Management of increased intracranial pressure

BACKGROUND-Increased intracranial pressure (ICP) is a pathological state common to a variety of serious neurological illnesses, all of which are characterized by the addition of volume to the intracranial vault. Hence, all ICP therapies (e.g., ventricular drainage, hyperventilation, mannitol) are directed toward reducing intracranial volume. REVIEW SUMMARY-Elevated ICP can lead to brain damage or death by two principle mechanisms: 1) global hypoxic-ischemic injury, which results from reduction of cerebral perfusion pressure (CPP) and cerebral blood flow; and 2) mechanical distortion, compression, and herniation of brain tissue, which results from mass effect associated with compartmentalized ICP gradients. In unmonitored patients with acute neurologic deterioration, head elevation, hyperventilation, and mannitol (1 g/kg) can lower ICP within minutes. Fluid-coupled ventricular catheters and intraparenchymal fiberoptic transducers (i.e., Camino system) are the most accurate and reliable devices for measuring ICP. In a monitored patient, treatment of critical ICP elevation (>20 mm Hg) should proceed in the following steps: 1) consideration of repeat CT scanning to assess the need for a definitive neurosurgical procedure; 2) intravenous sedation to attain a quiet, motionless state; 3) reduction of blood pressure if CPP is >120 mm Hg or pressor infusion if CPP is <70 mm Hg; 4) administration of mannitol; 5) moderate hyperventilation (P-CO2 26 to 30 mm Hg); and 6) high-dose pentobarbital therapy. Applied moderate hypothermia (32 to 33 degrees C) shows promise as a newer method for treating refractory ICP. CONCLUSIONS-Placement of an ICP monitor is the critical first step in effectively treating intracranial hypertension. ICP elevation is best managed using a stepwise protocol, with careful attention to sedation and CPP control before mannitol and hyperventilation are administered.