last time patient 4758 got surgery on the last hospital encounter?
select procedures_icd.charttime from procedures_icd where procedures_icd.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 4758 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) order by procedures_icd.charttime desc limit 1