Volatile Sedation With Isoflurane in Neurocritical Care Patients After Poor-grade Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE: Volatile sedation after aneurysmal sub-arachnoid hemorrhage (aSAH) promises several advan-tages, but there are still concerns regarding intracranial hypertension due to vasodilatory effects. We prospectively analyzed cerebral parameters during the switch from intravenous to volatile sedation with isoflurane in patients with poor-grade (World Federation of Neurosurgical Soci-eties grade 4-5) aSAH. -METHODS: Eleven patients were included in this pro-spective observational study. Between day 3 and 5 after admission, intravenous sedation was switched to iso-flurane using the Sedaconda Anesthetic Conserving Device (Sedana Medical, Danderyd, Sweden). Intracranial pres-sure (ICP), cerebral perfusion pressure (CPP), brain tissue oxygenation (PBrO2), cerebral mean flow velocities (MFVs; transcranial Doppler ultrasound) and regional cerebral oxygen saturation (rSO2, near-infrared spectroscopy moni-toring), as well as cardiopulmonary parameters were assessed before and after the sedation switch (-12 to D12 hours). Additionally, perfusion computed tomography data during intravenous and volatile sedation were analyzed retrospectively for changes in cerebral blood flow. -RESULTS: There were no significant changes in mean ICP, CPP, and PBrO2 after the sedation switch to isoflurane. Mean rSO2 showed a non-significant trend towards higher values, and mean MFV in the middle cerebral arteries increased significantly after the initiation of volatile sedation. Iso-flurane sedation resulted in a significantly increased norepinephrine administration. Despite an increase in mean inspiratory pressure, we observed a significant increase in mean partial arterial pressure of carbon dioxide. -CONCLUSIONS: Isoflurane sedation does not compro-mise ICP or cerebral oxygenation in poor-grade aSAH pa-tients, but the significant depression of CPP could limit the use of volatiles in case of hemodynamic instability or high vasopressor demand.