title: Patient-controlled analgesia.
mesh_terms: D000698:Analgesia / Q000379:methods*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008614:Meperidine / Q000097:blood / Q000506:poisoning*; D008875:Middle Aged; D012646:Self Administration / Q000295:instrumentation*
chemical_list: D008614:Meperidine