Diagnosis and management of increased intracranial pressure

Abstract

Increased intracranial pressure (ICP) is a pathological state common to a variety of neurological diseases, all of which are characterized by the addition of volume to the skull contents. Elevated ICP may lead to brain damage or death by two principle mechanisms: 1) global hypoxic-ischemic injury, as a consequence of reduced cerebral perfusion pressure (CPP) and cerebral blood flow; and 2) mechanical distortion and compression of brain tissue as a result of intracranial mass effect and ICP compartmentalization. All ICP therapies have as a goal, reduction of intracranial volume. In unmonitored patients with acute neurological deterioration, head elevation, hyperventilation, and mannitol (1g/kg) can rapidly lower ICP. Fluid-coupled ventricular catheters and fiberoptic transducers are the most accurate and reliable instruments for measuring ICP. In monitored patients, the treatment of critically raised ICP should proceed in an orderly step-wise fashion: 1) consideration of neuroimaging to exclude a new surgically operable lesion; 2) intravenous sedation to attain a quiet motionless state; 3) manipulation of blood pressure to keep CPP >70 and <120; 4) mannitol infusion; 5) moderate hyperventilation (P(CO2) 26 to 30 mmHg); and 6) high-dose pentobarbital therapy. Application of moderate hypothermia (32 to 33 degrees C) shows promise as a newer method for treating refractory ICP. Placement of an ICP monitor is the critical first step in management of ICP. Treatment is best done using a stepwise protocol, with careful attention to sedation and CPP control prior to using mannitol and hyperventilation.