instruction: What is the number of patients less than 43 years of age who have undergone the replacement of a tube or enterostomy device of thesmall intestine procedure?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.age < "43" AND procedures.long_title = "Replacement of tube or enterostomy device of small intestine"