How is intracranial hypertension treated

How is intracranial hypertension treated? 

Medical management: The initial steps in the medical management of elevated ICP are the universal mandates of assessing airway patency, breathing, and circulation. These goals should be followed sequentially and include the following:

• 1. Maintenance of adequate oxygenation helps with both brain and systemic perfusion. Additionally, normothermia, normoglycemia, euvolemia, and normonatremia help optimize outcomes.
• 2. Elevation of the patient’s head to 30° and positioning in midline facilitates cerebral venous drainage to decrease cerebral blood volume (CBV).
• 3. Controlled hyperventilation for a short period as a bridge to definitive therapy. Hyperventilation vasoconstricts cerebral arterioles and reduces CBV. Prolonged hyperventilation causes ischemia. The goal should be a minute ventilation to keep PaCO ₂ ∼ 30 to 35 mm Hg.
• 4. Sedation and analgesia help decrease cerebral metabolism. Agitation and pain increase cerebral metabolic rate of oxygen (CMRO ₂ ) and CBF. Propofol and barbiturates reduce CMRO ₂ and CBF. Patients should receive adequate sedation with propofol and adequate analgesia with fentanyl.
• 5. Neuromuscular blockade may lower ICP by both muscle relaxation and preventing Valsalva-induced spikes in ICP related to coughing and straining. Disadvantages are loss of the neurologic exam and an increase in the risk of critical illness neuromyopathy.
• 6. Osmotherapy with mannitol and/or hypertonic saline exerts osmotic and vasoconstrictive effects to reduce CBV. Doses of 0.5 to 1.5 g/kg intravenous (IV) bolus of 20% mannitol, followed by 0.25 to 1 g/kg every 6 hours via peripheral line are recommended. Electrolytes, renal function, and serum osmolarity must be monitored every 6 hours. Check osmolar gap = measured − calculated. Hold mannitol if the gap >20 serum osmoles. Hypertonic saline also is available for management of elevated ICP before or concomitantly with mannitol administration. Doses and concentrations include 23% saline 30 cc × 1 over 10 minutes via central line to avoid hypotension followed by 30 cc every 6 hours; 3% infusion 40 to 50 cc/h can also be used via central line. The serum sodium goal is 145 to 155 mEq/L.
• 7. Steroids should be used for vasogenic edema due to either brain tumors or encephalitis. Dexamethasone 10 mg IV × 1, then 4 mg q6h. Steroids must be avoided in traumatic brain injury (TBI) patients due to higher mortality.
• 8. Targeted temperature management has been advocated after the above measures have been utilized. The main goal is to prevent fever as fever has been associated with poor outcome. Active cooling to 32 to 34° C is used for refractory elevated ICP. It reduces CMRO ₂ and CBV. However, induced hypothermia in TBI with elevated ICP should be used in conjunction with available management protocols.

Surgical management: CSF diversion via an intraventricular catheter reduces CSF volume and decreases ICP. It is indicated in obstructive hydrocephalus, diffuse cerebral edema, or mass effect due to space-occupying lesions. 

Craniectomy reduces mass effect and CBV.

The main indication for craniectomy is either a large hemispheric ischemic stroke or posterior fossa lesion with significant mass effect.

Hemicraniectomy should be performed as early as possible, preferably before significant changes in the neurologic examination are observed.

There is currently no evidence of benefit of craniectomy in TBI patients.