There is considerable controversy about placing these catheters after general anesthesia, and a retrospective review of this issue (no neurologic complications in 4298 patients undergoing lumbar epidural catheter placement while under general anesthesia for thoracic surgery at the Mayo Clinic) challenges the old assumption that the risks are greater [Horlocker et. al. Anesth Analg 1547: 96, 2003], as does the practice of placing epidurals in asleep children [Krane et. al. Reg Anesth Pain Med 23: 433, 1998]. That said, most do not place these in unconscious patients for a variety of reasons [Rosenquist et. al. Anesth Analg 96: 1545, 2003]
