Increased Intracranial Pressure in Closed Head Injury

1. See Also
   1. Brainstem Herniation
   2. Severe Head Injury Management
2. Differential Diagnosis
   1. Increased Intracranial Pressure Causes
3. Pathophysiology
   1. Closed Head Injury with secondary Increased Intracranial Pressure
4. Signs: Findings indicating management below
   1. Intracranial Pressure >15 mm
   2. Severe Closed Head Injury (GCS 8 or less)
   3. Cerebral edema
   4. Cushing Response
      1. Severe Hypertension
      2. Severe Bradycardia
      3. Severe Hypopnea
5. Diagnostics: Intracranial Pressure Monitoring
   1. Indications
      1. Glascow coma scale 8 or less after Resuscitation (or <12 if abnormal CT Head) OR
      2. Criteria despite normal CT Head
         1. Age >40 years old
         2. Systolic Blood Pressure <90 mmHg
         3. Decerebrate or Decorticate motor posturing (unilateral or bilateral)
6. Management
   1. See Severe Head Injury Management
   2. Transfer to Neurosurgery
   3. See Cerebral Herniation
   4. Improve cerebral venous drainage
      1. Head of bed elevated (20-35 degrees, up to 45 degrees)
         1. Promotes CNS venous drainage
      2. Avoid internal jugular compression
         1. Keep head midline
         2. Internal jugular line placement is Contraversial (some advocate subclavian lines instead)
         3. Avoid tight Cervical Collars
            1. Switch to better fitting collar (e.g. Aspen) if C-spine cannot be cleared with exam and imaging
   5. Maintain adequate Cerebral Perfusion Pressure (MAP - ICP)
      1. Maintain MAP>65-80 mmHg (and ideally ICP <20)
      2. Keep systolic Blood Pressure <140-160 mmHg (higher BPs raise Intracranial Pressure)
         1. Nicardipine (or clevidipine) is preferred
         2. Avoid Nitroglycerin and Nitroprusside (if possible) to maintain adequate Preload
         3. Avoid Labetalol (if possible) to maintain adequate cardiac contractility
   6. Airway and Rapid Sequence Intubation Management
      1. Consider Delayed Sequence Intubation to avoid peri-intubation Hypoxia
      2. Etomidate is a preferred RSI induction agent in Head Injury
      3. Ketamine is a safe and effective RSI induction agent without risk of ICP increase
         1. Zeiler (2014) J Crit Care 29(6): 1096-106 +PMID:24996763 [PubMed]
         2. Cohen (2015) Ann Emerg Med 65(1): 43-51 +PMID:25064742 [PubMed]
      4. Premedications are not typically indicated
         1. Pre-Intubation Lidocaine has been debunked and offers no benefit in ICP (see Rapid Sequence Intubation)
         2. Fentanyl 4-5 mcg/kg may decrease ICP, but also risks Hypotension
   7. Sedation
      1. Propofol may be preferred (lowers cerebral metabolic rate)
      2. Start Propofol at 20 mcg/kg/min and titrate
      3. Limit Propofol boluses as much as possible to avoid Blood Pressure fluctuations
         1. If boluses are needed, use small, 20 mg IV boluses at a time
   8. Ventilation
      1. PEEP does not increase intracranial presssure (increase as needed)
      2. Avoid hyperoxygenation
         1. Goal Oxygen Saturation >90% and preferred at 94-97%
      3. Avoid Hyperventilation
         1. Normocapnia is preferred (pCO2 35 to 38 mmHg)
         2. Hyperventilation is generally no longer recommended
            1. Vasoconstricts (reducing ICP transiently) but also decreasing cerebral perfusion
            2. Some intensivists mildly hyperventilate with goal pCO2 30-35 mmHg
            3. Old guidelines hyperventilated to pCO2 25-30
   9. Acutely lowering Intracranial Pressure (e.g. impending Brainstem Herniation)
      1. Mannitol 20%
         1. Adult: 1 g/kg IV (50-100 g) bolus over 5 minutes
         2. Child: 0.25 to 0.5 g/kg IV bolus over 5 minutes
         3. Observe closely for Hypotension (and avoid if hypotensive)
         4. Monitor urine output
         5. Hold manitol for Hypotension, Hypernatremia with Sodium >152 or Serum Osms >305
      2. Other measures that are no longer recommended (debunked)
         1. Avoid Hyperventilation (see above)
         2. Avoid Hypertonic Saline (controversial)
            1. Does not improve Intracranial Pressure or benefit mortality in severe Closed Head Injury
               1. Berger-Pelleiter (2016) CJEM 18(2): 112-20 +PMID:26988719 [PubMed]
            2. Others still recommend Hypertonic Saline
               1. Expert opinion that Hypertonic Saline and manitol have equivalent efficacy
               2. Hypertonic Saline is safe, even in Hyponatremia, and without Hypotension risk
               3. Orman and Weingart in Herbert (2017) EM:Rap 17(6):8-9
   10. Definitive management with Neurosurgery
       1. See Skull Trephination (if imminent Brainstem Herniation)
       2. Ventriculostomy or
       3. Surgical decompression
7. Precautions
   1. Sustained ICP > 20 mmHg is associated with worse outcomes (ischemia risk)
   2. Maintain adequate Cerebral Perfusion Pressure
8. References
   1. Orman and Weingart in Herbert (2017) EM:Rap 17(1): 5-6