Article Text
Abstract
Objectives Penetrating gunshot head injuries have a poor prognosis and require prompt care. Brain CT is a routine component of the standard evaluation of head wounds and suspected brain injury. We aimed to investigate the effect of brain CT findings on mortality in gunshot head injury patients who were admitted to our emergency department (ED) from the Syrian Civil War.
Methods The study group comprised patients who were admitted to the ED with gunshot brain injury. Patients' GCS scores, prehospital intubations and brain CT findings were examined.
Results 104 patients were included (92% male, mean age 25 years). Pneumocephalus, midline shift, penetrating head injury, patients with GCS scores ≤6 and patients who had to be intubated in the prehospital period were associated with higher mortality (p<0.05).
Discussion The results of this study demonstrated that pneumocephalus, midline shift, a penetrating head injury, GCS scores ≤6 and prehospital intubation are associated with high mortality, whereas patients with temporal bone fracture, perforating or single cerebral lobe head injury had a higher survival rates. The temporal bone has a relatively thin and smooth shape compared with the other skull bones so a bullet is less fragmented when it has penetrated the temporal bone, which could be a reason for the reduced cavitation effect. In perforating head injury, the bullet makes a second hole and so will have deposited less energy than a retained bullet with a consequent reduction in intracranial injury and mortality. Further studies are required to reach definitive conclusions.
- penetrating gunshot
- brain computed tomography
- emergency department
- prehospital intubation
- glasgow coma scale
- perforating head injury
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- penetrating gunshot
- brain computed tomography
- emergency department
- prehospital intubation
- glasgow coma scale
- perforating head injury
Key messages
In this study, there was a correlation between the temporal bone fracture and perforating head injuries.
The temporal bone has a relatively thin and smooth shape compared with the other skull bones so a bullet may be less fragmented when penetrating it and this can be a reason for the reduced blast effect.
Patients with perforating head injury have a higher survival rate—by exiting the cranium less energy is deposited than if it is retained (penetrating path) leading to reduced intracranial pressure and mortality.
Introduction
Ballistic head injuries still have a poor prognosis and these injuries sustained on the battlefield require prompt care; intracranial injuries remain a leading mortality factor in military settings.1 ,2 A wide variety of diagnostic tools are available for the assessment of gunshot injuries, but in a battlefield setting, it is extremely difficult to make sufficient assessment of an injury. Under these conditions, first responders must make a diagnosis from clinical examination, including visual inspection and palpation.3
When a bullet penetrates the skull, its energy is distributed within a confined space and the expansion of temporary cavitation is restricted by the rigid bony skull until the cavitatory force exceeds the tensile strength of the bone, leading to an increase in intracranial damage. A bullet may follow the curvature of the interior of the skull and this path can produce significant damage. CT of the brain provides the most accurate and trustworthy information on the pattern of destruction and the location of the projectile4 and is a routine component of standard evaluation of head wounds and suspected brain injury. Thus, it is generally assumed that intracranial pathologies and foreign bodies in the brain will be detected by using CT.5 A lack of imaging may result in delayed discovery of intracerebral foreign bodies to the potential detriment of the patient's health.6 Patients with a GCS of ≤8 have significant neurological injury and are classified as having a severe traumatic brain injury (TBI). In general, these patients have pathological CT scan findings, such as a skull fracture, traumatic intracranial haemorrhage or contusion injury and require rapid admission to the intensive care unit for immediate airway control, mechanical ventilation, neurosurgical evaluation and consideration for intracranial pressure monitoring.7 High-energy blast mechanisms from advanced explosive devices result in severe polytrauma and injury patterns, which are often significantly different in the nature of the injury compared with penetrating gunshot wound head injuries (PGHI).8 This study aimed to investigate the relationship of brain CT findings and mortality in patients admitted to the emergency department (ED) with PGHI sustained in the Syrian Civil War.
Material and methods
Standard protocol approval
After obtaining the approval of the Clinical Research Ethics Committee (Medipol University Hospital/14.05.2015/13-10), the authors reviewed the records of all patients admitted between 1 January and 7 June 2014, with PGHI.
Data collection
Evaluation was made of patients with PGHI sustained in the Syrian Civil War who were admitted to the ED between 1 January and 7 June 2014, a period of increasing numbers of terrorist attacks. The brain CT findings were examined for epidural, subdural, subarachnoid haematomas, intracranial haemorrhage, midline shift and pneumocephalus, with reference to the anatomical regions and localisation of the skull fracture. GCS scores and prehospital intubation were documented for dead and surviving groups. Any patient with a GCS score of ≤8 was considered to have a severe TBI and required immediate intubation for airway protection.
Exclusion criteria were injuries to any part of the body except the head, blunt head trauma, injury not caused by gunshot, no bullet fragment in the skull, presentation at ED with no trauma-related complaints and PGHI patients who died on the battlefield or who were transferred before 24 hours.
Statistical analysis
Statistical analyses of the data used SPSS V.15.0 software (SPSS, Chicago, Illinois, USA). Categorical variables were presented as number and percentage and were compared with the χ2 test. Continuous variables were expressed as mean±SD. For comparisons between two groups of continuous variables, the Student's t-test or the Mann-Whitney U test were used as appropriate. A two-tailed value of p<0.05 was considered to be statistically significant.
Results
Demographic and injury characteristics
In the 5-month study period, 908 patients were admitted to the ED with terrorist attack-related polytrauma, of which 199 were an isolated head injury: there were 95 bomb explosion injuries and 104 sniper gunshot injuries, which comprised the study population. No one was wearing a helmet. Overall, 96/104 (92%) patients were male with a mean age of 25 years. Comparison was made between those who survived and those who did not. PGHI is classified as a penetrating or perforating injury. Penetrating head injuries, where a projectile breaches the cranium but does not exit it, were present in 90 patients and perforating head injury (the object passes through the head and leaves an exit wound) in 14 patients.3 There were no cases of tangential-type injury in this study group. Thirty-eight patients died within 24 hours of admission. Although pneumocephalus and midline shift were related to a higher mortality rate, there was a significantly higher rate of temporal bone fracture in the survivor group (t-test, p<0.05). The brain CT findings of the patients are summarised in Tables 1 and 2. The common brain CT findings of the patients are shown in Figures 1⇓–3.
If two bones were fractured the mortality was 43%, if three bones were fractured the mortality was 69%, if four bones were fractured the mortality was 47%.
There was statistically significant correlation between frontal bone fracture and subdural haemorrhage, parietal bone fracture and pneumocephalus, occipital bone fracture and subarachnoid haemorrhage, temporal bone fracture and intracranial haemorrhage (t-test, p<0.05).
In this study, there was a correlation between the temporal bone fracture and perforated head injuries (t-test, p<0.05).
Urgent airway control was required in 27 patients (26%) and it was achieved with endotracheal intubation; nasotracheal intubation, cricothyroidotomy or tracheostomy were not performed. A higher mortality rate was observed in patients requiring prehospital emergency intubation (PEI) (Table 3). Rapid sequence intubation was not used for PEI in these patients. The relationship between prehospital intubation and mortality is shown in Table 3. Hyperosmolar therapy for cerebral oedema, including mannitol and 3% hypertonic saline was administered intravenously to all patients in the ED.
The GCS of the patients ranged between 3 and 12 in the ED; mortality rates were significantly higher in patients with scores of 3–6, whereas scores of 7–12 were statistically associated with higher survival rates (Table 4).
Pneumocephalus was seen more often in the brain CT in patients with GCS of ≤6 (t-test, p<0.05).
Discussion
The primary aim of this study was to investigate the relationship of brain tomography findings with mortality in patients with sniper gunshot head injuries sustained in the Syrian Civil War.
Pneumocephalus is the presence of air in the cranial vault; it is usually associated with disruption of the skull, neurosurgery, barotrauma, basilar skull fractures, sinus fractures, nasopharyngeal tumour invasion and meningitis.9 Although a single air pocket is associated with a good prognosis, multiple or large air collections are related to a higher mortality.10 In this study, most of the patients with pneumocephalus had diffuse, multiple and large air collections on the brain CT and this was associated with statistically significantly higher mortality rates.
Of the 104 cases in the present study, 30 showed evidence of midline shift and those patients had a higher mortality rate, in accordance with previous studies identifying it as a significant predictor of mortality.11 ,12
In this study, patients with perforating injury and single lobe head injury had a higher survival rate. In patients with single lobe head injury, the higher survival rate is likely explained by the lesser degree of parenchymal damage compared with the involvement of two lobes. When a bullet penetrates the skull, its energy is distributed within a confined space and that energy is retained within the skull exerting a greater damaging effect on the brain.4 This could result in a more damaging cavitational effect of penetrating injury than in a perforating injury, where the fact that the bullet exits the skull through a second hole implies that not all the available energy is transferred to the brain tissue, which in turn may result in reduced intracranial damage and mortality.
Patients with TBI present significant challenges for the prehospital provider, as they often present with a depressed level of consciousness, aggression and intact airway reflexes. PEI is an emergency procedure most often performed on patients who are unconscious or who cannot breathe on their own.13 ,14 Early intubation is critical for the prevention of secondary anoxic brain injury and to reduce the morbidity and mortality associated with TBI; however, some studies have emphasised that prehospital intubation in patients with TBI is associated with higher rates of mortality. Hence, it remains unclear as to whether or not PEI should be thought of as the gold standard for prehospital care with respect to combative, head-injured patients.15 In this study, there was a higher mortality rate in those who underwent PEI but those patients who need early intubation also have a worst outcomes; therefore, PEI might not be the only reason for a higher mortality rate.
There is insufficient evidence to recommend the use of sedatives alone to simplify intubation in prehospital settings as etomidate or midazolam might induce sedation and relax a clenched jaw but they may not relax the vocal cords.16 If the goal is placement of an endotracheal tube, sedation without paralysis may only place the patient at risk of failed intubation and increased mortality.
There are no studies in literature examining the relationship between skull bone fracture localisation and mortality; this study showed a statistically higher rate of temporal bone fractures in the survivor group. The temporal bone has a relatively thin and smooth shape compared with the other skull bones,17 ,18 so a bullet may not be destroyed or fragmented when it has penetrated the temporal bone giving it a greater chance to perforate rather than simply penetrate and this could be a reason for the reduced blast effect. There was a correlation between temporal bone fracture and perforated head injuries, and the characteristic of the bone could explain the high survival rates.
This study has some limitations which should be highlighted, most notably the retrospective nature of the data acquisition that may have resulted in unavoidable data loss. The patients were only followed-up for 24 hours due to the nature of the conditions in which the study was performed, and information about long-term complications was not available.
Conclusions
The results of this study demonstrated that pneumocephalus, midline shift, penetrating rather than perforating head injury, GCS ≤6 and PEI are related with high mortality after penetrating gunshot head injury. Further studies are required to reach definitive conclusions.
References
Footnotes
Contributors Planning: ÇC, MB, AS; conduct: ÇC, MB; reporting: ÇC, MB, AS, YS, AÇA, MB.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Clinical Research Ethics Committee (Medipol University Hospital/14.05.2015/13-10).
Provenance and peer review Not commissioned; externally peer reviewed.