Intracranial Pressure Monitor

Indications and Contraindications

Intracranial pressure (ICP) monitors directly measure ICPs in the epidural, subdural, intraparenchymal, or intraventricular space. Although they do not allow for direct cerebrospinal fluid (CSF) drainage, unlike external ventricular drains (EVD), ICP monitors are associated with fewer complications (e.g. hemorrhage, ventriculitis), and may be preferred in cases of ventricular displacement or effacement following traumatic brain injury. The different types of ICP monitors include piezoelectric strain gauge, fiberoptic monitors, and pneumatic monitors—all placed similarly. Urgent and emergent placement of ICP monitors typically occurs in the setting of trauma or stroke; however, other indications include monitoring of ICPs in venous sinus thrombosis, pseudotumor cerebri, and intracerebral hemorrhage.

Several recommendations exist regarding ICP monitor placement, but historically, the Guidelines for the Management of Severe Traumatic Brain Injury by the Brain Trauma Foundation (BTF) in conjunction with the AANS/CNS were commonly referenced. Level IIb recommendation advised ICP monitor placement in all salvageable patients with severe traumatic brain injury (TBI) with a Glasgow Coma Scale of 3–8 after resuscitation and an abnormal CT scan. The BTF defined an abnormal CT scan of the head as one that revealed hematomas, contusions, swelling, herniation, or compressed basal cisterns. In the setting of a normal CT scan, ICP monitor placement was considered if two or more of the following criteria were met: age greater than 40 years, unilateral or bilateral posturing, or systolic blood pressure less than 90 mmHg. In the updated fourth edition BTF/AANS/CNS guidelines in 2017, ICP monitoring was recommended in the management of severe TBI patients to reduce in-hospital and 2-week post injury mortality (Level IIb recommendation). The guidelines also support cerebral perfusion pressure monitoring to decrease 2-week mortality (Level IIb recommendation) and jugular bulb monitoring of AVDO ₂ (arteriovenous oxygen content difference) to reduce mortality at 3 and 6 months post-injury (Level III recommendation).

Practically, an ICP monitor can also be considered in patients with an abnormal head CT who are at risk of neurological deterioration and when close monitoring of their neurological examination is not feasible (e.g. heavy sedation for ventilator dyssynchrony; prolonged procedure under general anesthesia).

Contraindications to ICP monitor placement include patients with coagulopathy (abnormal INR/aPTT/PT), thrombocytopenia (platelet count <100 K/mm ³ ), platelet dysfunction (e.g. concomitant aspirin use), and local infection at the site of insertion.

Stepwise Procedure ( Video 78.1 )