instruction: how many hours have passed since patient 28447 has been admitted to icu?
response: SELECT 24 * (STRFTIME('%j', CURRENT_TIME()) - STRFTIME('%j', icustays.intime)) FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 28447) AND icustays.outtime IS NULL