Skip to content

Coma

Overview

  • Description of consciousness: Lethargy, confusion, stupor, obtundation, coma
  • Both RAS and one cerebral cortex is required for normal consciousness
  • Metabolic disorders > intoxications > anoxic brain damage
  • Glasgow Coma Scale
  • Posturing responses (subcortical):
    • Decerebrate: extension of all extremities
      • Uncal or tonsillar herniation
      • Worse than decorticate
    • Decorticate: flexion of upper limbs, extension of lower limbs
      • Upper motor neuron lesions
      • Anoxic/traumatic brain injury, stroke, ICH, tumor, enceophalopathy
  • CBC, electrolytes, BUN/Cr, glucose, ABG, urinalysis, LFTs, ammonia, tox screen
    • CT/MRI/EEG, CSF tap

General

  • Testing
    • Cerebral Function (EEG)
    • Brainstem Function (Reflexes, corneal, cold water calories, doll’s eyes, spontaneous respirations)
    • Heart Function (ECG)
    • Motor Function (Physical)
  • Normal: Aroused, Positive, Positive, Positive
  • Locked In: Aroused, Positive, Positive, Negative
  • Coma: Depressed, Positive, Positive, Positive
  • Persistent Vegetative State: Absent, Positive, Positive, Positive
    • Lasts <3months, usually progresses one way or another within 2 weeks
    • Anoxic brain injury, Alzheimer’s, CJD
  • Brain Death: Absent, Absent, Positive, Negative
    • Clinical
      • Lack of spontaneous respirations
      • CT Scan/MRI with devastating CNS event with known cause
      • Absence of confounding factors
      • No confirmed confounding drug intoxication or poisoning
      • Core temperature >36, SBP >100
    • Neurological
      • Comatose patient
      • Absent CN reflexes & motor responses (including flexor/extensor posturing)
      • Absent oculovestibular reflex (caloric response)
      • Absent cough with tracheal suctioning
      • Absent sucking or rooting reflexes
      • Apnea by apnea test
        • Hemodynamically stable, temp >36, normal pH, normal PaCO2/PaO2
          • Pre-oxygenate with 100% oxygen for 10 minutes
          • Discontinue MV, continue 100% O2 passively for 10 minutes
          • Get ABG to confirm PaCO2 >60 or that it increased >20 from baseline ABG
        • Objectively confirms brainstem failure if pt cannot generate spontaneous breaths or trigger the vent in response to elevated PaCO2 levels >10 minutes after disabling control mode
        • Positive
          • Repeat clinical exam
            • Suggestive of brain death: Brain dead
            • Inconclusive or unreliable: Testing below
        • Inconclusive or unable to tolerate
          • Consider testing below
        • Negative
          • Not brain dead, no further testing
    • Further Testing if:
      • Unable to examine CN
      • Patients with neuromuscular paralysis or heavy sedation
      • Unable to complete apnea test or inconclusive results
      • Numerous confounding variables (multiorgan failure)
    • Other Testing
  • High-Altitude Cerebral Edema
    • Treatment
      • Dexamethasone