Assessing Traumatic Brain Injuries
Traumatic brain injury (TBI) is a leading cause of death and disability, particularly in young adults. Prehospital assessment and management of head injuries directly affects patient outcomes. The two most important assessment tools for head injuries in the field are the Glasgow Coma Scale (GCS) and pupil assessment. Together, these provide critical information about the severity of the injury and whether the patient's condition is improving or deteriorating.
Primary brain injury occurs at the moment of impact and cannot be reversed. Secondary brain injury develops over minutes to hours after the initial trauma and results from hypoxia, hypotension, increased intracranial pressure, and cerebral edema. The focus of prehospital care is preventing secondary brain injury through aggressive airway management, adequate ventilation, and maintenance of blood pressure.
The Glasgow Coma Scale
The GCS is a standardized scoring system that assesses level of consciousness based on three components:
- Eye Opening (1 to 4): Spontaneous (4), to voice (3), to pain (2), none (1)
- Verbal Response (1 to 5): Oriented (5), confused (4), inappropriate words (3), incomprehensible sounds (2), none (1)
- Motor Response (1 to 6): Obeys commands (6), localizes pain (5), withdrawal from pain (4), abnormal flexion/decorticate (3), extension/decerebrate (2), none (1)
The total GCS ranges from 3 (deep coma) to 15 (fully alert and oriented). A GCS of 13 to 15 indicates mild TBI, 9 to 12 indicates moderate TBI, and 3 to 8 indicates severe TBI. Patients with a GCS of 8 or less cannot protect their airway and require aggressive airway management. Always document the individual components (E3V4M5 = 12) rather than just the total, as this provides more useful information for trending.
Pupil Assessment
Pupil assessment provides information about brainstem function and intracranial pressure. Check pupils for size, equality, and reactivity to light. Normal pupils are equal in size (2 to 6 mm), round, and react briskly to light. Document findings as PERRL (Pupils Equal, Round, Reactive to Light) or describe abnormalities specifically.
A unilateral fixed and dilated pupil (the pupil does not constrict in response to light) on the same side as the head injury suggests uncal herniation, where increasing intracranial pressure is pushing the temporal lobe downward onto the brainstem. This compresses the oculomotor nerve (cranial nerve III) on that side. This is a critical finding that indicates the patient needs immediate neurosurgical intervention. Bilateral fixed and dilated pupils suggest brainstem herniation and carry a very poor prognosis.
Serial Assessment and Transport Decisions
Head injury patients require serial assessments every 5 minutes. Any decline in GCS by 2 or more points, development of pupil asymmetry, or onset of posturing indicates deterioration and should prompt rapid transport to a trauma center. Avoid hypotension (maintain systolic BP above 90) and hypoxia (maintain SpO2 above 94%). Ventilate at a normal rate of 10 to 12 breaths per minute; hyperventilation is no longer recommended routinely as it causes cerebral vasoconstriction and can worsen ischemia. Elevate the head of the stretcher 30 degrees if spinal injury has been ruled out.