instruction: What is the total number of patients who had allo hem stem ct w/o pur and died in or before the year 2138?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.dod_year <= "2138.0" AND procedures.short_title = "Allo hem stem ct w/o pur"