Traumatic Brain Injury and Spinal Cord Injury
TBI fundamentals
Separate primary from secondary injury. Primary injury is immediate and untreatable; secondary injury (hypoxia, hypotension, hyperthermia, hyperglycemia, seizures) is the target of ICU care. Avoid the "double hit": a single episode of hypotension or hypoxia markedly worsens outcome. Follow a tiered ICP/CPP strategy: head-of-bed elevation, sedation, CSF drainage, osmotic therapy (mannitol or hypertonic saline), then barbiturates or decompression.
Know the CT Marshall classification and the significance of midline shift, cisternal effacement, and contusions that may expand. Recognize herniation syndromes (uncal vs central) and their clinical signatures.
Spinal cord injury
Spinal cord injury care emphasizes MAP augmentation (often 85–90 mmHg) to preserve cord perfusion, immobilization, and early recognition of neurogenic shock (bradycardia + hypotension from loss of sympathetic tone) versus spinal shock (transient reflex loss). Distinguish neurogenic from hypovolemic shock by the presence of bradycardia and warm extremities.
Traps
- Using hypotension alone to explain deterioration while ignoring hypoxia or expanding mass.
- Confusing neurogenic and spinal shock; only neurogenic causes hemodynamic instability.
- Overlooking concomitant injuries and the cervical spine in obtunded trauma patients.
Rule of thumb
In TBI, "avoid the second hit": keep SBP ≥100–110, SpO2 high, normothermia, normoglycemia.
Worked example
A TBI patient's ICP rises to 28 despite sedation and CSF drainage. Escalate to hypertonic saline or mannitol, ensure CPP target, and prepare for decompression if refractory.