Intracranial pressure monitoring.

Recent studies have demonstrated that bedside cranial burr hole and insertion of intraparenchymal catheters for intracranial pressure monitoring performed by intensive care physicians is a safe procedure, with a complication rate comparable to other series published by neurosurgeons. The overall morbidity rate is comparable to, or even lower than, that caused by central vein catheterization. The procedure is also quite simple and modern disposable intracranial procedural kits are available. After the skin is prepped the landmark for skin incision, called the 'Kocher's point', located about 2-4 cm lateral to the midline (mid-pupillary line) and 2-3 cm anterior to the coronal suture, is found. Then the surgical field is prepared with the sterile drapes and the skin infiltrated with local anaesthetic (0.5% lidocaine with 1 : 200000 epinephrine). After skin incision and retraction of the skin and subcutaneous tissue, the periosteum should be scraped off in order expose the skull. The skin is then divaricated, exposing the underlying bone. The hole is drilled with either an electric drill or a twist drill (the drilling procedure must be performed with the drill held within 10 degrees of the perpendicular position to the incision site). The hole is then irrigated with sterile saline and an 18-G spinal needle may be used to open the dura (exercise caution when perforating the dura so as to avoid damage to the underlying structures). Following opening of the dura, the Bolt, containing a stylet, is screwed manually into the skull at approximately 5 mm to 1 cm for adults. The stylet is then removed after the bolt has been screwed in, after which the bolt should be filled with saline. Finally, the zeroing of the transducer is performed by simply holding the tip in air while zeroing on the monitor. The transducer is inserted inside the bolt and the screw tightened. The intracranial pressure value can then be read.