Introduction: Conventionally traumatic brain injuries (TBIs) have been associated with a clear trauma to the head. However, patients with elevated intrathoracic (ITP) and intraabdominal pressures (IAP) as a result of crush injuries may potentially also have potentially undiagnosed TBI due to elevated intracranial pressure (ICP).

Methods: We prospectively recruited 625 trauma subjects and healthy non-trauma controls in whom we analyzed serum samples and performed eyetracking to characterize and classify the nature of their brain injury, if any. Eight subjects were noted to have sustained crush injuries and were subcategorized as isolated thoracoabdominal, thoracoabdominal with blunt head trauma, isolated extremity, and extremity with blunt head trauma. The eye tracking metrics and biomarker concentrations were then compared to non-trauma control and known TBI subjects.

Results: Serum biomarkers and eye tracking metrics in patients with significant isolated throacoabdominal crush injury more closely resembled those found in the CT-scan positive TBI population versus healthy controls. GFAP levels at the time of admission for an isolated thoracoabdominal crush subject as well as those with crush injury and blunt head trauma were elevated when compared to the control population [4549.6 ± 9951.0] vs [11.5 ± 8.9]. Eye tracking metrics, indicative of elevated ICP, were also found to be altered in both isolated thoracoabdominal crush subjects. Patients with isolated extremity crush had levels of GFAP and eye tracking similar to healthy non-trauma controls.

Conclusions: Thoracoabdominal but not extremity crush can lead to elevated ICP resulting in eye tracking and serum biomarker findings consistent with brain injury. Future work may elicit the intraabdominal pressure and intrathoracic pressure elevation necessary to increase the ICP and produce these demonstrated ocular motility dysfunctions as well as explore the impact of other crush injuries on ICP.

Patient Care: This research will help us better identify patients who may have sustained a TBI without a clear impact to the head which have potentially gone undiagnosed.

Learning Objectives: - Isolated thoracoabdominal crush injury increases intrathoracic and intraabdominal pressures which may lead to decreased cerebral venous return and in turn increase intracranial pressure (ICP). - This elevated ICP results in intracranial trauma producing elevated biomarker concentrations as well as ocular dysmolities which have been shown to indicate a traumatic brain injury (TBI). - Isolated extremity crush injuries do not produce findings similar to those found in TBI which suggests that redistribution of blood volume is not significant enough to cause a significant elevation in ICP.

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