 Sodium nitrite was delivered intravenously for 14 days in 18 patients with SAH from a ruptured cerebral aneurysm using a dose escalation scheme in three cohorts of 6 patients each 3 nitrite, 3 saline, with a maximum dose of 64 nmolminkg. Sodium nitrite blood levels were frequently sampled and measured using mass spectroscopy and blood methemoglobin levels were continuously monitored using a pulse oximeter. 