Continuous intracranial pressure monitoring: review of techniques and presentation of method.

Continuous monitoring of intracranial pressure has proved to be of value in guiding the treatment of patients with diffuse cerebral trauma or edema. The evolution of monitoring devices is reviewed from simple lumbar puncture through intraventricular, subdural, epidural and external monitoring with progressively more sophisticated equipment. The device reported in detail connects the subarachnoid space to an on-line data reducer that calculates the percentage time the intracranial pressure is in 16 pressure ranges of 5 mmHg each and portrays it on a histogram. The pressure at that moment, the total range of the intracranial pressure, the level of pressure the patient has had for the largest percented of time, and pressure waves, if present, can all be determined by this process.