A Prospective Clinical Trial to Evaluate an Automated Cerebral Ventricular Drainage System in Patients in the Neurointensive Care.

Introduction

There is a diversity of acute conditions that may affect the brain, many of which need emergent treatment in a neurointensive care unit with a combination of neurosurgery and neurointensive care. Neurosurgery aims at, when possible, remove pathologies that cause increased pressure on the brain, for example tumors, intracerebral hematomas or, in some cases, cerebrospinal fluid. The neurointensive care aims at diminishing the secondary events that may arise as a direct cause of the initial pathology, for example additional bleedings, brain swelling, stroke etc. Many patients that receive neurointensive care, are fitted with a ventricular drainage (V drain) that is surgically implanted into the fluid filled cavities in the center of the brain. The V drain serves to keep the amount of cerebrospinal fluid at normal levels, but is also used to monitor the intracranial pressure (ICP). By draining the cerebrospinal fluid, ICP can usually be kept at close to normal levels. The V drain is connected via a tubing system to a fluid canister to the side of the patient. The canister can be positioned at different levels in relation to the patient´s brain, allowing for drainage of cerebrospinal fluid when the ICP reaches a certain level. In order to define the so called "zero level", i.e. the level from which the ICP is measured, and the level from which the canister is raised in order to define at which pressure the cerebrospinal fluid should start to drain, a laser pointer is usually directed at the level of the patient ear. In patients that are nursed on the side, the pointer is directed at a point between the eyes, or in the middle of the skull.

Each time a patient is moved, the "zero point" must also be corrected in order for the ICP measurements to be correct, and to make sure that the patient does not over- or under drain cerebrospinal fluid. In a patient that is in a medical coma, this may occur 6-12 times during 24 hours, whereas in an awake patient, it may occur several times an hour.

If the patient´s head suddenly would be high above the zero point, such as when a patient goes from supine to sitting position, the V drain may drain the ventricular system for cerebrospinal fluid quite rapidly. This may result in bleedings on the exterior of the brain due to the collapsed ventricular system, and the patient will get severe headache as a result of the greatly decreased ICP. If the patient´s head is far below the zero level, underdrainage and increased ICP with headache and, in worst case coma may result.

Vguard is a system that has been created to ensure that the patients´ ventricular drainage system and pressure monitor closely follows the patient when the head is adjusted vertically. The system consists of a pressure sensor that is connected to the patients´ head. The pressure sensor is connected to a motorized column that automatically adjusts to keep the zero level at level with the patients´ head at all times. The idea for the system came from an employee at the neurointensive care unit (NICU) at Skane University Hospital, Lund and was developed in collaboration with the regional innovation company, Innovation Skåne.