Lidocaine Infusion Treatment for Subarachnoid Hemorrhage Headaches

The goal of this observational study is to evaluate intravenous lidocaine efficacy and safety in treating headache following non-traumatic subarachnoid hemorrhage. Through this prospective analysis, the investigators hope to: 1. show that intravenous lidocaine infusion causes a clinically significant reduction in pain scores in patients with moderate/severe headache pain following non-traumatic subarachnoid hemorrhage; 2. show that intravenous lidocaine infusion is safe in treating headache following non-traumatic subarachnoid hemorrhage; 3. and report vasospasm prevalence in the cohort. Participants will receive lidocaine infusion as treatment for non-traumatic subarachnoid hemorrhage headache and provide pain scores (on a numeric pain scale) every two hours the patients are awake for a maximum of seven days. Monitoring for vasospasm will occur as part of the patients regular medical care.