when did patient 16248 get the procedure for the first time on the first hospital visit.
select procedures_icd.charttime from procedures_icd where procedures_icd.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 16248 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) order by procedures_icd.charttime asc limit 1