A Pilot Study of Biomarkers in Obstructive Sleep Apnea

All study patients will have previously consented to undergo either spinal or spinal-epidural anesthesia. Patients will undergo their planned spinal or combined spinal-epidural placement in the OR. At the time of confirmation of placement of the spinal needle (positive CSF flow), 5 mL CSF will be collected and stored. CSF will be drawn using a standard 25g or 27g needle commonly used for anesthesia. The volume of CSF removed will be replaced with 4 cc local anesthetic (1.5% mepivacaine for spinal anesthesia).