What does ICP mean medically?

Medically, ICP most commonly stands for Intracranial Pressure, which is the pressure inside the skull and in the brain tissue and cerebrospinal fluid. Intracranial pressure is a critical vital sign in neurology and neurosurgery because the skull is a rigid compartment with fixed volume containing brain tissue, blood, and cerebrospinal fluid. Normal ICP in a healthy adult lying flat is 5 to 15 millimeters of mercury or mmHg. When ICP rises above 20 to 22 mmHg sustained, it is called intracranial hypertension and can be life-threatening because it reduces blood flow to the brain and can cause brain herniation. Causes of elevated ICP include traumatic brain injury, stroke, brain tumor, hydrocephalus, meningitis, and brain hemorrhage. Doctors measure ICP invasively using devices like an external ventricular drain or intraparenchymal monitor placed by a neurosurgeon. Treatment for high ICP includes elevating the head, sedation, draining cerebrospinal fluid, osmotic therapy with mannitol or hypertonic saline, and in severe cases decompressive craniectomy. Other less common medical meanings of ICP include Intracranial Pressure monitoring, Idiopathic Intracranial Hypertension, and in obstetrics, Intrahepatic Cholestasis of Pregnancy, which is a liver condition in pregnancy, but intracranial pressure is by far the most common medical use.