instruction: give me the number of patients whose year of death is less than or equal to 2126 and procedure short title is umbilical vein cath?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.dod_year <= "2126.0" AND procedures.short_title = "Umbilical vein cath"