Intra-operative monitoring of brain tissue O2 (PtiO2) during aneurysm surgery

Regional cerebral blood flow may be compromised during aneurysm surgery. This may occur during vessel occlusion by temporary cliping or result from the malposition of an aneurysm clip. In this report we monitored intra-operatively the brain tissue oxygen concentration (PtiO2) to visualize regional ischaemic events.

During surgery of 10 intracranial aneurysms, monitoring of PtiO2 was performed using a polarographic microcatheter (Licox, GMS-Kiel-Germany), which was placed in the vascular territory of the artery harboring the aneurysm.

No complications were observed after implantation of Licox electrodes. In 6 patients PtiO2 decreased during transient clipping. In two patients PtiO2 decreased below 2 mmHg without morphological or clinical signs cerebral ischemia. In four patients, without incidence during surgery, only minor oscillations were observed.

Intra-operative monitoring of PtiO2 is a complimentary procedure to monitor cerebral perfusion and detect episodes of ischaemia. Given the rapid detection of these events, therapeutic intervention may be initiated before irreversible neuronal damage occurs.