Permanent Cerebral Oxymetry Monitoring for Early Diagnosis and Treatment of Delayed Vasospasm After Subarachnoid Hemorrhage

Transcranial Doppler ultrasound (TCD) monitoring and CT-scanner perfusion are useful but imperfect tools to identify vasospasm and allow intervention to avoid infarction. Permanent monitoring of cerebral tissue oximetry (rSO2) by NIRS, a noninvasive method could allow better vasospasm detection. This study will evaluate diagnostic accuracy of cerebral oxymetry (NIRS) -by rSO2 measurement - in order to detect vasospasm in patient with severe subarachnoid hemorrhage compare to standard monitoring tools.

Delayed vasospasm is a serious complication of aneurismal subarachnoid haemorhage (SAH) significantly influencing morbidity and mortality. Mostly observed between days 4 and 10 after aneurismal rupture, its incidence is higher in cases of severe SAH. Vasospasm strongly affects prognisis generating delayed cerebral ischemia. Clinical deterioration (focal neurological deficit) is the best way to detect severe vasospasm. Unfortunately, most of severe SAH are intubated and sedated prohibiting neurological evaluation. In these frequent situations, Transcranial Doppler (TCD), clinical and biological monitoring, CT-scanner (angio-CT and Perfusion-CT), MRI and cerebral angiography are routinely used to detect vasospasm. Yet, these tools have imperfect sensitivity and specificty delaying diagnosis and treatment. Near-InfraRed Spectroscopy (NIRS) is a non-invasive method measuring tissue oxygenation by regional saturation of capillary-oxygenated hemoglobin (rSO2). This technology demonstrated ability to measure cerebral oxygenation and has previously been reported to monitor carotid and pediatric surgery. To date a few studies also reported NIRS monitoring feasability in post-SAH vasospasm. Our aim is here to evaluate NIRS monitoring for the diagnosis of vasospasm in severe SAH.