Is Nitrous Oxide considered "Conscious" Sedation? We are using Nitrous Oxide during a radiofrequency ablation for veins and billing 99152 and 99153 for the Nitrous. Blue cross Blue shield are denying the 99152 and 99153 stating "anesthesia performed by the operating physician is not payable" Can someone please help, I need to know If I am billing the correct code for Nitrous Oxide.