Epidural injection will be completed under fluoroscopy and all patients will receive 1-4 mg of Midazolam for relaxation before procedure and, if needed, 50-100 mcg of Fentanyl intravenous (IV). Radiopaque contrast (Omnipaque 300), for confirming the epidural position of the needle, steroids and local anesthetic agents will be used according to the physician performing the block and will not be controlled by the study. Patients will be randomly assigned to receive either inhaled Entonox along with the interventional block they are scheduled for or oxygen. They will be blinded about the treatment they are receiving. Those randomized to Entonox will inhale the gas through a mouthpiece throughout the procedure and also continue to receive it for a total of 4 hours in the recovery. Those randomized to the oxygen group will receive oxygen through a similar mouthpiece for the entire duration of the procedure and recovery for 4 hours. Following completion of procedure the patient will be transferred to recovery and monitored for 3-5 hours then discharged home with instructions. Possible side effects will be monitored and recorded, pain score of patient will be recorded before discharge. All the patients will receive standard instructions regarding physical back exercises. This will be repeated for every procedure up to maximum of three blocks.