Oslo University Hospital (OUS) is the primary hospital for the southeast health region in Norway for the treatment of patients with non-traumatic SAH, serving 2.7 million inhabitants. Patients are referred to the Department of Neurosurgery after the diagnosis of SAH at their local hospital and are discharged back to the local hospital as soon as the acute neurosurgical treatment is completed. There is a 24/7 service of surgical and endovascular aneurysm repair performed by a dedicated vascular team. All aSAH patients are treated with early securing of the aneurysm. Patients are treated at the general intensive care unit (ICU) under neurosurgical supervision as long as they require invasive mechanical respiratory support. Thereafter, patients are trans- ferred to the neuro-intermediate ward (NIW), which is an intensive care unit taking care of patients in need of noninvasive respiratory support. Patients who need prolonged care in the ICU but no further neurosurgical care were directly transferred to the ICU at their respective local hospital.