analysis is used to explain the relationship between variables in models whose set of empirical propositions already indicates the strength and direction of the relationship and allows to identify whether the association is direct or mediated by the effect of other variables (20) .
Of the complications in the ICU, severe circulatory and respiratory, renal, pulmonary, neurological, cardiac and hepatic dysfunction, sepsis, pressure injury and unplanned intubation were associated with death (Table 3).       (19) . In two regions of Estonia, the results of hospitalizations for severe trauma in 2013 were compared and a mortality rate of 20.7% was identified (21) . Similar data were recorded in a Brazilian ICU, in Sobral -CE, between 2013 and 2014, which identified a mortality rate of 28.6% in traumatized patients (8) .
The determinants for death from trauma in the ICU observed in this study were some existing at the time of trauma, such as age over 60 years and In this study, age 60 years and over remained a predictor of death, increasing the risk by three times.
Worse prognosis for traumatized elderly compared to younger patients has been constantly presented in the literature (8)(9)(22)(23)(24)(25) . This weakness is explained by Care for traumatized older people should consider the impact of aging on specific organ functions and, as a result, may affect interventions (26) . In this sense, interdisciplinary care improves quality because it addresses the comorbidities, processes, and outcomes of geriatric syndromes, identifies additional diagnoses, assists in advanced care planning, manages drug changes, and pain management (29) and identifies early risk factors for death (30) . There are gaps in the development and implementation of treatment protocols for traumatized elderly, lacking guidelines and specialized centers (26) . This fact was observed in this study, which points to the need to adopt instruments that facilitate the identification and screening of traumatized elderly patients, from PHC to ICU as a priority (31) .
It was also found that with each increase in the CCI score, the risk of death, regardless of age adjustment, increased by 41%. Comorbidities may contribute to negative ICU outcomes, such as the greater possibility of complications (9,19,(23)(24) . In this sense, it is important to adopt a classification system that is capable, in whether circulatory complications occur before or after ICU admission, or even if they have a direct relationship with comorbidities, trauma can become a decisive factor for its triggering by making the individual fragile. and by exposing you to excessive interventions and procedures.
The development of complications during ICU trauma hospitalization may be a clinical factor to safely and carefully determine the outcome of intensive care, such as death or longer hospital stay (19) .
Another factor contributing to mortality in traumatized patients is hemodynamic instability and, in such cases, adequate tissue perfusion with early administration of crystalloid fluids should be ensured.
Vasoactive drugs may be transiently required in the presence of life-threatening hypotension (34) and early use may limit organ hypoperfusion and prevent multiple failure (28) . However, evidence identified in a systematic review of the early use of vasopressors after traumatic injury highlights that, in addition to the benefits, some damage from vasopressor therapy in the early phase of trauma is also reported, such as the risk of bleeding, coagulopathy, compartment syndrome, and surgical complications (34) .
In this study, the use of vasopressors remained independently associated with death. Similarly, research that tracked trauma-level inpatients in the US between 2011 and 2016 who used red blood cell transfusion upon admission found that mortality gradually increases with increased use of vasoactive agents (35) . Even in the face of controversies regarding the use of vasoactive drugs for traumatized patients, the admission of these patients to an intensive setting allows careful and continuous management with instant monitoring of their vital functions.
Despite the heterogeneity of trauma patients with different respiratory needs, a large proportion of patients require mechanical ventilation due to acute respiratory failure (ARF) (36) , as is the case of the population studied.
In this regard, the use of ventilatory support depends on the severity of respiratory dysfunction, impairment of gas exchange, associated trauma, and the feasibility of using noninvasive mechanical ventilation (NIV) (36) or for airway protection and prevention of secondary brain injury (37) and other conditions such as hemorrhagic shock and multiple organ damage (38) . Thus, regardless of the need for mechanical ventilation, trauma patients share common ICU care. In this study, mechanical ventilation, regardless of the justification for its use, increased the probability of death fivefold.
With the exception of patients intubated for airway protection, there are alternatives to avoid mechanical ventilation and reduce associated complications (36) . To prevent complications and death, the use of noninvasive mechanical ventilation (36) and pressure-controlled Measuring disease severity is critical to drive care, and one of the most commonly used routine indicators in an intensive care setting is APACHE II, which has been shown to be sufficient to predict death in trauma patients (32,46) .
The results of this study also demonstrated the association of patient severity as measured by APACHE II and death. Although the use of APACHE II is time consuming and costly, the index estimates the prognosis for ICU admission and may be appropriate for assessing and monitoring trauma patients by identifying abnormal physiology (46) and reducing preventable deaths (32) .
Regardless of the type of trauma and the place where the traumatized will be assisted, it is considered one of the health problems with the greatest impact on the health and economy of contemporary society.